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Sunday, April 7, 2013

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
            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.

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.

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

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.

Milky Spore Product Probably Not Best Choice for Southern Nevada

Q. In my attempt to plant seedlings this year in my 4x8 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.


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 time. We have already seen Lindane become more restricted in its use and availability. Admittedly, using chemicals such as Lindane, Dursban, Thiodan and Sevin as cover sprays on large trees has its community environment and health drawbacks. The effectiveness of cover sprays always depended on a narrow window of time when the spray would be effective.

Applications of chemicals such as Metasystox R as a soil injection for borer control pose similar environmental problems. Applications of pesticides into the rootzones of plants pose an immediate threat to shallow groundwater supplies, wells and public health concerns.

 Application methods of pesticides such as trunk injection certainly minimize some of the environmental and community health concerns. Active injection systems exist, like Mauget, which rely on a pressurized system to inject pesticides such as Bidrin and Merit, into the tree's vascular system. Once inside the tree these chemicals become mixed with the vascular fluids and thus become systemically distributed. There are passive injection systems, such as trunk implants, that have no pressurized system but rely on the vascular fluids to carry the pesticide throughout the tree. This mixture of vascular fluid and pesticide poisons the immature borer feeding on the vascular tissue.
In my opinion, never use systemic insecticides or inject insecticides systemically into fruit trees or other edible crops.
Entomologists have been concerned that trunk injections, made late in the protected borer's life cycle, would not be effective. They reason that borer feeding activity disrupts the flow of vascular fluids and prevent the pesticide from coming in contact with the borer. In the case of borers in an advanced stage of its life cycle, this may be the case. However in the very early stages of an infestation, injection may provide some measure of control.

The injection of pesticides into trees poses other problems such as the damage created when holes are drilled into the trunk. Research many years ago in the United States and Canada has both come to the same conclusions. If holes have to be drilled into trees then the holes should be as small as possible. The other piece of research conducted with injection equipment is that on larger trees, injection should be made as low on the trunk as possible. Injection holes drilled in the root flares provides better mixing and a larger trunk circumference to absorb the damage created from drilling the holes.