10 Easy Soil Tests

Find out if your soil is ready for planting.

By Julie Monahan

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Test 3. Workability

You may have already learned about your soil's workability the last time you got the garden ready for planting. If tilling or digging the soil produces cloddy or platelike clumps, the workability is low. Farmers measure workability by monitoring how much tractor fuel they use; you can simply judge the effort necessary to prepare beds for planting.

Why it's important
Soil that's easy to work allows water to reach roots efficiently and is less prone to compaction. Fail this step, and your garden will likely show disappointing results for many of the other tests. "If the soil isn't easily worked, other problems have already been going on for a while," says Raymond Allmaras, a soil specialist with the USDA's Agricultural Research Service in St. Paul, Minnesota.

Test 4. Soil Organisms

Measure the animal life in your soil by digging down at least 6 inches and peering intently into the hole for 4 minutes. Tick off the number and species of each organism observed, such as centipedes, ground beetles, and spiders. Because most soil organisms spurn daylight, gently probe the soil to unearth the more shy residents. If you count less than 10, your soil does not have enough active players in the food chain.

Why it's important
A thriving population of diverse fungi, bacteria, insects, and invertebrates is one of the most visible signs of soil quality. The more that creeps and crawls under your garden, the less opportunity there is for pests and disease. Each level of soil life does its part to break down plant residue and make more nutrients available for plant growth.

 

Test 5. Earthworms

When the soil is not too dry or wet, examine the soil surface for earthworm casts and/or burrows. Then dig out 6 inches of soil and count the number of earthworms squirming on the shovel. Three worms are good; five are better. The absence of worms means the soil does not have enough of the organic matter they feed on. An exception: If you live in the Southwest, don't waste your time looking, even if the soil displays other conditions of soil quality. "Earthworm activity is less likely in the desert," says the University of Arizona's Walworth. "Worms don't like hot soil."

Why it's important
Not only do earthworms aerate the soil, but their casts infuse the soil with enzymes, bacteria, organic matter, and plant nutrients. They also increase water infiltration and secrete compounds that bind soil particles together for better tilth.

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