Water, Water Everywhere

Someone once said that the three biggest problems faced by gardeners in the High Desert are water, water, and water. We are most aware of this in the hot, dry months of late spring and early summer when we can't seem to pour enough water on our plants to keep them alive. We watch them desiccate right before our eyes in the super dry air, and we yearn for the summer rains, knowing that the higher humidity, cooler temperatures, and abundant rainfall will make our gardens flourish. How ironic, then, that some of our most prized plants seem to languish in the rain and sometimes even die. It doesn't seem fair that a plant we carefully nursed through the dangerous dry season begins to die when life-giving rains begin to fall. What's happening?

You may be tempted to think that your plant has somehow grown in tolerant of water during the long dry season or perhaps has fallen prey to some water-borne disease. Although disease is always a possibility, another likely cause - and one that should always be investigated - is death by drowning. Our heavy clay soils, often liberally laced with caliche, compact to a concrete-hard substance that is impervious to penetration by water. When we dig (or blast!) small holes in this stuff to create homes for our plants, we create sumps where rainwater collects and never drains away. The submerged roots of the plants that live in these holes become starved for oxygen and the plants die. So what's a gardener to do?

If you have a caliche problem, the New Mexico State University College of Agriculture and Home Economics has a Web page (http://elroy.iimsu.edu/CAHE/ret ops/a-127.html) just for you. The author. County Extension Agent C. E. Siepel, points out that in addition to creating water problems, caliche can restrict a plant's ability to use soil nutrients by reducing root penetration and creating a high pH environment. For this reason it is a good idea to keep plant roots out of contact with the caliche. Caliche soils can be managed by breaking up and physically removing the caliche and back filling the hole with a good soil mixture. The author suggests that reasonable sized holes range from 2 feet deep by 6 inches wide for flower beds to a whopping 6 feet deep by 8 feet wide for large trees. Before installing a plant, every hole should be checked for drainage by partially filling it with water and watching how fast the water level drops. About 1 inch per hour is an acceptable rate. If the hole does not drain properly, you need to either dig it deeper or at least punch some drain holes in the bottom.

If you have a heavy clay soil, you need to amend it so that it absorbs water and can better provide nutrients to your plants. Oregon State University has an excellent Web page (http://wwwagcomm.ads. orstedu/AgComWebFile/Garden /soil/howtoimproveclaysoU.html) describing how to do this. The key is to work in plenty of organic material and sand but the sand should only be added after the organic material so that you don't create natural concrete instead of garden soil. A couple of inches of compost or other organic material and a similar amount of sand should be thoroughly mixed into the top 6 or 7 inches of soil. Since the organics decompose slowly to yield nutrients for plants, the best time to add the organic material to the soil is in the autumn.

Before I sign off for this month, I want to invite you to the Cochise County Master Gardeners Association "High On Trees" adopt-a-tree program to be held at Veterans Memorial Park Bandshell in Sierra Vista from 9:00 am to noon on September 13th. For the price of 90 minutes of your time to attend a class on the planting and care of trees in the High Desert, you can adopt a tree. If you're not interested in adopting a tree, come any way. The class on tree care will be well worth your time. Don't miss it!