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Sunday, February 4, 2018

Keep Compost Away from Young Plants

Q. When I apply compost to plants, do I avoid the main trunk area or do I apply up to the trunk?  

A. If soils have no plants in them, I use about 1 inch layer of compost applied to flowerbeds and vegetable beds every year. This compost is turned under or rototilled into the soil before planting. 

Compost can be used as a substitution for fertilizer in vegetable and flower beds even when plants are actively growing in them as long as you can see bare soil. Apply the compost to the soil between the plants or between rows and water it in. 
Compost can be applied to the soil surface and watered into the soil and act like a fertilizer

Compost can be applied to fruit trees in a circle around the trees under the canopy where the soil is wet. The compost should not be piled against the trunks of the trees. 
Compost can be added around fruit trees to the soil surface but keeping in from contact with the tree directly and then watered in. It is very effective when combined with a surface layer of wood chips.
Compost can be applied around desert landscape plants on top of coarse rock mulch. If the rock is coarse enough, it can be washed onto the surface of the soil under the plant canopy through the rocks with a hose. It is best if straight compost does not come in contact directly with soft succulent plants or young trees.
Compost tea brewer, top, and applying compost tea with an injector directly into the soil.

Compost can also be put in with pure water and allowed to "seep" just like tea in a tea bag. The water separated from this combination, compost tea, can be used as a liquid fertilizer and in some cases helps reduce disease problems in the soil or when used as a spray on the foliage.  After the tea has been made the compost can still be used as a soil amendment, but, of course, wit;h a lower nutrient content.

Be careful, though, the type of compost used can make this tea solution very concentrated and can harm plants unless it is diluted with water. It is good to use a salinity meter to judge whether it is safe to apply to foliage directly without dilution or knowing how much to dilute it. The salmity of the compost tea should be below 4 mmhose/cm or dS/m. 

Compost Should Finish Its Cycle before Application

Q. How do I know when compost is safe to apply to plants? Do I measure temperature?

A. Compost is safe to apply when the composting process has completed. Look and smell a compost to see if it is finished. A finished compost will have the same color throughout and the components are not recognizable. Everything looks the same.
Finished compost should have a dark color, the color should be consistent through the compost and the components used tof composting are not distinguishable. 

Commercial compost is safe to apply any time it has finished the composting cycle. Most commercial compost is never sold or marketed before it is finished. The components of a compost will eventually break down and supply nutrients to plants separately but there are some problems doing it this way.

Composting is the same process used by Mother Nature when things “rot”. But in composting, this rotting process is sped up and managed. If you are making your own compost, it is probably a good idea to purchase a compost thermometer.

The type of composting I would use is pile composting. This method mixes all the components together and puts it in a moist pile. The fastest way to get a finished compost using this method is by turning this pile or aerating it when the core of the compost reaches 160° F and wetting it down.

A slower method is the static pile composting method where the pile is never turned. There are much fancier ways of making compost like using forced air or in-vessel composting which can finish compost extremely fast.

Saturday, February 3, 2018

Soil: They Don't Live in the Desert

Soil: the upper layer of earth in which plants grow, a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles. (Oxford Dictionaries, online version)

Typical Mojave  (or Mohave) Desert scene
            It is obvious the authors who wrote this popular definition of soil did not live in the Inland Empire, Great Basin, Mojave (or Mohave), Sonoran or Chihuahuan deserts. Is it any wonder that people moving into desert environments from less agri-hostile locations have so much difficulty growing things? The importance of soils in desert production should not be underestimated.
The further a plant is from its native environment, the more time, energy and money is needed for it to perform satisfactorily. When we design landscapes with plants less suitable to desert environments, we can be certain man-hours and resources must be increased resulting in higher costs and increasing budgets.
Selecting the right plant, planting it in the right location, in the right soil and managing that soil correctly is paramount to managing limited resources efficiently.
When I was studying at the University I was taught that the average soil for plant production should have test results like these: pH of 6.5-7.5, organic matter content of 3 to 5%, maximum salinity less than 4.0 mmhos/cm (dS/m) and a porosity (collective air spaces) of approximately 50%. As an inexperienced student, I assumed soils outside of these ranges would extensively damage or even kill plants.
Typical raw Mojave Desert soil, low in organic matter, pH 8.2 and higher and never has been cropped or developed.
Then I moved into the Mojave Desert and became aware that plants could live outside of these ranges. Valid soil tests from desert soils under development, but already growing honey mesquite, rabbit brush, desert sage, creosote bush, Opuntia, Cholla, Agave and other desert species, routinely provided a pH of 8.2 and above, organic matter content that was not measurable, salinity exceeding 100 dS/m and toxic salt levels like boron over 50 ppm. I knew I wasn’t in plant Hell, but thought I could see it from here.
Studying and working in the arid and desert West and finally the deserts and arid regions of the Middle East, Central Asia and northern and southern Africa I have learned that nearly any desert soil is manageable. Management decisions change when the plant palette changes.
Orchard management in Ethiopia
My personal definition of soil has changed. Soil is a mixture of substances, either natural or man-made, which will grow plants if properly managed. Irrigated desert soils must be managed if they are to grow plants. Soils do not need to be black or dark brown and they may not have organic matter in them but they will still grow plants.
Years ago friends of mine at the University of Sonora in Hermosillo taught me a valuable lesson about amending desert soils. I began production trials of two selections of edible Opuntia from Sonora, Mexico. I planted pads the same distances they were planted at the field station in Hermosillo. They were planted in unamended, raw Mojave Desert soil at UNLV’s Center for Urban Horticulture and Water Conservation in North Las Vegas, Nevada.
Nopal cactus from Hermosillo, Mexico, (USON) planted without organics (left( and with organics (right) after two years (left) and one year (right).

One year later faculty from the University of Sonora came to visit the plots and see the progress that was made. The Opuntia were all growing but I was disappointed in their progress and production of nopales (edible immature pads) and tunas (cactus fruit).
They asked me if I had amended the soil with composted manure before I planted the pads. I had not. I assumed that because these were desert plants they would perform better in a desert soil that was not amended. I was wrong.
We replanted a second area with fresh pads of the same varieties, this time amending the soil with composted manure. The results were remarkable. The second planting of Opuntia caught up to the older planting early in the first growing season and exceeded it soon afterwards. This was my first lesson: desert plants might tolerate unamended desert soils but they may not thrive in them.
The desert provides a unique environment for the evolution of soils and plants that can grow in those soils. High temperatures, low humidity, intense sunlight and lack of rainfall contribute to desert soil’s unique appearance, structure, biology and chemistry. Once water is added to this mix, everything changes and it can change rapidly.
This does not mean desert soils should not be improved. They can and should be improved if we are to grow a wide range of plants. But it is important to understand that amendments produced in desert environments may have different qualities from amendments produced in wetter, cooler climates.
Desert soil improved with compost for vegetable production. It will be deeply incorporated and the  amended soil shaped into beds for production.
Two major problems which can occur in soil amendments produced in desert environments are high levels of salts and difficulty in wetting (hydrophobic) the amendment due to a very low moisture content. These are frequent criticisms of amendments and composts produced in desert climates.
Salinity problems arise from a high total salt content in the amendment or from specific compounds which contain elements that can damage plants. Specific elements that can damage plants, and should be reported in laboratory tests by suppliers, include boron, sodium and chlorides. With some monitoring by amendment producers, levels of these specific elements that can be damaging to plants can be lowered or minimized.
Salt damage to Meyer lemon.
Total salinity of amendments produced in desert climates may be a problem if the range in salinity acceptable for soil amendments is 3 - 4 dS/m and poor quality water, such as Colorado River water, is used to leach excessive salts. It takes more water to reduce salts in desert environments than in wetter climates. More water usually translates to higher costs of production.
Remember that the salinity of Colorado River water in the Lower Basin approaches 1.2 dS/m. In other words, for every 300,000 gallons of water used for leaching, about 1 ton of salt is delivered to the compost. These salts must also be leached, reducing the leaching effectiveness of the applied water.
Colorado River
Compounding this problem is very high evaporation, exceeding 4/10 of an inch of water per day, during summer months. Evaporation of this water leaves behind salts, adding to the salt load which must be lowered. This increased salt load also requires more water for leaching.
Where does this water used for leaching go? In the case of Las Vegas and other desert communities along the River, these plant nutrients are fed into the Colorado.
Soil amendments which contain quite a bit of course plant fibers can become excessively dry in desert environments. Once dry, these amendments can be difficult to wet without a lot of effort or wetting agents. Hydrophobic amendments like these can also increase the difficulty in leaching salts.
Poor root development in sweet corn growing in a raised bed due to hydrophobic soil forming from incorporated compost.
Establishing acceptable physical and chemical criteria for soil amendments is important for the landscape and nursery industry. Even more important is to educate consumers how to interpret tests for soil amendments when applying them to specific landscapes. In this way soils and soil amendments can be better managed. “Me too” standards is not a sustainable answer to across-the-board recommendations for all landscapes.

Friday, January 26, 2018

Leaf Cupping on Asian Pear

Persimmons for the Mojave Desert

Harvesting Green Almonds

Free Spring Planting Class Feb 10 by Master Gardeners

There are still raised beds available!!!!!
For more information contact 702-257-5555

Grow beds are still available at this community garden. Raised beds are 4 x 8 ft and only $10 per month which includes water. A water spigot is provided at each bed and they are ready to plant NOW. The $75 initial startup fee is waived this spring but will resume. For more information contact Nedra   nedrahoogland72@gmail.com

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Thursday, January 25, 2018

Minor Differences between Snap and Sugar Snap Peas

Q. Have had much success with sugar snap peas, but lately I’ve been planting sugar snap peas and getting snow peas instead.  Is it because the seed is old? 

Flowering of snap peas

A. I’m not sure the difference you are seeing between these snow peas and snap peas. Snow peas have flat pods when young and we see them frequently used in stirfry. Snap peas, or sugar snap peas as they are sometimes called, have round pods when they are young and not used conventionally in stirfry.
New growth of bush form of snap peas
            Snap peas, when they first emerge, are flat. As the seed inside the pod begins to enlarge the pod becomes round. If you pick snap peas too early they will look like snow peas. When harvesting snap peas, wait a little bit longer for the seed to enlarge and the pod to become round. But harvest the pods before the seed becomes mature. If you wait too long, the seed contains more starch rather than sugar and not as sweet.
            The differences between the two are genetic so it should have nothing to do with the age of the seed. Snap peas were genetically bred from their ancestors, the English or garden pea and snow peas, to be less fibrous when they are young.
            You also might be referring to the “strings” in the pod or how tough the pod is. If strings are a problem, harvest when very young or the pod may get tough when older. If you’re having problems with strings, remove the strings from the pods before using them and start harvesting earlier.

Apple Tree Seeping Water

Q. I noticed my Anna apple tree is seeping fluid and a white patsy substance from a previous cut done last year. What shall I do to help it?
Anna apple seeping fluid from old pruning wound

A. Smell the fluid. Take your finger and wipe it against this wetness and judge your nose whether the smell is “yeasty” or not. If there is a strong yeasty smell, there might be a bacterial infection going on. If it does not smell “yeasty”, then there is probably no infection. 
Wetwood or slime flux disease on older tree from a reader. Slime flux is caused by bacteria "feeding" on inner wood of tree and causing the fluid to smell "yeasty". Often times this liquid attracts flies and has a foul odor. This "disease" is not fatal to the tree but can be unsightly and create a nusiance.
            I would not do anything to the tree regardless. The yeasty smell is caused by a non-lethal infection.
            The inside of a tree has a central core of dead wood. The living part of the tree is an outer cylinder of living wood that enlarges year-to-year. The inside of the living cylinder increases the diameter of this dead, central core each year.
            Growth in the length of branches is called primary growth. Growth in width or diameter is called secondary growth.
            Secondary growth is responsible for “rolling over” pruning cuts and they can no longer be seen. When this secondary growth rolls over a wound, it surrounds or engulfs the wound, covering it, but the wound doesn’t “heal” like it does in animals.
The  cylinder of living "wood" of a tree is alive and can "roll over" a wound, even a large one, and "bury" it in the older dead wood inside the tree.
            The central core of the tree is dead. This dead wood can “rot” due to different microorganisms. This rotting caused by microorganisms can cause the “seeping fluid” you are seeing.
            I would do nothing to the tree at this time unless you see other problems developing in its overall health. Judging from the picture you sent, the old wound seems to be healing and rolling over the pruned cut very nicely.
            I would not disturb it in any way but let the tree heal on its own. It should stop weeping when tree growth begins in earnest in the next few weeks.

Leaf Damage Can Come from Salts

Q. Do you have any idea what causes deformed leaves to appear on my shrubs? I thought it was from heat this past summer but I also see it on trees not in this sunny spot.

Readers picture of small, deformed leaves from shrub. Except for the scorched leaf margins, the plant looks healthy.

A. If you look at the edges of the deformed leaves on your shrubs, they have brown margins or edges, very typical to salt burn.
            Fertilizer? If too much fertilizer is used or placed too close to the plant, it can cause this kind of brown leaf margins. They can also cause unusual growth. Most fertilizers are salts and can cause salt burn if too much is applied or applied too close to the trunk or main stems.
Extreme salt damage to vegetable leaf
            Salt damage sometimes occurs after a heavy rain. This is because salts are pushed away from the roots with applied irrigation but rain can push the salts back toward the roots. The return of salts to the roots can cause plant damage. For this reason, it’s a good idea to run drip irrigation right after a heavy rain.
Minor salt damage to pepper leaf margins. Enough to cause eventual leaf cupping.
            Salt damage is much worse for plants when air temperatures are hot rather than cool.
            Not enough water applied? This has nothing to do with how often water is applied, how many days each week, but about how much water is applied during each irrigation. Drought like this can also cause smaller leaves with brown margins.
            Salt burn can look a lot like drought.
            Mulch problem? Mulch placed too close to the trunk can cause disease problems when the trunk is in contact with wet mulch too often? This is true of wood chip mulch and rock mulch.
            Zinc deficiency can cause something similar, but I don’t think this is a zinc shortage.
            What to do? Flush the area under the canopy with a large volume of water to wash salts away from the roots. Secondly, pull wood mulch or rock mulch away from the stems or trunk of the plant. Third, add one or two more drip emitters to the plant so as to increase the volume of water applied without having to change the minutes on your irrigation clock.

Cut Back Bougainvillea or Not?

Q. Should bougainvillea be cut back in the winter?  I have two in large pots. I want to see them grow fuller this spring and summer. Cut back or leave them?

Bougainvillea used as a landscape shrub in Bullhead City, Az, USAa

A. Wait until about March 1 and see if there is any winter damage from freezing. Then decide. If there is, cut it back close to the ground and let it regrow again.

Bougainvillea will regrow after damage quickly on established roots from year to year. As long as the winter temperatures were not cold enough to damage the roots and crown. Mulch the plant during winter months if you think it will freeze.

            If there is no winter freeze damage, make this plant fuller by cutting the stems back at various heights (so it doesn’t look like a butch haircut) anywhere from a foot to foot half from the ground. For every cut you make, three new shoots will grow and increase the density of the plant.

How to Grow Oaks from Acorns. Do you really want to?

Q. I picked up 10 acorns that were laying on the ground in Illinois. If I were to plant these, would the acorns germinate and produce an oak tree? What are the chances it will survive in the desert climate? 

Acorn from southern live oak, which grows in the desert southwest, from previous submitter
A. There are about twenty different kinds of oaks native to Illinois. Two of the more common oaks are northern Red Oak and White Oak. Both of these oaks are not native to the Southwest and you will have trouble growing them here as they get older.
Oak leaf gall does occur on our native oaks in the desert southwest
           We have oaks native to the Southwest and you are better off planting those than bringing some from Illinois. But you could have fun with them for a while.
            If you found acorns on the ground, then most likely the seed inside the acorn is mature. However, the seed may not be “alive”. Put them in a bowl of water and use the ones that sink and discard the ones that float.
           Plant them on the north or east side of a building. Mix compost 50/50 with native soil in an area 3 feet wide and 2 feet deep. Plant the acorns on their side in this amended soil, about 1 inch deep, in mid-November. If the winter is cold enough, the seed inside the acorn will grow when it warms in the spring.
           If you missed this November window, put them in a plastic bag with a moist sponge in the refrigerator. Take them out after two months and then plant them in the same way.
           Oaks have a very strong taproot. If you move them from this spot, do it when they are very small. They do not move easily to new locations once they establish a taproot. Otherwise, remove extra seedlings and grow the strongest ones the same way you would grow any other landscape tree.

Urban Agriculture Pays Off

New research from collaboration between Arizona State University (ASU) and Google provides an assessment of the value of urban agriculture and the benefits it provides on a global scale.

“For the first time, we have a data-driven approach that quantifies the ecosystem benefits from urban agriculture. Our estimates of ecosystem services show potential for millions of tons of food production, thousands of tons of nitrogen sequestration, billions of kilowatt hours of energy savings and billions of cubic meters of avoided storm runoff from agriculture in urban areas,” said Matei Georgescu, an ASU associate professor.
Using the Google Earth Engine, the researchers analyzed global population, urban, meteorological, terrain, and Food and Agricultural Organization datasets to arrive at their global scale estimates – and then aggregated them by country. The estimated value of four ecosystems services resulting from existing vegetation in urban areas was found to be roughly $33 billion. This includes a projected annual food production of 100 to 180 million tons and energy savings of 14-15 billion kilowatt-hours.