Hay-bale gardening is a nontraditional gardening technique that works well for gardeners with limited gardening space or those with limited mobility. For gardeners with a tired back or stiff knees, a hay-bale plot virtually eliminates bending and stooping: There is no soil to dig, and it requires very little weeding. Plants thrive in hay bales because there is no soil to become compacted, and rich organic matter is continually available to the growing plants.
Purchase a bale of clean, weed-free straw. Although the terms "hay" and "straw" often are interchangeable, straw, which consists of the stems of the plants, will be clean and contain very little seed. Hay, which farmers use as animal feed, contains more seeds. A garden you plant in hay will require constant weeding. Wheat and alfalfa are good choices, but any rectangular bale of straw will work.
Place the bale of straw in its permanent location, with the twine parallel to the ground, as the bale will become very heavy after preparation and planting. Locate the bale where the plants will receive at least six hours of sunlight every day.
Drive a metal stake into the ground directly behind each end of the bale. Do not cut or sever the twine holding the bale together. If the twine eventually rots, the stakes will hold the bale together. You do not need to stake the bale if its binding is plastic or wire, because these materials won't rot.
Start conditioning the bales 12 to 14 days before planting. Spread 1/2 cup of nitrogen-rich fertilizer such as 15-10-10 over the top of the bale. Water the bale deeply. Fertilize and water the bale every other day. On the "off" days, water the bale deeply but do not add fertilizer. The bale will become hot as the straw begins to compost, but the straw should cool down and be ready for planting by the 12th or 14th day.
Sprinkle 1 cup of a balanced granular fertilizer with a ratio of 10-10-10 or 12-12-12 over the top of the bale on the final day, when the bale is cool. Water deeply.
Cover the bale with a 3- to 5-inch layer of a mixture of half commercial potting soil and half compost when you are ready to plant. Although applying the soil and compost mixture isn't absolutely necessary, adding mixture prevents the bale from drying out quickly during warm weather. Water the bale with a fine spray to avoid washing off the soil.
Spread the straw to create a hole, then place your plants in the hole. It doesn't matter how deep you plant, as long as a portion of the green, leafy part of the plant extends above the straw. A bale can hold two tomatoes, four pepper plants or lettuce plants. Nearly any plant will grow in a bale, but avoid tall plants such as corn because the plant can become top heavy and destabilize the bale.
Water the straw-bale garden regularly and keep the straw moist but not dripping wet. Pull any weeds that appear.