Growing Tomatoes: Preparing the Soil

Tomatoes thrive in well-drained soil high in organic matter with a pH of 6.2 to 6.8. Preparing the soil before transplanting tomato seedlings to the garden gets them off to a good start. Although tomatoes grow in inferior soil, growing healthy vigorous tomato plants brimming with abundant fruit often requires amending the soil before planting to provide the nutrients they need to thrive.

Site Selection

Choose a sunny location that receives full sun for the majority of the day. Observe the location of trees, buildings and other structures before selecting a location. While dormant trees, trellises and shrubs may not cast shadows on the gardening area, when in full foliage they may shade your tomato garden and inhibit growth.

Check the area throughout the day to determine sunlight as the sun travels across the sky. You may be surprised to discover that for portions of the day you garden bed is shaded. During summer months, the sun rises and sets at nearly opposite points in sky (rising in the east and setting in the west) and follows a path directly overhead. Select an area that captures full sun during the summer months.

Tilling the Soil

Till the soil to a depth of 8 to 10 inches. Tomatoes produce large roots that require loose soil to develop. Remove any rocks, roots or other debris from the soil. Winter freezing and thawing often exposes rocks from lower depths of the soil. Remove any weeds that are upturned in tilling. Many weeds take root and continue to grow after tilling.

Soil Testing

Test the soil to determine the condition of your soil. Fall testing is preferred as amendments require time to break down and release the necessary nutrients into the soil, but spring testing can be beneficial as well.

Inexpensive soil test kits found at your local hardware store or home improvement center provide a quick analysis of the soil. Home soil test kits are useful for established gardens when you simply need a quick assessment of pH and nutrients and are relatively familiar with your soil's needs.

For a more in-depth assessment of your soil, contact your local extension office. They provide soil testing services for a minimal fee that includes a detailed summary of the condition of your soil and recommendations for amending the soil, including directions for adjusting pH. Following the recommendations conditions your soil and balances nutrients giving you a good starter soil.

Check Drainage

Even though tomatoes require generous amounts of water to thrive, soggy soil promotes disease and chokes out oxygen needed for growth. Well-drained soil provides moisture plants need while protecting against soil borne diseases that thrive in wet soil.

Dig a hole 4 inches deep. Insert a 46-ounce juice can into the hole and secure it in place by packing soil around the base. Fill the can with water and note the time. Observe the water level inside the can to determine how well your soil drains. Water levels that drop more than 4 inches in an hour indicate that your soil drains too quickly. Water levels than drop less than 1 inch an hour indicate that your soil does not drain well. A drop between 2 to 4 inches indicates your soil is well drained, but also retains enough moisture for tomato plants to thrive.

Amend soil with organic matter like compost or well-rotted manure to adjust drainage. Ironically, organic matter assists in improving drainage and in retaining moisture and is effective for both soil that drains too quickly and soil that retains too much water. Peat moss is an excellent soil amendment, but may alter the pH. One part peat moss to one part either well-rotted manure or compost is a good option.

Other articles in this series:

Growing Tomatoes: Seed Starting

Growing Tomatoes: Caring for Tomato Seedlings

Watch for further articles by this author for tips on growing robust tomato plants producing juicy ripe fruit.

Sources:

Pelczar, Rita. SmartGarden-Improving Soil Drainage. The American Gardener

Bass, Larry.Growing Tomatoes for Home Use. North Carolina State University

Watch Your Garden Grow: Tomato. University of Illinois Extension