For almond trees to produce nuts, some need pollinators

Q: We have two almond trees and since they produce nuts we assume that one is male and the other one female, although we do not know which is which. However, one tree bears almost no nuts. I just checked and could find only two nuts on the entire tree. The other tree is loaded with nuts. The two trees were planted at the same time, eight or 10 years ago. Can you explain this disparity in production?

A. Even though almond flowers contain both male and female parts, some almonds require pollinators while a few others do not. Since you did not tell me the varieties I am not sure which you have.

It is possible that you have one almond tree which requires a pollinator while the other one does not. For pollination to occur, the flowers need to be open at the same time. So if the almond flowers are not open at the same time, it is possible that the tree will get flowers with no nuts produced.

See if you can find out what the variety is and let me know. Once I know that, I can tell you a good pollinator to use. You probably do not want a third almond tree but maybe you can talk to your neighbors into getting one.

The other option you have is to drive around town looking for another almond tree in bloom at the same time you're nutless almond is blooming. If you can find one in bloom at the same time, see if you can persuade the tree's owner to let you cut a few branches from his tree to supply pollen for yours.

Immediately after cutting the branches, put them in a bucket of water directly beneath the nutless tree. This bouquet of almond flowers, providing it is a different variety, can act as a source of pollen for your tree. Otherwise, get rid of the nutless almond and put in Garden Prince or All in One almond variety, which are self-fertile.

Q. My question involves composting in the home garden for spring planting. There seems to be no definitive answers as to when is the best time to add compost to the garden, and exactly how much compost to apply.

I hear that it may be better to apply the compost before the first frost so that it has time to break down before spring planting, and then again I hear that you should add it maybe a month or so before you plant. The latter is normally the approach I take. So far, so good, but can you share your thoughts with me on these two topics?

A. Regarding the compost, I usually look at the color of the soil to determine how much compost to add. For instance, a dark, rich soil that crumbles easily will need less compost than one that is hard to dig and does not crumble easily. Look at my blog and you will see several pictures concerning compost.

A well-prepared vegetable bed should be so friable that you can dig it nearly with your hands, unaided by a shovel.

Once we achieve this state in a vegetable garden soil, we just need to replenish the organic matter which was lost during the growing season. Generally we figure that we lose about one-third of our organic matter content of our soil each year. So the first year it is one-third of our total organic matter content. The second year it is one-third of our remaining organic matter content, etc. So you see it will not run out in three years to zero. It will continue to diminish annually but at a different rate as the total amount of organic matter diminishes.

When preparing a raw (never amended) desert soil for a garden it will take about three years of applying a heavy amount of compost to the soil each year. These applications of compost must also be accompanied by growing vegetables in it.

Just putting compost into a soil and doing nothing else and waiting for three years will accomplish absolutely nothing. Water and microorganisms must be in the mix as well. I like to compare it to making bread or a cake. You can add all the dry ingredients to a bread or cake mix you want but without adequate liquid they will sit there and do nothing.

In the raw desert soils of the Las Vegas Valley we have less than one-tenth of 1 percent organic matter. That is amazingly low. In other raw desert soils the organic matter may reach three-tenths or four-tenths of 1 percent, still not much.

We want our soils to get to 5 percent to 8 percent organic matter. This is 50 to 80 times higher amounts than we have. To achieve this I like to add a minimum of 50 percent compost to our raw desert soils. I would even push it higher, closer to 75 percent the first year.

Every time the soil is prepared for a new planting, organic matter or compost should be added. The time of year does not matter in the warm climate of Las Vegas. In colder climates, when soil temperatures drop into the 40s, most compost will sit there and not do much. As soon as the soil temperatures hit the mid-50s the microorganisms will kick in and start to work.

Compost, by definition, has finished its decomposition. It is then ready to release all the goodies that were built up into it during the composting or rotting process. So if compost is a finished compost, it will not continue to decompose. This is not true of unfinished composts or manure. These will continue to "rot" or decompose and they create their own heat when they do so and are piled together into a pile. Heat builds in the center of the pile to more than 160 degrees Fahrenheit, which is what you need to start killing weed seeds and bad plant pathogens.

So add finished compost every time you plant. The amount varies with the color of the soil. Darker, rich soils need less than lighter-colored, less-well-developed garden soils. But if you add compost every time you plant, and you continuously garden for three years in it, then the garden soil will be sustainable with small amounts of compost every time you plant. I hope this helps.

Bob Morris is a horticulture expert living in Las Vegas; he is on special assignment in the Balkh Province, Afghanistan, for the University of California, Davis. Visit his blog at xtremehorticulture.blogspot.com.