You don’t have to take a soil sample to a plant lab to measure its drainage ability. Here is a simple measurement technique: A few days following a good rain, dig a hole 4 inches deep to accommodate a large 46-ounce juice can. Pack soil around the outside perimeter of the can. Then fill it with water. If the soil drains well but not too rapidly, the water should sink by at least 2 inches after the first hour. If the water drops less, the soil needs to be amended with coarse sand and organic matter, such as compost, until it meets the juice-can test. Conversely, if the water drops more than 4 inches in an hour, it is draining too quickly and needs extra organic matter.