Tomatoes Not Setting Fruit? Shake It Up Baby!

Q. I have only gotten into gardening in the Vegas area the last 3 years and have been successfully growing tomatoes the first 2 years. But I noticed last year that I didn't get nearly the same number of tomatoes that I harvested in previous years. I have a raised bed that I started with a blend of about 4:1 of cheap compost and our desert soil.  The soil level is at least 2 1/2 feet deep.  Each year I have continued adding compost from my own yard and vegetable scraps, at least 3-4 inches of compost each year. I have periodically used a Star Nursery fertilizer as well (the one designated "for vegetables/fruits"). 

 

The watering for the tomatoes is set to a timer such that during the full heat of summer the plants get watered twice a day (about 10 minutes each time), less frequently when the temperatures are lower. There is microtubing with an adjustable drip emitter used to water the plants. The watering scheme has been unchanged the past 3 years. The plants get full sun all day.

So last year the tomato plants themselves grew well and I saw lots of flowers, but the tomatoes just never developed. This was even before the heat of summer hit. I think I harvested about a third of what I did the year before.

 

I noticed a lot less honey bees this past year in general as well. I have grown other mixed vegetables that have all done well so I am assuming the nutrient content in the soil is ok. Is there anything I could be doing differently to help get more tomatoes?  What about Mason bees? Are there flowers I can plant to attract bees for better pollination?

 

A.  Let's look at the list of things that could affect fruit production. These would include the right temperature range, wind, good soil preparation, disease, pollinators such as bees, humidity, sunlight and a few other things as well. If we have a long, cool spring we can expect to potentially have good production of fruit. If the spring is erratic and goes from cold to hot in a short period of time we can expect poor fruit production. I will tell you a little trick you can use in a bit but I want to make sure you read the rest of what I have to say. Little tricks do not work all by themselves. You have to do the whole package to be truly successful.

 

Irregular Production

 

Let me first comment on the irregular tomato production. Our desert climate is not the best climate for tomato production. We have a very short spring sometimes. The spring months as well as the corresponding fall weather, are the best times for tomato production here. When it gets too hot, tomatoes stop producing. Tomatoes are very sensitive to both hot and cold weather and have a more narrow acceptable temperature range than peppers or eggplant which are in the same family.

 

Tomatoes do not set well above 90°F and don't set it all when it stops 95°F. If bees are not working during the cooler parts of the day, you will get poor fruit set. Pollinators are very important and if they are not working when you need them or they have a very narrow window of opportunity then production will be down. Fruit set in the cool spring usually means you will get tomatoes in June and July and then they stop producing Et al. in August because it was too hot for fruit set.

Soil Improvement

Desert soils that are raw (never in production before) are ripped deep with an irrigation
trencher prior to preparation to open the soil for organic matter additions.

You have to be very careful about compost and if you use cheap compost your garden could be in trouble. When I prepare our desert soil for production I use an equal mix of good compost and native soil to begin with and I construct raised beds with outside walls. I will use compost that I know is good quality or make my own. I emphasize this... there is no good quality compost available for sale in Las Vegas. They are making some compost at the Las Vegas Springs preserve which is pretty good stuff but they are not allowed to sell it. 

 

The second year of production I add about half of the amount I used the first year. The third-year I add about the same amount as the second year. By the third year, that desert soil will become extremely productive. At that point, I only add compost to the area that I'm planting, not the entire growing area.

 I typically modify the soil to a depth of about 12 to 18 inches. However, I do rip the soil as deep as I can with an irrigation trencher when I first began constructing the raised beds.

 I strongly suggest not to use any compost without knowing what's in it. I am going to put a caveat here... the last time I looked one bagged compost that didn't seem too bad was Kellogg's. However, I believe they were using biosolids from Southern California. I believe the bag said not to use it for vegetables. I think this was available either from Lowe's or Home Depot but I have not looked for quite a while.

Good Varieties

Yellow pear tomato

You don't mention which varieties of tomatoes you are using and that can have a huge impact on production. Usually, varieties like Early Girl, Celebrity, Jet Star, Big Boy, Better Boy, and a grape tomatoes, yellow pear and cherry tomatoes will set when others do not. A couple of those plants are good indicators that least you are getting pollination.

Check your varieties and make sure they get in early. Try to keep them out of windy locations and you mention full sunlight but make sure they have a minimum of six hours.

Pollination and Pollinators

 It is not just getting flowers that are heat tolerant, you need flowers that are blooming at the right time as your tomatoes. Having bees coming to your yard during the heat will not help tomato production. They need to be blooming at the same time and this usually means spring flowering perennials and fruit trees.

I was only taking a guess about mason bees. Rather than encourage that type of be which might struggle in our climate I would encourage you to look at our native leafcutter bees which pollinate alfalfa and other legumes. You might also consider clovers and other legumes as a mix for attracting bees.

 

Finally the Hint

There are two ways of getting tomatoes to set fruit without pollinators. One is the use of applied hormones you can spray on the flowers to set fruit (parthenocarpically) without bees. These are sprays you can buy in the nursery.

The second method is a technique that green house growers use when they grow tomatoes because they dont have pollinators in their houses either. An electric toothbrush. It appears that the physical visit of a bee to the flower is not the only thing that trips the setting of fruit but the vibration caused by the wings of the bees. So when temperatures are good and you see flowers, walk over to your tomatoes and gently flick the flower clusters with your finger or use an electric toothbrush and vibrate the flower clusters for a few seconds to improve flower set.

 

Effect of High and Low Temperatures on Tomatoes and Peppers

The Effect of Extreme Temperatures on the Tomato and Pepper Crop

Author: Janice LeBoeuf - Vegetable Crop Specialist/OMAF Creation Date: 16 June 2004 Last Reviewed: 2 December 2004   Freezing and chilling injury in tomato and pepper plants Although frost occurs, by definition, when the temperature drops to 0º C at 1.5 meters above the ground, this may or may not result in freeze damage to crops. The actual temperature at which freezing will occur depends on such factors as plant species and variety, plant vigor, soil conditions, surface cover, duration of the freezing temperature, thawing conditions, cloud cover, and wind conditions.   In tomato, freezing causes a darkening of the leaf or stem tissues. Damaged areas later wilt and turn brown. It may be difficult, initially, to determine whether the growing point has been killed and damage may become more evident on the day after the frost. Peppers are more sensitive than tomatoes to freezing temperatures and may be injured or killed by a light frost.   Tomato plants are also susceptible to chilling injury at temperatures between 0 and 5º C. Chilling can cause stunted growth, wilting, surface pitting or necrosis of foliage, and increased susceptibility to disease. Low soil temperatures also stunt plant growth and prevent root development. Temperatures below 10ºC during flowering can interfere with pollination and result in catfacing of fruit.   Pepper plants experience chilling injury with prolonged temps of 0-10º C (32-50ºF). Injury may show up as puckering of the leaves and stunting of the plant.   The effect of temperature on flowering in tomatoes and peppers It is well known that flowering, pollination, and fruit set of tomatoes and peppers can be adversely affected by temperature extremes. The effect of various temperatures during flowering and fruit set of peppers and tomatoes is shown in Tables 1 and 2.   Table 1: The effect of temperature during flowering and fruit set of tomato Temperature Effect on flowering, pollination, fruit set Greater than 35° C (95° F) Reduced fruit set 18.5 – 26.5° C (65-80° F) Optimum for fruit set Less than 13° C (55° F) Misshapen or catfaced fruit may result Less than 10° C (50° F) Poor fruit set     Table 2: The effect of temperature during flowering and fruit set of pepper Temperature Effect on flowering, pollination, fruit set Greater than 32° C (90° F) day temp. Pollen sterility occurs, flowers may drop 16° C (61 ° F) Optimum for flowering and fruit set Less than 15.5° C (60° F) or greater than 24° C (75° F) night temp. Poor fruit set   What you may not think about when you see blossoms and fruit developing, is that low temperatures experienced by the plant weeks before flower buds were visible, can also affect flowering and fruit set.   A tomato plant which experiences temperatures below 15.5ºC (60ºF) for extended periods of time will begin to flower profusely. These flowers may remain open on the plant for several weeks, without fruit being formed. Larger flowers and increased branching of clusters can show up as a result of low temperatures experienced by the plant weeks before flower buds are visible. Believe it or not… Daytime temperatures of 15.5°C (60°F) with night-time temperatures of 10°C (50°F), four to five weeks before a tomato flower cluster blooms, may result in misshapen or catfaced fruit. Fact… Night temperatures of 7-10°C (45-50°F) during pepper flower development can cause the fruit to be smaller than normal, or somewhat misshapen. Chilling and freezing injury of tomato and pepper fruit The fruit of warm season crops like tomato and pepper can be injured by low temperatures. Chilling injury occurs in tomato fruit if they experience temperatures of 10ºC for longer than 14 days or temperatures of 5ºC for more than 6 to 8 days. Tomato fruit exposed to a shorter duration of low temperatures may still be prone to storage problems, even if obvious injury did not occur in the field. Pepper fruit can be injured by prolonged temperatures below 8ºC.   Frost injury is more severe than chilling injury. Tomato and pepper fruit are usually damaged between 0 and –1ºC. http://www.omafra.gov.on.ca/english/crops/facts/info_tomtemp.htm

Japanese Privet Invasive in Landscapes?

Q. I have a narrow area and the local Vegas nurseries have Japanese privet However, I have read on various blogs that birds eat the berries and they get dropped in other areas of the yard and gardens, sprouting up all over. They say it is considered an invasive species in many areas. Have you found this problem to be true and if so, is there anything that can be done so that the plant will not produce berries?

A. I have not heard this to be true in desert landscapes. We can control most growth by controlling water. Where water is applied to desert landscapes, these are the places where weeds and other unwanted plants will grow. There are many invasive species in California and Florida that are not invasive in home landscapes in our desert for this reason.

Leaves of Japanese privet under stress. Notice the curling, lack of density of the foliage and off color appearance.

            However, invasive species can be a problem in persistent or perennial waterways such as the Colorado River basin, washes like the Las Vegas Wash and irrigation ditches. So you do have to be careful with invasive species but in the middle of the desert with no such waterways it is not usually a problem.

            During the establishment period you would want to push stem growth as quickly as possible with deep irrigations and light fertilizer applications about four times a year. Pruning should be done about monthly during establishment and to keep the trellis looking neat and trim.

Kumquat Yellowing in Landscape Planting

Q. Here is one of two kumquat trees that I am trying to grow. As you can see it is not working.  I feed and water them what is the problem? Can you help?  Or should I discard?

 

A. The issues on the other picture could be related to a mineral fertilizer problem. This one could be the same but with the leaves gone it is hard to tell.

It also might be related to whatever soil amendments you put in the ground when you planted the trees. But I am pretty confident it has to do with the soil, fertilizer issue or irrigation.

It does not help much that they are surrounded by rock mulch. Let’s handle one at a time. Make sure the tree was planted in your soil at the same depth it was in the container. If there was some extreme cold weather, it might also be cold weather damage if you did not see this before it got real cold.

Irrigation. Irrigations should be generous but not frequent. A tree that small can get by with ten gallons of water at each application. If these are on drip emitters you should have enough emitters or run the minutes long enough to deliver ten gallons at this size in its life. This time of the year once a week is often enough. When you start to see new growth, bump it up to twice a week with the same volume of water each time.

Fertilizer. Go down to Plant World Nursery on Charleston (they are the only nursery I know of in town that carries this) and buy a one pound container of iron chelate fertilizer. If you ask for Doug, Brian or any of the main staff they will direct you to the right one since I recommend it a lot. They even have my name on the label now so people will believe them when they direct them to this product.

 

For each tree mix about two or three tbs in a one gallon container, stir it and distribute it around the base of the tree where the drip emitters are. Water it in with another gallon since it is sensitive to light. Get some rose fertilizer (like Miracle Gro type) and use it on the kumquat or get some fruit tree fertilizer stakes and put the fertilizer under the rocks or drive two stakes close to the emitters. I think the Miracle Gro is better. Fertilizers are salts. Keep all fertilizers at least 12 inches from the trunk when applied.

Mulch. If this were me, I would pull the rock mulch back a couple of feet and put down some good compost (don’t buy cheap stuff) and lightly dig it around the trees from the trunk to a distance of about two feet from the trunk. I would cover the area around the tree in wood mulch but not bark. Keep wood mulch six inches away from the trunk so that it does not cause the trunk to rot if it gets wet. Older trees it doesn’t matter.

Lets see if this works for you.

Suggested Landscape Practices for HOAs and Their Landscape Contractors

Q. We need expert opinion soon about what  to use as fertilizer for Greenway grass, bushes, and trees. Your advice please.

Greenway grass:

A. What is the range of N-P-K in cow manure that some landscapers use for grass?

Not sure what you mean by a "greenway" grasss.... but....It's really not fair to compare cow manure to a fertilizer because it isn't. They are using it more as a top dressing than as a fertilizer application. Manures vary in fertilizer content but are generally about 4% nitrogen and usually low in phosphorus and potassium. You should not rely on cow manure as a fertilizer. The fertilizer should be applied separately from a cow manure. An inexpensive fertilizer for starting plants and getting root growth from seeds, seedlings or newly planted trees and shrubs is 16-20-0 or DAP (18-46-0).

 

B. What inorganic fertilizer would you recommend and the amount/acre?

For turfgrass you should never apply more than 1 pound of nitrogen every 1000 ft.² or 43 pounds of nitrogen per acre. In my opinion, this is excessive and should be closer to 1/2 pound of nitrogen per thousand square feet or 22 pounds of nitrogen per acre. This would be for inexpensive, quick release agricultural nitrogen fertilizers. If you are applying more expensive horticulture fertilizers that contains slow release nitrogen, then you can bump the application rate up and apply it less often. How much to bump it up depends on what percentage of the nitrogen is slow release in the fertilizer.  

 

The fertilizer you mention (10-10-10) has 10% nitrogen. It is not a good turfgrass fertilizer but it's fine for trees and shrubs. In fact, turfgrass fertilizers are fine for trees and shrubs as well. The best turfgrass fertilizers are in the ratio of 3-1-2 or 4-1-2. An example would be 21-7-14, is a 3-1-2 ratio fertilizer. To apply 1 pound of nitrogen with your 10-10-10 fertilizer requires 10 pounds of fertilizer. Using your 10-10-10 fertilizer you would apply 435 pounds of the fertilizer to get 43.5 pounds of applied nitrogen (there is 43,560 square feet in an acre or 43.5 thousands of square feet). Like I said, I think one pound of nitrogen per thousand square feet is excessive and you will not see the difference once you exceed three quarters of a pound of nitrogen per thousand square feet or about 33 pounds of nitrogen per acre. In fact, if you apply 1 pound of nitrogen per thousand square feet it will push turfgrass growth quite rapidly and cause alot of mowing during cool weather. Do you really want that?

 

Negotiate. If you use only half the fertilizer (1/2 pound per thousand instead of one pound per thousand) then use a better fertilizer at half the rate. Cost of the fertilizer is the same or better.

C. How many times per year and which month(s)?

For tall fescue turfgrass I would apply nitrogen four times a year; Labor Day, Memorial Day, Fourth of July and Thanksgiving. During the hot summer months I would always make sure you do not exceed 1/2 pound of nitrogen per thousand square feet or you could end up with some burning if people are not careful. If you are using mulching mowers you can skip the Fourth of July application. If you are using mulching mowers you should never exceed 1/2 pound of nitrogen per thousand square feet in a single application.

 

D. Should a roller of punchers be used immediately after fertilizing?

I assume you mean aeration. Core aeration can be done any time of the year and does not really relate to a fertilizer application. The only exception might be when you are applying a high phosphorus fertilizer

 

E. Should organic fertilizer (cow manure) even be used to fertilize grass?

Cow manure is not a fertilizer. Fertilizers will have the amount of N-P-K listed on the bad as required by state law.

Bushes:

A. What inorganic fertilizer (N-P-K) would you recommend and the amount/bush?

Turfgrass fertilizers in the ratio I mention above are good for most trees and shrubs. You would apply this fertilizer in the very early spring or late winter. The amount to apply is similar to the amount you would apply to turfgrass but is calculated under the canopy area of trees and shrubs. A small tree that occupies 100 ft.² of canopy space would get 1/10 of a pound of nitrogen. A tree that had 1000 ft.² under its canopy would get 1 pound of nitrogen. The driver of growth for trees, shrubs and turfgrass is nitrogen.

B. Applied dry, or liquid, in the gravel around bushes?

Dry fertilizers are applied near the irrigation source. If trees and shrubs are irrigated by sprinklers, then you distribute the fertilizer so that the sprinklers pushed the water into the rootzone. If these are drip irrigated, it is applied in the soil next to the drip emitters and the water carries a fertilizer into the rootzone. If you are applying a liquid fertilizer to the foliage obviously you have to wait for the foliage to appear in the spring to make an application. If this is a liquid fertilizer applied to the soil and make the application close to the drip emitters within a few inches under the mulch or under the turfgrass. Never apply a fertilizer to trees and shrubs deeper than about six or 8 inches. Fertilizer spikes are convenient but expensive. Liquid applications to the foliage last about 4 to 8 weeks. Dry fertilizers applied to the soil last longer if that's important.

C. How many times per year and which month(s)?

Most trees and shrubs will require a single application of a fertilizer to the soil during the months of December through about March. In a pinch you could go as late as April. Some plants tend to get yellow due to iron chlorosis or a lack of available iron. Usually a single application of an iron fertilizer that contains the chelate EDDHA is enough to keep them from yellowing. If these plants have been yellowing and are in poor condition for several years, this will probably not work in correcting a severe problem. The iron fertilizer should be applied at the same time as the other fertilizers, in early spring or late winter.

Tall trees:

A. What inorganic fertilizer (N-P-K) would you recommend and the amount/tree?

You can use a good turfgrass fertilizer for most tall trees and shrubs. To be effective this fertilizer should be applied close to a source of water for the trees so that it is washed into the rootzone. It should not be applied deeper than 6 to 8 inches in the soil. Other fertilizers in ratios like 1-1-1 are also okay but the high phosphorus of the middle number is really not needed unless these are flowering trees.

B. Applied dry, or liquid, near the end of branches around trees?

Fertilizer is fertilizer whether it is applied dry or liquid. The amount of nitrogen applied per tree is what is critical. Liquid fertilizers applied to the foliage or short lived. Dry or liquid fertilizers applied to the soil last longer.

C. How many times per year and which month(s)?

Once per year is enough in the very early spring just before new growth or not long after it begins.

Watering, Mulching and Fertilizing Desert Landscapes

Q.  I have three questions. How often should I water? Do I need to put mulch around the plants and then cover them with rocks or keep the mulch exposed? Do I need to fertilize plants with a desert-type fertilizer or can I use the same stuff I use on my regular plants and how often?

 

A. How often to water. Winter; once every ten to 14 days. Spring until May 1^st; once a week. May 1 through the summer; twice a week. September 15 to December 1; once a week. These are approximate dates. Adjust with the weather.

Purple leaf plum mulched with wood mulch in a desert landscape of rock mulch. Wood mulch
adds organic matter back to the soil as it decomposes and is needed in soils around
some plants like purple leaf plum.

            Wood mulch is a substitute for rock mulch. Rock mulch will cause problems with some plants. If you want all rock mulch, then make sure the plants used can tolerate rock mulch. Wood mulch is used without rock mulch and should be three to four inches deep around plants.

Ammonium sulfate is a high nitrogen fertilizer containing 21% nitrogen (21-0-0)

            Fertilizers are the same for all plants. If you want growth, use high nitrogen fertilizers. If you want flowers and root growth, use a fertilizer with high phosphorus. Good fertilizers are more expensive than ordinary fertilizers and are frequently worth the money.

Sprint 138 iron contains iron in the chelate EDDHA
form which works very well in our highly alkaline soils

            If you can’t afford good fertilizers then make sure you use a good fertilizer at least once a year and use less expensive fertilizers the remainder. Use them when you can and the first application of the season is usually the best time to use them.

            One application per year is enough for most plants except lawns and plants that you appreciate for their flowers. In those cases four applications are best; Labor Day, Fourth of July, Memorial Day and Thanksgiving. If the plants are tender to winter cold, skip the last two fertilizers of the season.

            Plants that turn yellow are usually iron deficient and will need a GOOD iron fertilizer. Not all iron fertilizers work in our soils.

 

 

Eight Fruit Trees in a 10ft x 10 ft Space

Q. I have an easement in the backyard where I cannot plant trees. I have decided to plant as much as possible in the space I have left which is about an area 10x10. I would like to plant fruit trees in a high density there and keep the trees small for easier picking.

 

Multiple trees in a single hole about 18 inches apart. This provides a sequential harvest of
fruit from different varieties at different times of the year.

A. I would really caution you on a high density mini orchard unless you are truly committed to it. It will take more time and effort and require gaining some extra knowledge if you commit to any intensive gardening technique. If you are willing to spend a bit more time and effort (not a lot but the extra time is critical) then give it a shot.

            A 10x10 area is quite limiting but you could still probably get about 8 trees in there with a combination of multiple trees in a single hole and trellising them. You might consider planting fruit trees in a hedge with no space between the trees and letting them grow together.

Apples trellised along a fence on trellis wires about one foot from the fence and shade cloth protecting it from direct
sunlight from the south side of the fence.

            I personally wouldn’t plant any trees closer than about six to eight feet apart for a hedge or trellis. If you use apples or pears try to make sure they are on dwarfing rootstocks such as M111 for apples and OHxF333 for European pears.

            There really is no true dwarfing rootstocks for the stone fruits like peach, apricot or nectarine but the Citation rootstock may give you a little. These stone fruits are normally planted full size and kept small through aggressive winter and summer pruning.

            Another possibility instead of a hedgerow is trellising and I prefer it over hedging for small spacing. Trellising costs more because you have to construct the trellis but gives you more control of the plant and helps you keep it smaller.

What to Use on Vegetable Seedlings Decimated by Insects

Q. The day after I planted seedlings in my 4x8 raised bed I noticed they were decimated by some kind of insect. When I was amending the soil I noticed some small worm-like critters in the soil. I sprayed Bt but it evidently didn't do anything to help the situation. I was told to use a powder called "milky spore disease" to kill any grubs or grub-like insects in the soil. Have you ever heard of this product? They said it works and I only have to apply it one time. Can you advise me on this product and where I might find it or some other solution? 

Decimated pepper

 

A. The milky spore product only works on Japanese beetle and a few closely related insects which we do not have in southern Nevada. It is a bacterium and works rather slowly, if it will work at all, on pests we have in southern Nevada.

            Bt works differently. It works on those insects that mature or pupate into either moths or butterflies. So if the immature insect turns into a beetle for instance it will not work. So without knowing which insect is doing damage it is hard to know what will work.

Cutworm larva

 

            The other alternative is to use a conventional pesticide approved for use on vegetables and has insect grubs or larvae on the label. These insecticides leave a poisonous residue for longer-lasting insect control.

            This time of year Bt is a good product to use because it will control many of the insects causing damage right now. Look for products with a label that says Dipel or Thuricide. Forget the milky spore bacterium control in your case.

            I am sending you a picture of what the cutworm larva looks like and its adult form, a moth. I will also post it on my blog. Bt can be sprayed on the soil and left undisturbed (no hoeing or irrigating after the application) for a few days but you have to repeat your applications to get any long term control.

Corn earworm moth adult
http://ipm.illinois.edu/ifvn/volume15/frveg1506.html

            This is the time of year that moths are flying, mating, laying eggs and larvae are out looking for food. Usual cutworm damage is at the soil surface, not on the leaves.

Planting Two Cherries in a Single Hole to Save Space and Pollination

Q. I have two cherry trees and one needs to pollinate the other. Can I plant both trees in the same hole so save space?  The trees grow to 20 feet and I will keep them pruned to a smaller size.

Sweet cherries produced at the Orchard. Production is erratic in the Las Vegas Valley.

 

A. Yes, you can. Plant them about 18 inches apart, one on the east side and one on the west side of the hole. Try to pick varieties that are similar in vigor (how strong they grow) and on the same variety of rootstock.

Multiple apple trees planted in a single hole at Dave Wilson Nursery

            I will warn you that sweet cherries are squirrely in our hot desert environment. They produce cherries in some microenvironments and not in others. They usually seem to do better in backyards that are somewhat protected (no strong winds) and have a more humid environment during pollination.

            If you plant these two trees together, keep them occupying only half of the canopy. Do not let them compete with each other but keep them occupy their own, separate spaces. This means there will be a clear physical separation between the plants in their own half circle of canopy space. Also, do not let one get bigger than the other. Keep them pruned to a similar size.

            These cherries must also bloom at the same time if they are to pollinate one another. Check your pollination charts to make sure they are compatible.

Some Fertilizers Will Cause Staining

Q. I have a question regarding fertilizing.  My husband used a fertilizer that stained our pavers and the bottom of our pool in spots. Do you know of a solution to remove those stains?

A. The fertilizer most likely had iron sulfate in it. The spots would be dark reddish brown or brown. Muriatic acid would remove it. Be careful using it.

Iron spray staining grape berries. Be careful spraying iron on fruit vines and trees that have fruit on them if you
care about appearances.

            If it is in the bottom of the pool and water is in the pool there is not much you can do about that unless the pool was empty. The bag should have warned you, hopefully, to use a drop spreader if it was for a lawn.

Plants Need to be Placed in Outside Environments with Care

Q. Last Christmas a friend bought for me a tiny pine tree about 6" tall. It is now 2' tall and I need to transplant it. When is the best time of year to do this?

 

A. It is April and getting too late now. I would wait and plant it some time between mid-September and mid-October as temperatures are cooling. However, if you run the risk of losing it, plant it now.

            You don’t mention how you were growing it. If you were growing it inside, not outside, you will need to gradually bring it into the outside environment or it could go into shock. This is called plant acclimatization and requires about three weeks inside a garage or outside shade shelter and then planting it.

Black Spots on Watermelon Leaves Could Be Several Different Insects

Q. I have attempted to grow watermelons for the first time last summer and everything was looking good until it got hot. These tiny black specks appeared on the back of some of the leaves.  I was told it was aphids but they weren’t sure.  I hope you can see them clearly from the picture I've attached. Should I use insecticidal soap as recommended or something else? 

A. I tried to magnify the picture so I could see the black spots better. I was curious if these were in fact from insects or not. I could not see it clearly but whatever it was, it appeared that it was no longer a problem and the leaves seemed nice and healthy.

            Aphids are cool weather insects and so when the heat hit they should have disappeared. The big insect problems for you on watermelon would be aphids earlier in the season during cool weather, squash bugs shortly after planting and whiteflies (during the heat).

            Yellow sticky traps can provide a method to determine if whiteflies are a problem or not. I will post a short video on my blog on how to make these rather than buy them. They are handy to place in the garden for insect monitoring.

            Soap and water sprays are good but must be done about every three or four days and the underside of the leaves must be sprayed as well. Squash bugs are nasty and can be vacuumed or hand-picked or delay planting by seed until after June 1. If you are hand picking or vacuuming squash bugs then be diligent for about three or four weeks and keeping the plants cleaned off every couple of days by hand until mid-June to avoid most of the problems with this insect.

 

 

 

Thanks to Garry Pearson, Lead Greenhouse Managerat UC Davis CAES,
                Department of Vegetable Crops, during his presentations on greenhouses in Afghanistan.

Rolly pollies, Pillbugs, Sowbugs Potential Big Problem with Strawberries

Q. We are growing the most beautiful strawberries, the problem is that the rollie pollies are eating them before we get a chance to pick them. We have applied dicotomes earth but it has barely slowed them down. What else can we try.

A. I feel your pain. This is a tough problem. The roly pollies, sometimes we call them pillbugs or sowbugs, can be a very common pest of soft fruits and vegetables. These crustaceans (they are not insects but are more closely classified closer to lobsters) usually feed and abound in rotting or decaying plant matter which we usually call organic matter. Stuff from plants which collects on the surface of the soil where it is wet will begin to decay.

Technical information on sowbugs in the Southwest

This decaying organic matter is a usual source of food for these common pests. They can be good guys since they feed on decaying plant matter and convert it to something that can be recycled and benefit the plants. Once they get established they can get a little overzealous and start to consume other plants or plant parts which are soft and succulent.

If strawberries come in contact with the soil surface where these creatures are feeding they don't distinguish between soft decaying organic matter or soft succulent strawberries. So the control measures usually focus on keeping the strawberries from touching surface of the soil or decaying plant matter and picking when they are ripe and not letting them get soft.

This would require that the fruit be kept elevated off of the soil surface. I wish that I had a good answer for you on how to do this. I don't. Other people may recommend using diatomaceous earth but I am not convinced that this will work with your roly pollies. It is better suited for very soft bodied pests which crawl along the surface of the soil. These very sharp diatoms, at least this is the thought process, cuts or lacerates the pest and they succumb to the lacerations.

You can also use traps in the beds and remove them from the traps as they accumulate. This does not exterminate them but it does help to reduce their numbers and hopefully the damage from their numbers. These traps can be something that lies on top of the soil surface such as strips of carpet, cardboard or wood.

Removing these pests from these traps is simple. Since they like their social gatherings in darkness they tend to gather in these shady spots. Remove the shade and remove them by hand. You can also put out semi rotten tomatoes or other vegetables which will act like magnets and attract these varmints.  Then you can scoop up these rotting fruits and vegetables along with the pillbugs and dispose of them.  That won't get rid of them but it will take the numbers down. 

Sluggo Plus contains iron phosphide and spinosad and is labeled for sowbugs, pillbugs, and cutworms and is registered as an organic pest control product for gardens and available at Home Depot. The original sluggo is for controlling slugs and snails.

Harvest Garlic Different Timing in Desert Environment

Q. When do I know to harvest garlic, Walla Walla sweet onions, green onions and garlic?
 

A. Garlic should be harvested in our hot, dry climate when the tops have browned down by about 1/3. In other locations where it is not so hot they usually will harvest when the ½ of the tops have turned brown or when they fall over. We cannot wait that long in the hot desert.

A common mistake is to wait too long to harvest garlic in the desert. This is elephant garlic in the foreground, not one
of my favorites (but it is big and impresses nongardeners), but this is close to ready for harvesting. You can note the change in color of the foliage and dieback. Garlic that was in front of it was already harvested as it was an earlier garlic variety. The irrigation is drip tape with emitters spaced every four inches with the tape spaced one foot apart.

            There is a thin, tight “wrapping” around the cloves when you harvest garlic correctly. For appearance purposes and storage it is important that this wrap be continuous and tight around the cloves. If you wait too long before the final harvest, this covering starts to rot away, leaving the cloves exposed.

            Sweet onions like Walla Walla are harvested when the tops have fallen over. Do not step on the necks to ready them for harvesting unless you plan to eat them fresh and not planning them for storage.

This is Contessa sweet onion. The top of the plant in the center has fallen over signalling the bulb is ready to harvest.
The others are close but not ready yet. When the bulb is ready for harvest the neck will collapse near the bulb and
the weight from the top will cause it to fall. This closes off the bulb and will not allow diseases to enter the interior of
the bulb and helps for long term storage. The other thing to do for storage is cure the harvested bulbs. Leave the collapsed
tops on the plants and put them off the ground and in the shade to cure for a few days.
After the tops dry down, cut them off leaving an inch of the dried top remaining.

            The drying down of the tops and tops falling over is a natural “sealing” process of the bulb. Stepping on the tops can allow disease organisms to enter the bulb because the neck has not dried down properly and may prevent any storage of the bulb.

            Scallions are really nothing more than green or immature onions that have not yet begun to bulb, just barely started bulbing or cannot bulb. In the case of the Welsh onion, which is traditionally grown as a scallion, it cannot bulb up. White Lisbon onion is also grown as a scallion but this onion will bulb up if left in the ground too long. Harvest it before it starts to bulb.

 

Should I Add Vinegar or Citric Acid to My Water?

Q. Have you ever heard of adding vinegar or citric acid when fertilizing indoor plants in our area? We collect the rain water and use it for our indoor plants.



Diagrammatic representation of pH scale
as found at
https://en.wikipedia.org/wiki/PH
Numbers are logarithmic so each unit
change represents a factor of 10 (e.g.
6 to 7 = 10; 6 to 8 = 100; 6 to 9 = 1000)
similar to the same scale used for
measuring earthquake intensity. 

A. Quite a few people do this to lower our water’s alkalinity but the effect is short-lived. Our tap water carries a lot of calcium and magnesium salts. The acids are neutralized by these and other salts.

You could determine how much acid to add fairly simply by using some pH litmus paper, like they use for swimming pools. You would add small amounts of acid until you see a shift in the pH of your water into the acid range.

The perfect pH is 6.8 which is the pH of the plant sap of many plants. Let this water/acid mixture sit for 30 minutes or so and check it again. Keep adding small amounts until you see the pH stay steady in that 6.8 pH range then you can use it for watering.

As long as you stay with the same water source, you would add the same amount of acid each time to arrive at basically the same pH. If you change water sources, then you would have to do it all over again.

However, as soon as you pour this mixture on our soils it will shoot back up again to the alkaline range because of the massive amounts of alkaline types of minerals that reside in our soils. In short, I wouldn’t waste my time doing this unless it helps you sleep better at night.

Just adding a big scoop of good compost to your water instead of vinegar will probably do more good. Let the compost steep for a few hours through a porous sock like old pantyhose. Use it immediately for watering. Put the spent compost around some outdoor plants or in your garden. Good compost is likely to still have gnats so don’t apply the spent compost to the soils of indoor plants.

Eliminating Lawn Can Lead to Problems for Established Trees

Q. I have a beautiful Loquat tree where the leaves have suddenly started to turn yellow and fell off.   Most of the fruit has also fallen off. The tree was located in the middle of grass. I had the landscape converted to desert rock in September. At the same time watering schedule was changed. I suspect it is being under watered. But before I increase it I want to ask if the cold winter we had here could have caused this yellowing.

A. Thanks for the pictures. It is probably not the cold. In a lawn situation the roots go everywhere and anywhere and usually spread to about 1½ to 2 times its height away from the trunk.

Loquat with rock mulch applied after growing in a lawn for a few years. In many cases the drip emitters do not
apply the water in the same places as lawn irrigation and the plant roots of established trees and shrubs die back.
This results in leaf drop and eventual die back of the limbs of established trees and shrubs.

            In drip irrigation we usually place the emitters a foot or so from the trunk. This bypasses about 80% of the root system it created when growing under a lawn.

            So, yes, it probably is drought but perhaps not because you are not delivering enough water. It is more likely that most of the tree roots are not receiving water. You can place emitters over a greater area under the canopy of the tree. But I would also reduce the size of the root system.

            Try root pruning the tree to reduce the size of the root system so it is closer to the emitters. Keep tree roots contained in the area directly under the canopy. Wet the soil thoroughly under the canopy and vertically slice the roots in a circle all around the tree at the edge of the canopy. This can be done with a sharpened spade.

Leaf drop of established loquat due to replacement of lawn with rock mulch and drip irrigation.

            At the same time, thin the canopy by removing wood. This reduces the tree’s demand for water. A tree that size will probably require 20 to 30 gallons each time you water. With the lawn now gone, the tree will actually use more water since the cooling capacity of the lawn has been removed.

How to Keep Harvested Garlic a Long Time

Q. I know garlic will keep 4 to 6 months in cooler climates. Since I don’t have a root cellar, what are my options for storing garlic?

Tom at the Orchard tying garlic in onion netting for storage and sale. You can use pantyhose
and cut the bulbs loose from the netting when one is needed.

A. After harvesting garlic from the field or garden, we will tie the garlic together in bunches and let them hang outside to dry in the shade for a week or two. This helps “cure” the garlic bulb and readies it for storage. Some people want fresh garlic and in this case it is not “cured” but should be consumed soon.

            Ideal storage environment is cool and dry, away from other food items that might absorb the flavor of garlic. Garlic under home conditions will store for about 2 to 3 months in a kitchen environment.

Garlic hanging under shade cloth, tied in bunches, for curing for a couple of weeks.

            An option is to dry the garlic and it will store indefinitely. If you still have garlic left after two to three months of storage, you can peel it, slice it thin by hand or in a food processor, dry it outside in the shade and low humidity of our Las Vegas environment. Always dry food in the shade, not in direct sunlight here. Keep drying temperatures below 140F if using a commercial drier or oven.

You Missed the Planting Dates for Onions if its April

Q. I need to get the bulbs of onions (yellow and red) and garlic planted now that it is April.  I was thinking of planting them in the semi shade of my Texas ranger shrub. The ranger grows along a wall that faces West so this area doesn’t get full sun until 1-ish.

A. You have missed the planting season for onion transplants. This would have been in mid-March in our climate.



Onion transplant on either side of drip tape

            Onions can be started from seed but onion seed is planted normally in late September to mid-October. Onion seed will germinate in the fall and overwinter with periodic waterings. I normally plant onion seed close together by broadcasting the seed in a small area and putting about ¼ inch of topdressing and mulch over the top.



            In mid-March I “lift” the young onion plants (transplants) with a spading fork for planting in rows that are about 12 inches apart and four inches between transplants. Onions are planted in full sun. They will not do well when planted in competition with other landscape plants like your Texas ranger.

            Garlic “seed” are not seed at all but the cloves inside the garlic bulb. These “seed” are separated from the bulb and left in the shade to heal over for a few days. They are then planted in a permanent location in the fall, the same time as onion seed. Garlic is harvested from May through June depending on the variety.

            Get ready to start onion and garlic in the fall and plant transplants of onions in mid Spring.

I would not mix onions with your Texas ranger. The competition from the Texas ranger will not be good for the onion. They will compete with each other for space, nutrients and water. This will result in not developing good size for the onion (unless you don't care about size). If you do want to add onions to your landscape I would do them in planting blocks of their own away from shrubs or trees. Just make sure you give them appropriate soil preparation and enough emitters to get good water distribution for their growth.