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Flowers, Fruits, and Frass

Straw Bale Gardening

Originally published by Kelly Allsup on May 7, 2020.

Straw bale gardening has transformed the way I grow vegetables. With a minimal amount of preparation, a delivery of straw bales, and an understanding of how straw bale gardens work, I have had some of the most productive vegetable harvests in my gardening career. The advantages are: limited weeding; I can choose the sunniest spot on my property, even if it is the end of the driveway; and I only must commit to that location for a year.

Straw bale gardening is essentially growing your garden produce in a working compost pile. The science behind the decomposition of the straw bale is what makes it the ideal growing media for vegetables. Nitrogen and water added to straw through fertilization feeds bacterial growth to create "green manure." The bacterium then break down the straw, releasing nutrients. After a 10-day recipe of cooking your bales, you are ready to grow vegetables for less than the cost of building a raised bed, starting a garden bed amended with compost, or even a bag of high-quality soil.

  1. Orienting your bales from north to south, planting the taller plants on the north side, will give you the most sun exposure. Set bales up with the wires on the sides. You can double them, placing them side by side. If you are placing them in a grassy location, you can put newspaper or landscape fabric under the bales but I found that the grass grows back the following season. Be sure to allow yourself ample room to mow around or between the bales, and somewhere with access to the water hose.
  2. Joel Karsten, author of "Straw Bale Gardening" touts a specific 10-day recipe for getting the bales cooked and ready for planting. I have found that any combination of general fertilizer and water has worked to cook the bales. I have had less success with organic fertilizers as they don’t provide as high of nitrogen inputs as non-organic fertilizers. Karsten also discovered that it didn’t matter what recipe was adhered to, it all worked.
  3. During the cooking process, the bales will form dark soil clumps known as peppering. Mushrooms will form and can be removed or left but not eaten. Mushroom growth is a good indication that the process is working. Using a digital thermometer to make sure the interior temperatures reaches 160 degrees will let you know the bale is cooked.
  4. After the cooking process, I have been surprised by how malleable the top portion of the bales have been and had no problem planting. However, if there is still a lot of heat, do not plant in the bale until the top 4 to 6 inches cool down.
  5. If planting seed, place a 2-inch layer of soil on straw bales. Put down paper towels. Lay down your seeds and cover with soil. I always plant my basil and greens in this manner.
  6. If planting vegetable transplants, dig a hole, fill it with soil and plant.
  7. Give you’re your plants room to grow. Plant two tomatoes, four cucumbers, four peppers or two squash per bale and add supports as necessary.
  8. Add flowers like sweet alyssum, scaevola, petunias to the sides of the bales for added beauty. 
  9. Watering may be more important in dry hot summers. I have found that the straw bales are good at holding water.
  10. Vegetables that grow in the ground only need fertilizers at certain points in their development and that also depends on your garden soil. Most garden soils are rich in organic matter. However, when you are growing in a straw bale, you will need to add a complete fertilizer monthly. You want your fertilizer to work right away, so don't use the slow-release kind.

Just about every vegetable except sweet corn can be grown in bales, and the only reason sweet corn is discouraged is that it tends to flop over because of its height. If you have never gardened before start with plants that are easy to grow like herbs, greens, tomatoes, peppers, eggplant and onions.