Straw Bale Gardening

The first year we had our garden was 2015, and we soon ran out of dirt to beg, borrow, buy, or steal (okay, we’ve never stolen dirt…only sand). Instead of a fourth raised bed we tried straw bale gardening. We set 3 pairs of straw bales together where the future raised bed would be and carefully followed the instructions from some blog. It worked. We grew loads of zucchini, pattypan squash, brocollini, yellow crookneck squash, and King Stropharia mushrooms.

The bales broke down by the end of the summer and made amazing mulch. Throughout the summer loads of wood-loving mushrooms kept popping up, indicating the cellulose was being eaten (and don’t worry, it doesn’t affect the plants!). We took the bales and mulched our existing beds for the winter, hoping the mycelium would continue to break down the straw and horse manure (and maybe pop a few more mushrooms). We watered the bales with a sprinkler every morning, and never ran into an issue with the bales drying out. The only downside to the bed was it was calcium deficient…leading to blossom end rot on the squash if I didn’t spray with a calcium-rich foliar spray every week or so. In McCall this is sometimes a problem with soil on the ground. Calcium is less available to plants when the soil is acidic, and no surprise, mushrooms tend to favor/create acidic soil. My bales were WELL populated. To try to combat the calcium deficiency this year, we added a bit of bone meal to the bale setup, and we’re also growing a different crop…potatoes! They are supposed to like acidity and be easy to harvest from the bales. I’m going to add just a little mushroom mycelium, probably oyster and pioppino, because I haven’t seen any wild mushrooms growing on these bales. Supposedly, pearl oyster mushrooms are not great to plant with your garden plants, but if I get zero potatoes and lots of mushrooms, I can buy more potatoes at the grocery store for like 25 cents per pound. We are in Idaho, after all. This year I carefully documented the straw bale setup process in case anyone wants to follow along!

Starting a Straw Bale Garden in McCall, ID

Step 1. Procure a few straw bales. They can be free or $8 per bale from Alpha Nursery. They are cheaper and more available in the fall ’round these parts.

Step 2. Soak the bales. Last year we soaked them with the hose for a few days. You could also use a sprinkler and get those puppies wet. This year we put two bales at a time in Toby’s giant plastic snowmobile sled and filled it with water. Then we wrestled them out and got really dirty. Wet straw bales are HEAVY.

Step 3. Gather your materials. I use chicken manure, blood meal, and bone meal. Generally I use one small bag of bone and blood meal per 2 bales, and about a bag of chicken manure per 3 bales, but it’s not down to a science.

Step 4. Sprinkle blood and bone meal onto the tops of the bales. Try to get a nice even distribution. Don’t panic if you don’t. The blood meal is a high source of nitrogen, which jumpstarts the breakdown process in the straw bales. The bone meal adds calcium and other nutrients that might be lacking in the bales. Don’t be afraid to use a handful of a micronutrient additive like Azomite. Rumors say it makes your vegetables and fruits taste better (and have more nutrients). I will tell you in the fall if I noticed a difference.

Step 5. Spread chicken manure or other nitrogen rich compost on top of the bales. Again, I use about one bag of chicken manure per 3 bales, but you can always use more. Yes, that is my pink-sleeved arm lovingly sprinkling aged poo across the bales, one handful at a time. It took me ages to get that photo just right, and then I never even Instagram-ed it. In reality I would be dumping the bag out while holding onto both bottom corners with my hands. This is much harder to get a photo of without using a tripod. You do it however you want.

Step 6. Water. Water, water, water. Water from the top and get that nitrogen down into the middle of the bales. Yes, lots of water is going to run through and come out the sides. Keep the bales wet for about two weeks, giving them a good soak every day if you can. The bales will start to heat up, and if you do this while the temperatures are still low, you will have steam coming out of your bales! It’s awesome. You’ll know the bales are done when they start to soften and the internal temperature decreases. They are basically just composting a little!

Step 7. How do I get the plants into this bale? you might ask. Use an ax (or a trowel if the bales have softened enough). Trust me, I’m the world’s worst ax-wielder, and I can manage to chop a hole in the bale without too much effort. It’s kind of fun.

I recommend using seedlings instead of starting your seeds in the bale. We didn’t have much luck from seed the first year, but we had a ton of little red mites in the bales. They didn’t affect the seedlings but the seeds didn’t germinate or had the cotyledons snacked on by something. Dig a hole a little bigger than you would need for your transplant, and put a little soil in the bottom (and any supplements). Pack in soil/straw around your transplant just like you would do if you had dirt.

*Bonus: stuff mycelium into the straw bale and watch it go!

Sam