This article will cover some of the benefits of straw bale gardening, what you can grow in the bales, and tips on how to grow in them.
There are many good reasons to plant in straw bales. One is that plants in straw bales are reachable from a wheelchair or walker since they are up off the ground, easily accomplished without the enormous expense of building tall raised beds. Another boon is that a straw bale garden is very weed-free, something quite desirable for those of us who no longer bend or kneel as we once did, or just plain hate weeding!
A third benefit is the lovely compost that remains as the straw decomposes over one to two years. If you have poor soil, you can spread out the old bale remains, place new bales on top of them the following year, and eventually you will have some very good soil full of earthworms. If you choose , you can even slightly scatter the old bales into a thick but loose layer and plant directly in them in a no-till method. This works quite well for potatoes if you keep mounding up more old bale material around the potato plants as they grow.
Another advantage happens if you use bales on top of hard, rocky soil, or heavy clay soil with poor drainage that makes normal gardening difficult if not impossible. It is even possible to garden in straw bales placed directly on a concrete patio slab or an old asphalt parking area.
What You Can Grow
After following the experiences of many gardeners over the last 3 years in the Strawbale Gardening Forum, I found that growing almost everything has been tried. The most successful included tomatoes, peppers, lettuce, spinach, summer and winter squash, okra, broccoli, beans, herbs, and even corn. Annual flowers also did well. The least successful were root/underground crops like onions and potatoes.
How to Grow in Bales
Although this method is commonly called “Straw Bale Gardening” not everyone uses or has access to oat, wheat, rice or other straw. Pine straw will not work because it will not break down quickly. (Straw is the remains of cut stalks of grains after the seed hears are threshed out.) Some folks have used hay bales if they were more readily available. Whatever the type of bale used, there are certain steps that make planting in them easier.
First, consider layout. If you are going to place the bales on a grassy area, be sure to leave room to mow between rows (if you have rows). Or, you might put down a layer of cardboard or newspaper under the bales, extending out into a pathway area to keep down weeds and tall grass around the base of the bales. I didn’t do that step last year as I had winter squash vines eventually running at least 15 feet out from the bales.
At this stage, you want to consider which way to run the strings wrapping the bales. What worked best for me was with the strings on one side touching the ground, which meant the stalks in the bales ran horizontally across the bales rather than vertically. This had the benefit of making it easier for me to part the stalks to get the seedling roots down into the bale, plus my bales seemed to hold water better.
Next, some bale preparation. The goal is to get some straw breakdown starting so the bales are past the initial heat of decomposing before planting lest you burn the seedlings. (It’s the decomposition of the bales that makes them a good planting medium.) An easy way to do this is to water the new bales thoroughly and keep them wet for 2-3 days. For the following 3 days, spread ½ cup ammonium nitrate* (34-0-0 NPK, available at agriculture/ feed stores) on top of each bale and water it in. Keeping the bales moist is very important. The inside of the bales should start to warm up. Stick your hand down in the bales to check!
Some folks have used bone meal, blood meal, urea or compost tea rather than ammonium nitrate for this step; just be sure it is something high in nitrogen so decomposition begins. For another three days, add only ¼ cup ammonium nitrate per bale, again watering it in well. Caution: Be careful not to water so much that you wash the ammonium nitrate out of the bales!
The next day, discontinue the ammonium nitrate and add about a cup of 10-10-10 or some organic fertilizer of your choice. Water it in well, keeping the bales moist. The following day, stick your hand down in the bales again. If they have cooled down (to less than your body heat) you may safely begin planting in them. Depending on a variety of conditions (bales, weather, rain) it could take 2-3 more days for your bales to heat up and cool down again before planting. Just continue the ¼ cup ammonium nitrate/watering regime until they begin to cool down.
Let me tell you some surprises you might have even before you begin to plant in your bales. Depending on the bale material, there may still be some grass or grain seeds remaining, in which case they may start to grow skinny green shoots. Just give them a haircut! Also, mushrooms may grow in the moist bales. They won’t hurt anything and will soon go away. But please do not eat them.
On to planting: I found just parting the stalks by hand or with a shovel to open up an area about the size of a 1 pound coffee can worked for me, but some folks cut out a small section instead. Add some potting soil to the opening and plant your seedlings a little deeper than in a regular dirt garden. Plant tomatoes deeply. I have seen people cover the whole top of the bales with 2-3 inches of compost, too. The idea is to build a good planting medium. You might plant only 2 summer squash, cucumbers or tomato plants in one bale, or 3 peppers, or fully cover an entire bale with lettuce or spinach. Just consider the mature size of the plants to decide spacing.
Fertilize and water as necessary, just do not let the bales dry out between waterings. The bales will dry out quickly in the beginning and may need watering twice a day, but as they decompose they will hold water longer. Soaker hoses work well and over-watering is difficult because the bales drain well.
Anything tall like tomatoes and peppers will require staking since the roots are anchored in loose straw rather than dirt. I built a long fence with very tall poles and stapled cattle panels (welded wire panels 16' x 50", available at farm supply stores for around $15) to it above the bale top height before placing a row of bales on each side. This gives me a permanent grid to tie up tomatoes, or for beans to climb. This year I will pile up the old bale remains on one side of the fencing and plant potatoes in it. The other side will have just one row of bales.
Other Uses for Straw Bales
Some folks place straw bales in a rectangular shape with an open center space to use as a cold frame, covering the opening with an old window or plastic at night. I have also seen bales placed with a center opening where compost materials were placed in the center. And of course, we all have seen photos of houses built with straw bales.
The uses of straw bales are only limited by your imagination, but choosing to use them for gardening makes growing so much easier for many folks who might not garden otherwise. Try it, you might like it!
Thanks to Strawbaleman, Hmstyl, Dea, CajuninKy, and Melissa_Ohio for their photos in the Strawbale Gardening Forum. Other photos are by the author.
A Special Thanks also goes to StrawbaleMan for bringing the bale gardening idea to Dave’s Garden 3 years ago, and for all the detailed how-to’s and hand-holding he has done for all of us new to strawbale gardening.
*Purchase of Ammonium Nitrate is now closely monitored by Homeland Security and you may be asked for identification.