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Thursday, May 5, 2016

Viragrow Delivers! : My Palm Leaves Have Brown Spots

Viragrow Delivers! : My Palm Leaves Have Brown Spots: Q. My fan palm has black spots on the fronds.  Someone said it may lack iron.  Or, is it getting too much water? A. Without seeing ...

Viragrow Delivers!

Tuesday, May 3, 2016

No Lemons on My Lemon Tree

Q. My tree has been in the ground for six years and each year I get plenty of new growth, leaves and flowers. The problem is, no lemons at all. I have applied fertilizer and even  miracle grow--no luck. What do you suggest other than removing the tree and starting fresh?

A. The usual reasons for no lemons is either freezing temperatures after they bloom that kill the flowers or small fruit (usually in January or February) or irregular watering that causes trees to stress and drop flowers and fruit before they can mature.
A light freeze will kill flowers and fruit without damaging the tree. If you have been pruning the tree, stop pruning it. Fertilize it once a year in January or February. Put a surface mulch of wood chips around the tree at least 6 feet in diameter and 3 inches deep.
Cover the tree with a sheet or light blanket if temperatures during the winter approach freezing. Put a basin around the tree and fill the basin with water each time you irrigate. Avoid watering daily. Skip at least one day between irrigations.

Tomato Problems Growing in Containers

Q.I  have about 20 tomato plants, mostly in containers. They have been receiving 6-7 hours of direct sunlight every day and they were planted the first week of March. Every year, I get a handful of plants that develop what appears to be two different problems. Some develop little brown spots on the leaves, and then die. I promptly remove the affected stem but can’t keep ahead of it. I also have plants with leaves that develop yellow and brown edges. I have two plants with the spots, both are cherry tomato plants, Sweetie variety. The plant with the brown/yellow dying edges is also a cherry, Blue Berries variety.

I have 17 other plants, all close by, on the same watering schedule, with no problem.  I use drip irrigation. The plants are in high quality potting soil amended with compost and the soil gets changed and amended each season. The soil is covered with mulch.

I’ve attached some photos for you.

A.Thanks for all of the good information you included along with the pictures because it really helps me a lot to try to decipher what's going on.

We grow tomatoes in containers every year and don't have any problems. However, these containers are on the east side of a building so they gets shade from the afternoon sun.

I looked closely for disease problems and I didn't really see them but as I looked closer some of the brown spots might be the development of early blight. One of the simplest methods is to remove the older leaves at the first sign of browning. Don't leave them in the container but dispose of them somewhere else. Also remove the older leaves that are in shade as I mentioned in the other email. 

You can apply a fungicide that is labeled for early blight of tomato. Commonly these are copper fungicides. Some varieties are more prone to these disease problems than others. Next year you might try switching to different varieties that will give you similar types of tomato fruit.

One thing you didn't tell me is whether you bought these plants as transplants or if you started them from seed. If you started them from seed always sterilize the seed prior to planting. The following link tells you how to treat seed either with hot water or Clorox

The following link tells you how to treat seed either with hot water or Clorox

The scorching along the edges appears to be a water or salt problem or both. Make sure the containers are irrigated often enough so that the soil does not become too dry between irrigations. When salts are present in the soil, and this can be from soil mixes or compost as well, when the soil begins to dry than the salts begin to become concentrated and cause more damage.

I would also suggest that you either double pot these containers… One nestled inside another one with a 3 inch layer of rock or wood chips at the base… Or paint them white or shade the outside. At 95° F, the black exterior of the container will reach about 160° F on the outside and in direct sun. This can cause problems.

Water management is always going to be a challenge in containers. Water them daily if they have good drainage and make sure the soil is wet at the beginning of the day. If these containers drain extremely well, you may need a second irrigation during the day. Water management is going to help in salt management and possible scorching to the leaves.

If you use the same containers each year, make sure you sterilize the inside of the containers with a bleach solution and let them air for a couple of days before filling them with soil and planting in them. When applying the mulch to the container, keep the mulch away from the stems of the plants so that the plants do not develop crown rot.

The small brown spots on the leaves do not appear to be a disease problem. If it were a disease problem the brown spots would most likely have a small yellow halo around them. These do not. At least they don't now.

I know you are using drip irrigation but avoid watering overhead with a hose end sprayer or other type of sprinkler. Leaves that are in the shade will be weaker than those in full sun. Thin out the canopy of your tomato plants to improve air circulation around the leaves and allow better light penetration inside the canopy. You can do this by pinching off suckers coming from the crotches of the leaves. You want light penetration inside the canopy and you want air circulation. If you don't have this, disease problems are highly likely.

Feed your tomato plants with your favorite tomato fertilizer once a month after they begin to develop small fruits. This is important because plants pull nutrients from the soil and these nutrients should be replaced as plants become larger.

Take a look at this link

What Causes Brown Spots on Tomato Leaves?

Q. What is causing brown spots and leaf scorch on my tomato plants? I grow about 17 different tomato plants and several different varieties in containers. I always use good potting soil and compost each year in the containers. They are drip irrigated.

A. This is the time of year that brown spots begin to develop on tomato leaves. As the season progresses, disease problems on tomatoes are often in inevitable. Prevention of disease should be high on your list of things to do with tomato plants.
            It’s too late this season but some varieties are more susceptible to diseases than others. If you don’t know which variety you have, do a little homework and pick varieties more resistant to disease that give you the types of fruit you like.
            Tomato cages are nice. They support the fruit off of the ground. Fruit lying on the ground is more likely to rot than fruit supported off of the ground.
The beginnings of tomato disease probably early blight
            Tomato cages can also be a menace. They force crowding of the interior of the plant. Leaves and vines growing in the center don’t receive enough sunlight to stay healthy. They also don’t provide good air circulation. This encourages disease. Remove the oldest leaves near the center of the plant to improve air circulation and reduce disease problems.
            Drip irrigation is good. Watering at the base of the plant helps. Many vegetable plants, unlike us, don’t like showers. Avoid overhead watering of these plants. Overhead watering keeps the center of the plant wet which encourages disease. Splashing water can spread disease from leaf to leaf.
            Regular feeding of plants is important. When fruit has set then continue monthly feeding of tomato plants. They are taking nutrients from the soil as they grow. You should be replacing these nutrients as they are removed.

            At the first sign of possible disease it is important to take action. Applications of fungicides may be your last alternative. Choose a fungicide for controlling the more common tomato diseases such as early blight. Most fungicides are preventive and don’t cure a disease once they have begun and running rampant.

Passionfruit a Challenge for Las Vegas but Possible

Q. I put a passionfruit tree on the north side of our house. I noticed many flowers but later on after self-pollination the flowers fall off. What do I do to prevent it?

A. Passionfruit is tropical and at best a semi tropical vine that bears a delicious, seedy fruit with very little care under tropical conditions. It is not a tree so it does need to be supported by a trellis of some sort. This is the cold desert so this plant is handled a little bit differently here.
Intercropping passionfruit, strawberries and kale in Kenya

In the desert, passionfruit requires more care than it does in the tropics and it will most likely freeze back to the ground every year. But if the roots are protected from winter cold it will grow again in the spring.
It is good you planted it on the north side of a building but the East side would be even better so that it gets light in the morning and shade from the late afternoon sun. It likes a lot of compost added to the soil at the time of planting and to the top of the soil each year.
Giant passionfruit growing on a trellis over aquaculture in the Philippines
Wood chip mulch applied to the surface helps keep the heat off of the roots and preserve moisture in the soil. Drip irrigation works but this plant may perform better if rooted in a large basin or donut that fills with water.

There are many different types and varieties of passionfruit and some perform better than others in the desert. Varieties that have performed in the Phoenix, Arizona, area include Frederick, Incense and Blue Crown. More can be read about their care in Phoenix at http://www.phoenixtropicals.com/passionFruit.html

Just remember that Phoenix has warmer winters than we have so we must apply better winter protection. They generally have better soils than we have as well.
Passionfruit is a heavy feeder so fertilize them frequently. They set fruit easiest during the cooler times of late spring and early summer but may have difficulty during the heat.

They may need to be hand pollinated if they fail to set fruit by themselves. 

Lawns Don't Need Expensive Fertilizers

Q. I was very interested in a recent article about adding ammonium sulfate to one's lawn to keep it green. Can I do this all summer long, every 8 weeks?

A. The short answer is yes. Once a year use a high-quality lawn fertilizer as one of the applications.
A good turfgrass fertilizer should be high in nitrogen (the first number), low in phosphorus (the second number) and moderate to high in the last number (potassium). Also the ideal turfgrass fertilizer would have half of its nitrogen as slow release.
The best lawn fertilizers have a ratio of nitrogen to phosphorus to potassium of 3-1-2 or 4-1-2 with most of the nitrogen available as slow release. One example would be 21-7-14 (e.g. 3-1-2). Another might be 20-5-10 (e.g. 4-1-2).  There are many others or others close to these ratios. The important part of this, for mature lawns, is high nitrogen, low phosphorus and moderate to high potassium.

The principle nutrient lawns need is nitrogen on a regular basis. Nitrogen fertilizers keep lawns green and lush. Nitrogen is the first number in the triad of numbers on the fertilizer bag.This is why fertilizers like ammonium sulfate (21-0-0), nitroform urea (38-0-0) would be good choices to use in between the more expensive fertilizers. 

Lawns require constant growth to stay healthy and look good. This growth is mowed leaving behind lawn clippings. Lawn clippings are very high in nitrogen.Clippings are removed from the lawn because they are unsightly after a mowing. However, when mowers are used with mulching blades attached the clippings are cut into very fine pieces that fall between the leaf blades and decompose. When they decompose, they release nitrogen to the lawn. When mulching mowers are used, it is recommended to skip one application of nitrogen fertilizer every year.
This was a common scene years ago. Lawns were mowed and the clippings set on the curbside waiting to be taken to the landfill. This threw one nitrogen fertilizer application away each year.
In the case of ammonium sulfate this is 21–0–0. A bag of ammonium sulfate contains nitrogen, hydrogen, sulfur and oxygen in mineral form. There is no “filler” in it. Ammonium sulfate is 21% nitrogen. The usual recommendation for lawns is 1 pound of nitrogen every 1000 square feet.

This is applied with some sort of spreader such as a drop spreader, a broadcast spreader or hose end applicator. Since ammonium sulfate is 21% nitrogen, then 5 pounds of 21-0-0 delivers about 1 pound of nitrogen.

However, I find this rate is higher than necessary and lawns do just fine at half to three quarters of this rate. This is particularly true if mowing with a mulching mower and the clippings are allowed to fall back on the lawn. 

            In about 99% of the cases we have two types of lawns out there; tall fescue and Bermudagrass. Both of these lawns require a high nitrogen fertilizer about every eight weeks. However, the timing of these applications is different.
Cool season grasses like tall fescue grow best in the cooler spring and fall months. In our climate they are fertilized 12 months of the year., usually avoiding or reducing the nitrogen fertilizer during the hottest months.
A fertilizer application at Thanksgiving is extremely important if you want a dark green lawn tall fescue through the winter. It is unnecessary for Bermudagrass.

To make it simple, I recommend applying lawn fertilizers too tall fescue on Labor Day, Memorial Day and Thanksgiving. For Bermudagrass switch the Thanksgiving application for the Fourth of July.

There is no problem applying a fourth application to tall fescue during the heat around the Fourth of July as well but it is probably unnecessary. Any application to tall fescue during the summer should be the half rate I mentioned earlier.

How to Water Apricot Trees Loaded with Fruit

Q. Our 3 apricot trees are loaded with fruit. What is the ideal amounts of water? We have dripers at each tree
1-how much - each day(how many days a week) or per week
2-how much at one time
3-should we do more than one cycle per day

A. It is difficult to tell you how many minutes to irrigate but basically you want to wet the soil beneath the tree to a depth of 12 to 18 inches every time you irrigate. On small trees, this should be the entire area under the canopy. On larger trees this should be at least half of the area under the canopy.
This is a fruit tree which was removed from the orchard and going in wood chip mulch. You can see the majority of the roots are 18 inches deep in the soil and less. Most of the feeder roots that take up water and fertilizer quickly are only about 6 inches deep.
You should have enough drip emitters and spaced so that it will do this. For most of our soils this means they should be no further apart than 2 feet. 
This is an irrigation basin surrounding a fruit tree. Water is applied to the basin by a bubbler that produces 2 gallons of water each minute. If the basin were not present, water would flow everywhere. With the basin present it captures the water and forces it to percolate where the roots are located.
Right now we should be irrigating fruit trees twice a week. Fruit trees perform much better and are more likely to hold their fruit if there is a thick carpet of wood chips on the surface of the soil beneath the canopy. This layer of wood chips can also cushion the fruit if they were to fall during strong winds. Very common if they are ripe. This carpet of wood chip mulch should be 3 to 4 inches deep. You will add more wood chips every 2 to 3 years because they will begin to disintegrate into the wet soil. 
Here wood chip mulch was applied to the soil surface all through the Orchard. This much is not necessary. It would be adequate if the mulch was 4 inches deep inside the irrigation basin.
There is no need to water more than one cycle each time you water provided the water is kept under the canopy. If the water tends to run off to another location then you should build a basin under the canopy to hold the water. These basins are generally about 3 to 4 feet wide. With most good drip emitters they release water so slowly that the basin is not necessary. More than one cycle a day each time you irrigate is only necessary when water is applied on slopes or when the water is applied so rapidly that it runs everywhere. Otherwise there is no magic involved in watering more than one cycle per day.

Now Is the Time for Summer Pruning

Q. Back in January you had an article about Apricot trees and you mentioned cutting back excessively long growth over 18-24 inches when it is growing. I planted an apricot a couple of years ago and this year it is growing like crazy with many branches now exceeding 18 inches and still growing.  Would you recommend continuing to cut back excessively long growth and throughout the summer if necessary?

A. When fruit trees are growing like crazy some of it can be part of their genetics and some can be caused by management. Some fruit trees are naturally more vigorous than others. Fruit trees are also affected by the type of rootstock they are grafted to. For example, the variety Katy apricot is much more vigorous than the variety Gold Kist when grown on on the same rootstock. Gold Kist is more restrained in its growth and tends to stay smaller.
Young peach requiring summer pruning
Growth is also be affected by management. Applying too much fertilizer or watering too often can produce excessive growth. Growth is good. Excessive growth is not because it has to be pruned out and that's wasted energy by you and by the tree.

Summer pruning is a dwarfing technique used to help restrain the growth of fruit trees. Fruit trees have stored energy held in reserve through the winter. Trees "invest" this stored energy into new growth in the spring. Vigorous trees invest more of this energy into growth than trees with restrained growth.
Young fruit tree requiring summer pruning because of excessive new growth. Summer pruning only removes some of the new growth, not older wood.
Summer pruning in our climate is done during the months of late March, April and perhaps the beginning of May depending on the weather and the type of tree and its growth. When summer pruning, new growth that is undesirable is removed from the trees after the tree has made its "investment" in this growth. This robs the tree of stored energy that might be used for excessive growth.
Fruit tree restrained after summer pruning
There are two types of pruning cuts. One is total removal of a new shoot (thinning cuts) and the other is cutting excessively long growth, shorter (heading cuts). Total removal of a new shoot opens the canopy of the tree and reduces excessive shading. Cutting long growth shorter creates three new shoots from a single cut. Three shoots created by one cut increases shade created by the canopy.
Upright, vertical growth is usually not desirable in fruit trees. This kind of growth tends to produce lots of leaves and twigs and very little fruit. This type of growth should be totally removed with thinning cuts.
This second type of cut, heading cut, also encourages the development of short shoots along the cut branch. These short shoots begin to flower and produce fruit often times during the next season. These short shoots are called "fruiting spurs". Cutting back excessively long growth to about 18 inches restrains the tree and improves fruit production closer to the trunk.
Heading cuts are made anywhere along a branch just above a bud that is pointed outward.
The result of a heading cut (near my thumb) is seen next year when bud below the cut begin to grow. One cut can result in three to five new shoots. I refer to heading cuts sometimes as "thickening cuts".
What to do? Totally remove (thinning cut) new, long shoots that are 100% vertical. These shoots are sometimes called "water sprouts". Shoots that grow vigorously and vertically upward are not good fruit producers. This type of growth normally produces all shoots and leaves, no flowers.
Undesirable succulent new growth can be pulled from the tree and does not need to be cut if it is done early enough. Pulling new growth from trees, rather than cutting, reduces the amount of regrowth.
New shoots that grow vertically downward are also poor fruit producers. These should be removed as well (thinning cut). The best fruit producers are shoots that grow upward at a 45° angle; halfway between vertical and horizontal. Remove these shoots only if they are crowding or crossing other shoots. If they are excessively long (24 inches or longer) cut them back along the shoot leaving behind about 12 to 18 inches of new growth. This single cut of an excessively long shoot restrains the size of the tree and helps produce side shoots or spurs that will eventually flower and fruit.

Sweet Cherries Are Hit and Miss in the Las Vegas Valley

Q. Cherries are on my mind.  I know you have spoken of them before but I guess I did not have the ears to hear then.  Can you suggest the right kind?  Do I need two different varieties and if so, can I plant right now safely? 
A. Cherries are hit and miss in this desert climate. In some places they produce very well and other places they set nearly no fruit at all. I think this has more to do with the setting than anything else. 
Poor fruit set in Bing cherry growing in the desert. Growing suite cherries can be hit or miss. Good fruit set of cherries happens but usually in backyard locations where lawns or a pool is nearby.
My personal observation is they set better in backyards where they are close to a lawn or a pool. I think this higher humidity may have something to do with it. They don't seem to be particularly sensitive to chilling hours or the number of hours it gets cold during the winter. They flower very nicely every year but the problem is setting fruit from these flowers.

I have not tried them but I am speculating that the so-called low chill varieties of cherries may have the same problems as traditional cherries such as Bing, Lambert and the like. You will get better fruit set with two cherries in your yard that help pollinate each other rather than relying on neighbors.

There are low chill varieties of sweet cherries that have been released and promoted for our climate such as Minnie Royal and Royal Lee which pollinate each other. I have no experience with these low chill varieties so I don't know how they will perform here. I tell people that all sweet cherries are hit and miss as I mentioned above.

You can plant from container now without too many problems. Have the hole pre-dug, the soil amended with compost and plant it from the container into a wet planting hole as quickly as possible and have the water running with a hose at the same time you are putting soil back around the roots. This will help minimize transplant shock and setbacks.

Get Bigger Grapes. Give Grapes a Pinch Now!

The concept is simple. I tell this to those who come to my classes and demonstrations. There are two families; family A and family B. Both families each earn $30,000 a year. Family A has two children. Family B has 12 children. Which family can provide more food for their children? Hint: welfare is not involved.
Italia, a seeded table grape that can be used for wine as well
When plants have fewer "children" to nourish, each child as the potential for becoming bigger, healthier and stronger. Thinning a tree or vine to remove fruit is a form of pruning. Fruit is removed when they are very young so that the remaining fruit has enough time to get larger. The earlier you get it done while the berries are small, the greater the amount of food that will be transferred to the remaining berries.

Grapes are thinned in two ways; small bunches are removed and the remaining bunches are "pruned" so that the berries that remain get larger. This is how to do it for table grapes.

After the grapes of flower you will see the development of very tiny grapes at each of the flowers. Space the bunches of grapes so that they are about 12 inches apart along the vine. Look for bunches that are smaller or have not filled out well. Prune these inferior bunches from the vine with a pruning shears and compost them. Cut them off so that you do not leave any stub behind.

Secondly, look at the remaining bunches of grapes. These bunches grow in a triangular shape with a lot more berries at the top of the triangle, closest to the vine, and fewer of them at the bottom of the triangle near the point. Divide the triangle along its length into three equal segments.

Remove the bottom segment, or about one third of the bunch, by cutting with a pruning shears or pinching with your thumbnail.

Yes it's painful… To you...Not to them. There. You have reduced the size of this family so that the vine can provide more food and make the remaining berries larger.

Myrtle Makes a Good Desert Landscape Plant

Rain in the Desert Can Be A Bad Thing

You are probably thinking this rainy weather was a good thing. It is and it isn’t. Let’s talk about some of the problems this rain has created for us now and over the next month.
            Expect an explosion of disease problems. Look for diseases on tomatoes, Asian pears, some European pairs like Bartlett and even some apples.
Tomatoes sprawling on the ground frequently have a higher percentage of fruit that rot than those kept off the ground. One popular way around this is the use of tomato cages.
'Early Girl' tomato crowded in a tomato cage
Tomato cages keep tomato vines from laying on the ground and suspend fruit in the air where they are less likely to rot. The bad thing about tomato cages is they force all growth into a dense, upright tangled mess.
The center of this tangled mess, if left to grow without human intervention, is dark with very poor air movement. Tomato diseases love this environment particularly if it is wet and humid. Because of poor air movement and shade, the center of these plants tend to remain humid and dark.
The beginning of Early Blight disease on tomato
Plant diseases love moisture, shady areas and older leaves, particularly if the plants have not been fed. If tomato plants growing in cages are wet from overhead sprays or extended periods of rainy weather, diseases can be a big problem.
Tomato plants grown in cages should have suckers removed from leaf crotches as they are growing. This thins the plant and the remaining leaves get more sunlight and better air circulation. Tomato fungicides should be applied before things get really bad.

            I am predicting there will be an explosion of fireblight, a bacterial disease, on Asian pears, many European pairs and some apples. Asian pears are the most susceptible but look for it on European pairs like Bartlett and even some apples. You might see it also on pyracantha and ornamental pear.
Fireblight in May
            This virulent disease enters susceptible trees through the flowers, blown around during wet, rainy weather. Pears and apples were flowering when the first of these recent rains occurred. That was the clue that something was likely to occur this year.
Blackening and hook commonly seen with a fireblight infection
It takes time for fireblight to incubate inside the flowers and spread so signs of this disease will begin over the next couple of weeks. The first sign is the blackening and death of flowers and fruit and “hooking” of new growth. This disease spreads very rapidly and, if not controlled early, kills branches and possibly later, the entire tree.
Advanced stage of a fireblight infection
When symptoms are first seen use a sanitized pruning shears to remove the infected area 10 to 12 inches below where it is seen. Always sanitize pruning shears with alcohol, bleach or Pine-Sol after each cut. Bleach rusts steel so oil the shears soon after using it. Bag the infected plant parts and put them immediately in the trash. Do not compost it.

It is normal to see mushrooms coming from wood mulch and newly planted lawns after rains. Mushrooms are a close relative to fungal diseases and are not inherently bad. Mushrooms are signs that decomposers are at work and feeding off of decaying wood. They are generally not safe to eat so knock them over with a rake when you see them and don’t worry that these indicate plant disease.
Mushrooms popping up in wood mulch after rain

Master Food Preserver Classes Offered in Moapa

Are you or someone you know i interested in becoming a Certified Master Preserver? If so, the Cooperative Extension in Northeast Clark County is offering a two-day Master Preserver Certification class May 20-21, 2016 from 9:00am-5:00pm. The cost of this informative and useful class is $150 and the fee includes instruction, supplies AND certification.
The class will cover all methods of food preservation from water bath canning/pressure canning to dehydration/freezing. (The class will also include preserving fruits, veggies, jams/jellies, pie fillings, pickling/relishes and more!)
We are excited to bring Carolyn Washburn, our Master Preserver instructor, from Utah State University and here is a link with more class information: http://extension.usu.edu/utah/home_family_food/master_food_preservers[extension.usu.edu]

Please let us know if you would like to sign up or have any questions at 702-397-2604 ex.0 or walkerd@unce.unr.edu

Monday, April 18, 2016

Best Fertilizer for Lantana?

Q. What is the best fertilizer to use on Lantana?  I have yellow and purple and the yellow just never seems to keep the flowers long in the summertime, they come and go and do no not look very vibrant.  Is there such a thing a mild fertilizer to use?

A. Lantana are not particularly fussy about fertilizers but all plants benefit from improved soil “health”. Fertilizers only replenish some of the minerals in the soil that plant roots remove. Focusing your efforts on improved soil “health” make plants more lush and vibrant.
Lantana flowers
            Plants growing in desert soils covered in rock improve if organic materials are applied to the soil rather than only fertilizer. Ideally, organic materials should be mixed with the soil at the time of planting but these disappear in a couple of seasons and need to be replenished with surface applications on a regular basis.
Biosolid free compost
            The ideal organic application is 100% compost applied to the soil surface, not a soil mixture containing compost. Soil mixes commonly contain a large percentage of sand which adds volume to the landscape when applied. Compost on the other hand doesn’t add volume because it “dissolves” into the soil.
Pure compost, 100% compost, can be difficult to find in stores. However, 100% compost can be purchased from composting facilities such as A1 Organics or a compost supplier like Viragrow in North Las Vegas.
Lantana in bloom
Applying compost is simple. It is applied to a soil surface, or rock mulch, and simply watered in with a hose. Compost “dissolves” into the soil giving the plants nutrients and improves soil “health”. Improved soil health, along with the nutrients it contains, makes new growth darker green, with larger leaves, and larger, more vibrant flowers.

Sunflowers Can Be Critter Magnets

Q. After this last rain and gusty winds some sunflower leaves are scorched. The sunflowers are 3 feet tall, sown from seeds saved from last year. The leaf scorching runs between the veins but not on all the plants.  Is this normal after this kind of weather?

A. This had nothing to do with the weather. Look at the bottom of the leaves. Sunflowers are notorious bug traps. If this scorching is from bug damage, you will find lots of bugs feeding on the bottom side of the leaves.
Bottom leaves of sunflowers beginning to scorch showing signs of pest problems on the underside

Bug damage is noticed on the lowest leaves first and progresses up the plant. Usually insecticidal soap sprays applied to the bottom of the leaves kill these critters but will not repair the damage they created.
If the lower leaves turned yellow, it could be from not enough nitrogen fertilizer. If they are 3 feet tall, they have already removed a lot of nutrients from the soil to get that large. Feed them once a month with fertilizer or they will run out of food, the lower leaves turning yellow and scorching.
Checking on the undersides of the leaves we can see aphids beginning to colonize, perhaps placed there by ants moving them into virgin territory

Another possibility is irrigation or damage from salts. They go hand-in-hand since water washes salt from around the roots and pushes it deeper. Little plants only require small amounts of water. Big plants require more water so make sure they are getting enough water and it is applied often enough.

Improve the soil at the time of planting with compost, feed the plants regularly with a fertilizer, water them enough and check for bugs. Then they will be healthier.

Keep Grape Vines Away from Walls

Q. I was going to plant a grape vine directly in front of my cement block wall. I decided to check the internet to see how far away from the wall I should plant. The site said grapes should not be planted close to walls because the roots cause structural failure. Is there is a minimum distance from the wall to plant the grape?

A. Roots of grapes are not a big problem for walls, particularly when grown in the desert with drip irrigation. However, do not plant a grape vine immediately against the wall. Put them on a trellis at least 1 foot away from the wall. Place drip irrigation away from the wall to encourage plant roots to grow away from the wall as well.
Keep grapes away from walls for better production of fruit

Grapes need to be pruned and harvested. Planting directly against the wall makes these practices difficult. Generally speaking, table grapes grow more vigorously and are more aggressively than most wine grapes. Wine grapes might be a better choice for smaller areas and they are more versatile as a food.

Oleanders Struggling in Desert Soil

Q. We planted new oleanders a month ago and fertilized them with Epsom salts and gypsum. They have yellow leaves that are dropping already. What can we do to stop the yellowing of the leaves?

A. Oleander should be one of the easiest plants to grow in this climate and soils. Something is definitely wrong. Gypsum and Epsom salts are not complete fertilizers. They contain a lot of calcium and sulfur as well as some magnesium but nothing to encourage plant growth.
            Select a fertilizer that contains nitrogen, phosphorus and potassium such as 16–16–16 or some type of fertilizer for trees and shrubs.

You didn’t mention mixing compost with the soil when it was planted. I hope the soil was amended with organic matter like compost at the time of planting. This is extremely important for plants growing in our desert soils.
It is important to add compost with the soil at planting time

Make sure the planting hole is filling with water at planting time. This practice is not as important in soils found in wetter climates but can be an extremely important practice for our soils.

Add enough water at each irrigation to thoroughly wet the soil surrounding the plant roots to a depth deeper than the container. Build a donut or moat around the plant that can be filled with water. Irrigate with a hose, filling this moat, the first three weeks after planting.
Add water to the planting hole at the same time you are backfilling it with soil

Tomato Plants Don't Need Shade Cloth

Q. My tomatoes have blossoms all over. When should I cover it with shade cloth?

A. Tomatoes do fine without shade cloth. Be careful using shade cloth because too much shade stops plants like tomatoes from flowering and producing fruits. Shade cloth is best used for leafy vegetables and herbs. Shade decreases bitterness and improves tenderness of leaves.
This is 30% shade. Leafy green vegetables and herbs grown for their leaves will benefit from shade cloth when grown under intense sunlight in the desert

            Many people use shade cloth which produces too much shade. Never use shade cloth meant for people when growing vegetables. Shade cloth for vegetables and herbs should not produce more than 30 or 40% shade.

            Generally speaking, grow tomatoes, peppers, eggplant, cucumbers, squash, melons and other flowering vegetables without shade. Also include onions, garlic and potatoes on that list. Use shade cloth for lettuce, spinach, collards, basil, parsley and other leafy green types.

How to Judge How Much to Water a Lawn

Q. I am responsible for maintaining a bermudagrass lawn at a church where the foot traffic is pretty high. The lawn gets 25 minutes of water three days a week, all in one watering because the lawn is very flat. But it still looks thin in spots. Can you tell me if this is the right amount of water?

A. Water is tough to measure in minutes. It is usually measured in gallons or inches of applied water. Right now, March and April, lawns need about 1/4 inch of water per day. After four days, apply 1 inch of water.
This was how we measured how evenly water was applied to turfgrass on a golf course. There are hundreds of quart plastic containers placed on this grass. You can do the same on a much smaller scale with your home lawn. But you must have several cups to be accurate.

To translate 1 inch of water to minutes put several cans out in random places, measure how much water is applied in five minutes and then in 10 minutes. Translate the lowest amount caught in cans into minutes.
Another method is to water the lawn for 15 minutes. Take a long pointy device, like a long screwdriver or piece of 3/8 inch rebar, and shove it into the lawn in five different places. Measure how deep the water has penetrated. It gets harder to push when it is dry and pushes easily when it is wet.
A long screwdriver can be substituted for that piece of rebar

Run the irrigation long enough for water to penetrate to one foot. When the water penetrates to this depth, then this is the number of minutes to run the sprinklers. These minutes aren’t changed much throughout the year.
What is changed is how OFTEN the sprinklers come on. Three times a week seems quite often for bermudagrass this time of year. It should be about every three or four days between irrigations when watering a foot deep.
Applying enough water helps fill in bare spots. But what really causes bare spots to fill in quickly is enough water PLUS a nitrogen fertilizer. Apply ammonium sulfate, 21-0-0, to the lawn every 8 weeks. Use 3 to five pounds of this fertilizer for each 1000 square feet of lawn.

Apply it with a handheld spreader over the entire lawn and water it in. Apply it more heavily in bare areas. Mow it somewhere between 1/2 and 1 inch in height. Taller grass is more wear resistant.