Q. All the YouTube videos say when tomatoes form and we get a rain, they tend to start splitting. We are on a drip system and have steady water all through the growing  season. Any help you can give would be appreciated. Tomato fruit splitting A. To prevent cracking or splitting of the largest fruit, the best thing to do is to turn on the drip system just before it starts to rain. I know this sounds counterintuitive but here is the scientific explanation.  Science Behind It Rainwater enters the fruit and causes it to split because of differences in salt concentrations inside the fruit, which include the sugars and starches, and the rainwater. Turning on the drip system when it begins raining puts water into the fruit, diluting the salt concentrations, and helps reduce cracking or splitting of the fruit.             The second thing to do is harvest large fruit close to maturity before it rains and let it ripen inside the house. The fruits most affected by rain are the larger ones and usually red ones. These two things will reduce fruit splitting but not eliminate it unless you are just plain lucky. 

Q. Is it possible to get more tomatoes on my plants in the fall? What needs to be done to produce them? Tomato was pruned back in late Summer to stimulate new growth and new flowering and fruit set when the temperature cools below 95F. A. Yes, you can get a second crop from the existing plants by cutting existing plants back or start new plants directly in the garden from seed. Here’s how to do it. Plant Seed             If you plant seed directly in the garden to replace existing plants do it now. Plant an early variety from seed such as the ‘Early Girl’. Rake the surface of the soil to create some ridges and put a group of 3 to 4 seeds, 6 inches from the base of some existing plants you plan to remove. This is for shade. You only want one plant to remain from this group when starting them from seed.             Cover each group of seed with a quarter inch layer of sand mixed with compost. Water the seeded areas by hand three or four times during the day while it’s hot. Reduce watering to once a day when the seedlings emerge. Remove all other seedlings in a group except the most vigorous. Lightly fertilize the remaining plant when it’s 2 inches tall. The Early Girl tomato plant should start flowering in about 50 –60 days. Pruning Back             When cutting back existing tomatoes make sure they are healthy. Cut them back sometime around early to mid-September when it’s no longer unbearably hot. Remove the top one third of the plant by cutting just above aside shoot. Spray the plants with a liquid fertilizer early in the morning. They should start producing flowers and fruit in about 3 to 4 weeks.

Q. How do you easily separate earthworms from the castings. I raise them in a big pot. A. There are three basic ways of separating earthworms; by pulling them to a new food source, using light to “herd” them, or screening the soil. Let’s get some “vermiculture” terminology out of the way first. Red wigglers or other worms used in vermiculture can be separated from the vermicast physically by screening, food or herding with light.             Vermiculture is the raising of surface-dwelling earthworms for the purpose of vermicomposting. Vermicomposting is using surface-dwelling worms to make compost rather than a traditional composting method. The end-product is not called “compost” but rather “vermicast”. Vermicast is basically “worm poop”. The proper way to talk about it might be, “I am making vermicast through vermiculture rather than composting.” Screening Method             All three of these methods require screening of the vermicast end product to remove worms and egg cases called “cocoons”. It’s faster to screen for renegade worms and cocoons than to rely on screening alone for separation but it can be done that way. Food Method             Putting “fresh worm food” in a pile for the worms to eat separates them. This method attracts them to one location where they can be transferred to a new location and the vermicast screened and collected. When they congregate around this new food source, remove them from the vermicast, transfer them, and begin the process all over again. Herding Method             The “herding” method uses light which they hate. Vermicast is dumped into a pile, the worms migrate away from the light as you screen the top of the vermicast. Always leave a thick bottom layer for worm migration. When finished, use the bottom layer full of worms as the “inoculation” for creating more vermicast.

Desert horticulture is a unique form of horticulture, very different from traditional horticulture in many ways. People who have gardened for many years in wet climates find themselves disoriented in desert climates. However, the laws of plant science have not changed, only how these laws are applied to the growing of plants. Rainfall Officially deserts should receive less than is of rainfall (4 cm) each year to be classified as a desert. However in a looser definition it has to do more with how much water plants could lose when irrigated. This involves both evaporation of water from nonliving surfaces combined with the transpiration of water lost from plants. Irrigation is artificial rainfall. Desert plants respond to very quickly to rainfall and many times have evolved ways that keep them alive when rainfall is limited. When these rains come again, they spring to life. Drip irrigation is important in desert horticulture because it delivers this precious resource inexact amounts to plants and has the potential for conserving the most water of any form of irrigation. When water is applied to native desert soils that have never been irrigated, rapid chemical and physical changes occur in many forms. Irrigated desert soils can damage plants, damage structures and cause many problems for the desert horticulturist. Plants Desert plants are uniquely tied to their climate. They respond to changes in their harsh climate that might threaten their lives. Soils Desert soils are unique because they develop under low rainfall conditions. There are oftentimes high in pH or alkaline in nature, salty, have very low organic content and contain a unique invertebrate and microbial community ready to flourish when water and organics are added. Desert soils can be chemically and physically unstable when first irrigated because they have remained dry for so long. They are frequently rich in nutrients that have remained stable in this low rainfall environment for hundreds of years. Some of these high concentrations of minerals, like boron, sodium and chlorides can be toxic to plants. Others like sulfates can damage structures and other manmade contraptions in contact with this soil. Sunlight Sunlight intensity, the brightness of sunlight, in the desert can be quite strong. By some measurements, substantially stronger than sunlight in humid climates. Shade cloth that provides about 30% shade benefits many vegetables grown in direct sunlight. Temperature High temperatures are a hallmark of desert climates. It’s one of the first things we think about when visiting the desert. The range in temperatures can be extreme in the desert, sometimes varying as much as nearly 75 ° F or more in a single day. Seasonally, temperatures might range as much as 100° F. Shade is very important in desert climates. For humans and other animals, 100% shade can be extremely inviting on a hot summer day. But for plants, that rely on sunlight for a constant supply of energy, this is excessive. As an average, 30% shade is ideal for many flowering and fruiting plants. Plants that produce insignificant flowers and fruit may perform well under a higher percentage of shade. Low Humidity Low humidity does not sound like a big deal when growing plants. In fact, it is one of the reasons why plants grown in the desert have fewer disease problems than the same plants grown in a humid climate. Salinity Salts are common in desert soils and in some irrigation water. Wind Strong and erratic winds are a common feature of desert climates. Microbursts of winds approaching tornado speeds can be a common occurrence during cool spring weather hot summers.

Q. I spent days dealing with the green residue from a summer of thousands of midge infestation. We live near a pond, not sure if that is the reason for our problem. Wondering if they are in the plants in our yard and if we could spray something to stop them before the warm weather comes back in the spring. There are still a few holdouts even now. A. I am curious about what you are calling “midges”. I know the word, but this term does not tell me which insect it might be. Without knowing exactly what this critter is makes it tough to understand what the effective control might be. Their exact Latin name is not necessary, but I think you need another set of eyes to identify them more accurately. There are some biological and organic controls that might work if its more accurately identified and I would hate to recommend a chemical spray if you don’t need it. Proper Identification Leads to Using the Right Control Measure             Catch some of these critters and put them in a jar with alcohol (clear vinegar will work in a pinch) and take them to the State Department of Agriculture in Las Vegas on East St. Louis. See if someone there has a more precise name for them. Phone ahead of time at (702) 668-4590 and see if there is someone in the office who might give you some ideas. While you’re at it, ask them what they would use for control. They have access to the state Entomologist in Sparks, Nevada, but it might take awhile to get it identified.              Another place to take it is the Master Gardener help desk. Call 702-257-5555 and take them a sample in a glass jar and see if they can help get the right name for it and possible controls. Doesn’t need to be the exact insect ID name but close enough so we are on the same page.             Once you find out what it is and get some ideas about how to control them, contact me again and let’s go from there.

Q. My new trees (apple, plum, peach) were planted a month ago and appear healthy. I watched several YouTube videos and am nervously ready to trim these trees. Being nearly May and heat coming on, should I wait until next year or just do it now?   Delay major pruning of any tree to the winter months. It is safer for the tree, it reduces sun damage, the form of the tree (if its deciduous) is easier to see. A. I usually prune right after planting in January or February. My rule of thumb is 90% of my pruning is directed towards improving the structure of the tree and only 10% is concerned with production; the second year focuses 50% of my pruning efforts on the structure and 50 % toward  production and by the third year only about 10% focuses on the trees structure and 90%  on production. Tree Architecture is Easier to See             Each year the trees structure is evaluated but most pruning focuses on entering production no later than the third year of growth in the ground. Some older varieties may take longer than that. Do I keep a few fruit to savor earlier than this? Of course! But only a few. I’m encouraging as much good growth as possible and getting rid of unnecessary growth as early as possible. Always Carry Your Hand Shears             I always carry a sanitized and sharpened hand pruner on my walks through the Orchard any time of year. I never know when I’ll see something that needs my attention. Better to remove small amounts of unnecessary growth early in the season than wait until December or January and remove a large limb. This is a locust tree that had too much pruning. The bark of this tree burned in the strong Mojave Desert sunlight. Be careful when you remove limbs from trees growing in the desert. Removing too much or removing at the wrong time of year can result is sunburn of the trunk and limbs of trees.             Light pruning can be done now or anytime but in the Mojave Desert be careful of removing too much which can contribute to sunburn of the limbs and fruit. Since we are in late spring, wait until December or January to do any major pruning. You can  lightly prune fruit trees all year long if they need it but don’t remove too much. Summer pruning is done about now to older trees to keep them smaller but that’s for the experienced fruit tree grower.

Q. My newly planted fruit trees you told me to, “Check for root problems by bending the tree over and see if it wiggles in the soil.”  How hard should I push?  When I push my tree, it does move in the soil, but I wouldn’t say it “wiggles”. A. The tree should be solid in the soil, and not “wiggle”, after it is planted. Staking helps but doesn’t replace proper planting. Moving the top of the tree back and forth (like a strong wind is blowing) says a lot about potential problems during the first year and future establishment. “Wiggle” the Tree After Planting             After the soil has settled from planting and watering, move the top of the tree back and forth (wiggle it), before staking, to see if it was planted too deep . Once staked, a tree is tough to “wiggle” and for you to make that determination.             If your tree never leafed out or, if it did, the leaves promptly died, the tree was most likely planted too deep. A tree should not be planted more than ½ inch below the surrounding soil. After planting this tree, it was “wiggled” or the stem moved back and forth before staking. Wiggling the tree shows where the roots are planted and how deep the tree is in the soil. If the tree is more than 1/2 inch too deep then it must be removed from the hole and replanted. Planting a fruit tree too deep can result in the tree dying from trunk diseases. Plant the Same Depth Where it was Growing in the Container             Plant the tree at the same depth it grew in the container or (if bare root) the same depth it grew in the field when harvested. When no soil is attached to the roots (bare root) look for a color change in the trunk separating below ground and above ground parts. A metal stake (or stakes), driven deep enough so it is in solid ground, and tied to the tree with stretchable, plastic tape a few times keeps the trunk and roots from moving. All plants should be planted the same depth they were in the container. If they are “bare root” trees, there is a change in color on the trunk that will show you the depth it was growing in the field. It should be planted at the same depth. Not deeper or soil piled against the trunk. That will kill the tree! Mistakes Made at Planting Time             Mistakes I see frequently at planting time are planting trees too deep, planting too shallow (so roots are exposed after watering), not staking, and digging the planting hole too deep when there is no good reason for doing that. Some people don’t stake trees because they think its not necessary. Well, staking shouldn’t be necessary when the tree is small and there is no wind. Bareroot trees have no soil attached to them. Container plants are easier to plant because you can see exactly how deep to plant. If you are not sure, look at the roots. The roots are growing immediately below the soil and grow deeper. Barely cover the roots when finished planting.             When trees are planted correctly, and before they are staked, they should feel like they are solid in the ground when moved back and forth. Then stake them so the lower trunk and roots don’t move later on. Wiggle, Wiggle, Wiggle             “Wiggling” the tree from side to side (when it’s not yet staked) visually exposes trees that are planted too deep. Look down. The tree trunk makes a larger hole in the soil when its moved back and forth. That’s a sign the tree just may have been planted too deep.             You know that old saying, “Dig a $50 hole for a $5 tree,” is still a valuable adage even if the money is wrong. 

Q. I have a well-established, prolific peach tree. About this time every year it loses some of its immature fruit and I know that is normal. However, this year it’s losing an abundance of fruit. I’m literally picking up 50-100 peaches a day. I have checked the irrigation and it seem to be fine. (drippers, 15 min per day, twice a day.) A. I don’t like that you are applying water every day, twice a day in fact! Is there any way that can be changed to less often? That irrigation frequency sounds like watering a lawn or vegetable garden when it’s hot and windy out! I don’t know about the amount you are applying, but you are applying water way too often. Peach trees will probably set less than 5% of the fruit that results from flowers. If you don’t remove the fruit, the tree will do it for you. The end result is, what are the size of the peaches when you harvested? And how did they taste. Far more important to consider than fruit drop. Also, letting the soil become too wet or too dry will encourage fruit drop and loss. Change your irrigation practices! What’s Happening?  Fruit trees should have water applied to them twice a week in May when growing alone in the desert and in most soils. The applied water should wet the roots to a depth of about 18 inches each time its watered.   Sometimes people will ask me…how much mulch or woodchips should I have around my trees? Its like asking how far should you keep weeds from growing near a plant. The futher, the better for weeds. For mulch, at least to the dripline of the tree. But further is better! For fruit trees growing in the desert, I like to see a layer of woodchips on the soil surface 3 to 4 inches deep. These woodchips provide a layer that protects the roots from getting too hot, conserves water, prevents most weeds from growing and helps keep the soil dark and rich. Only a few months after applying wood chip mulch to the soil surface in the irrigated area you will see the color of the soil become darker. This is from the decomposing wood chips covering the soil. It decomposes and adds organic matter to the soil and you see worms flourish in those areas.             I imagine the tree roots  are only growing about 2 inches deep if watering is this often. They should be growing 18 inches deep to anchor the tree in the soil. Roots like this are cycling back and forth between too dry, too hot or too wet. Roots can’t grow deeper because they are drowning (if you are watering a lot) or getting too hot and dry (if you aren’t watering enough). I need to know how many gallons you are applying, not the minutes, and where it’s being applied. What to do?  Cover all the soil under the tree’s canopy with 3 to 4 inches of woodchips. Apply water to the soil 12 inches from the tree trunk all the way to the edge of the canopy. This can be done by constructing a donut around the tree trunk 6 to 8 feet in diameter. Irrigation donuts or moats around trees when they are small, are smaller. As the tree increases in size, the donut increases in size as well.             Fill the inside of this donut with a 1-inch layer of compost with woodchips on top. Fill the inside of this donut with water once a day. At the end of August, begin watering every other day. At the end of September water every third day. By December you should be watering once a week.

Q. We want to plant some tropical trees and shrubs in our garden. I am wondering if I should turn the soil in the whole flower beds over and amend the soil OR I should only dig holes where the plants go and fill the holes with amended soil. A. A lot depends on the soil that you have, but I  think you can amend the existing soil where these plants will grow and won’t need to amend the entire area. Keep tropical plants grouped together for planting and irrigating ease. Organics Added to the Soil are Important             Cover the area where these plants are growing with a thick woodchip surface layer (mulch) when you are finished. You will rely on the woodchips decomposing to improve the soil where roots will be growing over the next few months. Basins, or donuts, around trees can be important to capture water if they are not on drip irrigation.             After planting, surround each plant with a “donut” of soil about 3 to 4 inches deep. This “donut” acts as a water reservoir to get the applied water deeper in the soil. Smaller plants have smaller “donuts”. Bigger plants have bigger “donuts. Water daily the first few days after planting and before turning it over to an irrigation system.