How To Test Soil

In this video, This Old House landscape contractor Roger Cook explains how to test soil.

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Sandy soil drains too quickly; requires compost or cow manure to hold moisture.
Clay soil compacts tightly and doesn’t drain well; mix in sand.
Quality topsoil contains proper proportions of sand, silt and clay.
Buy soil test kit from garden shop or hardware store; select one that tests for nitrogen, phosphorous, potassium and pH.
Dig small amount of soil from garden, yard or flowerbed using a garden trowel.
Add measured amounts of soil, water and reactive agent to plastic test chamber; shake well.
Wait 2 minutes for soil to settle and color to develop.
Compare the soil solution color to the color-coded chart printed on the test chamber.
If needed, amend the soil as recommended. For example, if soil is too acidic add lime; if it’s too alkaline, add peat moss or sulfur.
Test soil annually, and treat it as needed.