Straw Bale Gardening: Part 2 – Conditioning

Straw Bale Gardening: Part 2 – Conditioning

(Read part 1, Straw Bale Gardening: Part 1 – Introduction.)

Okay, so you’ve gotten yourself a mess load of straw bales. What now?

Well, first of all, it would probably be a good idea to make sure that what you have is actually straw, not hay.

Say what? There’s a difference?

Yes. If you’re unfamiliar with the difference, perhaps having grown up in the big city and always figuring the two things are synonymous, at its most basic it’s this: hay is animal food, straw is animal bedding. That  might seem kind of simplistic, but it’s important in understanding why we want to use straw instead of hay.

Straw bales are made up of dried, hollow stalks of a cereal grain like wheat, a secondary crop left over when a farmer harvests his field. Straw bales are mostly seedless, any remaining seeds in them merely accidental. Having little use beyond animal bedding, they are generally really cheap.

Straw or Hay?

For best results, make sure you’ve found straw bales, not hay bales. Hay will, I am told, also work quite well, but be prepared to have to deal with a lot more unwanted weeds.

Hay, on the other hand, is made of grasses, tends to be greener, and as a food source for animals is chock-full of seeds and grains just waiting to sprout up and fill your garden. They also tend to be more expensive, and heavier.

So be sure to ask for STRAW bales, not HAY bales unless you want to grow a Chia Pet.

Laying out your garden

Set up your bales in whatever configuration you would like, depending on the space available and what you want to grow. Look for a place with plenty of sun, but otherwise you can literally do this in your driveway should you so desire. I’d recommend laying down weed block underneath if setting them up over ground, and if your area has critters like mice or rabbits that might want to lay down some gopher mesh of some kind.

It seems like straw bale gardeners are a little bit divided on which way to lay the bales, but the majority lay them cut side up (i.e. with the strings on the sides) and I think it makes the most sense. You sacrifice a little bit of area, but I think the bales hold together and hold moisture better when they are cut side up.

We decided we wanted to have some areas dedicated to vegetables that would benefit from a high, strong trellis system for vining and support (tomatoes, tomatillos, zucchini, cucumbers, etc.), and have other areas for vegetables that don’t need that (kale, carrots, onions, etc.). Keep in mind that once the bales are full of water they will be incredibly heavy, so do your best to get your arrangement in place the way you like it before you start…

… Conditioning! A.k.a. “Getting the Bales Ready for Planting”

Straw Bale Gardens: The Breakthrough Method for Growing Vegetables Anywhere, Earlier and with No Weeding

Straw Bale Gardens, by Joel Karsten, is a great resource.

Before you go planting anything into the bales, there is a minimum 12 day process you need to do with them to get them ready. If you have a lot of time, you can simply keep them wet for 3-4 weeks and let nature take its course. In some climates bales can last multiple seasons, and in that case they will be ready to go right away.

But if you’re like me and are both anxious to get started and like want to be proactive, here’s the method I’d recommend, that comes from Joel Karsten’s book Straw Bale Gardens (which I found worth every penny). There are also some other methods out there, like this one, but they all follow a similar procedure.

Day 1: Sprinkle the top of each bale with 1/2 cup of a high nitrogen fertilizer, and soak ’em good and proper.

When you look on bags of fertilizer, you will see three numbers, which signify percentages of nitrogen (N), phosphate (P2O5), and potash (K2O). You may also use blood meal, or any similar organic substitute. You will need about 1 pound of fertilizer per bale.

Making sense of fertilizer labels

Fertilizer comes in many different varieties. Look for a very high nitrogen type, with no weed killer.

After sprinkling on the fertilizer, just use your hose to really soak it into the bales as well as you can.

Day 2: Just soak ’em.

Skip the fertilizer, and just make sure the bales are watered well again.

If you’re like me, this is a great time to get the kids involved. Since the goal here is simply “soak the bales” there’s not much they can mess up as long as you’re ensuring the bales actually get as soaked as they will almost certainly soak themselves.

Soaking the bales

Helping me soak the bales was one of my oldest son’s favorite jobs. Rain gear optional.

Day 3: Again, 1/2 cup of fertilizer per bale, washed well in.

If you have access to “warm” water from a rain barrel, this would work best, as very cold water from a hose can slow down the microbial activity inside the straw bales as it breaks down. No worries if you don’t. 🙂

Day 4: No fertilizer, just a good soaking.

You should start to notice by now that it takes less water to get the bales fully saturated.

Day 5: 1/2 cup fertilizer, washed in well.

By now you know the drill.

Day 6: Water only.

At this point you may start to notice the smell of decomposition within the bales. This is good! If you stick your hand inside you may be able to detect the extra warmth being generated inside, and the tops of the bales will begin to darken.

Days 7-9: Cut back to 1/4 cup of fertilizer each day, watered in well.

The bales will be very active in their decomposing over these days. Stick a soil or meat thermometer inside the bale a few inches and you will be able to see just how hot it can get (sometimes as high as 100 degrees, depending on the air temperatures).

While this isn’t specifically necessary, I also started wrapping my bales with plastic sheeting (tucked into the lower bale twine) over these days, and the “greenhouse” effect seemed to accelerate the process that much more.

Bales wrapped in plastic sheeting to create a "greenhouse" effect.

Wrapping the bales in plastic sheeting is a great way to keep them warm and accelerate the decomposition happening inside — especially if the weather in your area is still cool.

Hi-Yield Garden Fertilizer 8-10-8

Day 10: Sprinkle each bale with 1 cup of a balanced fertilizer, and wash in.

By “more balanced” I mean somewhere in the range of a 10-10-10- fertilizer. That is, one that contains some P (Phosphorus) and K (Potassium) that can be washed down into the bales and balance the root zone somewhat.

Day 11: NOTHING!

Yep, just leave ’em alone for the day and let the microbial dance inside them continue.

Day 12: You are ready to plant, son!

Get thee to your favorite local nursery for some seeds and seedlings, because your bales are done, and ready to be turned into a garden.

Bales darkened and ready for planting

The bales have darkened and are ready for planting!

To be continued in Straw Bale Gardening: Part 3 – Planting.



  • This is truly, actually, definitely, surprisingly, remarkably, completely, amazingly, absolutely, enormously, really, quite hugely, very much helpful! Thank you!


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