I've been a traditional gardener all my life, but tried straw bale gardening last year as well.
I tried several varieties of tomatoes, peppers, cukes, squash, and zucchini in the bales and they all did outstanding.
You can start your garden with seeds if you use some topsoil on top of the bales, but I transplanted all of my vegetables from flats and trays purchased from local nurseries.
I initially used 20 bales of wheat straw. The plants in the wheat straw were doing so well that I got 10 more bales of oat straw to see how that would do. (Pine straw wonít work.)
I recommend getting bales that have been tightly baled. The oat straw bales I bought were lighter and baled looser than the wheat straw, and I learned that they donít hold as much water. I paid about $2.50 for each bale.
Use bales that have synthetic twine if you can find them. The twine wonít rot and it will hold the bales together longer. If the bales use regular twine, thatís no problem. You may have to put a stake at the end of the bales. The bales I used had regular twine, and they started to rot and break, but I arranged 10 in each row, so the bales tend to hold each other together.
I oriented my bales with the strings off the ground. You can do it either way, but I like the twine off the ground. The transplanting seemed easier with the bales oriented with the strings off the ground. You can decide which way to orient yours.
If you make more than one row of bales, put them wide enough apart so your lawnmower can get between them. And because youíll be watering them, I recommend placing the bales where the water will drain away from your house or away from where youíll be walking.
How many plants per bale? Try two tomato plants per bale, three peppers, two squash, two sets of cucumbers.
Be prepared to stake the tomatoes, peppers and any tall growing plants. I recommend 6-foot stakes for the tomatoes. I used tobacco sticks last year, but they are too short. My tomatoes grew way over the tobacco sticks. This year I'll be using stakes and a horizontal trellis and arch way-type trellis.
I didnít plant any okra last year, but they will probably do well. Youíll definitely have to stake them. I donít think corn will work too well. The plants will be too top-heavy. I water the bales in the morning and after sunset. You canít over-water because any excess will just run out of the bales. Soaker hoses will work. The main thing is not to let the bales get dried out between watering.
I started out using some Miracle Grow once a week for a couple of weeks. Then I sprinkled in some 10-10-10. You donít want to over fertilize.
The bales will start to sprout wheat or oat straw, but that is no problem. If the grass gets too much for you, just whack it off with a knife. I give my bales a ďhaircutĒ every so often with a steak knife. It takes no time at all.
One thing Iíve noticedóand this could be just a flukeóis I have not had to spray my plants with any pesticides such as Liquid Sevin. I havenít had any worms, bugs or other pest bother my straw bale garden. Maybe it has something to do with the plants being off the ground.
Be prepared to use new bales each year. I donít think they will be suitable for two years in a row. You can burn them, use them for mulch or bust them up and set new bales on them next year.
Preparing Your Bales
It takes 10 days to prepare your bales.
Days 1Ė3: Water the bales thoroughly and keep them wet.
Days 4Ė6: Sprinkle the bales with 1/2 cup of ammonium nitrate (34-0-0) per bale per day, and water it well into the bales. I didnít have any trouble finding ammonium nitrate from my local ag-supply store. They sold it in 50-pound bags. I have heard, however, that some people have had difficulty finding it in more urban settings. Ask around. (See more about ammonium nitrate at the bottom of this page.)
Days 7Ė9: Cut back to 1/4 cup of ammonium nitrate per bale per day and continue to water it in well.
Day 10: No more ammonium nitrate, but do add 1 cup of 10-10-10 fertilizer per bale and water it in well.
Day 11: Transplant your plants into the bales. I used a spatula to make a crack in the bale for each plant. Place the plant down to its first leaf and close the crack back together as best you can.
P.S. - the recipe for preparing your straw bales calls for a little Ammonium Nitrate (34-0-0). Because of some Homeland Security concerns, you will probably have to give your name and phone #/address to the Seller. Ammonium Nitrate is just a fertilizer-type catalyst that acts like vitamins for the microbes that help decompose the straw bale to make it a great host for the vegetables you're going to plant. Farmers/gardeners have been using this product for years. However, if you can't find any Ammonium Nitrate or don't want to purchase a 50 lb bag, just add a week or so weathering process to your bales before you add your transplants. Be sure to wait until all danger of frost is over for your area.