Fertile Soil Needs Air, Water, Nutrients
Regardless of origin, plants have similar soil requirements. Before planting, make sure the soil is well-supplied with air, water and nutrients.
Aeration must be the first consideration, because plants can’t use nutrients if roots have no air. Poor aeration occurs when water fills all the soil pores, the result of a high water table or too much fine clay in the soil.
There are three options for dealing with a high water table: Move your garden; raise the roots above the water with raised beds; or lower the water table by draining water away in trenches or a buried, perforated plastic pipe.
Clay soils become poorly aerated because their small pores fill with capillary water. Improve aeration by clumping the clay particles into larger units, forming larger pores from which water can drain. “Glue” for clumping clay particles is organic matter, such as compost, peat moss, manure, rotted leaves, or sawdust. Mix an abundance of any these materials into the soil.
Inability to hold moisture is a typical problem in sandy soils. Watering plants is one cure, but also mix plenty of organic matter into the soil. The spongelike nature of the organic matter helps hold moisture.
With aeration and water taken care of, consider your soil’s fertility. Soils must supply plants with 12 essential nutrients, so test your soil with a home kit or send a sample out to a laboratory to see what is needed.
Before fertilizing, make sure soil acidity is in the correct range, or plants will not be able to use nutrients. Most garden plants thrive in slightly acidic soils. The soil test will also tell how much lime (to decrease the acidity) or sulfur (to increase the acidity) is needed to reach the correct range.
Finally, fertilize. The three nutrients needed in greatest amounts by plants are nitrogen, phosphorus, and potassium. The organic matter that you added for aeration and water-holding also supplies nutrients, perhaps enough so that no additional fertilizer is needed.
With aeration, moisture, and nutrients, your soil is ready for almost any plant, from a marigold to a forsythia to a maple.