K-State Research and Extension

Q: We have lots of community interest in straw bale gardening, so I did a little research and here is what I found!
A: What better place to try this than in Kansas where straw is so abundant. First, some pointers.
It is best to use the “small” straw bales that are about 2 feet high and 3 feet long. Place the bale on edge so the twine doesn’t rot. Bales can be placed anywhere including concrete or asphalt, just make sure there is plenty of sun and watering is convenient. Bales must be conditioned before use. Water the bales and keep them wet for 3 days. The bale will start to heat up as it breaks down. On days 4, 5 and 6, sprinkle fertilizer on the top of each bale with 1 cup of ammonium sulfate (21-0-0) or ½ cup of urea (46-0-0). Water the fertilizer in. This speeds the decomposition process. On days 7, 8 and 9, continue to sprinkle fertilizer on each bale but cut the amount in half. Stop fertilizing on day 10 but keep the bale moist. Check for heat on the top of each bale for each day after day 10. When the temperature drops to below 100, the bale can be planted.
There are two methods of planting. The first is the Pocket Method. Make a hole for each plant several inches deep and fill with growing medium. You can also try the Flat Bed Method. Cover the top of the bale with 3 to 4 inches of growing medium. The growing medium can be well-aged manure, compost or potting soil. With either planting method it is possible to plant two cantaloupe, or two cucumbers, or three to four pepper plants, or two to three tomato plants.
Watering will be the most challenging aspect of management. The straw will dry quickly. A drip irrigation system on a timer can work well but may take some time to set up. Gardeners may also use soda bottles or milk jugs to water by poking drip holes in the lid, filling with water and then turning upside down next to the target plant. This information was taken from an excellent publication from Washington State University that includes much more detail as well as images. See http://cru.cahe.wsu.edu/CEPublications/FS109E/FS109E.pdf .