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Wednesday, May 27, 2015

How to Control Powdery Mildew of Grape

Q. I have white powdery mildew on my green, table grapes.  This has not been a problem in the past.  What now? Is this related to the cool, moist weather?
Grapes should have air movement around them to prevent powdery mildew and bunch rots. In the hot desert we have to be careful about giving them full sun throughout the day because of sunburn to the fruit.

A. Yes, powdery mildew on grape is seldom seen here because of our very dry and hot weather. This very cool spring, higher humidity and recent rains has made powdery mildew, as well as early blight on tomatoes a problem. Powdery mildew will disappear when it gets hot and dry.

Horticultural oils can help reduce powdery mildew problems
One thing that really helps control powdery mildew forming on grape bunches is improved air movement around grape bunches as well as sunlight during the morning hours. Sunlight on grape bunches in the late afternoon can cause sunburn on the berries so be careful about giving the fruit too much sun late in the day.

We can usually prevent powdery mildew by removing the leaves around grape bunches for better air movement and keeping bunches dry. Once powdery mildew has started, you may have to apply a fungicide to keep it at bay or eradicate it.

One of the best organic controls of powdery mildew on grape are the horticultural oils. Horticultural oils are mixed with water and sprayed on grape bunches in the early morning hours. There is a precaution in using oil sprays and not to apply it when temperatures are high. However, I have had no problem applying oils during the cool early morning hours.

Insecticidal soaps labeled for disease control have also given some control as well as dusting dry bunches with sulfur dust.

Why Are My Boxwoods Dying?

Q. Can you tell me why my boxwood shrubs are showing signs of dying?

A. The usual reason for this kind of dieback in our climate is either a watering problem (keeping the soil too wet or not watering frequently enough which is drought) or wet mulch against the trunk of the plant.
Boxwoods dying back because soil is kept too wet, they were planted too deep or wet mulch is in contact with their stems.

Be sure you pull any mulch back away from the stems of the plants. Six or 8 inches is enough just so it does not touch the stem when it is wet.

Wet mulch can contribute to collar rot where the lower stem or trunk rots from too much moisture and the presence of disease organisms. The organisms are always there, they just need the right environment to develop. The right environment are wet conditions against the trunk and plant stress. Sometimes they don’t even need the stress.

Die back can also be because the soil is kept too wet. Roots need to dry out between irrigations. If they don’t, they will die back causing the stems to die back as well.

Keeping the soil too wet or too dry can look identical above ground. This is because root dieback or death is the same thing as drought. The roots die and can’t supply water to the top and the plant stems die back due to drought for different reasons; lack of water or too much in the soil causing roots to die.

Pull the mulch away and let it dry out before it gets too far along. It is most likely not a disease in the tops but in the stems or roots.

Black aphids on Chitalpa

Aphids on red Yucca flowers before they Bloom in February
Q. I live 40 miles east of Kingman, AZ and I'm having a bug problem this spring on our chitalpa and ocotillo. There are tiny black insects on every bloom and bud. I've started noticing them on the red-tipped yucca blooms as well. We've had all of these plants for years and they are well established. We would hate to loose them. Should we be concerned about these bugs? 

A. These are black aphids which are common on Chitalpa, its leaves and flowers as well as other plants. They suck plant juice out of the soft tissue of leaves and flower buds and petals, concentrate the sugars taken from the plant and drop it out of their rear as a high sugar, shiny and sticky concentrate.

Aphids and ants working together
 This sugary concentrate attracts ants and can foster the growth of sooty mold. Sooty mold is not sooty canker, a very bad disease of landscape trees. Sooty mold does not infect the plant but just grows along the surface of leaves and stems and is easy to remove.

 Ants herd and protect these aphids from other insects as well as move them around. Controlling the ants helps to control aphids and sooty mold. These insects will not kill the plants but they will affect your plants floral display. Spray these aphids off of your plants with a strong stream of water and control the ants.

Aphids and ants working together on red Yucca after they flowered
Alternatively, spray the flowers and leaves with insecticidal soap, neem oil, canola oil or horticultural oil. If you are still not satisfied with the results, then you can be more aggressive with a conventional insecticide with aphids and ornamental plants listed on the label.

Remember, conventional insecticides can be much more damaging to beneficial insects and honey bees.

Spray in the very early morning hours or at dusk when honeybees are no longer present. If you look at one of your pictures of the flower buds you will see a ladybird beetle immature (larva) feeding on them. It is grey compared to the black aphids.

They are voracious feeders of aphids but there are just too many for this solo beetle larva to handle. Spray them off with a strong stream of water or use insecticidal soap or horticultural oil to kill them.

Tomato Disease Causing the Leaves Happening Now

Early blight of tomato
There is an issue occurring now in home gardens that may need your attention called early blight of tomato. Early blight of tomato has been seen on the variety called ‘Big Boy’but is probably on others as well.


If left alone this disease will first cause leaf yellowing on older leaves, followed by grey or brown spotting, then dieback of the plant.

Once plant dieback occurs, the fruits are left exposed to intense sunlight where they sunburn.

This disease can be easy to control if you start early. The key to prevention and spread of the disease is sanitation and rotating your vegetables between garden spots.


Remove yellowing foliage at the stem by “snapping” off the leaves or by cutting with a scissors. It is important to remove the infected leaves and stems as early as possible and put them in the trash, not the compost pile.

Prevent the disease from spreading on new foliage by using a fungicide. Any commercial vegetable fungicide will work but those containing in the ingredients chlorothalonil, mancozeb and copper work the best. I talk about it more in depth on my blog.

Fertilize Lawns At Least Three Times Each Year

Q. What time of year should a lawn be fertilized?

A good  fertilizer for established lawns should be
high in nitrogen (first number),
low in phosphorus (the middle number)
and moderate to high in potassium (the third number).
A. For tall fescue lawns, this is 99% of our residential lawns, I recommend at least three times per year if you are using recycling mowers; Labor Day, Memorial Day and Thanksgiving.The Thanksgiving day application may arguably be the most important application of the year in keeping
a winter lawn green.

If you have bermudagrass I recommend Labor Day, Memorial Day and 4th of July. You don’t want to apply anything to Bermudagrass in the fall if you are planning to overseed your lawn to keep it green during the winter.

Most fertilizer bags recommend a rate of 1 pound of nitrogen per 1000 square feet of lawn area. I consider this to be excessive unless this is a very high-end fertilizer containing lots of slow release nitrogen. You can cut that rate in half and get very good results.

It is also very helpful if you can use a mulching mower that chops up the clippings find enough to return to the lawn as a fertilizer.

You can download a copy of my fact sheet on turfgrass maintenance from here

Look for Plants Dying Because of Grubs

This is the time of year when grubs are feeding on the roots of plants. Many of these types of grubs are the same types that feed in compost piles. Some people refer to them as “compost worms”.
Grubs feeding on the roots of Lantana


The adults of these compost worms are frequently large beetles that we see flying in June and July.
Grub Guard is one of the products containing beneficial nematodes
The eggs of these larvae or worms were laid in March. If there are lots of them, their feeding in the months of March, April and May can cause plants like Lantana and agave to decline and even die.

There are organic options. I personally have not used them but I have received good reports on the use of both beneficial nematodes and bacteria specifically designed for grubs.The bacterium is usually referred to as "milky spore".The nematodes are usually referred to as "beneficial nematodes".These do not kill grubs immediately but do have a long-term effect in keeping the populations low over a long period of time. Look for the words Steinernema carpocapsae in the ingredients.

Control of these immature insects is usually accomplished with applications of chemicals as granules or a liquid diluted in water and poured around the roots of the plants. Sprays or dusts applied to the leaves or foliage will not control these types of pests.

This is the insecticide that contains imidacloprid.
One of the most effective chemicals has imidacloprid, as an active ingredient listed in its label and sold by any nursery, garden or box store. But any chemical listed for controlling “grubs” should work and is permitted as long as it includes the plant that your treating on its label.

One word of precautionon the use of imidacloprid; It has been implicated (but not proven) to possibly contribute to some environmental problems including colony collapse disorder of honey bees (CCD).

Research implicating imidacloprid in CCD

If you do use this product, I would not apply it to flowering plants and only apply it as a liquid, soil drench and not as a foliar spray.

If you have any further questions contact me through my email, Extremehort@aol.com, or on my blog Xtremehorticulture of the Desert.

My Zucchini Will Not Produce Any Fruit

Here is a zucchini plant with both male and female flowers. The male flowers are supported by a long thin stalk. The female flowers have a stalk supporting it which is swollen and resembles a small zucchini.
Q. My friends are giving me grief because I can't grow zucchini or other squashes. I get female squash flowers with the squash below the flower. I have male flowers, too. We seem to have insects around enough to pollinate other plants. Fruit withers at about large grape size.  I am thinking that the two flowers aren't opening at the same time for the insects. What can I do to become one of those zucchini and squash growers who have so much they can't even give it all away?

A. The weather right now has been very strange. Give it a chance to warm up a little bit. Summer squash likes warm temperatures.

Zucchini fruit falling off due to high temperatures.
Zucchini usually produce male flowers first followed by female flowers a little bit later. It is possible that they are not open at the same time and having more than one plant should solve that problem.

Bees are needed for pollination. If the plant is very dense, bees may have trouble getting inside the canopy where flowers are located. Try removing some of the leaves in the canopy to make it more open so bees can find the flowers more easily.


Some zucchini have a hard time setting fruit when temperatures are high. You might try hand pollinating. This requires a soft paint brush and transferring the pollen from the male flower to the female flower. This is a pretty good video on hand pollinating zucchini.

Video on hand pollinating zucchini

It is also possible that you have a variety that is just not do well in our climate. I have one right now that I did not select and it is absolutely a lousy producer.

It is not true that you can just pick any old variety and it will do well here because it does well in South Carolina or Ventura, California.


Why Is My Queen Palm Yellow?

This is not the queen palm mentioned in the question.
But this is a very common yellowing that occurs
to queen palm in our desert environment and our desert soils.
Q. I have a queen palm that is recently beginning to yellow. It's done well every year until this Spring. I Miracle-Gro the soil around it every two weeks from spring through Summer. I've given it Palm Food a few times a year. One nursery told me I am watering too much. I severely cut back the bushes on both sides of the tree that were overgrown and covering the base and trunk of the palm for the past couple years. Could that possibly have anything to do with it?

A. First of all, Queen palms are very difficult to grow in this desert climate and in these very difficult soils. They really have trouble because of our hot dry winds and hours alkaline soils that contain no organic material.

Now that we have that out of the way…

Yellowing of palm in our soils is usually related to a lack of iron reaching the foliage. You might try applying some EDDHA iron to the soil. This type of iron works at highly alkaline pH which other irons do not.However it should be applied to the soil in the very early spring before new growth occurs.

Applying iron to the soil this late in the season only corrects foliage produced after you apply it to the soil.  Older foliage, foliage that grew before this soil application, will not green up with a soil application. Yellow foliage must be sprayed with an iron solution to get it to green up. Applications to the foliage have to be done several times to be effective.
This is an example of an iron chelate
used for correcting yellow foliage on plants
with liquid sprays.You must adjust
the pH of the spray or use distilled water
for sprays like this to work.

Here is the proper way to mix and apply iron to the foliage:

  1. Mix only enough that you will need for spraying. It will not keep after you mix the dry ingredients with water. You must use it up.
  2. Use distilled water if possible. If you use tap water you will have to adjust the pH or alkalinity of the water for an iron application to the foliage to work.If you use tap water, add 1 tablespoon of white vinegar to each gallon of water to lower the pH.If you really want to be sure about the pH, use the pool test kits to get your pH between 6.0 and 7.0.
  3. After you have adjusted the pH, add the iron fertilizer to the water. Do not add the fertilizer first and then add the vinegar. If you use distilled water you can skip the vinegar.
  4. Add a good wetting agent such as EZ Wet. Why? This is not a gimmick. It is very important when spraying liquids, whether its fertilizer or a fungicide, on the leaves of plants. Follow the label directions but you usually add about 1/2 to 1 tablespoon for each gallon of spray. Add this at the very end and mix it into the spray mixture.
  5. Apply this spray when temperatures are cool, such as the early morning or evening. Pump up your sprayer and spray it on the leaves with enough liquid to wet the surface of the leaves or when you see the spray liquid beginning to drip from the foliage. Spraying the foliage for longer than this is wasting your time, spray mixture and money.
  6. This is a good wetting agent for applying liquid sprays.
    It is made from an agave extract and cold pressed.
  7. Repeat this spray in four or five applications several days apart. The normal way for iron to get inside the plant is from the roots. You are trying to get iron inside the plant in the opposite direction. This is much more difficult. You need multiple applications and a wetting agent such as EZ Wet to get it inside the plant.
I would agree that if you water too often or if you have poor drainage you would see yellowing like this from root damage because the soil is kept to wet. All palms should be watered infrequently but with quite a bit of water when you do apply it.

Other mineral deficiencies that can cause yellowing on palm include manganese, potassium and magnesium. The better palm fertilizers will contain these elements and you will see it in their label. I noticed this is not the case with some palm fertilizers.

I don't see why cutting back shrubs next to the queen palm would have any impact on it.

Queen palms look really pretty in San Diego. They are very questionable growing in the Mojave Desert unless you’ve got the perfect spot for them. Stick to more desert adapted Palms next time and you will have fewer problems.

Controlling Spider Mites in Italian Cypress

Q. I have three Italian Cypress trees that are 20 feet tall.  I have a problem with spider mites and want to know the best way to reduce their populations.  I started spraying them with high pressure water and it got rid of all the webs. Since the trees are so tall I cannot effectively apply a pesticide using my Ortho sprayer and garden hose.
Webbing in Italian Cypress does not always mean spider mites. You need to do the paper test explained below to see if mites are the problem or not.
A. How did you confirm that the problem is spider mites? They are easy to misdiagnose and there are problems that can appear like spider mite problems and they are not.

For instance, not all spider mites create webbing and not all webbing in Italian Cypress means it has spider mites. You can find webbing in Italian Cypress from spiders that are actually good guys and helping you out.

Spider mites normally occur during hot weather. We seldom see them during cooler weather.
An Italian Cypress which has spider mites will have the green needles or foliage beginning to die or turn color, usually grey first. If I look at these needles they will have a dusty appearance if spider mites are present.

Spider mites are extremely small. This one is highly magnified.
They are about the size of the dot at the end of this sentence .

This isn't dust but these are dead spider mites that litter the surface of the foliage. If I see Italian Cypress with dusty needles or foliage I begin to think they might have spider mites. The way I usually determine if spider mites are the problem is to take a white piece of paper and slap the branch of Italian Cypress against the paper pretty hard. This dislodges the spider mites from the foliage and onto the paper.

I then hold the white piece of paper in bright sunlight very still for 15 to 30 seconds. If mites are present, I will see tiny little dots the size of a large period crawling around on the paper. If I brush my fingers lightly across this moving dot on the paper, I will see red smears on the paper.

If the Italian Cypress appears damaged, the foliage or needles appear dusty and I get red smears on the white piece of paper I will conclude the damages from spider mites.

Soap and water sprays are somewhat effective if done on a regular basis (couple of times during hot weather or after a dust storm) as a preventive. Otherwise you would have to apply a miticide effective against spider mites for good control. You would apply two applications about ten days apart to control the hatching of young mites from eggs which are not controlled with the first spray.

Unfortunately this would require that you spray the entire tree if mites are a problem. It is really hard for homeowners to spray much above 10 feet. I do not know of any miticides that you can apply to the soil and get good control.

First, make sure the tree has spider mites and that is the problem. Insecticidal soaps are good first choice but they are not extremely effective in controlling this pest. If you do get it confirmed that it spider mites and they are out-of-control, you will have to spray miticide. Watering Italian Cypress too often causing root disease problems can give them a similar appearance as branches begin to die.

Spraying trees above 10 feet is difficult for homeowners. Pest control operators and arborists have equipment to do this.

We Have Holes in Our Tomatoes!

Q. I have Early Girl green tomatoes with round holes in three of them. Otherwise plant is in great shape. Other fruits on plant OK. .

A. That is feeding damage probably by the tomato fruitworm. Applications of Bt or spinosad should slow them down and are "organic" controls.This is basically the same "worm" that attacks the ears of corn by laying its eggs on the new silk coming from the forming ears.

The tomato fruitworm is probably the most damaging pest to tomato fruits. As the name implies, the damaging part of this insects lifecycle is the "worm" stage or more properly called "larva".

Click here to see the larva or immature form before it becomes a moth

They don't all come in one color so they can range in colors from pale yellow, to red, green or even brown with pale stripes down its length. They are about an inch and a half long when fully grown but they can be smaller than this if they are not yet mature.

Unlike hornworms which are pretty easy to spot during the day or at night  with a black light because they glow green,  fruitworms you wont see until you see damage to the tomato fruit. With your black light you can go scouting for hornworms and scorpions at the same time!

The adult of the fruitworm is a night-flying moths that ranges in color from tan to brown with orange in it. They are about 1 to 1 1/4 inch across their wingspan.

Click here to see the adult moth

Because they fly at night that's when the egg laying occurs.They like to lay their eggs on tomato leaves close to green fruit or they might lay them on the leaves on the outer edge of the plant if the plant is dense. They are flying now and have been flying for quite some time.

Click here to see a close-up of an egg

The eggs that they lay are very difficult to see because they are so small.The eggs are white when first laid and then develop a brown stripe or mark just before they're ready to hatch. First they begin to feed on leaves before they attack the fruit. They prefer to feed on green fruit and the damage that they create by tunneling into the fruit causes the tomatoes to ripen more quickly. The fruit is pretty well demolished once they enter and feed and move on to a new fruit.

Shining a white light or black light against a white sheet at night is an easy way to see if they are flying.  You can try it now and you will probably attract some but the best time is when tomatoes begin to flower so you can time your spraying.

You can also use pheremone traps.

Black light or even light traps serve as a good indicator when these guys are flying and will be a problem in the garden in the future. This is a cool way to look for them and great to show kids and grandkids.

Wednesday, May 20, 2015

Early Blight Control on Tomato Step-by-Step

How to use a foliar spray of Neem Oil plus EZ Wet surfactant to prevent early blight from spreading in your vegetable garden.

Posted by Viragrow on Wednesday, May 20, 2015

Control Leaf Footed Plant Bug Now

Tuesday, May 19, 2015

Why Are My Tomatoes Not Ripening?

            This cool weather has caused some unusual plant problems we normally do not see in the hot desert. One reader contacted me to let me know that his tomatoes were not quite the size of a tennis ball, still green and didn’t seem to be growing anymore.
Tomato growth and fruit ripening slow during cool night temperatures

            Another reader told me his newly planted grapes were not growing. Both readers wanted to know what to do.

            The answer to both is to wait. Both of these plants love warm weather. In fact, grapes love the heat. Our nighttime temperatures have been in the 50s and 60s. Most plant growth occurs at night, not during the day. Tomato gets chilling injury at 45° F.


Be patient. It will get hot. Tomatoes will ripen. Grapes will grow an inch every 1 to 2 days when temperatures are above 100° F. All we need are warm night temperatures.

Shade Reduces the Flowering of Pomegranates

Q. I'm not getting a very big crop of pomegranates this year. They are about 6 years old. We have a large ash tree in the yard which throws some shade but the pomegranates both get morning sun.  I heard they don't require much water so I was worried they were getting too much. Then the Homeowners Association switched from grass to desert landscaping this past year.

Flowering of pomegranates requires the tree to be in full sunlight
A. To produce fruit, pomegranate need at least six hours of sunlight but does best in full sun. As shade increases on pomegranate, the number of flowers and fruits decrease. Switching from lawns to desert landscaping reduces the overall amount of water pomegranates are receiving. This will affect overall growth, flowering and fruit production.

Pomegranates produce flowers on new growth. If you are getting lots of new growth and there is enough sunlight there is no reason you should not be getting lots of flowers at that age. The key will be the number of flowers it's producing. If the tree is not producing flowers of course it can't produce fruit.

To stimulate flower production they need the same amount of water as other fruit trees. This plant is very drought tolerant but it needs water if it is to be productive. The amount of water depends on its size. The frequency of watering is the same regardless of size.

A six-year-old pomegranate should be at least 4 or 5 feet across. Its height depends on how it is pruned. An indicator it is getting plenty of water is the density of the canopy. Your pomegranate tree or bush should be dense enough you would have trouble seeing through it.

If you are not seeing much new growth and the canopy is not dense, this is usually an indication it's not getting enough water. Of course production increases if fertilizers are applied as well.

Surface wood mulches help retain water in the soil and improved growth and production of these plants.

Grapes like the Heat, Grow Slowly during Cold Nights

Q. My newly planted grapes aren't really growing fast and are a bit more yellow than dark green. I am wondering if I need to water more. I am only watering two times a week or water less. Or if I need to add something to the soil? Or do nothing and stop worrying?

A. Grapes love the heat. It is probably just not warm enough. Watering twice a week is right when temperatures are beginning to warm.

Apply about five gallons each time you water newly planted grapes. Put a steel stake next to them or a piece of rebar and tie them tightly to it so they are straight. Use the stretchable green nursery tape. Do not use wires.

If you are planning to trellis these grapes, remove all leaves along the trunk except the new growth at the tip. You do not want side shoots to develop along the trunk unless you are growing it in a tree form.

Grapes grow slowly during cool weather
The leaf yellowing could be caused by cool nighttime temperatures or a lack of nitrogen fertilizer. Apply nitrogen fertilizer once a month to the soil around the trees and water it in. Do not apply closer than about 12 inches to the plant or you could burn them or worse.

I see from the pictures you sent you have a lot of rock mulch surrounding your fruit trees and vegetables. Our soils have horribly low amounts of organic content, some of the lowest on the planet.

Grapes, all fruit trees and vegetables including strawberries do not like rock mulch at all. This will be a problem in the future. They like “organic” soils, not rock or mineral soils. The small amount of wood chips you have spread a few inches around your plants will not help them at all.


Wood surface mulches need to be at least 3-4 inches deep and a distance of at least three feet from their trunks. Keep wood mulches several inches away from the trunks of young trees and vines.

Gopher Control Includes Several Alternatives

Q. I live in Sandy Valley and will be building some raised bed planters in my backyard. I have seen gopher mounds all over the property and wondering what is the best way to get rid of them before I start this project. One neighbor says they are so prevalent on the north end of the valley they ignore them altogether.

Gophers make pretty big holes and you can find fresh soil pushed from the excavation.
A. Gophers are tough to control. The options are to kill them, exclude them from desirable plants or catch and relocate them. When gophers have other food sources in the neighborhood using repellent plants in your garden might work since your neighbor’s plants will then seem more delectable.


            When gophers find a food source, they make more gophers. Your raised beds will encourage them to set up a base camp, living quarters and a dining commons. The bottom line is they are attracted to your water and the soft, juicy succulent plants you are growing.

There are baits and poisons you can use but you’ll have to be very careful not to poison other animals in the process. Your best option is probably to exclude them from your growing area with a wire mesh barrier. You would need to move all your susceptible production into raised beds and place wire mesh at the bottom of the bed before filling it with garden soil.


It is best to read through this for your options. http://cesonoma.ucanr.edu/files/27165.pdf

Jujube Good Choice for Desert Production, Not Hachiya Persimmon

Fruit of one variety of jujube
Q. I just bought a new house with big yard at Summerlin. I am Asian and there are three trees I want to plant most but I don’t have any experience; Jujube, Hachiya persimmon and white saucer peach. I read some of your articles and decide to ask your advice before I take the action.

A. Jujube, or Chinese date, grows extremely well in our climate and you will have a lot of success growing it here.

The biggest problem is its invasiveness. Jujube suckers from its roots in new locations wherever there is water. These can be distances of 5 to 20 feet away from the mother plant. Over time, you could have a forest of jujube from a single plant. Just keep the suckers eliminated when you see them.

Sadly, Hachiya persimmon does not perform as well here as Fuyu and other persimmons. We have trouble getting good fruit retention (fruit staying on the tree) after the fruit has set. Plenty of blossoms but the fruit drops when it gets about ½ inch in diameter and the tree produces only a few fruit. I would suggest trying different varieties of persimmons such as Fuyu, Giant Fuyu, Coffeecake, and others).

The white, flat peaches perform very well here with a very high sugar content and excellent flavor. I would suggest donut peaches such as “Stark Saturn” or “Sweet Bagel” varieties. These peaches may also be called saucer or peento peach.


If you keep your trees healthy by planting with plenty of compost mixed in the soil at planting time and covering the soil surface with wood mulch you will have fewer problems. You can always email me with specific questions.

Salt Damage to Peppers Can Be Managed through Irrigation

Q. We are small farmers owning 2 acres of land in India, We have just seen your opinion on RO water for horticulture crops. We are growing roses and colour capsicum under poly greenhouse cultivation. Our ground water electrical conductivity level (salinity) is too bad that it comes to 1.8. So our plants came to death condition. We heard about reverse osmosis system and fixed it to our farm. By this system leaves shrinkage and nutrient deficiency had risen. So we are pleasing to suggest your idea about it. We are looking for your grateful suggestion.

A. Pepper plants are very tolerant of this level of salinity. It only becomes a problem if we let the soil becomes excessively dry or if the drainage of the soil is very poor and the water drains slowly. Improve the drainage of the soil and irrigate so that the soil never dries to less than 60% of its water content. With a little bit of experience, you can determine this just using your hands and feeling the moisture content by squeezing it and using your fingers.

The kind of salts that you have in the soil will dictate if you were to use soil additives such as gypsum or not to help flush the salts from the soil. Sending a soil sample to a soils laboratory to determine which salts are present would be very helpful.

Generally speaking we start to see yield reduction in pepper at about 1.5 dS/m (mmhos/cm). You are close to that threshold at 1.8. I think you would only need to dilute your irrigation water maybe 20% with RO water to get below this threshold.

New Mexico's advice on salt damage to peppers

Another option is to water with your irrigation water and then flush salts using an irrigation cycle using water with lower salts. Use these in an irrigation cycle of salts/low salts/salts/low salts/etc.

Monitor your drainage water for salt content. Monitoring your drainage water and recording it regularly will help you with managing salts (flushing, etc.)

Two types of salt damage occurs to plants; one is due to total salts (EC) and the other is due to the type of salts (specific ion effect). Particularly damaging are sodium, chloride and boron. If these salts are involved then this might mean a very different problem than just salts in general.

What to do?

  • If it is possible, determine which salts are present and not just the level of salinity (1.8). 
  • When irrigating never let the soil or substrate dry out too much. 
  • With high salts you should be irrigating frequently with a smaller volume of water. This prevents the salts from becoming too concentrated. 
  • If you can over irrigate and flush salts from your soils make sure you over irrigate by about 20% to keep salts moving through your soil profile and maintain a steady state of salts and prevent the buildup of salts.
Depending on the type of salts in your irrigation water you will see different nutrient deficiencies.

Note: This question was from farmers in India. Potable water, water in the Las Vegas Valley coming from the tap, is close to this level of salinity or salts. This is because a large percentage of this water comes from the Colorado River unless you are on well water. Salt levels of our native soils here in the Las Vegas Valley are 25 times this level. Water management is very important to control salinity.

Relocating Oleander Requires Drastic Measures.

Q. I dug up some standard sized oleanders from my neighbor’s yard. They were healthy for years and some were 8 to 9 feet tall. I transplanted them about six weeks ago and used transplanting fluid every 6 to 7 days. I also watered them every few days. The leaves are all dry and crinkled so I pull them off. They are dead now and just look like sticks. But I see new growth coming from the base. My husband tells me to pull them out and buy some new ones. Will these make it?

A. When you dig up plants that are this old you can only get about 10% of their root system. With a
Oleander will sucker from the base if it is cut back. When relocating an older Oleander you should cut them back to make up for the lost roots.
very small percentage of the root system they will have considerable die back. If they make it at all, they will do exactly what you've described and that is to regrow from the base.

If you want to keep them, it is best to just cut them off with a few inches above the ground and let them regrow from the base. Just keep the soil around the roots watering about once a week now and twice a week when it gets really hot.

They will survive and I would be surprised if anything grows from the stems that are taller. The transplanting fluid was not necessary. They would've done what they're doing right now with or without it.

In the future when you move plants that have been in the ground for more than two or three years the success rate is pretty low unless you have a history of doing it successfully.

Be Careful of Misdiagnosis of Sooty Canker

Q. Our flowering plums have been infected by what was diagnosed as “sooty canker” disease.
Sooty canker on Apple
They were treated by arborists but the blight continues. Infected limbs were cut until one of the trees needed to be removed entirely. I am advised this blight has become epidemic in Las Vegas Valley. Is there a solution to cure or at least treatment for sooty canker?

A. Be careful on any diagnosis of sooty canker. There are a lot of natural things that can look like it and if you've never seen it before or don't have much experience around it, it can be easily misdiagnosed.

Sooty canker on poplar
Sooty canker disease causes limb dieback and the bark of the dead limb to peel away revealing a black, sooty powder on the wood. When you take your finger and rub against this black powder it will come off on your finger and look just like soot from inside your chimney.

There are other natural black “powders” on limbs which will also rub off on your finger. But sooty canker is jet black on your finger and unmistakable once you see it. I will post a picture of sooty canker on my finger on my blog so you can see what I’m talking about.

Beginning of sooty canker on Mulberry
I disagree, it is not an epidemic in Las Vegas. It attacks a small number of trees every year at about the same rate for the past 30 years. Many trees can become infected but we see it most frequently on Mulberry and Poplar (cottonwood) and occasionally on Ash and Elm.

I don’t remember seeing it on truly desert trees such as Mesquite, Acacia or Palo Verde.


It can be spread easily on pruning equipment if the equipment is not disinfected between cuts and between trees. 

Be very careful when this is diagnosed. If a limb is dead, it is dead and must be removed. We don't want to be removing limbs with the wrong diagnosis.


Monday, May 18, 2015

Control Blight of Tomatoes Now!

Control Blight of Tomatoes Now!: Tomato early blight developing on lower leaves. Leaves first yellow, develop spots, wither die and progress through the plant. Early Bli...

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Friday, May 8, 2015

Viragrow May Coupons are Here!

Viragrow Delivers! : Viragrow May Coupons are Here!: Here are our May coupons.The prices are pretty amazing. Viragrow always has great prices but the compost and soil mix season is coming to a ...

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Thursday, April 30, 2015

Get Rid of Springtails by Mopping Up

Q. I was told by the Nevada Department of Agriculture the tiny insect I found jumping around in my bathroom were springtails. I have read they are very hard to kill which I finding out after I had an exterminator try to get rid of them.

A. Insecticides are not a good choice for controlling springtails. It usually requires several repeat applications of traditional household insecticides and they will return if the source of the problem is not corrected.

What are springtails?

Springtails are tiny jumping insects, about 1/16 inch long, that are found in cooler times of the year where there is standing water. I have seen them here outside in grass that is kept too wet or where there is a water leak.

Because they are such good jumpers they are sometimes confused with leafhoppers outside the home and fleas inside the home. They are neither.

Inside the house they can multiply where the flooring is kept constantly moist. They feed live off of mold and fungi that grow where there is shallow, standing water or very wet soils. If the area is kept dry and cleaned up they will disappear.

Save your money. Don’t apply pesticides. Fix the area so it stays dry and sanitize it.

Prevent Roaches from Mulches Entering the Home

Q. I know you recommend bark mulches around trees to help in water retention. However, there are negatives to consider such as cockroaches, bugs, etc.  I encounter lots of cockroaches in the ground when I have excavated in certain areas of our yard.

Untreated wood chip mulch including pine needles and leaves
A. I encourage the use of wood mulches more than bark mulches. Bark mulches seldom decompose much and add very little value to the soil. They are purely decorative. Wood mulches decompose easily in moist soils and add a lot of value to desert soils.

Benefits of wood chip mulch

You are absolutely right. Insects such as cockroaches are scavengers. Like many insects they like two things; water and a food source. This is why you frequently see tons of them inside irrigation boxes.

They feed on plants and animal life that have died and help in its decomposition. Feeding on dead and animal life helps return organic life back to the soil.

Cockroaches do not discriminate between dead plant or animal life whether it is inside the home or outside the home. They will enter the home if given the opportunity.

Using a foundation spray

Using a foundation spray or pesticide around the perimeter of the home and in valve boxes helps to keep them from entering our home. This is an insecticide spray barrier applied to the outside of the home at soil level and 12 inches above the soil. A good time to make this application is when temperatures begin to cool in the fall.

 It also helps if you keep wood mulches away from the foundation of the home. There is no reason you need to apply wood mulches up to the foundation.

Pruning Fruit Trees in Late Spring

Q. I have added some fruit trees such as Asian pear, peach and apricot to my yard. When is the best time for pruning these trees?

A. The pruning of fruit trees is done for two separate reasons; establishing the architecture or structure of the tree and encourage the production of high quality fruit. There is even a third reason that is not talked about very often and that is helping to keep trees smaller.
Winter pruning establishes the architecture of the tree. The most productive branches are at 45° angles.

Prune at the Time of Planting. When purchasing a tree and its structure needs improvement, you should prune for improved structure immediately after planting and not wait until the end of the growing season.

Prune in Winter Months. With established trees, major improvements to the architecture of an established tree that require a pruning saw or loppers should be done in the winter months. For deciduous fruit trees, it is much easier to see the architecture of the tree when the leaves are gone. Smaller changes in its structure requiring a hand pruners could be done anytime.

Summer Pruning. I encourage summer pruning during the month of April and early May in our climate. Summer pruning focuses on removing aggressive vertical growth that has grown since spring. Sometimes we refer to this growth as “suckers” or “watersprouts”.
Strong vertical growth can be removed very early in the season by pulling downward. This is called summer pruning and helps to reduce interior shading of the tree and improves fruit quality and production. It also helps to dwarf a tree by robbing it of its new growth.
Summer pruning is used to reduce the interior shading of fruit trees which decreases production and helps keep the size of fruit trees smaller. It is also used to take away the future growth potential of a tree. When a tree is pushing new growth it is making an investment in the future. The tree is using stored food reserves for pushing new growth. That tree will recover the food reserves it used and more after its new growth has matured.

Strong vertical growth is seldom fruitful in the short run. Strong vertical growth is used by the tree to gain height. This type of growth should be removed and is easy to do. Pulling downward on immature watersprouts will remove them cleanly and efficiently without using a pruning shears. If you wait too long this growth can no longer be removed by pulling. It must be cut off. This leaves stubs that will sprout in the future.

Raggedy Roses Probably Damage from Thrips

Q. My yellow roses were beautiful the first time they bloomed before Easter. However, the flowers aren’t pretty any more after they open. The flower looks burned on the edges of the petals. I haven't seen bugs on the flowers. Otherwise the plant looks healthy to me.

A. Your roses, from the sound of it, are probably infested with Western flower thrips. These are very small insects that are nearly impossible to see unless you use a magnifying glass and inspect the flowers very closely. They are also difficult to control.

Posting in pictures by Colorado MasterGardeners
Thrips damage on lots of things in Canada

Thrips are poor fliers and so stay close to the plants they feed upon. They have mouthparts that shred tender plant parts such as flower petals and flower buds before or after they open. The flower petals appear damaged and with streaks of brown.

Soap and water sprays are somewhat effective but the best to spray for controlling this insect contains Spinosad.

Dormant sprays of horticultural oil during the winter and applied before the plants start growing will also help. I would alternate sprays between an insecticidal soap such as Safer's and Spinosad sprays until you get some control.

How to Grow Moringa in the Las Vegas Valley

Q. I planted a Moringa tree for its health benefits. I understand it is native to the tropics. Can you tell me how to grow it in this climate?

A. You know that Moringa will be killed back to the ground every time we have a hard freeze. For this reason, we have to manage it similar to bougainvillea. Moringa grows on its own roots so we don’t have to worry about suckers developing from a rootstock like we do with most tender citrus.

Moringa is one of those plants touted for its health benefits. It is native to tropical and subtropical South Asia and has spread to Africa, South East Asia and more recently Latin America where the leaves and pods are used in cooking. Most recently it has been labeled a “superfood” by the media.

Moringa is also called the horseradish tree, drumstick tree or malungay. It will grow here but it has to be managed differently than in the tropics. Establishment of the tree by cuttings or trunk cuttings is quite common in the tropics. Establishment in our desert soils is similar to any fruit tree by using compost to amend the soil during the time of planting. This is a tree I would mulch with wood chips, not rock mulch.

Marine got can be started from seed very easily. Start them the same way you would start tomato seeds or any other tropical seed. They require warmth, above 70° F moisture and good drainage. Start them as early in the season as possible so that you get enough growth on them before you put them out.

Growth rates of this tree are extremely rapid and you can expect 6 or more feet of growth during the first year if it’s given enough water. This is a large tree in the wild and it will want to have one central trunk.

You should discourage this central trunk by cutting it close to the ground after it gets about 2 to 3 feet tall. This pruning cut will encourage suckering from the base of the tree which is what you want. You should probably grow it as a shrub, not a tree in our climate.

Let it get damaged in the first light freeze of the winter. After the freeze has passed, cut the plant to the ground and protect it during very cold weather.

You can do this by throwing a blanket over it and preventing the blanket from blowing away during high winds. Remove the blanket during warm daytime temperatures. Fertilize it with your favorite high nitrogen fertilizer that promotes leaf and stem growth. 

How to Move a Joshua Tree

Q. I am lucky to have a Joshua tree that is about 3ft tall and I am thinking about moving it now that it has been five or six years in the ground. Am I going to be successful in moving it or do you think I will kill it?

Joshua tree that was planted and still small enough
 to move without much difficulty.
A. Joshua trees are difficult to move from the wild but much easier when it has been planted once and watered with drip irrigation. It should move okay.

Your major precautions are to make sure its new home drains water easily and not to overwater it after planting. I would avoid moving it when it is hot but you could move it now during the spring or fall months.

Dig the hole where it will be planted ahead of time. Fill this hole with water and make sure it drains in a few hours. Amend the soil taken from the hole with about 25% compost and use it for backfilling the hole after planting.

Add a handful or two of a high phosphorus fertilizer to this soil mix to encourage rooting. It will be important to stake the tree the first season after planting to keep the roots from moving during establishment.

Take as much of the root system as possible when you move it to its new home. There will be far less shock to the plant and better establishment if the roots are disturbed as little as possible.

Moving a much larger Joshua tree with very little root system.
Most of the roots will be close to the drip emitters or source of water and within about 12 inches of
the soil surface. When you move it, take as much of the soil around the roots as possible and plant it with this “root ball”.

Make a mental note of the north side of the tree. Orient it the same direction as it was previously. Stake it after planting for one growing season.

Do not water too often. You can overwater it by giving it more water in a single watering but do not give it water more than every three weeks.

Late Application of Iron Fails to Cure Yellowing

Kerex iron application made to the soil after growth has already begun will result in yellow leaves on the older leaves while the new leaves coming out after the application will be green.

Q. I have a Burgundy plum tree that is 3 years old. The leaves became yellow in March so I applied Kerex iron to the soil when I first noticed the problem. Now the new leaves do not show any yellow in them but older leaves are still yellow so I do not think it is an iron problem.

A. Iron does not move once inside the plant. It is still an iron issue. You said the NEW leaves do not show any yellow. That means your KeRex application in March worked for the leaves which grew after your application.

Iron does not move around inside the tree once the plant takes it up, it only goes into the new growth after the application is made.We say that iron is immobile once inside the plant. It is not like nitrogen which can move from older leaves to newer leaves. Iron cannot do this. Iron can only be transported into new growth. Growth before the application will still stay yellow.

Correcting the problem. The only way to correct yellow of older leaves is with iron spray applied to the leaves. This is why SOIL applications of iron are so important to make in January before growth occurs.

An example of an iron product that can be used for foliar applications, or sprayed on the leaves. Spraying the leaves with an iron solution is the only way to correct yellowing once it is already started. Make sure you use a wetting agent mixed with the iron spray.
EZ Wet is one example of a high quality wetting agent that does not contain
any personal care products and made entirely from yucca extract.
It is not too hot too late to spray iron on the leaves. It may take four or five sprays a couple of days apart to get all the yellow leaves completely green.

Any iron product, labeled as a spray applied to the foliage of fruit trees will work. However, I would strongly suggest that any water mixed with this iron fertilizer should be distilled water so that the pH is close to neutral (pH of 7).

Alternatively, you can adjust the tap water close to neutral using vinegar or another mild acid as well.

You should add a wetting agent to the spray as well. This helps the iron penetrate the leaf surface and enter the inside the leaf. Otherwise the spray is not as effective. Some people use liquid detergents with good success. I worry a little bit about the other personal care products in liquid detergents so I would encourage you to use a commercial wetting agent.

If you are still unsure how to do this, you can read more about how to do this on my blog or email me at extremehort@aol.com

Fertilizer Injectors Have Advantages and Disadvantages

Q. I know of fertilizer systems which friends have linked to their home yard watering systems. These can be adjusted as to the quantity of fertilizer added to the water. However, it seems this might be quite a bit of fertilizer applied to the plants. Yet, a neighbor is very enthusiastic about the benefits. Can you advise me on this subject?

Simple fertilizer injector using a stock tank of a fertilizer dissolved in water. Here we are preparing the stock solution to be injected into the irrigation line using the Venturi effect. In Kosovo.
A. These fertilizer systems have different methods of injecting fertilizer into the water. They range in different prices based upon how precise they can deliver fertilizer. Collectively we call them fertilizer injectors. They can be adjusted so they deliver a very tiny amount of fertilizer or deliver a lot of fertilizer at one time and then turned off until needed again.

The fertilizer was injected into the irrigation line and was applied with overhead drip irrigation using micro sprays. This is seedling production in a greenhouse in Kosovo. Benches were created using bales of straw.
Background. Fertilizer injectors were designed primarily for agriculture and commercial horticulture use where one type of plant is grown or plants grown with similar water and fertilizer requirements. Their primary purpose was to save the cost in applying fertilizer.

Several types of injectors are available for home landscapes in a range of prices. The primary difference in these injectors is their level of precision. Most inexpensive homeowner fertilizer injectors operate on the "venturi effect". The venturi effect pulls a concentrated fertilizer solution from a bucket or small tank into a stream of water. This stream of water might be in a hose or an irrigation line. The principle of the venturi effect  is used in some automated pool cleaners, wine aerators, recoilless rifles and in the pressure regulator for scuba gear.

You can watch how the Venturi effect works in irrigation lines in this video from Jain Irrigation
https://www.youtube.com/watch?v=tGlZLwvI6PY

The venturi effect causes concentrated fertilizer solution to mix into the stream of irrigation water. You can operate your injector to apply fertilizer continuously or periodically on a fixed schedule; once a month; once every three months, spring and summer, etc. If you put fertilizer in the injector, it will fertilize. If you don't, it won't.

Advantages and Disadvantages. The primary advantage to the homeowner is less labor which saves time. Some may argue it also saves the homeowner money and the landscape looks better. Both are arguable but I don’t think anyone can argue it is not a timesaver. I will go into more detail on my blog.

The primary disadvantage for homeowners is that all plants which receive water at the same time also receive the same kind of fertilizer. When fertilizing plants by hand, you have the option of giving them different types of fertilizers, not all the same kind.

Plants which receive more water also receive more fertilizer and the reverse is true. The application of fertilizer in precise amounts should also require a very efficient irrigation system. These go hand in hand.

In short, make your decision based upon the saving of time and labor. All of the other points are arguable and may or may not apply. 

Operating Your System. Leaving water with fertilizer in it in your irrigation lines for more than a few days can lead to algal, fungal and bacterial growth. It is best to apply fertilizer and allow fresh water to clean the irrigation lines after the fertilizer has been applied. Make sure there is a screen filter downstream of your fertilizer injector to prevent plugging of your drip emitters.

Monday, April 27, 2015

New Product for Lowering Soil Alkalinity (pH)

This was a very interesting product. When a few ounces were mixed with tap water it dropped the pH of the water to 3.1. We do not have that many good options for lowering soil pH. The sulfur we get now is coarse and takes years to break down.This product breaks down quickly with applied water. It gets me wondering about our acid-loving plants like azaleas, rhododendrons, hydraneas, camelias and the like. I also wondered about southern highbush blueberries and their potential here if we could find a suitable product to lower soil pH. It might also help plants that struggle with iron problems like photinia, bottlebrush and mock orange. It might be worth a try!

Viragrow Delivers! : New Product for Lowering Soil Alkalinity (pH): Have you wanted to grow southern highbush blueberries in the Mojave desert but the soil pH was too high? How about azaleas and rhododendron...