Preparing Healthy Vegetable Garden Soil

Vegetable plants need nutrients from the air, water, and soil to grow and produce abundant yields. Making sure the garden has at least six hours of sun each day, has plenty of water, and is well-drained will take care of many of their nutritional needs. Yet it’s just as important to make sure the soil is in a condition that will make those nutrients available to the plants when they need them. Analyzing a soil sample with a soil test kit from a plant nursery center or state extension office can give a gardener valuable information about how to maximize the amount of vegetables a garden will produce.

Fertilizer, Compost, and Soil Nutrient Levels

Commercial fertilizers contain nitrogen, phosphorus, and potassium. The number on the bag refers to the percentage of each nutrient present in the fertilizer in relation to the other nutrients. For example, a 20-20-20 fertilizer contains equal amounts of nitrogen, phosphorus, and potassium, in that order.

• Organic fertilizer contains lower levels of nutrients, but release slowly and are available for a longer period of time.
• Chemical fertilizers contain higher levels of nutrients but can burn plants if over-applied.
• Compost may be bought or made at home and contains lots of beneficial micro-organisms in addition to many essential nutrients and trace elements.

Soil pH Levels

A soil pH test can reveal whether the plants can use the nutrients present in the soil. According to the Ohio State University Extension, most garden plants prefer soil in the slightly acidic 6.0 to 6.8 pH range. Plants cannot use nutrients in soil outside that range.

Anything above 7.0 is considered alkaline soil and below 7.0 is acidic soil. If the soil is too acid or too alkaline, nutrients that are chemically bound into the soil cannot be broken down into use by the plant, no matter how abundant that nutrient is in the soil. Lime can be added to raise pH levels and sulfur can lower pH. Both are available at garden centers and nurseries.

Clay or Sandy Soil

Depending on geographic location, soil may be sandy or contain a lot of clay. Sandy soil drains well, but tends to lack nutrients because of a lack of organic matter. The addition of compost and fertilizers can help sandy soil hold water longer and sustain healthy levels of nutrients. Clay soil may clump together like cement, leaving little room for tender roots to grow and keeping moisture from penetrating the soil. The addition of peat moss and sand helps loosen clay soil.

It’s pointless to add fertilizer or compost without making sure the soil is healthy so the plants can use available nutrients. It’s been stated that soil is only as healthy as its least abundant nutrient. Using soil test results to know how to amend garden soil can result in healthy, abundant yields year after year.

References:

Ohio State University Fact Sheet. Fertilizing Vegetable Garden Soils (accessed June 14, 2010).

Utah Sate University Cooperative Extension. Preparing Garden Soil (accessed June 14, 2010).