Hay Bale Gardening eliminates the need for site preparation, and greatly reduces stress on the back the same way that Raised Bed Gardening would. They can be used to cover up old tree stumps or line the edges of a driveway, sidewalk, or fence.
There are a few important principles for making the most of your garden.
Straw bales are preferred because there are very few seeds. However, hay bales are sufficient although you might have to pull a few more weeds. I advise using dry bales as opposed to green bales because they do not need to be seasoned as long before planting. See planting preparation below.
Just as with any garden, you want to choose your site based on plants' light requirements, within easy access to a watering source. Hay bales are too heavy to move once placed without destroying the bale.
Using a single bale is normally not recommended. Having several back to back, or end to end provides support. If you really don't have the space for more than one though, tie extra twine around the bale for support. Hay bale gardens typically last for two seasons (a single bale just one). Having said that, be creative. The size and layout is not constrained like a traditional or raised bed garden because there is minimal labor involved. You could do a traditional square, rectangle, or rows. Other ideas for your layout include mazes, horseshoes, and encircling a tree or other focal point. Leave enough space to mow your lawn or use mulch in between bales. Place plastic underneath bales because any hay or twine at the ground level will rot and deteriorate the whole bale.
Soak dry hay bales in water for at least one week (four for green bales). This is very important because it gives the hay time to break down, and become cool enough for seeds or plants. Called seasoning, the hay bales go through an initial composting process with internal temperatures exceeding 100°F. Do not allow bales to dry out.
Sowing Seeds and/or Adding Plants.
Top bales with a three inch layer of soil and compost. Apply and water in a nitrogen rich fertilizer. Fish emulsion and blood meal are great organic options for supplying nitrogen. Bone meal and potash provide phosphorous and potassium.
Sow seeds in the three inch layer of soil and compost.
For seedlings or plants, make cracks or holes in the hay a little larger than needed leaving room to add some extra compost (or soil) around the base of the plants. Place plants their first set of leaves are just above the top of the bale.
Caring for Your Garden.
Water new plants daily for the first week keeping bales moist. If the weather is especially dry, water again a few hours later. Hay does not retain water especially well; check moisture levels regularly. A drip irrigation system, or soaker hose saves time and reduces waste. Overwatering will wash away the fertilizer. The hay bales will gradually hold more water as they continue to break down. Fertilize and care for plants the same as you would for traditional gardening.
The Hay Bale Gardening method can be used for plants, flowers, herbs or vegetables. Perennials are not a good choice unless you don't mind transplanting them later, or plan to keep the bales in place for use as a traditional garden. (By the end of the second growing season, bales will begin to fall apart).
Root crops root crops like onions, potatoes, carrots, and radishes also do well. The roots sink through the bale.
*Potatoes - In normal soil gardens it is important to hill up the soil around the plant as it grows. The reason being that potatoes form on the stem, not on the roots. If planted too deep in the soil, the stem has a hard time emerging, because it cannot push up more than a few inches of soil. With a Hay Bale Garden, place seeds two inches from the bottom. The hay is loose enough for stems to emerge and adding soil or hay will not be necessary. At harvest time simply cut the twine and spread the hay out. Other crops can be planted at the surface and harvested early before the potato vine has stretched its way above and around the bale.
After the second growing season, the hay can be added to the compost pile, repurposed as mulch, or left in place to form a nutrient rich traditional garden.
Number of Plants Per Bale.
Two tomato plants
Four pepper or cucumber plants
Six lettuce plants
Three squash, broccoli, cabbage, or cauliflower plants