Irrigations should still be deep during cold months

Temperatures in the valley turned cool rather quickly and it doesn't seem like they will climb back up again this winter. Irrigations of course should be less frequent but just as deep as before.

Late fall fertilizers should be applied by now but they should be irrigated in. Foliar applications of fertilizers will have the most benefit now if you need to fertilizer. Things like cool season vegetables, lawns and winter annual flowers will benefit from a foliar feeding.

Nitrogen fertilizers like ammonium sulfate or ammonium nitrate will work just fine for foliar feeding since they dissolve readily in water and can be applied easily with a compressed air sprayer or hose end applicator. On trees, shrubs, fruit trees and other perennials, let them enter dormancy now by not fertilizing and withholding water for longer periods.

As I mentioned last time, organic mulches like shredded bark, wood or compost are important now and should be applied or renewed. Keep them away from the trunks of trees and shrubs.

Quince and pomegranate are both ready if you haven't picked them by now. Quince improves in flavor as the season gets colder and keeps on the plant for quite some time but must be picked before a hard frost. Some late pears are still coming on.

I tasted an apple at the Master Gardener orchard the other day called Pink Lady, and it was terrific. A very, sharp-tasting apple that reminded me of a Braeburn but the fruit had a pink color rather than the yellow green background common to Braeburn.

Remove dead fruit from plants and the ground to help contain any diseases that might be lingering to attack your garden next year. Any fallen leaves should also be picked up and composted to contain diseases.

Have you been thinking of having a greenhouse in your back yard? A small greenhouse can be quite useful throughout the year for many purposes. In the early spring, it can be used to germinate and grow bedding and vegetable plants earlier that would otherwise be possible.

In the summer it can be used either with or with out a mist system of humidifier as a propagation house to root cuttings. It can be used in the fall to start winter vegetable plants. During the winter, it can protect patio plants and other hardy but containerized woody plants.

They will work here but there are a few things you ought to remember about them. The greenhouse must be level. If it will be used primarily for plant propagation in the summer, place it in partial shade to minimize heat buildup. If a partially shaded site is not available, you can use a shade cloth or a white plastic cover to control the amount of sunlight reaching the interior. If the greenhouse will be used for starting transplants or growing plants to maturity, it will need maximum exposure to the sun.

An easy way to build a Quonset-style greenhouse is to use Schedule 40 PVC (the heavy, plastic irrigation pipe) for the ribs bowed and attached to a wood frame in contact and secured to the ground. The ribs would be 2 feet apart.

The wood should be treated with a preservative such as CCA not creosote or pentacholophenol. The house must be firmly attached to the ground or it may be moved around during high winds.

The doorway should be on the north side of the house if possible. If not then put it on the east side. Clear 4- or 6-mil plastic greenhouse film is generally the best covering if the house will be used for growing plants.

If it will be used exclusively for propagating or overwintering plants, consider using 4- or 6-mil milky or white copolymer film. However, shading clear plastic with a 30 percent to 50 percent polypropylene shade cloth or greenhouse whitewash available from horticultural supply companies will help reduce heat in the summer.

If you are planning to but a kit or a ready-to-assemble greenhouse, then choose a polycarbonate covering. It is more expensive but very durable and long-lasting.

When choosing a size, larger houses will be more efficient to run than smaller ones. In fact small greenhouses are nearly impossible to maintain the temperature with any kind of consistency. Consider a gable fan or venting system as well to help reduce heat.

There has been much interest in hydroponic greenhouses and hydroponic growing over the years. Hydroponic growing is the growing of plants without soil.

Usually some sort of rock or gravel base is used to hold the plant roots so the plants remain upright. The water added to the plants contains nutrients.

Hydroponic systems are usually under artificial light or in greenhouses. Before going back to the university for my education I constructed and installed commercial hydroponic systems back in the 1970s in Colorado when they were very popular. Since that time I have watched dozens of people get excited over their potential and I have watched dozens of people give up in frustration.

First of all, hydroponic systems are fine for the homeowner but I would not recommend it for larger houses. Although there are many styles that have been developed since 1940, when renowned scientist and professor Alex Laurie wrote his book titled "Soilless Culture," they still have the same basic problems then that they do now.

Much exaggerated publicity has given rise to the impression that a new era of agricultural development is about to be achieved -- an era that bids fair to revolutionize all our present methods of crop production. Enormous yields of crops have been predicted from limited areas. Unfounded claims have been made, and grossly misleading statements have been circulated.

Things have not changed much since then. I have used hydroponics to grow ornamentals and I have gotten tremendous growth compared to field grown plants.

Since I have a background in hydroponic growing I usually get five or six calls a year from someone who has just "discovered" hydroponic growing and is filled with the excitement from the claims of those who are selling or others who have had their first successes with the technique.

The basic problems are diseases, time management and fertilization. The safest way to operate a hydroponic system is to not reuse the same water but to renew your water and fertilizer solution daily.

Bob Morris is a horticulture specialist with the University of Nevada Cooperative Extension.