Winter dormant time is a good time to reflect on our gardening practices and consider what and how we could improve. I’ve been thinking a lot about fertilization.

For many years I collected and tilled fallen tree and shrub leaves (and shredded dead garden plants) into my garden’s desert soil. When I had to convert to raised beds, that soil, now richer with organic matter, was scraped into ridges, ultimately to become an incorporation of leaves that left my soil rich in N (nitrogen), P (phosphorus) and K (potassium) with a pH of about 7.0, neutral (which is far better than I started with). Since then I’ve occasionally added kelp meal and fish fertilizer, primarily for trace minerals needed for plant growth.

I’ve also added a cover of at least a half inch of compost on top of each bed before planting, and in some cases, strewed alfalfa meal over a bed. I have used Dr. Earth for the past two years for those crops that I transplant, but not for seeded row crops, and I’ve been happy with those results.

The question remains, could we do better?

If we build up too much phosphorus, it can kill the mycorrhizae fungi that feed your plants and reduce your plants’ ability to absorb iron and other micronutrients. If you apply more nitrogen than is needed, you get leafy plants without much fruit (such as tomatoes), leafy root crops, such as turnips and radishes with small roots, and you attract large numbers of destructive insects.

We’re advised to get soil tests every three or four years. State extension offices differ widely in what they charge and what test results they yield. In our state a soil test tells you amount of N, P and K in your soil. The cost is $35. In Georgia, the cost is $6, and they test for pH, P, K, calcium, zinc, magnesium and manganese. They don’t test for nitrogen, since it may vary through the year. N is variable in areas that receive abundant precipitation because it’s easily leached out. In Arkansas, the soil test is free.

There also are independent testing labs listed in the Yellow Pages under “Laboratories — testing.” If you’re going to test soil, telephone for prices, what results they’ll furnish and instructions on soil sampling. If something still is not right, you may have to hire a plant tissue-testing laboratory.

The safest and easiest thing to do is to continue using compost, and add fertilize only if plants show they’re deficient in something. Nutrient deficiency would show in stunted growth, distorted or discolored leaves, or dark spots on leaves, for instance.

DIVERSIFY YOUR PLANTINGS

Garden experts advise against monocropping, preferring that we vary our genuses (genera) and species within a bed. Commercial garden planners, however, usually show major clusters of one type of plant. Companion plant layouts often show mint or horseradish planted in a seasonal bed. Outrageous suggestions of impossible-to-eliminate plants in my opinion. I think that’s inappropriate for a bed of annuals.

Companion planting often works. Next year I’m going to plant nasturtiums with squash to repel squash bugs, even though I have had good crops since I’ve been killing squash bug eggs with Neem. It’s easy to miss some eggs, and I did lose some summer and winter squash plants to squash bug bites (injecting a plant-killing substance). Maybe I can do even better with the assistance of nasturtiums.

Sowthistle is a good trap crop for aphids. I usually wait until that weed turns black, loaded with aphids and some ready to fly before I pull out the weed and put weed and aphids in the garbage.

Send garden questions to melauter@earthlink.net or Gardening, The Statesman, P.O. Box 40, Boise, ID 83707.