Straw Bale Gardening – An Introduction

An important thing to know about me is that I am a fundamentally lazy person.  I’ll put a huge amount of effort into things that are fun, not so much things that are not fun.  My gardens in the past have been full of weeds, because I hate weeding.  I have, on multiple occasions, bribed someone to till my garden plot for me because that’s hard work.  Lucky for me, there are people willing to be bribed with baked goods.

So, when I found out about straw bale gardening, it was a revelation.  Our current home is on a lot that seems to be almost entirely heavy clay.  Previous tenants had removed the grass in a big chunk of the back yard, maybe for a garden, then covered the whole thing with plastic and that hideous “decorative” bark.  I assume this was done after they figured out that really, nothing but weeds will grow in the patch they chose for the garden.  I put in a huge amount of work to get that patch plantable again the first summer we lived here, and quickly learned the same lesson.  Not much wants to grow in heavy clay, and I lack the time, money, and energy to do the huge amount of amending that clay needs to actually be good for growing anything.

For planting season #2 in our house, I built a couple of small, shallow raised beds from kits I got at the home improvement store.  My two little 4×4 raised beds did kind of okay, but I didn’t get much of a harvest.  They were only a few inches deep, and the plants all eventually grew roots long enough to find that heavy clay that’s only a couple of inches down from ground level.

The first year I tried straw bales, I bought four and just plopped them right on top of the existing, nearly useless raised beds.  I figured if it worked at all, at least I wouldn’t be killing my back and knees by kneeling on the ground all the time.

before conditioning

Once the bales were in place, they needed conditioning.  Honestly, hauling the bales and then conditioning them is by far the most labor intensive part of straw bale gardening.


Protip #1: Plan ahead.  Make sure the place you put your bales is definitely where you want them to be for the whole season.  Straw bales are really heavy all on their own.  Once you get them wet, they weigh even more.  If you need to move your bales after you start gardening, you’ll need a forklift or something.  Even with a forklift, I’m not sure it’s doable.  Place them with the baling twine on the ground.  It will help them stay together for a second season, and retain water better.  If you place them so the twine isn’t touching the ground, the straw will be vertical and your water will just run straight through.

Once you’ve got your bales where you want them, it’s time to start conditioning.  This part isn’t hard, it just takes a while.  All you need is nitrogen fertilizer, a balanced (10-10-10, approximately) fertilizer, and water.

My first year, I spent a good week going to every garden center in town looking for the ammonium nitrate (34-0-0) the instructions I’d found said to use for bale conditioning.  I had absolutely no luck.  Most of the garden center employees didn’t even know what I was talking about.  Ammonium sulfate (21-0-0) will also work, and is a little easier to find.  I discovered, however, that I was just asking for the wrong thing.  Pure ammonium nitrate is the stuff people sometimes use to make bombs, which is apparently why it’s so hard to get.  Lawn fertilizer, however, is nearly the same thing and super easy to find!  I used Scott’s Turf Builder (34-0-4), and it worked great.  Just make sure you don’t get the stuff with added weed killer.  Just regular, no frills lawn fertilizer.  I could have saved myself so much time if I’d just realized that from the start.  This year I actually found a bag of ammonium sulfate at my neighborhood big box store and decided to try it, since I was out of lawn fertilizer and the pure ammonium sulfate was cheaper.  It worked, but really, I think the Turf Builder was better.  It’s easier to handle and has a higher nitrogen content.  I’m sticking with lawn fertilizer in the future.

A 10 day nitrogen sink is pretty easy.  Here’s how you do it.

Day 1: spread 1/2 cup of your nitrogen fertilizer over the top of each bale, then water thoroughly.

Day 2: water.

Day 3: another 1/2 cup of nitrogen fertilizer per bale, and water again.

Day 4: more water.

Day 5: 1/2 cup of nitrogen fertilizer per bale and more water.

Day 6: still more water

Day 7, 8, and 9: 1/4 cup of nitrogen fertilizer per bale, and more water.

Day 10: 1 cup per bale of whatever regular fertilizer you choose.  I use an all purpose 10-10-10 vegetable and flower fertilizer for this step, but you can choose yours based on what you’re planting.  If you want to use tomato-specific fertilizer on the bales where you’re planting tomatoes, that will work great.  I just find that using an all-purpose 10-10-10 works great for most crops, and I don’t have to keep a different fertilizer around for each bale.  Whatever you choose, don’t forget to water it in.  And don’t think you can get away with just continuing on with the nitrogen fertilizer.  That was just to get the decomposition going in your bales.  Your plants need a lot more than just nitrogen.

During your nitrogen sink, use a probe thermometer take the temperature of your bales every few days.  I find that the internal temperature will start to rise significantly on the 2nd or 3rd day.  By day 8 or 9 it will spike up to around 120-130° F, and then cool down to around 85-95° F by day 10.  Once you’ve completed conditioning and the temperature of your bales has dropped below 100° F, you’re ready to start planting.  If, on day 10, your bales are still too hot, just keep watering daily and taking their temperature.  They’ll cool down in a day or two.  I’ve read that they can sometimes take as long as two weeks from the start of conditioning to cool down enough to plant, but mine have never taken that long.

bales 2

Planting Your Bales

If you want to direct sow from seeds, just place your seeds on top of the bales and then cover with a layer of compost or potting soil. This is a great way to grow beans and peas.

Protip #2: If you need to trellis anything, you can stick a piece of rebar or some other kind of support in the ground at each end of the bale and then run twine between the supports.  This has the added benefit of supporting the bales on each end to help them stay together for a second growing season.

As I said, however, I’m impatient.  I like to just buy starts and plant them.  That way, I don’t have to wait and wait for seeds to sprout.  Instant gratification is much better for me.  To plant starts, just stick a sturdy trowel into the bale and wiggle it back and forth until you’ve made a space, then stuff the root ball in there.  If you want to, you can add a little soil or compost on top of the root ball, but it’s not strictly necessary.

Protip #3: Smaller starts are better.  Plants in 2″ pots are easy to plant.  4″ pots are certainly doable, but you’ll wind up having to break the root ball apart a bit to get it to fit into the space you’ve made in the bale.  This isn’t really an issue, just let the excess soil fall on the bale and into the hole you’ve made for the root ball.  Don’t even try buying those big, beautiful plants in gallon or half-gallon size pots.  You will never in a million years be able to cram something that size into your bales unless you cut big holes with a saw or something and scoop out a bunch of straw, and if you’re going to do that then you might as well just use regular pots.  I promise, the little tiny starts will grow.  They actually seem to do a lot better than larger plants.  Smaller starts are far less prone to transplanting shock.

Once you’ve got your bales planted, all you have to do is water regularly and harvest your crops!  If you do like I do and set up a drip irrigation system on a timer, you don’t even have to worry about watering.  I told you I was lazy.  Weeds will be few and far between, pretty much just from seeds blowing in.  Your bales may sprout a bit, but that’s not really a big deal.  Just give them a haircut now and then if it bothers you.  Sometimes if you look closely, you’ll see that you’ve got a whole seed head in there sprouting.  If that’s the case, you can just pull the head out and solve the sprouting problem in that spot.

You may also find mushrooms growing on your bales.  This is a good thing, as it’s evidence that you’re getting excellent decomposition inside the bales and plenty of nutrients.  I’ve most often had little black mushrooms that dissolve and look like they’re dripping black ink within a day.  I have no idea what kind of mushrooms they are, and of course you should never eat any mushrooms that haven’t been positively identified by an expert. I doubt anyone would want to eat these, regardless.

mushroomsblack mushrooms

When I started, I wasn’t convinced that plants would actually grow in straw bales.  The picture above was taken a few days after planting.  Here’s what those four bales looked like about 6 weeks later:

I planted three tomatoes and two peppers on this side.  In hindsight, that was too many, especially with the bales set side by side rather than end to end.

I planted three tomatoes and two peppers on this side. In hindsight, that was too many, especially with the bales set side by side rather than end to end.

The zucchini went kind of insane.  I originally had mustard greens planted on this side, too, but I lost them to aphids before I knew how to deal with an infestation.

The zucchini went kind of insane. I originally had mustard greens planted on this side, too, but I lost them to aphids before I knew how to deal with an infestation.

If you want to, you can also plant some things in the sides of your bales.  I tried strawberries the first year.  I haven’t done it again because I lost nearly all of the berries to birds and squirrels.

Tiny strawberry!

Tiny strawberry!

I think I’m going to do a whole series of posts on straw bale gardening, so watch this space for more information and pictures!


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