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Monday, July 4, 2011

Maybe Green Manure Crops Might NOT Be the Best Idea in the Desert

Q. I have a 1/2 acre on the east side of the valley ( Las Vegas), the lot is divided in quadrants with the house in one, a barn in another, yard/parking in the third, and the fourth is my chicken run. I was researching the idea of putting an orchard in that area and your work in NLV keeps popping up, but I can't find your list of trees or an article on your high density planting techniques. I know the soil needs improving so I am currently trying green manuring with buckwheat and soybeans. I figure that one way or the other my chickens will like it. Any help you can point me towards I would appreciate.

A. If you will go to my blog Xtremehorticulture of the Desert and in the search engine type "recommended fruit trees" you will see my recommended fruit tree list posted twice; once as a downloadable pdf document and the other posted in its entirety.

This past year the only nursery to carry my recommended fruit trees was Plant World Nursery on Charleston Blvd. Any of their fruit trees with a hanger or tag from Dave Wilson Nursery, a large commercial grower of fruit trees, is from my list. A local producer sold my recommended fruit trees to the public as bareroot trees but will not be doing that this fall. Anyone want to take it on? Contact me.

The idea of high density planting is not mine but adapted from Dave Wilson Nursery out of the Modesto, California area.You can find more information on concept of multiple trees planted in a single hole at davewilsonnursery.com, along with a lot of great information on growing fruit trees.

I produced some YouTube videos on growing fruit trees which can be found by typing "UNCE orchard" at the YouTube video website, another resource. Here is a sample on controlling the size of fruit trees.

Green manure crops are plants that can be started from seed which will either capture low amounts of nitrogen that exist in the soil or capture nitrogen from the air and return it to the soil. They also decompose and add organic matter.

I have mixed feelings about using green manure crops in the desert. Although they are tremendously beneficial to our soils and highly advantageous in most areas of the country, they may or may not make sense when using them in the desert depending on your situation.

The principle reason is water use. A secondary reason is the time that green manure crops take out of production. And thirdly is their cost. Green manure crops take time for the seed to germinate and the plants to grow to a size where they can be beneficial when turned back into the soil. Normally plants are allowed to get to a juvenile or early mature stage before they are turned back into the soil. This takes time, perhaps 5 to 6 weeks or longer which is time taken away from your production.

If you have plenty of space and the cost of water is not a concern then this makes a lot of sense. But if your space is limited and water is costly then this will probably not make a lot of sense for you. It may make more sense to concentrate your space and water into making compost.

Seed can be very expensive so look for inexpensive seed locally that you can use rather than to have it shipped in from some other location in the country. This also helps to lower your carbon expenditures for your small farm or garden.

A very good green manure crop that is inexpensive is annual rye grass. This is the same inexpensive rye that is used for overseeding Bermudagrass in the fall. Grasses, and in particular annual ryegrass, are fast to germinate when temperatures are at least 60° F. You can even speed up its germination by soaking the seed for 24 hours before planting it. The seed must then be carefully dried so that it is dry to the touch but not overly dried or the seed may be ruined.

Legumes harvest nitrogen from the air primarily and are not that terribly good at taking residual nitrogen from the soil. But they are an excellent choice for poor soils if you can get the seed inexpensively.

Annual grasses are wonderful at finding nitrogen in the soil that vegetable crops miss and they take this nitrogen and bioaccumulate it or, in other words, put it into its own plant tissue. The grass is watered and allowed to get about 6 to 10 inches tall and then turned into the soil just before it produces a seedhead. This nitrogen in the plant tissue is then slowly released as the rye plant decomposes in the soil.

However, using a green manure crop in a mixed planting where you are combining an orchard with chickens or other fowl makes a lot of sense provided these animals do not ruin in your production. I could see how you might be able to have a small orchard and, using the existing water required to irrigate your fruit trees, grow some green manure crops for soil improvement and that would also double as food for your fowl.

Keep your costs low by growing winter and summer green manure crops from seed that are inexpensive and that will do well in our climate. Some manure crops for our area might include annual ryegreass, timothy, wheat, oats, alfalfa, peas and Kentucky 31 tall fescue. But if you use tall fescue be sure to turn it into the soil while it is still young.

Just about any inexpensive seed will work if you know the germination temperature of the seed. Don't use bermudagrass. Recommended green manure crops from other climates may or may not work well here and it may be difficult to find inexpensive seed.


  1. Thanks for such a quick answer to my question! To continue the idea I am working basically with a blank slate. The area I am going to use is roughly 25' N-S and 75' E-W the east end has large pine trees and the south side has a 6' block wall. Where can I go for help with creating a site plan?

  2. Thanks for the quick reply to my question! As a follow-up, everything you read about fixing your soils issues starts by telling you to get a soil test done, how do you do that here in Las Vegas?

  3. I really would not use any local soil testing labs. There are or were a couple in town. They have no experience in agriculture so their database for making recommendations is poor to nonexistent. I usually send soil samples to A and L Labs out of Modesto,CA, for analysis. I would do make an initial soil test to see what I am starting with then make another after a few years of compost additions to the growing beds. I don't use that many soil tests. That is a standard response and it comes out of commercial agriculture where the difference between 150 bu of corn and 200 bu of corn means big buck on huge farms. Most of what you can do is visual and looking at how your plants are performing. You are not interested in maximizing yields but maximizing quality.