Potatoes are easy-to-grow vegetables popular in home gardens across the United States. Although they are relatively cold hardy and can be planted before the last frost in spring, they require several months of frost-free weather to produce an abundant crop. They prefer organic-rich, well-draining soil with a pH between 4.8 and 5.5. Completing a soil test and following the recommendations for amending the soil before planting provides potatoes with the conditions they need to grow.
Till the soil to a depth of 10 to 12 inches and remove rocks, roots and other debris from the area. Potatoes need loose soil to allow the tubers to grow under the ground. Stones and roots may inhibit growth or cause misshapen tubers.
Test your soil with a soil test kit or through a soil test service to determine the soil pH and nutrient levels. A pH of 7.0 is neutral; lower numbers indicate more acidic soil, such as that preferred by potatoes, and higher numbers indicate alkaline soil.
Adjust the pH level of the soil with the appropriate amendments as needed. Typically, 1 1/2 pounds of sulfur per 100 square feet lowers the pH by one unit. In some instances, the existing soil pH may be too acidic and need to be raised with limestone. The amount required depends on the product. Follow the recommended rate on your soil test or on the product label, tilling or digging it into the top several inches of soil.
Spread a 2- to 4-inch layer of organic matter, such as aged manure or compost over the area unless your soil test results indicate otherwise. Organic matter improves the soil's drainage, increases aeration and provides a source of slow-release nutrients to your potato plants.
Add 2 1/2 to 3 pounds of 8-16-16 fertilizer to the area, or follow the recommendations from your soil test. Your soil may require more or less fertilizer or may require a different formula. In the absence of fertilizer information with your test, use the amount given here.
Mix the organic matter and fertilizer into the top 6 inches of soil with a garden tiller or hand tools. Rake the area smooth to prepare for planting.
Things You Will Need
- Garden tiller
- Soil test
- Sulfur or limestone
- Garden tiller or shovel
- Organic matter
- Garden rake
- Test the soil on all new garden sites and every three years on regular garden plots to assess the condition of your soil. Nutrients can be depleted, and the pH can change.
- Limestone may take several months to alter the pH and is best added in the fall.
- Observe all safety precautions when handling gardening amendments. Limestone is caustic and can cause injury to skin or mucus membranes.
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