With little effort and expense, you can have your own garden growing from bales of straw. (BIG keyword there: straw works best, not hay! More on the difference here.) This method works well for those with limited gardening space or poor soil conditions and eliminates most of the tough back-work "normal" gardening requires.
What you'll need:
Straw Bale(s) • Plants • Potting Soil • Fertilizer or Plant Food
You won't be able to move your bales after they've been drenched in water, so set up your garden base exactly where you want to grow, with the straw cut side up. The straw is easiest to separate and absorb the fertilizer this way, and the string will keep the bales in tact for the season. If placed in a weed-prone area, consider laying out landscaping fabric or newspaper under the bale to prevent anything from growing up through your straw.
Tip: For tall or viney plants, it's a good idea to build trellis for support. If planting seeds early in the season, you can create a mini-greenhouse by placing plastic over the lowest level.
Two-Week Bale Conditioning
I've seen quite a few variations for this next two-week process, but the key components and ultimate goal accomplished should be the same. Soak the bales with only water for the first 2-3 days. Then you'll alternate every other day between water + fertilizer (herbicide free & at least 20% nitrogen) and back to plain water. Each bale only needs about 1 cup of fertilizer spread out on top, but be sure to drench it thoroughly afterward. You want it to seep down inside to help decompose the straw for a rich, organic medium. Repeat for about 8-10 days. Aside from the dramatic rise in temperature, sure signs of composting include a blackening, moldy appearance, as well as the sprouting of mushrooms throughout. The last 2-3 days can be spent reverting to only water once more, allowing the bales to cool back down.
Tip: For even less hassle throughout, lay down a soaking hose that continually soaks the bale at a steady pace.
Separate and pull out the straw in small sections, keeping any excess for mulching later. Simply place the seedlings and potting soil inside of these small sections, following recommended spacing for the type of plant you've chosen. Planting in a checkerboard pattern rather than rows will allow the bale to hold more plants. Utilize the entire bale by placing herbs or flowers on each side.
At this point, all you have to do is continue to water your bales daily and provide a plant food or compost tea on a weekly basis. Since you're not growing straight from the ground, you've eliminated most need for weeding. However, if you've happened to purchase hay, it may contain seeds that will eventually sprout all over the bale. You can get rid of it with a simple diluted vinegar solution if necessary.
Tip: Save that straw after the season ends! It will keep decomposing and be an excellent compost source for next year.
Images & information courtesy of:
Straw Bale Gardens™ by expert Straw Gardener Joel Karsten
modernfarmer.com: How to Build a Straw Bale Garden by Nicole Cotroneo Jolly (also following Karsten's method)