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.

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
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.

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.
 

 How to Use Mauget trunk injection

 

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.

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.

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.

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

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.

Center of Cassia Bush Died. What to Do?

Q. I have a cassia at the corner of my house to block the street view of my air conditioning unit.  The whole center section visible from the street has died.  I'm beginning to cut out the dead limbs. I check the cuts but am not seeing any green at the bark.  Is there a chance that partially cut back limbs might still produce new growth?  Or should I cut back to the main trunk?  With no center section it looks ugly. Can I hope the living branches will fill in eventually?  Dig it out and replant with a new one?



One of the cassias and what it should look like with proper care as it is getting at the Las Springs Preserve

A. Yes it is possible you had some winter kill but doesn’t sound like winter kill. Winter kill is most common on new growth, such as the tips of branches, if temperatures are just below their tolerance. If temperatures a considerably below their tolerance, then you will see death also in the older, larger diameter wood.



This is what a cassia will look like armed with hedge shears, improper watering and lack of
fertilizer 5 years after planting.

It is odd if it is just damaging the interior wood and leaving other parts of the plant alone. Another possibility is root rot if it is watered too often or the area is flooded. This should be fairly easy to determine by pulling the top of the plant toward you and looking at the base of the plant.

In cases of root rot, trees and shrubs the plant will not be securely anchored in the soil. When you pull on it the base will move around and not be firmly anchored in the soil.

In healthy plants that are not winter damaged you should be able to scrape the soft outer bark with your fingernail and see green beneath it. This is not easy to see in all plants. But at least the inner bark should be cream colored or white.

So I would not cut anything back at this time. If there is winter damage then the killing temperatures already “pruned” it back. If the plant or plant parts are alive they will show you where to cut after new growth emerges. When it emerges, cut a few inches below the dead part of the limb and into the strong growth, just above a bud or at a crotch (where two stems come together).

If you don’t see any new growth by mid-April, then it is dead. Whether to remove it or not is really a subjective call and not one I can direct. It is your call. With an established root system it should grow back very rapidly and will fill in the spots where there is strong sunlight.

Pink Leaves on Purple Plum Probably Iron Problem

Iron chlorosis on purple leaf plum

Q. I have two red leaf plum trees both about two years old. They started the year beautifully. One continues to look normal but the other one has all of a sudden taken a turn that bothers me. The leaves are getting pale, pink instead of red and see through-ish. It is a nice full tree yet young. Is it as simple as not enough water or something else? It had a great year last year.


A. It is most likely iron chlorosis. If you want to see if that is the problem try making a few liquid applications of an iron chelate to some leaves using a spray bottle to see if this turns them dark purple (I am assuming you have a purple leaf plum).

            It may take four or five applications with a spray bottle to the same few leaves a couple of days apart since liquid applications to the leaves are not typically as effective as applying it to the soil. Otherwise buy some iron chelate containing the EDDHA chelate and apply it to the soil in a bucket of water and wash it in around the roots.

            You should see it turn dark purple in growth that comes out AFTER you make the application to the soil. This discoloration is also possible if the tree roots are being kept too wet by watering too often or you have poor drainage.

Asparagus Should Be Cut Below the Soil Surface

Q. I have a raised bed (5 x 10 feet) dedicated to asparagus. The yield has been magnificent. However, the plot has gotten so overgrown with old asparagus stumps that I have had to totally remove and replace all the soil because cultivation was impossible. My question is how long can an asparagus garden last without being so impacted that it must be replaced; or, is there a way to deal with spent stumps annually to prevent this problem.




Purple passion asparagus with some rabbit damage. Rabbits love the
higher sugar content of Purple Passion

A. Asparagus rhizomes are normally planted about 12 inches below the soil surface. If started from seed, the seed is planted in a trench and backfilled as the plants grow so that the developing rhizomes are still at about 12 inches deep. 

Asparagus crown for vegetative propagation. Selecting crowns that
are male will guarantee a male crop. Spears emerge from the top
where the fleshy roots come together

When this is done the spears can be harvested by cutting below the soil surface with a knife so that these "stumps" don't stay on the surface. If you harvest the spears by "snapping" them or breaking them above the soil surface then you will get these woody stumps remaining above the soil surface and they interfere with future harvesting.

So, in short, if you can harvest by slicing with your knife an inch or so below the surface I think this will stop your "stump" problem. The woody part is cut off after harvesting during food preparation. The woody part should compost fairly easily.

Snapping off spears will cause the spear to break just above the woody portion. Nice
for the kitchen but leaves a "stubble" behind in the asparagus bed

Recent research has pointed out that asparagus spears can be harvested anytime the spears are pencil diameter or larger five inches above the soil level. Smaller spears should be left to grow into fernlike growth to replenish the roots for upcoming seasons. The plant is still expanding its root storage system and excessive removal of spears weakens the plants. However, there is a market that has emerged utilizing these very thin spears.

In commercial operations all spears are harvested cleaning the entire bed and spears are allowed to grow to ferns only after the harvest period. An asparagus plant will yield an average of 8 to 12 spears per year before the roots need to be replenished by letting the spears develop into ferns.

Harvest spears by cutting or snapping. To cut a spear, run a knife into the soil at the base of the spear and carefully sever it. Because the spear cuts below the point where fiber develops, it becomes necessary to remove the fibrous base from the tender stalk. Most homeowners and some small scale growers prefer to snap the spears. This eliminates any woody growth on the harvested spears. This does however leave a "stubble" on the surface that can make harvesting more difficult.


To snap a spear, grasp it near the base and bend it toward the ground. The spear breaks at the lowest point where it is free of fiber. Stalk diameter is not a good indicator of proper maturity and associated tenderness. Hydrocooling, or plunging freshly harvested spears into cool, clean water is strongly recommended.

Commercially, asparagus is graded by class (US Number One and US Number Two which are based on straightness and head compactness) and by diameter 5 inches from the tip (see table) according to USDA standards for canning asparagus.

Stems of Beans Devoured at the Base



Beans planted in cool soils can get collar rot or get devoured by cutworms

Q. I found a couple of beans in my garden that have been devoured at the base. Could it be some sort of soil born larva or possibly a virus?  Any ideas would be helpful. I did find one small white worm about a half of a centimeter long near the root about an inch away. 

 

A. It could be a couple of things. First, with cool weather and cool soils it might be collar rot disease that rots the stem at soil level. This will happen if you plant beans too early in cold soils. Some varieties of beans are more susceptible to this than others.

Most likely cutworm damage

            The first indicator is that some plants appear stunted and grow poorly.  I usually end up removing these plants and hope the weather warms up. 

            The other problem can be cutworms.  You should be spraying or dusting the soil surface around these plants with either Dipel or Thuricide, an organic pesticide.  This is the time of year you should be doing that anyway for a variety of pests in the vegetable garden.

Poisonous Plants: Dose Makes the Poison

Q. I have a volunteer gopher plant in my front yard that I nurtured into a bush.  I noticed that something is eating its leaves.  We have a great deal of rabbits in our area. Can it be rabbits?  I thought that the Gopher plant was poisonous even to rabbits.

What does gopher plant look like?

A. I assume we are thinking of the same plant. It is a euphorbia with white latex sap coming from a damaged stem, similar to the white sap you see in poinsettia which is also a euphorbia. We tend to react to poisonous plants with fear but there are degrees of toxicity when we call something poisonous.

            I watched a professor of mine in floriculture on television take a poinsettia leaf and eat it. He didn’t die or even get sick. He was demonstrating that the plant is toxic but it is the “dose that makes the poison”. If he had eaten many leaves the story would be different. Even table salt is poisonous if we eat enough of it.

            So it is possible for an animal to eat “poisonous” plants and survive. I have heard that some livestock will eat gopher plant in the range with no ill effects. They just don’t eat a lot of it and only when browsing is poor. Just like us, animals like to eat things that taste good.

Hybrid Bermudagrass Lawn Needs the Bumps Gone

Q. My hybrid bermudagrass lawn is flat and 30'x40', yet it seems bumpy when I mow. Can I get it as flat and smooth as a putting green? Should I top dress with sand or something else? If so, what and where do I buy the material, and how do I spread it? I do not overseed in the winter, thus it's dormant now.



Hybrid bermudagrass makes a beautiful soil cover but does require
work to keep it like this

 

A. You can do a lot of damage to hybrid Bermuda and it will come back but you should do this when it gets hot, not now. You can level it by taking the high spots out with a straight-nosed shovel, you can fill in low spots with soil (not sand, but something similar to the soil you have now).

Once you get these highs and low spots rectified, then this putting green (if that is what you want to do with it) will never have the same type of ball roll as a putting green because it is not built the same way. The best putting greens are constructed along very specific engineering specifics called the USGA Greens Section constructions specifications.

http://www.usga.org/Content.aspx?id=26124

In golf course terminology you have what is called a "push-up green", one that is made inexpensively from the local soils. These work just fine but will not give you the “feel” of the Augusta National.



Aerator for turfgrass.
Sorry but I dont remember where I got this years ago.
If you aerate lawns in LV, let me know.

Once you have your area level you should then start to aerate, fertilize and topdress your green on a regular basis. Topdressing can be done by hand with a shove with a little practice at "throwing" it.

I would look at sourcing stuff like this from sand and gravel company. Sand is used a lot because it is smaller and won't interfere with ball roll and it is inexpensive. For professionals they would select sand similar to the sand used for constructing it.

If you don't have one, you will need a greens-type mower (usually around $600or so for the inexpensive type or frequently you can find one used from people who have converted to desert landscaping). But this will be a reel-type mower, not the rotary type.

Greens are mowed at about 3/8 inch or thereabouts (bragging rights among superintendents is “how low you can go” with some at ¼ inch). These types of heights mean mowing daily in the summer months. If you let it go and mow it after a week you will not have the same quality. Mowing frequently makes the grass “tight" and helps keep weeds out as well.



Thatch is not just the light brown stuff, its the dark brown peat moss
stuff below it. It is mostly dead stems, not leaf blades

This climate can produce very high quality hybrid bermudagrass. It is similar to Tucson. I would rule out the climate as a problem. If it is flatter than this, then you should fill in the lower spots with soil similar to the soil in the lawn. I would not use pure sand to fill in these low spots.

Bermudagrass will start to have an inferior look if you don’t dethatch the lawn. An advantage of overseeding bermudagrass in the fall is that this process requires dethatching or opening up the turf for better soil and seed contact to improve germination. If the area is small, a hand dethatcher is adequate and gives a great upper body workout.

You would overseed sometime between mid-September and mid-October in our climate. Use high quality perennial ryegrass, not annual rye if you want a high quality winter lawn. Seeding rates are high if you plan on a greens height cut in the winter.


I would use something around 15 pounds of seed per thousand square feet. When you mow close, the grass plants need to be closer together so you have to use a higher seeding rate than it says on the bag.

Aerating is important but if you do not dethatch bermudagrass you will have problems with color, texture and just plain looks of the grass. If you don’t overseed in the fall then you should dethatch it, but earlier so it has a chance to recover and fill in before cold weather hits. I would dethatch any time it is actively growing fast.

Bermudagrass can handle that kind of stress in the heat. Cool season grasses like tall fescue cannot and must be dethatched in the spring or fall; fall is preferable, around mid-September to mid-October. Same time as overseeding (strange how that works).

Legumes Should Be Supplemented with Nitrogen for Optimum Results



One of the bird of the desert bird of paradise, a legume.
Most legumes have characteristic flowers and leaves.

Q. Do nitrogen fixers like trumpet vines and locust trees provide significant nitrogen to nearby plants?  For example the Bermuda lawn surrounding the locust or the iris and daffodils in a flower bed anchored by a trumpet vine.

 

A. No they don’t produce enough for our high expectations in landscapes and gardens. Nitrogen fixers (such as legumes, there are others) supply enough to help make sure they can reproduce and make seed. The objectives (if I can put it in human terms) of plants and humans are different. Plants want to survive, reproduce and out-compete with other plants for their niche. In nitrogen poor soils nitrogen fixers, like legumes, take nitrogen from the air and supplement what they can’t get from the ground. In nitrogen poor soils, legumes are fantastic competitors. In nitrogen rich soils they are not.

Typical legume flower leaf and pod

            The expectations of humans for the plants they care for are far greater than plant objectives. We want beauty and lushness from landscape plants and we want a good production of food from our legume crops.

            The nitrogen needed to meet human expectations is far greater than the nitrogen needed to meet plant objectives. So for this reason, we need to fertilize nitrogen fixing plants with nitrogen to meet our objectives. The basic rule of thumb I use is the question, “So I want my plants to meet what they consider to be adequate (reproduction and beat out the competition) or do I want them to do more than that?”

Snow pea flowers and leaves are good examples of what
many legumes resemble

            Most people want these plants to do far more than successfully reproduce. Some people are purists and they want that “native look” or for philosophical reasons they prefer the plant produce what it can they are happy living in the "nitrogen cycle".  Nothing wrong with that and it meets their expectations. If you want lushness or greater production, then add extra nitrogen.

            The general rule of thumb you can follow is that many nitrogen fixing plants receive only about 25%, at best, of the nitrogen they need to meet our expectations. However you can treat legumes just like any other plant and feed them extra nitrogen. Plants can be lazy. If you give them all this nitrogen, they may produce little to no nodules on the roots (the nodules contain the nitrogen fixing bacteria). Hey, its alot easier to take available nitrogen than it is to build these homes on their roots for these symbiotic bacteria that take nitrogen from the air.

root nodules of legume can resemble root knot nematode infestation

            We are lucky in that nitrogen fixation by legumes is far more efficient in our alkaline soils of the desert than in acid soils of high rainfall areas. So to answer your question with a short winded response, no, they will not produce enough nitrogen for surrounding plants if your landscape expectations are high. If you are a eco-purist, then maybe they will.

Removing Sucker Growth from African Sumac

Q. I have an African Sumac that has sprouts coming up from the roots. Besides trimming them every time they get above the soil level is there anything I can do to stop these sprouts from popping up?

 



Suckers coming from tree rose. These should be removed from
the roots by pulling back the soil and pulling them if they are
young enough. If older they should be cut off below ground.

A. I think I have enough information to answer. If these are naturally occurring “sprouts” and not coming from a damaged area then I would say no. However, usually if you keep these suckers controlled as soon as you see them and remove them at the trunk, not cutting them off with a shears, the number should slow down considerably.

            There are chemicals you can apply that are sprout inhibitors but I don’t think you have access to those chemicals as a consumer and not a professional. Besides, even if you did have access to them they would probably be expensive for you and a real pain to apply it. The best way to reduce the numbers is make a short term commitment to remove them as soon as you see them. Remove them directly from the trunk.

            This may mean you will have to remove some soil from the trunk and cut them as close to the trunk as you can. As you see new sprouts a couple of inches long, immediately pull them from the trunk.

            If you keep this up and do not let them get large before you remove them then I think you will see a reduction in numbers and easier maintenance. I wish there was a magic bullet for you but I doubt it.

Use Plants Resistant to Nematodes

Q. You have covered on one of your post about nematodes. Last fall, I pulled one of my cucumber plants. There were 4 plants in a row. One of the plants definitely had strange roots which I am almost positive were caused by root knot nematodes. I didn't do any solarization because it was cold during the time and I have read that it is best to do it during the hottest months. Are these nematodes harmful to humans and my dog? Will it give me a disease or worm if I touched the soil?

Swelling bumps on roots is root knot nematode infestation

You have covered that the only other way to fix this completely is through fumigation--which I can't really do since I only do organic gardening. Can I at least plant any other vegetables in the same raised bed, or will it cause me any ill effects after I eat the fruit/veggies that it bears? I was also thinking of maybe removing the soil from the raised bed and move them to the big pots where I will be planting citrus plants. Then I will replace the raised bed with new soil. Would this work well or will it just cause problems to my citrus plants? I'd love your input.

 

Root know nematode on tomato

A. Nematodes are very tough to impossible to get rid of if you have them. I should say they are basically impossible to get rid of. Be careful and do not move soil from this spot to other areas or you will move the nematodes as well.

Nematodes only infest plants, not animals so all animals are safe around these guys. Soil solarization will help knock back the populations but not get rid of them.

There are some products like Clandosan (a natural product) which are supposed to help but I would not be too optimistic. Even with fumigation it does not get rid of them buy just knocks them back.

            Use vegetables that are nematode resistant and fruit trees on rootstocks that resist nematodes. On vegetables they will have the designation "N"below the name somewhere. Other letters might also appear like "V" "F" and the like which just stands for resistant to other pest problems like Verticillium (V) and Fusarium (F), two prominent disease problems.

Nematode resistant rootstocks for fruit trees include Nemaguard, Citation, Viking, Atlas, Myrobalan, and Marianna. Hope this helps.

 

Organic Control of Stinkbugs

Q. What is the best way to control Shield Bugs here in Las Vegas?   They were found on my Italian Cypress.   My concern is that they will invade my garden.  The broccoli and cabbage seem to be ok right now but the new garden is going in this week.  

Shield or stink bug. They have a hypodermic-like mouthpart
lying under their abdomen that can pierce fruit or vegetables
and withdraw fluids.

A. These can also be called “stink bugs” because it can release an odor from its abdomen when attacked or threatened. Many of these types of insects will damage fruits and vegetables and they have no really good predators here for them. Even birds will leave them alone because of their “stink”. 

            We will find lots of bugs on our plants. It is really the numbers that count. They are overwintering right now and waiting for a chance to find some food with the new growth and make some babies. I would at this point just hand pick them when you see them and put them in a bottle with vinegar or alcohol.

Stinkbug and apple to give you relative size. The dimples
on the fruit were probably caused by stinkbug feeding

            If you do not need to use a pesticide, I wouldn’t. These guys have wings under that shield and can fly from yard to yard. Pesticides used unnecessarily will also kill other insects, good and bad.

            Also if you just take a spray bottle with soap and water and spray them directly this will also kill them. This is true of all insects, good and bad. The water is made “wetter” or it loses its surface tension and can then invade the tiny spiracles that insects have on their body for taking in air and “breathing”. This causes them to basically drown.

            Soap and water sprays are good to use but must land directly on the insect to “drown” it. It will not leave a poisonous residue behind like pesticides can.