Xtremehorticulture

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.

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Fertilize Garden Plants When They are Growing

 Blood meal is one form of organic nitrogen that can be used to side dress             Earlier in the season, around mid-March, I was encouraging you to plant your own onion transplants and grow your own onions. They are so much better tasting and I gave the readers here and on my blog some varieties to choose from. Many are available from seed and started from seed in about mid-October, the same time as you would plant garlic.             Most people forget a very important concept in their home gardens – regular fertilizing. As plants get bigger or start producing they are taking all of these “goodies” from the soil to get bigger or start producing. I will get back to onions in a minute.             What would happen to you if you were always giving and receiving nothing in return? Plants can’t continue to “give” without getting something in return if you expect them to be healthy and productive. So all plants as they get bigger and you harvest require fertilizer.   Plant health depends on regular fertilizer applications if you are always “taking”.   “As expectations for plants increase….more inputs (water, fertilizer, time, energy)are needed.”             Fertilize your garden plants monthly when they are producing. Think about what they are taking from the soil. Was the soil enriched at the time of planting so they have plenty to “pick from” or is the soil’s nutrient reserve running low?  Ammonium sulfate granular fertilizer also known as 21-0-0 since it is all nitrogen (21%) and no phosphorus or potassium             The first nutrient to disappear from the soil, for a number of reasons, is nitrogen. It is very important to supplement your vegetables with some extra nitrogen monthly.             If the plants are up and growing it is not wise to just broadcast the fertilizer (throw it out over the garden willy-nilly) or the fertilizer “salts” may burn foliage. Deposit the dry fertilizer next to each plant or dribble it along the row. This is called “side-dressing” with nitrogen.             Why did I mention onions earlier? Because they need to be side-dressed as well and are frequently forgotten. One more side-dressing on onion and garlic and then stop as you will be harvesting in two months.  Ammonium sulfate is a crystalline source of nitrogen that dissolves easily in water and can be applied as a granualr or liquid by dissolving it in water. Dissolve about one tbs in three gallons of water or apply it dry by sprinkling on the soil lightly and watering it in             Use your favorite source of nitrogen. If you are an organic gardener, select an organic form that you like. If you are not that fussy, then use a traditional ag-type nitrogen fertilizer like ammonium sulfate. When you side-dress, it is normally just nitrogen as it moves into the soil freely with an irrigation.             If these are annual plants, all the other nutrient “goodies” we normally put in the soil at the time of planting.             What makes big onions? The variety you select, improved garden soil, spacing them 4 to 6 inches apart, regular and frequent watering, weed control and side-dressing with nitrogen as they are growing and expanding. Pull or lift them when the tops fall over naturally. If you are pulling them, make sure the soil is wet when you are pulling or you will pull the tops off.             Remember, my blog, Xtremehorticulture of the Desert, has a lot of pictures that supplement my discussions here.

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Watering With Distilled or RO Water a Problem?

Q. In a past posting on your blog you mentioned that using 100% distilled water for container plant irrigation might mess with the potting soil.  What did you mean by that? A. Distilled water has no minerals in it. This can pose problems for soils and cause the soils to “deflocculate” which means the soils can start to seal and begin to slow the water movement through it by taking minerals from the soil particles.             So it is best to add just a small amount of fertilizer…very little… so that you replace the minerals that are no longer there. Think of it similar to drinking distilled water as opposed to water that has some “good” minerals in it and the effect on our bodies.             So good salts to use for replacing the salts taken out would be fertilizer salts from a good quality fertilizer or a light compost tea. How much to add? How much salt remains after water evaporates from irrigation water? Very little. A pinch or two of a fertilizer salt in a gallon is enough.

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Fertilizer for Cactus Is Limited by the Quality of the Soil

Q. I was wondering whether you could help and point me in the right direction. I had been using a great liquid fertilizer which I was able to obtain from the 99 cents store in Henderson. They have discontinued the product and I can’t seem to find it anywhere.  I have succulent plants and cacti on my patio and the liquid fertilizer really seemed to help. Could you suggest where I might obtain the liquid fertilizer or suggest some other product for my plants?   A. I know you probably got a pretty good deal with that fertilizer and that may not happen again for a while but there are some good liquid fertilizers out there. Sounds like you are into the bargain bins when you buy things so you may not like my suggestions. Good fertilizers are nearly never inexpensive. One of the best ones you could use would be to make your own compost tea using high quality compost. I can’t compare all the products out there available in Las Vegas but one that I know about is called Happy Frog compost. Be careful when using it because it has had fungus gnats in it still working the compost so don’t use it inside the house. It is fine for making tea or using outside (our desert heat will kill the gnats).  Happy Frog products are good quality organic products to use. There are others but this is one. You take about two handfuls of this compost and put it in about a gallon of warm water and let it soak overnight. No longer than this because you want the water to have air in it or the process will go anaerobic and kill all the microorganisms. Or bubble air through it to keep the microorganisms alive. The soaking will leach out a lot of the nutrients and microorganisms (goodies). Happy Frog still has a lot of microorganisms in it. Many do not. Use this gallon of water to water your flowering cacti. If you want a mineral fertilizer then any fertilizer made for tomatoes or roses will do well. Just use very small quantities. Products to look at include Peters, Miracid, Miracle Gro, Jobes, and others. Peters makes excellent fertilizers but they are expensive. In many cases, you get what you pay for in fertilizers Most importantly for cacti, make sure you amend the soil when you plant them with organic material such as compost or some manure based amendment. Cacti do much better in an amended soil than pure sand or our unamended native soils. If the soil was not amended, lift them during the warm months and replant using soil that drains freely and incorporating compost into it.

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Milky Spore Product Probably Not Best Choice for Southern Nevada

Q. In my attempt to plant seedlings this year in my 4×8 raised bed, I noticed the day after I planted some pepper plants they were decimated by some kind of insect. When I was amending the soil a few weeks before, I noticed some small worm-like critters in the soil. I sprayed a bit of Bt on the soil 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. Have you ever heard of this product? They said it works and I only have to apply it one time. Sounds too good to be true. This store said they used to carry the product but not any more for reasons unknown. I went to the Home Depot and Lowe’s, but neither store had the product. Can you advise me on this product and where I might find it or some other solution?  I removed the damaged plant and I’m trying to revive it. A. The milky spore product only works on some types of insects such as Japanese beetle which we do not have in southern Nevada, and a few closely related insects. “Milky spore” is a bacterium and works rather slowly, if it will work at all, on pests in southern Nevada.  Cutworm larva Bt works on those insect larvae that mature or pupate into either moths or butterflies. So if the larva turns into a beetle, for instance, it will not work. So without knowing which insect larva you have it is hard to know what will work unless you use a conventional pesticide approved for use on vegetables and has insect grubs or larvae on the label. This time of year Bt is a good product to use in home gardens because of the presence of cutworms. I am sending you a picture of what the cutworm larva looks like and its adult form (posted also on my blog), a moth. Bt can be sprayed on the soil and left undisturbed (no hoeing or irrigating) for a few days. Dipel in this form is a dry flowable product. Dry flowable pesticides are the same as what we call “water dispersable granules”. These can be mixed with water and they disperse in water easily and quickly BUT the spray mix MUST be constantly mixed or shook while applying or the pesticide with settle out and you will not be applying it anymore but will collect at the bottom of the sprayer This is the time of year that this moth is flying and laying eggs. Their larvae “hatch” from the eggs and are out looking for food right now. Usual cutworm damage is at the soil surface, not on the leaves. Other products to try to protect your plants are those that leave a poisonous residue for insects on the leaves. You can also use insect netting covering the rows in a low tunnel.  

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Science in Action: Controlling Borers in Landscape Trees

Options available for controlling borers have actually increased over the past few years. While the traditional approach of spraying an entire plant with a chemical such as Lindane, a chlorinated hydrocarbon, has become less available to pest control operators other types of IPM (Integrated Pest Management) control strategies have blossomed on the commercial market. The problem for most applicators is that the “security blanket” of a traditional pesticide approach is disappearing and the research to support the newer products is not available to give applicators confidence that they will work. The IPM model for borer control includes strategies such as cultural, chemical and biological methods. The most effective long-term control strategies are usually cultural in nature and should be our first consideration. Often times they are not used by commercial operators for a variety of reasons but usually get back to either economic reasons or lack of education on how to use them effectively.   Flat headed borer in small limb of peach tree. Sanitation would be removal of the small limb or cutting out borers from larger limbs with a knife When evaluating which method to use, we have to balance the efficacy of the control measure, it’s economic benefit to the customer and the operator and impact of the control measure on the environment. Lets take a look at each component in the IPM scheme. Cultural control options in traditional agricultural IPM include sanitation, crop rotation, tillage, host plant resistance and tolerance, mechanical or physical destruction of the pest and quarantine. Do any of these apply to controlling borers in landscapes? Sanitation refers to the removal of infested plants or plant parts which helps reduce the level of plant pest in the urban landscape. This may mean removal of entire trees heavily infested or removal of limbs to reduce the infestation level. This can be done on an individual yard basis or community wide if there is a community “epidemic” of a particular pest. Borer infested limb removed to save the tree from removal. A form of sanitation. We have seen communities, or entire sections of a community, devastated by certain types of borers. Clear winged borers, like the ash or lilac borer, can be serious pests in this regard since these types of borers are known to attack healthy trees and the number of these insects in a community may dictate the degree of infestation and damage. Community-wide borer control efforts need the strategy of a community forester or city arborist to make these efforts work. Crop rotation is the substitution of a crop (plant) with low pest susceptibility (host resistance) for a plant with high pest susceptibility. As an example, if we lose a tree to borers do we put the same type of tree back in that community or do we look for a reasonable alternative? As we begin planning a community or expanding a community are we checking to see what borers are problematic to the community or are we selecting plants only because they have aesthetic appeal? An example of this is the planting of weeping willows in climates like Las Vegas where they stress and become highly susceptible to attack by borers. These trees then become a source of infestation for other susceptible trees in the community. A proactive approach toward sound horticultural growth, balanced by future maintenance, requires public education and community coordination. Weeping willow planted in Las Vegas with borer damage from clear-winged moth. For this reason we never see weeping willows over about ten years old. Quarantine is a legal restriction or exclusion of infested plants being brought into a community. On a state-wide basis, inspection stations are established that control the entry of infested plant material or documentation is required by the buyer that plant materials have been inspected, and found clean of, certain pest problems. Sometimes plant materials are simply not allowed into certain communities due to the highly virulent or infectious nature of certain pests. This has happened with elm varieties, and some of its relatives, known to be susceptible to Dutch elm disease. Some arborists combine physical or mechanical control measures with their borer protection programs. Physical control can be as simple as noting borer activity in some young trees and carefully using a small knife to remove or kill the borer. This will work with borers such as some of the flatheaded types that that can be easily tracked and that feed near the surface of the trunk. A great deal of care has to be exercised so that the tree is not further damaged with the knife but with some experience it can be learned. Mechanical control includes barriers such as wraps that may help prevent sunscald and the physical entry of borers inside the tree. Some care has to be exercised that certain wraps don’t actually contribute to the problem by providing egg-laying sites for borers. We are all most comfortable with cover spray applications of chemicals for borer control. This strategy was either to spray the plant periodically through the entire growing season or time the spray with some sort of insect trapping device. Cover sprays applied a poisonous, pesticide barrier to susceptible plants. The traditional approach was to apply a pesticide to the trunk and major limbs of trees either infested with borers or “threatened” with borer activity. This cover spray was a prophylactic treatment aimed at preventing the entry of the borer inside the tree. Once the borer entered the tree, cover sprays were ineffective. Emerald ash borer damage to green ash which we do not have  in southern Nevada Our business practices, equipment and past education focused on chemicals for borer control. The problem with traditional cover spray applications of chemicals is that the chemicals traditionally used for this purpose pose a threat to the environment and human health, both by the nature of the chemical and how it was applied. This technique is still probably the most widely used one but is becoming more restricted with

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Xtremehorticulture of the Desert Exceeds 20,000 Hits per Month

I am excited that my blog now consistently exceeds 20,000 hits or visitors each month. My blog is my way of paying back to southern Nevada residents for all their support over the last 30 years in my tenure with the University of Nevada. I have learned alot about horticulture over the years teaching and conducting research in southern Nevada. It is a shame to retire and have that information retire with me. I hope you can use the information I am providing and, in the process, make you better gardeners and horticulturists. I have returned from my assignment in Northern Afghanistan and I am excited to share some of what I learned there. I was concerned sharing much at that time due to security issues. Any pictures of individuals who worked with me there must have their faces blurred for obvious security reasons. Please bear with me when I share these experiences. Northern Afghanistan’s climate is very similar to southern Nevada and their crops and planting schedules were nearly identical to ours. So stay tuned. More to come.

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Saguaro Leaning and How to Correct It

Q. I have a saguaro cactus with three big arms growing from it leaning toward the west. On the east is my house and shading the cactus from the morning sun. I also have been watering on the house side of the saguaro, the up slope side, and letting the water run downhill into the roots.  I water about 3 or 4 times a year and water very slowly. Do you have any suggestions about either stopping the continued leaning or how to straighten the cactus to upright?  Those two large saguaros have been in my yard for 17 years. Saguaro leaning due to shade from the house most likely A. These Sonoran desert monsters are top heavy. The root system of the saguaro is fairly shallow but expansive. This extensive but shallow root system can give this top-heavy cactus quite a bit of support under native desert conditions. But they have been known to blow over in high winds. These cacti, like most, are opportunists and take shallow water from the soil before it evaporates or taken by neighboring plants. Most of the roots away from the trunk can be found at depths less than 12 inches. Watering deeply around these plants is probably a waste of water. We put these plants in artificial desert landscapes and put them on drip emitters or run water close to the trunk. This can lead to a very small but dense root system close to the trunk. The roots don’t have to grow far from the trunk for water and so doesn’t help to stabilize the plant as the top gets bigger. Saguaro normally does not need to be staked when transplanted but here is one method that protects the trunk Your cactus could be leaning either because of the shade from the house or it might be leaning due to poor root support or both. If it is leaning and there is danger it will fall over then you will have to support it. In the meantime, we create a more expansive root system by placing enough other desert plants close to this plant so that the irrigations from these other plants can help the saguaro extend its root system further from the trunk. We could sprinkle irrigate the area around the saguaro, simulating desert rainfall. But sprinkler irrigation can lead to weed invasion in the landscape and weed control problems. From the pictures you sent, obviously your watering regime has given your saguaro some good growth but it sounds like the water is concentrated close to the trunk. I will post the pictures of your saguaro on my blog for others to see. Another possibility that could contribute to the leaning is how it was planted. If a hole was dug just large enough for the transplanted roots, and the soil was not conditioned properly, then this will encourage the plant to grow roots close to the trunk as well. All cacti grow better in amended soils than in straight desert soils or sand. Always amend soils for cacti at planting time. What can you do now? If the plant is leaning due to the house there is not much you can do. To give it better support put irrigation water at greater distances from the plant and use shallower irrigations. Like I said, giving saguaro deep watering is not going to help but getting its roots to grow wider might. If the soil is not loosened, it is best to loosen the soil surrounding the plant where you are watering to encourage growth at distances that will support top growth.

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Keep the Birds Out of Ornamental Grape Vines by Removing Flower Clusters

Q. I bought a house last December that has two large grape vines growing over a pergola that covers a hot tub. Last summer when the vines were producing grapes, the birds were unbearable. I know I could cover the whole thing to keep the birds out but it would ruin the aesthetic and make access to the hot tub difficult. Is there something I can to keep the beauty of the vine without it producing any grapes? This is a grape spur that has been pruned for producing good quality grapes. The top stem is reddish brown. At the base of the reddish growth is greyish-brown. The reddish brown growth will produce grapes because it grew last year. The greyish brown growth is older and will ot produce grapes. If all the reddish brown growth is removed from the vine, the vine will not produce any fruit A. Yes you can. It is a fairly easy solution. In the winter months prune out all the new growth. You can see it because it is a different color than the greyer oldish growth. Grapes only flower on the wood that grew last year.             Or it should be flowering now or very soon (late March). As you see these flower clusters on the vine, pull them off. These are unopened flowers of grape. They come around late March to early April in southern Nevada. The come from the reddish wood produced last year. Either remove all the reddish wood during the winter or early spring or wait until these flowers come out and remove these clusters. They snap off easily so you could probably knock them off with a broom if you don’t want fruit

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When and How to Prune and Fertilize a Cassia

Q. My cassia is full of beautiful yellow blooms. First year this two year old plant has done this. When do I trim it back and how far?  Type of fertilizer will it need?   The base of cassia has several strong stems coming from the base. Choose one or two of these strong stems and remove then at the base. Let it regrow from the base to rejuvinate it and let the leaves fill in from top to bottom from the strong young basal growth. A. Shrubs or other plants should be pruned soon after they flower. In spring flowering plants the flowers are produced during the late summer and fall months. Some finish maturing in the spring before they flower. But regardless, if these spring flowering shrubs are winter pruned with a hedge shears it will remove the spring flowers. If shrubs are pruned properly and not pruned with a hedge shears they then can be winter pruned. Hedge shears should be reserved for nonflowering hedges. Reach down inside the canopy, or from the outside, cut with a sharp and cleaned pruning shears about one inch above the surface of the soil and make your cut. Pick stems that are the largest or too close together. Pruning should be done with a few well-placed cuts deep inside the canopy to remove sections of the plant which are crowded, too tall or too wide. Cuts are made where two stems join together, removing the offensive stem. This results in a general thinning of the shrub removing larger diameter wood. By removing larger diameter wood, this “renews” the shrub and helps keep it young. I hope this helps.

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