Planting a garden in a bale of hay may seem like a strange technique, but there are several reasons why it makes perfect sense. Hay is rich and moist, making it an ideal planting medium, especially for gardeners with poor or rocky soil, or those who lack adequate space for a traditional garden. There is less bending and stooping involved, making gardening more gentle on sore knees and stiff backs. Use the bale for one or two growing seasons, then add it to the compost heap.
Purchase a bale of grass hay or straw from a local farm supply store. Straw bales are often preferable to hay, because hay includes seeds, which can be difficult to remove. Straw consists of only the stems of the plant and will have few seeds. However, straw is generally more expensive than hay. Choose tight bales securely bound with twine or wire. If possible, purchase the bales the autumn before you plant.
Place the bales carefully, because they will be heavy and difficult to move when they're wet. Use as many bales as you like. You can even stack the bales two deep, but be sure you can reach the center of the bales. Situate the bales so the twine isn't against the ground, as some types of twine will decompose quickly, and the bales will fall apart. This isn't as important if the bales are tied with plastic or wire.
Soak the bales thoroughly with a garden hose every day for four days. If the weather is warm, water the bales two or three times each day. By the end of the fourth day, the bales should be completely saturated, and should have begun to break down.
Sprinkle each bale with 1/2 cup of ammonium sulfate or ammonium nitrate each day for the next three days. Water the bales thoroughly after each application.
Apply half the amount of ammonium nitrate or ammonium sulfate for the next three days, only 1/4 cup per day. Soak the bales deeply each time.
Allow the bales to sit for a day, but keep the hay damp. On the following day, put on a pair of gloves and stick your hand into the center of the bale. If the hay has cooled to the point that it feels warm but not hot, it is ready to be used for planting.
Place one to two inches of commercial seed-starting mix on the top of the bale if you want to plant vegetable seeds. Simply plant the seeds in the seed-starting mix according to the directions on the seed package. If you intend to plant seedlings or bedding plants, divide a spot in the hay with a trowel, and allow the hay to bounce back around the plant. Spread a handful of commercial seed-starting mix around the base of each plant.
Water the bales daily in the beginning, and don't allow them to dry out. Soon, the bales will begin the process of decomposition and will require less water.