- Published on Wednesday, 26 June 2013 01:00
- Written by Tanya Kucak
Molasses, left, stimulates the growth of beneficial bacteria in the soil, and liquid seaweed products add a range of trace minerals, both of which help plants resist pests and diseases.
Organic gardeners like to say they’re growing soil, not plants.
The basis of a healthy garden is soil and the life in the soil. To evaluate soil, you can feel it, smell it, look for worms and see if plants growing in it seem healthy. Clay soil is a wonderful soil to start with because it can hold onto lots of minerals and release them to plants.
But ultimately, whether you’ve been gardening a few years or are just starting, you may want a soil test. Soil tests are problematic for organic growers because the recommendations focus on synthetic fertilizers. The solution is to analyze the soil-test results yourself.
Two new books that discuss amending your soil to produce nutrient-dense food advocate soil tests. Though the authors’ approaches are different, they are complementary. Both stress the importance of adding minerals to the soil, and both recommend far less compost than many organic gardeners are accustomed to using (at most, add a 1/6-inch layer of compost per year). Both authors avoid dolomite lime, because its calcium/magnesium ratio is bad for most soils. Instead they recommend calcitic lime (also known as agricultural lime). Both discourage gardeners from adding too much of anything without a soil test, because even moderate amounts of some amendments can throw the soil chemistry out of whack.
In “The Intelligent Gardener: Growing Nutrient Dense Food” (New Society, 2012), author Steve Solomon (with Erica Reinheimer) takes a linear approach, once you get past the opinionated and curmudgeonly first chapters. Solomon recommends a specific $20 soil test from Logan Labs. You can analyze your own soil by completing worksheets, conveniently available online at tinyurl.com/c45cfsb, and then purchasing amendments. Solomon explains which amendments to include and how to use the worksheets. He also includes his formula for Complete Organic Fertilizer, which he considers a reliable alternative if you can’t conduct a soil test.
But soil chemistry is as far as he goes. If you’re more interested in the life in the soil, then Phil Nauta’s “Building Soils Naturally” (Acres USA, 2012) is the book for you.
Nauta presents a more detailed and nuanced discussion of stimulating the soil food web, covering soil biology as well as soil chemistry. He includes cutting-edge topics such as Brix testing, seawater, mycorrhizae, paramagnetic rock dust and culturing essential microorganisms.
The most useful part of the book is at the end – a five-page summary of Nauta’s recommendations. One of his most valuable suggestions is to add rock dust to the compost pile, where it can get chelated with organic matter to make the minerals more biologically available to plants.
He also recommends adding smaller amounts of minerals two to four times during the year, rather than all at once.
“Plants and microbes need continual access to a small amount of nutrients rather than everything at once,” Nauta writes.
He also stresses the use of molasses and other biostimulants to unlock soil nutrients.
For gardeners who don’t do a soil test, Nauta said, “it’s rare to find a soil that wouldn’t benefit” from 1/2 pound of calcitic lime per 100 square feet.
He includes a recipe for the foliar spray that he recommends using with new seeds and transplants, and throughout the garden every one to four weeks.