Xtremehorticulture

Xtremehorticulture of the Desert

When to Plant Tomatoes

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Q. When can I put tomato plants outside in the garden? We all want these, right?Putting tomato plants into the garden at the right time is critical in our hot, desert climate. They don’t set fruit when temperatures get above 95° F. They grow poorly at temperatures in the 60s. That “sweet spot” for tomato fruit set can disappear quickly in the hot desert climates, particularly after prolonged cool wet springs. A. This has been a crazy Spring! Tomato plants grow best when soils are warm and air temperatures are above 60° F and below 90°. Traditionally, our last freeze is after mid-March. Most gardeners like to get their tomato plants out earlier than this, any time after mid-February, if its warm enough. Tomato stem rot occurs on tomato plants frequently when soil temperatures are cold and tomatoes are put outside too early.             Start watching weather projections, up to a few weeks ahead, around mid-February. As soon as weather projections predict warm weather for a 2 to 3 week period after mid-February, put transplants outside and help them to adjust from the protected greenhouse to the harsher garden environment.              Put transplants in a location protected from strong wind and intense afternoon sunlight. They should get eight hours of sun every day to remain vigorous. Never plant them in the same spot in the garden year after year. Plant them in a different part of the garden each year to reduce disease problems. This tomato plant stem was buried in the garden soil. New roots were supposed to grow from the buried stem. Instead, the tomatoes them died along with the plant. The transplant was put in the garden when soils were still cold and the soil did not drain water easily. Instead, the tomato transplant developed stem rot.             Prepare the garden soil for planting while transplants acclimate. Remember, tomatoes like warm soils so garden preparation should focus on “fluffing” the soil so that it warms more quickly. Add compost to it and double dig, spade or till the soil to open it and let warm air and sunlight raise its temperature. Hot caps and wall-o-waters are sometimes used to protect tender new transplants when air temperatures are still cold and potentially freezing. Transplants are protected from freezing temperatures but unfortunately the soil temperatures are still cold. These cold soil temperatures don’t permit transplants to grow as fast as they might.             Heavy, wet soils warm slowly when temperatures are rising. Alternatively, cover these spots with clear plastic, if you have to, to trap heat and warm it more quickly. Pin the edges of the clear plastic to the soil to keep the heat trapped under it. A potentially better technique is to warm the soil first with clear plastic and plant tomato seed directly into trenches in the warmed soil. This can be done in the middle of winter. This was demonstrated at the University Orchard in North Las Vegas.             When weather projections are positive, plant tomatoes transplants into warm soil along with a pre-plant fertilizer to improve rooting. If a generous application of compost was used during garden preparation, then add only a phosphorus fertilizer to the soil surrounding the transplant. This phosphorus fertilizer could be a mineral type such as triple super phosphate or a natural phosphorus source like bone meal.

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If it Survives the Winter, Don’t Cut Bougainvillea Back

Leave a Comment / Bougainvillea, freezing damage, Winter freeze /

Q. Should bougainvillea be cut back in the winter?  I have two in large pots. I want to see them grow fuller this spring and summer. Cut back or leave them? Bougainvillea is a witty perennial shrub in semi tropical and tropical parts of the world. We can grow it in winter freezing climates because it grows back from the roots if the top part freezes. If it gets very cold, the crown or top part of the plan may die each winter this happens. In our climate we grow it as an “herbaceous perennial” like lilies and Iris. If it freezes during the winter, we cut off the top debt part and let it regrow from the roots. Otherwise, leave it alone. A. Wait until about March 1 and see if there is any winter damage from freezing. Then decide. If there is, cut it back close to the ground and let it regrow again. Winter freezing damage to bougainvillea. When temperatures drop just one degree below freezing, damage begins to occur on bougainvillea. When this freezing temperature remains for any length of time, more and more freezing damage occurs. It will grow back from the crown (that part of the stem and roots that connect the two) if temperatures do not get too cold for a long time.             If there is no winter freeze damage, make this plant fuller by cutting the stems back at various heights (so it doesn’t look like a butch haircut) anywhere from a foot to foot half from the ground. For every cut you make, three new shoots will grow and increase the density of the plant.

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Sugar Snaps Peas Producing Snow Peas

1 Comment / snow peas, sugar snap peas /

Q. Have had much success with sugar snap peas, but lately I’ve been planting sugar snap peas and getting snow peas instead.  Is it because the seed is old?  Snow peas after harvest in Kenya. A. I’m not sure the difference you are seeing between these snow peas and snap peas. Snow peas have flat pods when young and we see them frequently used in stirfry. Snap peas, or sugar snap peas as they are sometimes called, have round pods when they are young and not used conventionally in stirfry. Kenya producer using sticks and string to trellis their snow peas. High elevations in Kenya is a perfect cool year around climate for snow pea production.             Snap peas, when they first emerge, are flat. As the seed inside the pod begins to enlarge the pod becomes round. If you pick snap peas too early they will look like snow peas. When harvesting snap peas, wait a little bit longer for the seed to enlarge and the pod to become round. But harvest the pods before the seed becomes mature. If you wait too long, the seed contains more starch rather than sugar and not as sweet. Sugar snap pea seedlings in bloom and ready to climb the chicken wire. Cold weather near Bloom time can cause problems and a lack of pea production inside the pod.             The differences between the two are genetic so it should have nothing to do with the age of the seed. Snap peas were genetically bred from their ancestors, the English or garden pea and snow peas, to be less fibrous when they are young. The perfect size for snow be export to Europe from Kenya.             You also might be referring to the “strings” in the pod or how tough the pod is. If strings are a problem, harvest when very young or the pod may get tough when older. If you’re having problems with strings, remove the strings from the pods before using them and start harvesting earlier.

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Spider Mite Problem from Nursery Tomato Transplants

Leave a Comment / disease, fruit trees, insects, nursery plants, transplants /

Q. Two years ago, you correctly diagnosed our tomato plants with spider mites from pictures we sent. Last year we got spider mites again. We started most of our tomatoes from seed last year but bought a few plants from a local nursery and planted them in each of the vegetable beds. Is it common to get spider mites from nursery plants?  A. I don’t know how common it is for pests to be brought in from plant nurseries but I know it is more common than I would like. I have personally witnessed and identified disease and insect problems coming from nursery plants (houseplants, transplants, fruit trees and landscape container plants) before they were planted. Some disease problems on locally purchased container fruit trees. Sometimes insects and diseases can be problems when purchasing nursery materials. This disease infection may have started in the wholesale nursery first and passed on to the local consumer by the retail nursery.Avoid buying problem plants and introducing them into your home garden or landscape.             Some plant problems are easy to see and others are not and don’t develop fully until later. Growing plants free of insect and disease problems requires knowledge about the pests, a clean growing area and a regular prevention and treatment program. Off-color leaves and spotting of leaves can be indicators that they are not healthy or they were poorly cared for. Purchasing nursery transplants can sometimes bring problems into the garden. It can be a problem when low prices are an expectation by the nursery or garden center which may encourage a lack of care or over application of pesticides by the greenhouse producer. Inspect your plants before purchasing and avoid buying those with problems at the get-go.             If possible, put plants in isolated areas until you are sure they are “clean”. This is a common recommendation when buying houseplants. Houseplants are frequently loaded with disease and insect problems and infest other plants once inside the house. Fireblight disease was brought into this planting of apples and pears by introducing an infected Bartlett pear tree from a retail nursery. Once established, this disease spread to other European and Asian pears causing a lot of destruction and loss of plant life.             When bringing home plants, spray them with oils and soap and water sprays before planting. Don’t bring home “bargain bin” or dumpster plants thinking you’ve got a deal. You are asking for trouble unless you know what you’re doing. Don’t risk contaminating pristine plants by mixing them with plants unknown to you.If you must do it, keep them isolated from other plants until you are sure they are healthy.             As far as spider mites on tomatoes are concerned, inspect plants using the “white paper method” and a hand lens. Remove weeds growing in the containers, remove dying or damaged leaves, spray plants with soap sprays, and alternate with neem and other oils when you see them. Inspect plants

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Use Compost in Place of Fertilizer

1 Comment / compost, fertilizer /

Sudan grass without compost (above) and with compost applied (below) growing in Amargosa Valley, Nevada. Composts can provide alot of benefits to plants including much needed nutrients that improve color and growth. Q. If I make my own compost, can I use it instead of commercial fertilizers for grass, plants, trees, shrubs? A. Yes you can. But please be aware that homemade compost is not consistent in fertilizer content and quality. This is because of variability of different ingredients used to make the compost. The ingredients used to make compost directly impact the nutrients found in compost made from it. However, compost is universally good, whether it’s commercial or homemade, when added to soils as a soil amendment. Spreading compost on vegetable plots between palm trees for soil improvement and fertilizer content.             When using compost as a substitute for fertilizer, it is important to know its carbon to nitrogen ratio (C:N), in other words how much nitrogen fertilizer it contains. The nitrogen content of a compost is critical. High nitrogen content (low carbon to nitrogen ratio) makes compost “hot” and less of it should be used. If compost has a high carbon to nitrogen ratio (low nitrogen content), then more of it should be applied when substituting it for fertilizer. When applying compost to lawns a compost drum spreader is used to apply it evenly.             Commercial composts aim for a carbon to nitrogen ratio close to 20:1 or twenty times more carbon than nitrogen. As this ratio increases to 40:1, the nitrogen fertilizer content decreases. At a ratio more than 40:1, the compost is still valuable but it’s value is greater as a soil amendment rather than fertilizer. When applied to fruit or landscape trees, compost can be applied in a circle around the trunk so that it doesn’t damage the tree. It is then watered in.             The carbon to nitrogen ratio in homemade compost is managed through what is added to the compost mix before composting. “Woody” additions to compost like wood chips, sawdust and shredded newspaper (sometimes referred to as the “brown” component) increase the carbon to nitrogen ratio. Compost piles have ingredients that are shredded, water is added to help it all “rot” and  the pile is turned when the temperature inside the pile gets hot, around 160F. Manures are usually used to get the nitrogen content high enough for rotting to begin.             Additions of grass clippings, leaves of trees and shrubs, and vegetable scraps (referred to as the “green” component) lowers the carbon to nitrogen ratio and make it more valuable as a fertilizer.             Animal manure (think of it as a concentrated “green” component) is high in nitrogen and added to get the carbon to nitrogen ratio low and improve fertilizer content. If lots of different components are mixed together in the right proportions, green components are balanced with brown components, homemade compost has all the nutrients needed by plants.             The short answer is “yes”. But substituting a homemade compost for a fertilizer application varies from batch to batch depending on what was used to make the compost.

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Not Too Late to Fertilize

1 Comment / fertilizer applications /

Q. My schedule was to fertilize my citrus plants on President’s Day but because of the drop in the temperatures, I decided to postpone. It has stayed cold. So, when should I fertilize? Keep fertilizer away from tree trunks so it doesn’t damage the tree. A. Everything has slowed down because of the low temperatures. As soon as it warms up would be fine. If they need some extra help, consider foliar feeding them with a tomato-type water soluble fertilizer in three or four weeks.  Don’t forget to apply iron either in the soil or combined with your foliar feeding. Cold, wet cloudy weather did not let many honeybees out for pollination so these early flowering trees may not have very good fruit set.

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Lime Tree Pruning Tips

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Q. Please give some tips on pruning my three-year-old sweet lime tree: when to prune, how tall to keep its growth on my limited backyard space, fertilizing, and does the tree have to be pruned annually?  Readers young lime tree A. Read most information on pruning of citrus and it will tell you to prune citrus very little. Citrus of any type have few issues that need correction by pruning. They do not need to be pruned to improve fruit production like other fruit trees. Reasons for pruning citrus             The primary reasons for pruning citrus are to reduce its size, remove problems like crossing and broken branches, and some thinning to reduce excessive growth.             They do need to be pruned if you want to keep them smaller. They can be pruned to backspace to about 60% of their mature size. But it should be done every year.             Prune just after harvesting the fruit so that it doesn’t interfere with next year’s flowering and fruit production. This is also the best time to apply fertilizer. Light pruning with a hand shears and applications of fertilizer can be done anytime of the year. First, control its height Identify backspace stems backspace contributing to an undesirable height. These will be vertical or nearly vertical. Follow the stems along their entire length and remove them, entirely, at the point where they become vertical. This may be somewhere deep inside the canopy. It doesn’t matter if that’s the case. Remove them with a clean, close cut.             The tree wants to become tall. You want the tree to stay smaller. This is where you are at odds with tree. You must control the tree, it should not control what you want. Get rid of vertical growth             The best production of fruit comes from stems that are NOT vertical. Consistent fruit production comes from stems that are near horizontal or no more than 45° above horizontal. Reduce its width if needed             If the width of the tree is a problem, reduce the length of horizontal or near horizontal stems. To do this, follow the length of the offending stem toward the inside of the tree. Remove the portion of this stem that is offensive at a juncture with another stem. DO NOT LEAVE STUBS. Remove crossing or broken limbs             Adding fertilizer to plants, particularly those high in nitrogen (the first number on the bag), should be done every year to maintain a high level of fruit production. But the amount applied should be adjusted according to the needs of the plant. If the tree is growing excessively, reduce the amount of fertilizer applied but don’t eliminate it.

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Cool Wet Spring Perfect for Fireblight

Leave a Comment / fire blight, fireblight, fireblite /

Bacterial diseases like fireblight need openings to enter the susceptible plant. Flowers provide temporary openings and let this disease enter inside plants. So do fresh pruning cuts. Fireblight disease spreads from infected to uninfected plants through these openings. Rainy and windy weather helps spread this disease when flowers are open. Honeybees are suspected to spread this disease as well by visiting these flowers. Cool, rainy weather when pear and apple are in bloom, is perfect weather for fireblight disease. Fireblight is a very aggressive and dangerous plant disease that shows up as new infections in about May in Asian Pear, European pear like Bartlett and some apples. It can be a major problem on Quince as well. This is why the first evidence of fire blight disease is usually seen by the blackening of the flowers in late spring. From here it can spread into branches and cause severe problems.             But the disease problem, although unseen, can begin now. The point of entry for this disease into susceptible plants are the open flowers and fresh pruning cuts. Open flowers and fresh pruning cuts provide “fresh wounds” or points for this disease to enter inside the plant. Wind and rain are the usual culprits that spread the disease from plant to plant but even honeybees can be responsible. Fireblight has spread from a flower or pruning cut and caused more dieback.             If this disease is seen early enough (usually in late April or May) it can be eliminated easily with a few snips of a sanitized hand pruner, eliminating the infection. But the hand pruner must be disinfected between each cut on the tree or the disease can be spread on the hand pruners through each cut. Classic textbook dieback and progression of fireblight disease             There is some disagreement about what to use to disinfect hand pruners but chlorine bleach seems to be the favorite among orchardists. Heat from the open flame a cigarette lighter also seems to work. Some people suggest alcohol and others suggest household cleaners like Pine-Sol.             Plants that were infected in previous years will show evidence of this disease when new growth occurs in the next couple of weeks. As the name suggests, this damage resembles the black from fire damage. This can be confusing because any damage to pear leaves can turn black. If you are unsure, send me a picture.             We have had a surge in this bacterial disease over the past few gardening seasons because of our cool wet springs. I will post more pictures of this disease from past years on my Internet blog, Xtremehorticulture of the Desert.

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