Container gardening is a great way to grow flowers, vegetables, and herbs if you don’t have access to areas of ground suitable to garden in—but container gardening isn’t cheap when you factor in large containers and the potting soil needed to fill them. Luckily, there is a simple and much less expensive alternative: using straw bales as planters.
This method is known as straw bale gardening and is similar to container gardening, but the straw bale stands in for the container and—as the center breaks down and turns into compost—the potting mix. Bonus: There’s no digging required! You can put straw bales on top of the existing soil, on paved surfaces, or perhaps even on a deck or rooftop.
Here, we cover the pros and cons of this gardening approach, and how to plant your own straw bale garden.
(No room? No problem! See how you can grow tomatoes in the driveway, dill on the deck, and peppers on the porch with Rodale’s Edible Spots & Pots.)
Cheap and easy: With a straw bale garden, there’s no container to buy, just the bale and possibly a handful or two of potting mix; no big tools to buy, as your hand and maybe a sharp knife are the only tools you need; and no digging, raking, cultivating, or rototilling required either.
Zero-waste: Unless your store sells bales in plastic bags, the most trash you might end up with are two loops of plastic baling twine, which are reusable for quite a few seasons.
No weeding: Straw rarely contains weed seeds. There may be a few stray grains that will sprout, but if you pull the grass-like seedlings out when they are young, it is quick and easy.
Stand up gardening: Since the top of the bale is a foot above the ground there is less leaning over to plant and harvest.
Conversation starter: Depending on your location, you may find your neighbors think they look really cool.
Compost creator: At the end of the season you have a nice pile of compost and a little mulch to reuse next year in containers or in your garden. Straw bale gardening is also fast way to start improving a new or existing garden area. Don’t want to dig up the lawn to make a garden, or need to improve the soil in an existing one? Spread a thick layer of cardboard, arrange bales on top to grow in this season, and then spread out the decomposed straw at the end of the season to make next year’s in-ground garden.
Heavy: Setting the bales up takes some strength. Dry bales weigh around 40 pounds and a prepped bale weighs a lot more (which is why prepping in place is wise). If not working on the ground, be sure your deck or rooftop is strong enough to support the wet weight.
Not tidy: There will be run-off when you water your bales, plus the bottom of the bale may stain the surface it is sitting
on over the course of the season (of course, this won’t be an issue if bales are placed on the ground). Toward the end of the season, the bales can get downright scruffy looking, and they may even sprout interesting mushrooms. Some gardeners build trays or shallow planters with legs or wheels to set their bales in, which adds to the cost of the method, but will solve these issues.
Rustic: Depending on your neighborhood, the exposure of your gardening area, and your personal tastes, straw bales may not be a look that appeals to you. You could wrap the sides in burlap (available in natural pale brown and a variety of dyed colors at most fabric stores) for a slightly more refined look.
When you go shopping you are looking for straw (the dry, hollow stems of grain) not hay (dry grass). Straw takes longer to break down, so the outside of the bale will hold together for a whole growing season, and is much less likely to contain weed seeds that will sprout and make work for you.
Look for rectangular bales that are about 14″ X 18″ X 36″. Farm stores that cater to horse owners are a good place to find them in suburban areas, in rural areas look for “straw for sale” signs on farms you pass for more economical shopping. If you want a lot of bales, check Craigslist or local classifieds for farmers who will deliver small square bales.
Also look for organic straw. Commercial straw may contain persistent herbicides (long lasting man-made weed killers designed to kill any plant except those in the grass family, like grains) that are used in commercial grain production. Residue will stunt the growth of anything you plant that isn’t in the grass family. Peas, beans, tomatoes, peppers, eggplants, potatoes, sunflowers, lettuce, petunias, melons, squash, and cucumbers are especially sensitive. The best way to avoid persistent herbicide residues is to buy certified organic straw or to buy direct from a farmer that you trust doesn’t use them.
If you can’t find organic straw, you may want to test your straw before investing time and putting seeds/plants in them. These instructions for testing compost for contamination can be modified by filling a bucket with straw, covering it with water, letting it soak for a couple of days, and then using the resulting straw tea to water half the pots, and using plain water for the others. If the seedlings all look the same, you are good to go. But if the tea-watered seedling are stunted, you probably have contaminated bales. Return the bales to your supplier, or use the straw as mulch somewhere you don’t want anything but grass to grow for the next couple of years.
Plan on acquiring and starting to prepare your bales 2 weeks or so before you want to plant. Move your bales to where you want them. Set your bales so that the cut ends of the straw are facing up (this helps the water get inside initially). The twine will be around the sides of the bale, where it will hold the bale together.
Water your bales every day for 3 days with plain water. Use a fine spray and move it back and forth to wet the bale all the way through. For the next week or so, use a watering can and water the bales with a diluted organic high-nitrogen fertilizer such as fish emulsion. (When shopping for fertilizer, look for the three large numbers on the label and make sure the first number – which is the nitrogen content – is larger than the other two). You can also use a free high-nitrogen fertilizer instead of purchasing fertilizer. During the first 2 weeks, the inside of the bale should get quite hot, as the microorganisms break down the straw; once it starts to cool down and you can poke a finger into it without it feeling super hot, the bales are ready for planting.
If your plants will need a trellis or stake to help support them as they grow, it’s a good idea to set the supports up now. Drive stakes into the underlying soil, use a support that will stand on its own, or place the bale next to a fence. The bale may be solid now, but as the season progresses and the straw breaks down, anything stuck into it alone will fall over, causing your plants to crash over as well.
You can plant pretty much any vegetables, flowers, or herbs in prepped bales, but it is best to stick to annuals (or have a plan for transplanting perennials at the end of the growing season). Either seedlings or seeds are fine. Use your fingers to open a hole about the size of your fist in the top of the bale. Make as many holes as you like, just be sure to leave about 3″ around the edge of the bale intact. For seeds, fill the hole with compost or organic potting mix and plant the seeds in that. For seedlings, make the hole large enough for the rootball, wiggle the rootball in, and use compost or potting mix to fill up
any nooks and crannies.
Water as needed to keep the interior of the bales moist. You may want to use a diluted organic fertilizer (pick one that matches your plants: high nitrogen for greens and lower nitrogen for fruit, flowers, or root crops) per the label instructions. Pull out any grain seedlings as soon as you see them, before the roots go nuts. Other than that, enjoy your plants!
Once the season comes to an end, you have the remains of your plants, a little straw, and a nice little heap of compost for next year. If you are on soil and aiming to build and in-ground garden, just spread it out. You can also save just the loose, brown compost in a container for use next season; and add the dry bits to your compost pile.