I knew of growing vegetables in straw bales and using them to create raised beds or cold frame space, but the recipe for creating a straw bale garden was just recently shared with me. I’ve been working with a client in the New River Valley who added three rows of straw bale gardens to his traditional, vegetable garden plot. He invited me to see it and learn more.
The idea started when he was given a book by Joel Karsten simply titled, “Straw Bale Gardens.” Karsten has a website by the same name. Wheels began to turn and ideas began to spark. These types of gardens are great for folks with limited space, poor soils and unprepared garden space, as well as those with disabilities. Most of the bales are high enough to sit by without bending, allowing for low maintenance gardening.
According to Karsten, straw bale gardening is simply a different type of container gardening, this container being the straw bale itself, held together with two or three strings; the outside crust of the bale serves as the walls of the container. Once the straw inside the bale begins to decompose, it becomes “conditioned” and ready to plant. The step by step process of conditioning creates an extraordinarily productive, warm, moist and nutrient rich rooting environment for young seedlings. Getting the straw bales conditioned is an essential part of the process, and should be started approximately two weeks prior to the target planting date. This technique works for seasonal spring, summer or winter gardens with added frost protection.
To “condition” the bale, water new bales thoroughly and keep them wet for three days. Keeping the bales moist is very important. Once watered, each bale will be very heavy, so be sure they are situated where you want them. As the inside of the bales begins to decompose, they will warm up. This is part of the conditioning process. On days 4, 5 and 6, sprinkle the top of each bale with 1 cup of ammonium sulfate (21-0-0) or a half cup of urea (46-0-0), watering the fertilizer in well after application. (Note: I would like to try an all organic version with a high dose of fish emulsion, but it may be hard to keep the critters out.)
The act of watering in the fertilizer application speeds up decomposition. On days 7, 8 and 9, cut the amount of fertilizer per bale in half. On day 10, stop adding fertilizer, but keep the bales moist. On day 11, feel the top of the bale for heat. If still hot, check every day until it cools down to body temperature or lower, still keeping bales moist. Once cool to touch, you can plant your straw bale garden. If you are unsure, use a meat or soil thermometer to measure the heat several inches down inside the bale. If weeds, oat grass or alfalfa starts to sprout in your bales, remove the plants when small. Because the straw is decomposing, mushrooms may also sprout. There is no need to remove them, but they could be poisonous so don’t eat them.
Each bale can hold two to six plants, depending on mature size. A good rule of thumb is to plant two to three tomatoes per bale for optimum results and to ensure adequate space for the plants. Straw bale gardens are not only for vegetable production, but also great for annual ornamentals, cut flowers and pollinator attractors. Staking may be necessary. (See photos.)
The bale needs to be continually fertilized. “Conditioning” does not ensure enough nutrients for an entire season. It is recommended to fertilize once a week with a balanced liquid fertilizer. As the season progress and flower set starts, it is advantageous to move from a balanced fertilizer formulation to a “bloom buster” type of formulation. Look for a fertilizer with a high phosphorus reading (the middle number in the three-number series). Once the season is over, break up and compost the bale. It will create a nice organic mulch to use in the landscape next season.
Keep dirt under your fingernails ~ Happy Gardening! Kelli
Kelli H. Scott is the Agriculture & Natural Resources Agent for Virginia Cooperative Extension, Montgomery County and also works with regional agents to supervise the New River Valley Master Gardener Program. (540) 382-5790, email@example.com.