Soil Test is Key to Unlocking Great Lawns

Grass emerging from its winter slumber.

DURHAM, Conn. - The most important step to having a lush, green, organic lawn is to have your soil tested.

"You have to know things about your soil in order to take care of it," said Diane St. John during her talk on organic lawn care for the Coginchaug Area Transition lecture series. St. John is a NOFA Accredited Land Care Practitioner and retail manager at Natureworks in Northford, Conn.

Here's an example of the paperwork UCONN will
return after analyzing your soil. Click to enlarge.
Lawns like a neutral pH between 6.5 and 7. If the soil is not near that pH, the lawn will not do well no matter what you do, said St. John.

The University of Connecticut offers a basic soil test for $8 for homeowners. (I had several samples done back in 2011, as seen in the example to the right.) Using a small trowel or bulb planter, take samples of soil from 10 different spots in the sample area. Mix the samples in a container and then take a one cup sample to send out for analysis.

Once your test results return (the website estimates 7-10 days) you can use the information to determine what the soil needs for correcting.

For Connecticut gardeners, a grass blend which includes tall fescue grass will perform well. The best time to renovate the lawn is in the fall, but "spring is OK too, but you need to water more," she said.

Mowing the lawn on the high side (four inches) not only helps shade itself but also the weed seeds. St. John recommended leaving grass clippings on the lawn to be mulched back into the soil since the clippings are full of nitrogen. "It's like free fertilizer."

Reading the Weeds
You can also determine what is wrong with the lawn by "reading the weeds."

"Crabgrass usually grows where soil is really compacted," said St. John. "If you are living in a semi-new development (in the last 30 years), you probably have compacted soil." To help correct the problem, she suggests aerating the soil (using a pitchfork to poke holes in the ground helps with this).

"If you can ID the weeds in the lawn, you can see what the soil needs," said St. John. Here are five of the most common weeds found in lawns:
  • Crabgrass: low calcium, high potassium
  • Dandelions: low calcium, low pH, high potassium
  • Creeping Charlie: low nitrogen, high calcium, poor drainage
  • Plantain: poor drainage, very compacted soil
  • Wild Onions: low calcium, poor drainage
Clover, considered by some a weed, actually feeds the lawn by fixing nitrogen in its roots. "The part I really enjoy is the [white] clover and [the oxalis with] the little yellow flowers - I actually kind of like some of the weeds," she said.

St. John said pests can also be an indicator of what is wrong with the soil. "Patchy spots in the lawn mean roots are being eaten by grubs." The grubs are the larvae stage of Japanese beetles. To get rid of grubs in the soil (which also attract moles, who prefer to dine on them), St. John recommends applying beneficial nematodes to the lawn in late May/early June and again in mid-August/early September.

Life Without Pesticides 
Now is the time that pesticide warning flags begin to appear in neighborhoods to warn that spraying has occurred. St. John tells her children to stay off the lawns that have chemicals applied. "I worry about them walking on those lawns," she said.

The premise of organic gardening is to feed the soil, which will produce healthy plants. The soil is alive and filled with bacteria, fungus and protozoa, she said. "All these little guys you can't see [...] the whole web of life starts with life in your soil."

However, microscopic life is killed off by chemicals. If your lawn was previously treated with chemicals, St. John suggests replenishing life by applying a thin layer of compost to the top of the soil or by using a compost tea. (She recommends Organic Plant Magic, which is a dehydrated compost tea.) The transition from a chemical lawn to an organic lawn may look worse for a little while until the life kicks back in.

St. John originally started off with 1 acre of lawn at her home. Not only does St. John have chemical-free, gorgeous green grass that her children can play on, but she has removed 7,426 square feet of lawn from her original acre. She replaced the lawn with trees and plants to provide a place for wildlife to reside. Now instead of a monoculture of lawn, she has a more welcoming habitat.

"The lawn is part of your ecosystem and your yard as a whole," she said. "It's amazing when you stop using chemicals, what comes to your yard."

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