Test Your Soil this Fall

Dear gardeners, I know you are already thinking, “I’m going to do some things differently next growing season! I want even bigger and better plants! What fertilizer shall I use?”

Sadly, I have no magical talents to determine the answer. When you ask me, “What does my soil need?” I can only provide 1) a dumb look and 2) a plea: please don’t spread fertilizer products randomly. Feeding soil this way can go seriously awry. Your soil may not need those substances. It’s also easy to get over-generous, thinking, “if a little is good, more would be better!”

Don’t fall for that. Too much fertilizer can be as detrimental as too little. If you apply too much of a good thing on your vegetables, flowers, and fruits, you may stunt your plants, resulting in lower yield, poor taste, and more pests and disease. Soil imbalances directly affect crop performance and can take years to correct.

My best advice is to send a soil sample to a laboratory (I don’t advise a home test kit). Find out if you’re dealing with mineral deficiencies and excesses. You’ll avoid expensive and harmful guesswork about a fertility program. Choose between a basic soil chemistry test and a more comprehensive soil test.

The Palmer UAF Research Center, in conjunction with the Cooperative Extension Service, provides a basic soil test. The lab measures the levels of three major nutrients: nitrogen, phosphorus and potassium, or NPK. The analysis will also give you feedback on your soil’s pH. The pH refers to your soil’s acidity or alkalinity. Necessary minerals may be present in your soil but locked up chemically if your soil is too basic or acidic.

The Research Center can be contacted 746-9450, and their basic soil test will cost $40. The actual lab cost is much more; you will get a subsidized rate.

The comprehensive lab test serves those who want to 1) build soil holistically for peak performance for the long term, and 2) grow nutrient-dense foods.

The focus of a comprehensive soil analysis is on soil food web health with a full mineral representation beyond NPK. The comprehensive lab tells you about levels of other necessary minerals like calcium, magnesium, sodium, soluble salts, as well as conductivity, and the level of organic matter present. For a few more dollars, consider using one of these test labs which specialize in sustainable fertility programs: International Ag Labs, Crop Services International, Peaceful Valley Farm Supply, Woods End Laboratory or Timberleaf Soil Testing.

The basic lab will recommend NPK fertilizers in chemical form unless you ask for organic ones. The comprehensive labs above will recommend non-chemical amendments that will stimulate rather than harm your soil food web, and will gradually bring your soil into balance over several years.

Regardless of which type of soil test you buy, be sure to ask for recommendations, not just an analysis. Recommendations will tell you how much of what to apply in the spring.

At this moment, you have the perfect opportunity to get a jump on spring. Send in your soil samples this week, while you can still chip a trowel into your garden. You’ll avoid waiting for results in the spring when labs are slammed with orders, and you can plan your fertility program this winter. You can also purchase amendments you need before the rush. Then, ta-da! You are ready when the ground thaws next May.

How do you collect a sample? See the Cooperative Extension Service’s Soil Sampling bulletin FGV-00044 (also online) with precise instructions. To watch a YouTube explanation, go to the Peaceful Valley Farm Supply website and find the 5-minute how-to video.

Also, be sure to grab your clean trowel and Ziploc bag, soil lovers — the temperatures are falling out there.

Ellen Vande Visse operates Good Earth Garden School and offers educational workshops through goodearthgardenschool.com.