Xtremehorticulture

Xtremehorticulture of the Desert

When to Fertilize Cacti

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Q. I have some cacti in my backyard.  Should I fertilize them and when? When cacti flower they need high phosphorus fertilizer. A rose or tomato fertilizer should work. A. The standard answer is to fertilize them lightly in the spring of each year. That is the standard answer. The purpose of fertilizer is to give the plants what they need or what is lacking in the soil. Once plants have what they need, stand back, and give them a chance to grow. Giving more fertilizer than they need, and watering plants more often, does not necessarily make them grow faster. Fertilizers are not a magic “on and off” switch; you can’t force plants to get larger and bigger by giving them more fertilizer than what they need. All plants have a genetic “maximum” at which they can grow. That is why most cacti grow slowly, and other plants may or may not, depending on their “genetics”. For cacti, it depends on the fertilizer level, watering and soil mix besides their “genetics”. There is one fertilizer exception and it is a bit tricky. Nitrogen fertilizers increase the speed at which any plant, including cacti, get larger but you must be careful. There is a danger from “growing too fast” for all plants including cacti. The fancy term is “luxury consumption”. To maximize growth, apply nitrogen fertilizers no more than twice during their growing season. Be judicious when watering them and don’t let the soil stay wet. But if your cacti are growing well without it, then don’t use it.

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Fertilizing in the Fall?

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Q. Is it too early to fertilize now my oleanders, lantana, rosemary, and chase tree? This could be temperature, nitrogen or iron. Try different fertilizers. If you find the right fertilizer it will become darker and greener. That’s how you know its a fertilizer problem. A. You can fertilize now (October) and skip the spring application. Woody plants put nitrogen fertilizer (whatever is “left over”) into “storage” until spring. The only plants you want to skip are the so-called “winter tender” plants which you don’t list (except the tops of lantana which are damaged at 32F). Those are the plants which are sensitive to winter cold damage and include most of our citrus and freeze tender plants like bougainvillea. You don’t want to stimulate new growth that could be damaged by freezing temperatures. This might include the more tender dwarf salmon colored flowered oleanders (5 foot and tender at 20F) but not the traditionally big ones like the reds and white flowered types (18 foot) which are cold hardy to about 10F.             Skip fall soil applications of iron fertilizers and wait to correct yellowing due to iron in early spring. Plants will respond to soil applied iron fertilizers best in the early spring. Fall applications of iron fertilizers are best when sprayed on the leaves. Use liquid detergent like dishwashing soap or (best) use a spray surfactant such as a wetting agent when you spray. Also it is best to use distilled water so the pH is not alkaline or acid. Better for iron uptake by the plant through its leaves. Makes more iron available.

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Pine Trees Don’t Need as Much Fertilizer as Fruit Trees

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  Pine trees in the desert do not need as much fertilizer as fruit trees. We don’t expect as much from them as we do fruit trees. Q. I have a few Aleppo pine trees that I fertilize and water regularly growing in Logandale. I am wondering how much fertilizer to give them each year and how much to water them. I am wondering if I can get them off of the irrigation due to a shallow water table here and apply less fertilizer. Pine trees access water from shallow aquifers if they are within a few feet of the surface of the soil. One way to see if that is the case is to look for salt pushed to the soil surface by shallow water. A. In my experience trees like Aleppo pine need fertilizer applied AT THE MOST once a year and perhaps less often. In the case of pine trees mostly nitrogen and potassium because we don’t need them to flower or fruit. That requires fertilizer higher in phosphorus, the middle number. Whenever the trees are “improved” (hybridized or improved for some reason) they need to be fertilized more often and need more care. For example, most fruit trees require one full or a split application of fertilizer twice a year. This is Burgundy plum growing in Las Vegas, NV. Fruit trees will need more fertilizer if we want large fruit to be produced. Are expectations aren’t as high for pine trees so they can get by without applying as much fertilizer. My guess is that your pine trees, at the most, will need fertilizer applied once a year in the spring. Improved trees like fruit trees need about one pound of a nitrogen fertilizer in the spring (or the fertilizer divided in half and applied twice) for each 1000 square feet under their canopy. Aleppo pine trees require it less often or apply less total amount each time you fertilize. New growth of older pine trees should be at least 8 inches or more to give adequate growth for a full canopy. Look at the results of irrigations and applications of fertilizer. The fertilizer is needed every year or every other year. A tree of that size should put on about 8 inches of new growth every year to keep it full. That takes primarily nitrogen similar to a lawn fertilizer (21-7-14). Don’t skimp on nitrogen and potassium in the fertilizer for pine trees. Because they are “all green” and no flowers or fruit you can apply less of the middle number (the amount of phosphorus). As far as applying irrigation less often or eliminating them, you need shallow groundwater to about 5 to 7 feet deep. At the same time force its roots to grow deeper in the soil so it can discover the water. Pine trees have taproots or large roots that can grow deep if given the chance. Groundwater can go down in the summer months and up to normal in the winter. What I am telling you is that you might need to water occasionally during the summer months. This is bubbler and basin irrigation on pine trees. The basin doesn’t have to be deep but it must be flat and capture the water from the bubbler so it stays put long enough and penetrates the soil deeply. When you irrigate, water the trees deep when you do, water them less often and watch the tops. Force the tree roots “to go after” deeper water and see how much fewer extra irrigations they need and still maintain 8 inches of new growth during the early summer months.

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Pines in Logandale Need Less Fertilizer But the Same Amount of Water

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In my experience trees like Aleppo pine need fertilizer applied AT THE MOST once a year and perhaps less often.  Non-Flowering and Non-Fruiting Trees Need Mostly Nitrogen and Potassium In the case of pine trees mostly nitrogen and potassium because we don’t need them to flower or fruit. That requires fertilizer higher in phosphorus, the middle number. Whenever the trees are “improved” (hybridized or improved for some reason) they need to be fertilized more often and need more care. For example, most fruit trees require one full or a split application of fertilizer twice a year. Force Them After this Water My guess is that your pine trees, at the most, will need fertilizer applied once a year in the spring. Improved trees like fruit trees need about one pound of a nitrogen fertilizer in the spring (or the fertilizer divided in half and applied twice) for each 1000 square feet under their canopy. Aleppo pine trees require it less often or apply less total amount each time you fertilize. Look at the results of irrigations and applications of fertilizer. The fertilizer is needed every year or every other year. A tree of that size should put on about 8 inches of new growth every year to keep it full. That takes primarily nitrogen similar to a lawn fertilizer (21-7-14). Don’t skimp on nitrogen and potassium in the fertilizer for pine trees. Because they are “all green” and no flowers or fruit you can apply less of the middle number (the amount of phosphorus). As far as applying irrigation less often or eliminating them, you need shallow groundwater to about 5 to 7 feet deep. At the same time force its roots to grow deeper in the soil so it can discover the water. Pine trees have taproots or large roots that can grow deep if given the chance. Groundwater can go down in the summer months and up to normal in the winter. What I am telling you is that you might need to water occasionally during the summer months. When you irrigate, water the trees deep when you do, water them less often and watch the tops. Force the tree roots “to go after” deeper water and see how much fewer extra irrigations they need and still maintain 8 inches of new growth during the early summer months.

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Apricot Poor Leaf Color Could be Fertilizer or…..

Leave a Comment / fertilizer, growth, iron, leaf color, nutrients /

 Q. I have an apricot tree and the leaves are a lighter green during the past couple of months. Are the leaves lacking nutrients? Apricot leaves should be dark green when it is growing and in the summer. This color is a problem or late in the fall or winter just before leaf drop. Correct yellowing apricot leaves with an iron chelate applied in the spring or compost applied to the soil surface or both. A. Perhaps. Look at this year’s growth in several places as well as its leaf color. New growth should average about 18 inches for productive trees. Leaf color should be dark green. If leaf color is a light green and new growth is well under 18 inches, then consider applying a fertilizer or rich compost. Not all new growth of apricot is red. Some stays green. This is excessive new growth on a mature apricot and should be cut back. Prune it back with a hand pruner anytime you see it. You don’t have to wait until winter or leaf drop. Look at Growth and Leaf Color  Fruit tree fertilizer is applied in the early spring, usually once a year. Unless the soil is very, very, sandy, once a year application of a fruit tree fertilizer is usually often enough. Use the rate on the fertilizer bag as the maximum rate to apply. If applying twice a year, divide the rate on the bag in half. Apricots when young should get an average growth of 18 inches in a year. When it is mature maybe 8 to 12 inches of new growth each year. Apricot leaves showing inter veinal necrosis…or leaf yellowing. Defintely needs some iron chelate applied in early spring. But what about the leaf cupping? Weed killers can cause the leaves to cup. So can excessive heat in the summer. Soil Improvement Soil improvement may be needed also. Use rich compost instead of a fertilizer. Never apply a fertilizer or rich compost closer than 12 to 18 inches from the trunk. Both fertilizers and rich compost can damage plants if applied too close. To be on the safe side, water the soil immediately after the application of a fertilizer. Water “dilutes” fertilizer and rich compost. Never apply compost or fertilizer near the trunk or main stem of a plant. When applying a rich compost, rake rock or bark mulch away three feet from the trunk in all directions. Apply a thin layer (1/4 inch) of rich compost, water it in and rerake the surface mulch back into place. Do this once every year. If it is a nutrient issue from a lack of fertilizer, you will see a change in the leaf color in about two weeks. This color change will last months. Apricot tree near a lawn but the roots can choose where to grow. Growth might not be enough. Check fruit production last year, fertilizer applications and soil improvement. Inspect Irrigation Light green leaves can also be from either drought or watering daily. First correct daily irrigations during the summer. That’s a big no-no except for lawns, flower beds and areas for growing vegetables. Big trees and shrubs can’t handle that. When watering, apply water deeply to tall plants. If it calls for more continuous watering, increase the size of the irrigated area under the tree. Apply water to at least half the area under a plant. If the leaf color is light green, it may be a sign the tree is watered too often. Give the roots at least one day between irrigations during the summer otherwise the roots may “drown”. This gives the soil a chance to drain water and the roots to “breathe.”

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Canary Island Date Palm Problems

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Q. I have a Canary Date Palm that developed yellowing leaves last year. I planted this palm about 10 years ago in my landscape. Canary Island Date Palm A. The proper name is Canary Island Date Palm. Eliminate simple possibilities first.  Water and drainage Make sure whatever method you are using to irrigate the tree has not changed because of a broken irrigation line or malfunctioning irrigation emitters. Check the soil around the tree to make sure it’s not still wet before it is irrigated the next time. The soil at four or 5 inches deep should still be starting to dry when you water again. Watering cycles of palms is similar to other large trees on your property and not to other locations like lawns, flowerbeds that require frequent irrigation. Watering palm trees as frequently as you would these locations would be a mistake. Fertilize with a palm fertilizer Palm nutrient deficiencies such as potassium, magnesium or manganese deficiencies can cause yellowing as well. Use a palm tree fertilizer such as Arizona’s Best the next time this palm tree is fertilized. Disease Possibilities There are a couple of disease possibilities that have not yet, to my knowledge, been diagnosed in southern Nevada. Three palm diseases have been noted in Southern California on this Palm. The only disease which causes fronds to yellow on Canary Island Date Palm is Fusarium Wilt. This disease can be spread from tree to tree through pruning tools. Wiping or spraying the cutting blades of pruning tools with at least 70 – 90 % isopropyl alcohol will effectively keep the disease from being spread due to a lack of sanitation to other palms. Anyone pruning these palms should never use dirty tools. Tools should be cleaned with soap and water first and then sanitized before pruning begins.

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Garage of Old Fertilizers – What to Do?

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Q. What do I do with all the partially used chemical fertilizers in my garage? Chemical storage. A. Most mineral fertilizers can be applied as the fertilizer bag recommends. They dont go bad unless they get wet.  Some fertilizers that contain pesticides must be disposed of properly. If your fertilizer does contain a pesticide then ask me how to get rid of it. If permitted and you no longer want or need these types of fertilizers, give them to your non-organic neighbors for application. It’s best to use them up as normal applications rather than put them out as garbage.             The mineral fertilizers considered “hazardous waste” usually have a weed killer or insecticide that is no longer permitted to be applied by homeowners. These fertilizers should be considered hazardous waste and disposed of according to county regulations that are intended to protect our water supply. Other types of mineral fertilizers can legally be applied. But ask to make sure.

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Replace Conventional Fertilizers with Organic Fertilizers

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Q. I want to replace all my chemical fertilizers with organic formulations. The problem is that I’m not finding any organic fertilizers for landscape trees and shrubs such as podocarpus and photinia. Is it possible to make my own? Please tell me what you recommend. For the USDA National Organic Program find fertilizers that are OMRI Listed or Approved for the USDA NOP. Other countries, places and people have different definitions of “organic”. A. The definition of “organic” can be difficult. To some people organic means free from pesticides and mineral fertilizers. To others it’s things like fish emulsion, kelp meal, bone meal guano, etc. To others it means strict adherence to the USDA definition of organic. In the United States the term organic usually means it’s a listed product of OMRI (Organic Materials Review Institute) which recommends products for the USDA’s National Organic Program (NOP). OMRI Listed – USDA NOP             There are fertilizers in bags listed as OMRI approved. I would look for the word “Organic” mentioned somewhere on the bag. Technically, a product cannot mention the word organic unless it’s recommended for USDA’s organic program. One that comes to mind is the OMRI Listed fertilizer called, “All Purpose” manufactured by Grow More. It resembles a mineral fertilizer when you open the bag but it’s one of the “organic” types.

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Washington States Department of Agriculture: Fertilizer Composition

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I think it was the cleric and economist Robert Malthus who developed a theory that large populations of organisms would slowly make their own environment more “toxic” and no longer sustain themselves. In some ways what he observed is true. We are living in an environment that is becoming more “toxic” as we grow our own food. Some of these “toxicities” come from industrial processes and some of them from our own efforts. Plastics found in human blood Fertilizers and Toxicity Our worlds are becoming more and more toxic. A few states in the US have posted the level of toxicity in fertilizers for home gardens. There has been lots of research on this topic. Brochures exist on heavy metals and gardens. And here. These toxicities are below what the US EPA considers “safe” for human health but they do exist. Another problem with additions to garden soils are the levels of pharmaceuticals used when producing gardens soils and compost. This is from the Washington State Department of Agriculture website

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How and Why to Take a Leaf Tissue Nutrient Sample

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A leaf tissue analysis would show that this ornamental pear is lacking iron. Why Send a Tissue Analysis? The purpose of submitting leaves for a leaf tissue nutrient analysis is to find out the reasons why plants might look sickly or not performing the way we would like. These types of leaf tissue analysis identify nutrients found in the leaves and help to identify which ones may be in short supply. These types of tools are used by growers to adjust which fertilizers are applied and their timing of application in efforts to boost production or performance. A leaf tissue analysis would show this peach tree is iron deficient What the Sample Wont Tell You Submitting a leaf tissue sample has nothing to do with identifying an insect or disease problem, chemical poisoning problems from weed killers or other toxic chemicals. These types of problems are best handled a different way. Baseline Sample is Needed Submitting leaf samples from a problem plant are not enough. Leaf nutrient analysis information is needed from acceptable plants (this establishes a baseline) as well as the problem plant. It’s best these plants are genetically close to each other (the same variety or cultivar is best), they are approximately the same age, the leaf samples taken from the same locations and similar times of year.  even though it looks like it might be nutritional, its not. Leaf tissue analysis wont show a disease problem developing like this Sometimes two samples are submitted; one from acceptable plants and another from problem plants. When historical information exists, this information can be used as the baseline for submitting leaf tissue from problem plants so always keep old leaf tissue analysis reports! How to Take a Sample Select a plant or group of plants showing a suspected nutritional problem.  The plants may all be in the same area or they may be scattered through the growing area. If this problem is on only one plant, sample a single plant. If the problem is on several plants, take subsamples from several plants showing the same symptoms and combine them into one sample.   Take leaf samples at a time of year used to establish historical baseline information. For example, if the baseline information you are using were from plants sampled in the spring of the year, take samples in the spring. If baseline information was in Midsummer, take samples in Midsummer. In some cases, a new baseline may be needed. If submitting one sample from problem plants and another from acceptable plants to establish a baseline, then these are taken on the same date. Take leaf samples from similar areas of the plant and establish where on the plant samples should be taken from. In some cases, this might be newer growth and in other cases older growth. A simple way to do this is to take leaf samples at similar distances along the stems. Document and Label Label these samples in a clean plastic bag using a permanent marker with a 4 letter Code name, date they were taken, and area of the plant taken from (old growth vs new growth). Place these leaf samples in a refrigerator until they are ready to be sent to the lab for analysis. Take notes. Write what you did and how you did it in a log or notebook. Believe me, you wont remember it next year. Contact the Laboratory Download submission forms from the laboratories website and fill out the paperwork.  Call the laboratory and make arrangements for the shipment and any fees that must be paid ahead of time. It is important that these samples are as fresh as possible so keep them in the refrigerator until they are ready to be sent, overnight, to the laboratory. Send them to a laboratory at the beginning of the week so they’re as fresh as possible. A plant tissue analysis laboratory that I frequently use is A and L Laboratories in Modesto CA with the website http://www.al-labs-west.com/

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