Years ago I had some straw bales I’d used initially as fall décor that ended up in my chicken coop. The bales were used partially as a wind break all winter and partially as a roost. Well, chickens do what chickens do when they roost and by the spring of the following year those straw bales were full of nitrogen-rich chicken poop and starting to fall apart. So, I moved the out of the coop, watered the down really well for about a week, and planted a bunch of plants into them.
This was my first introduction to straw bale gardening and it worked wonderfully! The nitrogen from the chicken manure had kickstarted the decomposition process of the straw, providing essential nutrients for the microbes that do that work, and the decomp of the straw inside the bale created a fertile growing medium. I expanded the gardens quite a bit after that, as you all know, and haven’t worked with straw bales as a growing medium since. But this year, that changes. I’ve got a new spot I’m putting together behind my greenhouse with eight planter boxes already in place, but there’s also a fence at the back of that space I want to both cover and use as a trellis. I don’t want something permanent against that fence so I’m jumping back into straw bale gardening.
Today on Just Grow Something we’ll talk about how to use straw bales as a growing container and medium. I don’t have naturally conditioned bales this year, so we’ll talk about the process I’ll need to go through to get those bales ready. I’ll also cover the benefits of gardening in bales, what to watch out for, what plants do well with this method, and how to maintain them. By the end of the episode I think you’ll be convinced that straw bales are an effective way to increase the growing space in your garden without needing a permanent solution. Let’s dig in!
Question of the month for March: “What is your biggest pest in the garden and how do you manage it (if at all)?”
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Karin Velez [00:00:00]:
Years ago I had some straw bales I'd used initially as fall decor that ended up in my chicken coop. The bales were used as a windbreak all winter and partially as a roost. Well, chickens do what chickens do when they roost, and by the spring of the following year, those straw bales were full of nitrogen rich chicken poop and starting to fall apart. So I moved them out of the coop, watered them down really well for about a week, and then planted a bunch of plants into them. This was my first introduction to straw bale gardening, and it worked wonderfully. The nitrogen from the chicken manure had kick started the decomposition process of the straw, providing essential nutrients for the microbes that do that work, and the decomp of the straw inside the bale created a fertile growing medium. Now, I expanded the gardens quite a bit after that, as you all know, and I haven't worked with straw bales as a growing medium since then. But this year, that changes.
Karin Velez [00:00:58]:
I've got a new spot I'm putting together behind my greenhouse with 8 planter boxes already in place, but there's also a fence at the back of that space I want to both cover and use as a trellis. I don't want something permanent against that fence, so I'm jumping back into straw bale gardening. Today on just grow something, we'll talk about how to use straw bales as a growing container and medium. I don't have naturally conditioned bales this year, so we'll talk about the process I'll need to go through to get those bales ready. I'll also cover the benefits of gardening in bales, what to watch out for, what plants do well with this method, and how to maintain them. By the end of the episode, I think you'll be convinced that straw bales are an effective way to increase the growing space in your garden without needing a permanent solution. Let's dig in.
Karin Velez [00:03:19]:
Really quick, I wanna shout out my gardening gang over at Patreon and the support that they provide for this show each and every month, and welcome Catherine to the gang. Catherine has joined at the seed patron level and now has access to all the posts and bonus episodes and videos at that level. I'm also getting ready to send out the special merch for flower patrons and above. Those bonuses will get out at the end of April. That merch is not available in the shop. This is a Patreon exclusive for flower patrons and above who've been at that level for at least a month prior to the ship date, which means it's not too late for you to join and get in on the goodies. There are levels that just buy me a coffee at $2 a month, but the bonuses start in at the $5 a month level. You can check out all the ways to add your support at patreon.com/just grow something. That link will be in the episode description, and I am super appreciative of Catherine and all my patrons over on Patreon. You guys rock.
Karin Velez [00:04:25]:
And don't forget the question of the month for March. What is your biggest pest in the garden, and how do you manage it if at all? Leave a voice message from the link in the show notes. Respond to the question in Spotify if that's where you're listening. Send me an email, drop it in the Facebook group or in a DM. You know what to do. I think this question is one where we can really help each other out. You have until March 31st to respond, and I will air the answers the 1st week in April.
Karin Velez [00:04:58]:
So what exactly is the straw bale gardening method? Essentially, it involves using straw bales as a growing medium for your vegetables, and they are also the container. It's almost like a giant version of soil blocking. It's like creating compost. Straw will eventually decompose just like any organic material, but they'll decompose more slowly when they are still intact bales because the outsides are less insulated than the center, just like our compost piles. We turn our compost to be sure that we're not only adding air, but we're bringing that material on the outside into the middle where it's nice and hot, and it can also break down. If we don't turn our compost, the stuff on the outside isn't composting. That's what's happening when we condition a straw bale to grow our veggies in. The interior of the bale begins to compost, and the outside remains intact. What you're left with is a straw shell filled with the beginnings of a compost pile, a ready made planter, planting medium, and plant food all in one.
Karin Velez [00:06:06]:
There are a lot of benefits to growing or gardening in straw bales. Straw bales provide excellent drainage, reducing the risk of waterlogged roots if you've got heavy rains going on or if you have normally tight soils. And if you're having to water the garden frequently, straw bales dry out slower in hot, sunny weather due to their mass. So the inside of the straw bale remains damp even in high heat. They can help prevent soil borne diseases because you're not planting directly into the soil, and there is no actual soil component involved. So if you have struggled with soil borne disease in the past, these are an inexpensive alternative to putting in a permanent solution like raised planters. You're gonna have fewer weeds in the straw bales. And usually, the only ones that you'll get will just blow in on the wind, and those ones are easily plucked out.
Karin Velez [00:06:58]:
And you also will get fewer slugs if that's an issue for you like it is is me, because generally, the slugs aren't climbing the sides of these straw bales. Of course, the bales act like an elevated planting surface, which is, you know, making gardening easier on the back, for sure, but can also be helpful for those who have mobility issues. And finally, by using straw bales, we are repurposing an agricultural product. Straw is simply the dry hollow stalks left over after cereal grains like wheat and barley are harvested, which makes it an environmentally friendly choice. So where do you find quality straw bales? Depending on where you garden, you may have luck just going straight to a local farm, especially if you live in a heavy cereal grain production area. If you don't, check farm supply stores, gardening centers, or nurseries. Since straw is often used as animal bedding and for mulch, You're likely to find it somewhere. Now, if you can plan ahead and pick them up in the fall, you can often find them pretty inexpensively being sold just as fall decor or for Halloween.
Karin Velez [00:08:15]:
Just can't find straw, or can't find it at a reasonable price, then this method may not make sense for you. You might be tempted to use hay bales, but here is a word of caution. Hay is essentially grass grown and sold as feed for livestock. Hay bales contain not only the stalks of the grass, but also the seeds of those grasses, like Timothy and alfalfa. Straw does not. You know what happens when you condition a hay bale like you do a straw bale? All that water prompts all those seeds to sprout and grow new grass plants. And the nitrogen used to to condition the bale just feeds that green growth. So you have nothing but grass growing in your bale instead of the plants that you want.
Karin Velez [00:09:05]:
Now this can just be a minor nuisance in some cases, but it's not the only reason you wanna avoid hay. More and more hay farmers are using persistent herbicides, like aminopyrrolids and others that are in that category. The problem with that, well, among other things, is that word persistent. Those herbicides are still present in the hay after harvest. So whatever vegetables you attempt to grow in that bale aren't gonna stand a chance. This is one of the reasons why I no longer use hay as a mulch in my gardens unless I personally know the source. Unless I can guarantee the grower isn't using one of those herbicides, I don't trust the hay to be in my garden. Straw is less likely to contain these types of herbicides, but it's not a guarantee.
Karin Velez [00:09:59]:
So if you can verify the source, like if you're getting your straw bales straight from a farm, then ask if herbicides have been used and what kind. If you're buying from a store and you can't verify that nothing's been used, you can do a bean test to be sure. So before you go and buy your bales, plant 3 or 4 bean seeds in a container away from any other plants. Make sure it's self contained, including any drip trays. Let those beans sprout and get a few days worth of growth on them. When you locate your bales, buy one bale and bring it home, or see if the seller will allow you to just grab a handful of the straw and just take that home to test. Put a handful of straw into a large container that holds at least 2 quarts, and fill that container with water. Allow the straw to soak overnight.
Karin Velez [00:10:51]:
The next day, begin watering your bean seedlings with this water and only this water when they need a drink. If the straw contains any of these harmful herbicides, by the time your beans have developed 3 sets of true leaves, you will be able to tell. You'll get unusual cupping or thickening or distorting of those leaves. That signals the likelihood that there is herbicide contamination, and you will need to find another source for your bales. Now, if you need a control to compare it to, then plant 2 sets of bean seeds and treat 1 normally, and then water the other one with only the straw water so you have a side by side comparison. If everything looks normal, then go grab the rest of your bales. I have yet to have a problem with any of my straw bales. I have heard of people in this area having problems with hay bales.
Karin Velez [00:11:45]:
So that doesn't mean it won't happen at some point, so it's better to be safe than sorry, and I will absolutely be testing my bales before I decide to condition them and plant into them. Now when selecting straw bales, once you're sure they're they're good, just make sure they're clean and intact. You don't want a bale that's already falling apart before you get it home. So just make sure they're not, like, overly weathered or they're not moldy, like they've already been sitting out in the elements for multiple seasons, because then they're likely not gonna be, you know, have much left there to break down or to grow your plants in. Now, you want to get your straw bales in place wherever you plan to garden before you prep them for planting. The conditioning process for straw bales involves a lot of watering, so be prepared to have the bales somewhere your hose can reach. You do not wanna be moving these bales after you've started them on their composting journey. They will be heavy, and they will be messy.
Karin Velez [00:12:51]:
So get them in place beforehand. And this is one of the great things about gardening in straw bales. You can put them anywhere you need a little extra growing space. Tuck them in between beds, put them up against fences, or in rows, or even circles, or whatever arrangement fits your garden and your plan. Just make sure you're getting the correct amount of light for whatever you plan to grow. So this is generally gonna be 6 to 8 hours or so. You can choose to lay down some sort of a weed barrier first if you like. But what I experienced the last time I did this was having the bale sit directly on the soil also conditioned the soil underneath the bale at the same time.
Karin Velez [00:13:36]:
So if you've got a spot where you wanna garden in the ground eventually, but maybe the soil isn't broken up enough yet and it just needs some help, plop a bunch of straw bales on top of it and grow in those for the season. And then the soil should be looking pretty good underneath them for the next year. Now position the straw bales with the cut edges of the straw facing up. This is the open side that doesn't have the twine or bailing wire running across it. And make sure that your arrangement is stable. Being creative is fine, but we wanna be sure the bales are level, and they aren't gonna topple over once whatever we're growing gets to full size. If you're growing low vining squash or melon plants, that's one thing. But if you're growing tomatoes that need something to climb up, that's gonna get top heavy.
Karin Velez [00:14:28]:
So keep that in mind when you're positioning your bales. Tie them together if you need to. Use t posts for stability, whatever. Mine are gonna be up against a fence, but I'm still making sure they're all level and stable so they don't fall forward away from that fence once they're loaded with mature plants.
Karin Velez [00:15:35]:
You've picked your bales. You've positioned your bales. Now it's time to prepare your bales. This step is crucial for turning the straw into a fertile growing medium. Remember, the first time I did this, my bales were already rotting just from exposure to the elements in the chicken manure, which contains high amounts of nitrogen. This time around, we're forcing the bales to break down and start composting, and it's gonna need a little help to speed up the process. This is called conditioning the bales, and we are going to do that with nitrogen and water. When conditioning straw bales, the amount of nitrogen and the volume of water that we're gonna need to use is gonna vary based on the size of the bales, how tightly they're baled, and the environmental conditions where we're gardening. But there are general guidelines to follow that will ensure successful conditioning, and we can change those on the fly if we need to. It's important to monitor this process by checking the internal temperature of the bales so we can make those adjustments. So if for some reason I haven't already convinced you through all of these episodes that you should have a soil or a compost thermometer on hand, now is the time you definitely need a soil or compost thermometer on hand. I will link to the one that I use in the episode description. If you're comfortable with it, you can just grab a meat thermometer from out of your kitchen. But I don't know if you wanna reuse that in your kitchen again, so I'm gonna leave that up to you.
Karin Velez [00:17:10]:
In addition to having a soil thermometer, you're also gonna need a nitrogen source. The more water soluble, the better, and a lot of resources are gonna say just to choose a high nitrogen grass fertilizer or ammonium sulfate. We do things a little bit more organically here, so an organic urea based fertilizer would be perfect. I believe Espoma has an organic one, but blood meal, feather meal, or bat guano are decent alternatives too. I have feather meal on hand because that's what I feed my onions and garlic with this time of year. So that's what I'm gonna be using. Urea based amendments have about 45% nitrogen, so that process is gonna go fairly quickly. Where feather meal has only about 12%, so I'll need more feather meal, and it's gonna take longer to condition than if I were to choose a urea based amendment with a higher nitrogen level.
Karin Velez [00:18:06]:
So just make your choice accordingly. Conditioning your straw bales is going to take a minimum of 2 weeks with a high nitrogen amendment, at least a week or so longer if you're using one of those lesser nitrogen sources that I listed. And this is also gonna depend on your environmental factors. Colder air temperatures may slow it down. Higher humidity may speed it up. So start the process early enough so that the bale is ready in time for your plants to go in. I plan on using mine for warm weather plants like tomatoes, eggplant, and zucchinis, plus some companion herbs and flowers, and those don't get planted here until after the 2nd week in May. So I can wait until my air temperatures have warmed up a little bit before starting this process, likely around mid April or so.
Karin Velez [00:18:56]:
If you garden in a warmer climate though, you may be starting sooner. Let's break the conditioning process down day by day. On day 1, water the bales thoroughly, ensuring they are completely soaked. Apply approximately 1 cup of nitrogen rich fertilizer evenly on top of each bale. Water the bales again to help dissolve and activate the fertilizer. On day 2, soak the bales with about another gallon of water. No fertilizer added on this day. On days 35, repeat adding 1 cup of fertilizer and about a gallon of water.
Karin Velez [00:19:36]:
Begin checking the temperature of the bale each day. The temperature should start to climb and should reach in excess of 120 degrees Fahrenheit as the bale begins to break down. On days 46, we're going to water only. On days 7, 8, and 9, add just half a cup of fertilizer and then water as usual. Keep checking the temperature. If it hasn't gotten to a 120 degrees Fahrenheit or above, you'll likely need to add more fertilizer to boost decomposition. On days 10 through 14, check that the bales are staying moist. Keep an eye on the temperature of the bale.
Karin Velez [00:20:17]:
Once the temperatures have peaked, they will begin to drop steadily. Once the temperatures drop below 100 degrees Fahrenheit, the conditioning is complete. At this stage, do an application of a balanced fertilizer at the same rate you would a soil garden to give the plants what they need to get off to the best start. That's it. Once the temperature has stabilized, the bales are ready to plant into. The bales should feel a little bit warm to the touch because decomp is gonna continue throughout the planting season, creating a nice fertile environment for your plants to grow. Now remember, these are general guidelines, and factors like temperature, humidity, and the specific type of straw that you've got can impact the process. It's always a good idea to monitor the bales very closely during the conditioning and adjust the water and the fertilizer as needed to get it composting to your desired level.
Karin Velez [00:21:16]:
Once you've got your straw bales all conditioned and ready to go, it's time to transplant your seedlings. This is pretty straightforward. You're basically gonna prepare your seedlings the same way that you normally would for going into the ground by loosening up those roots very gently. And then you're gonna create planting pockets in the bales. You can do this by using a knife or a sharp trowel. I'll use my hori hori, and just push aside the straw enough to fit the plant in. Now, some sources are going to tell you to make this pocket bigger than the existing plant roots so that you can add some potting soil or compost with the plant. Others make no mention of adding anything extra.
Karin Velez [00:21:56]:
I am going to on the side of caution and add some potting mix when I plant, just so I know that the plant roots have something to grab onto while they begin to stretch out into the straw. Once the straw really continues to break down, the roots should have no problem doing their thing, but I want that little level of extra insurance just in case. No matter which way you do this, you wanna plant your seedlings at the usual depth and spacing that you normally would, just like you would in soil. So follow the recommendations for each vegetable as usual. The exception to this might be tomatoes. Normally, I try to plant my tomatoes so they only have a few inches, sticking up out of the soil. But this may not be as easy in a straw bale, so just do the best you can here. Speaking of vegetables, which ones thrive in straw bale gardens? Popular choices for this include tomatoes, peppers, cucumbers, squash, lettuce, herbs, just about anything.
Karin Velez [00:22:58]:
The only thing is I would probably avoid crops that have roots that would normally need, like, very loose soil to grow properly. So like carrots or beets or turnips, they might struggle a little bit in the limited space in a straw bale. I've also known people to grow potatoes, but they've loosened the bales up quite a bit, which to me kind of defeats the purpose. But, hey, these are your bales. Plant what you want. What about watering and feeding? When you're watering your straw bales, it kind of adheres to the same thought process I always do when you want more thorough but less frequent watering. So watering really deeply to ensure saturation of the bale, especially in the beginning when the roots are still really close to the tops of the bales. You really wanna soak them down.
Karin Velez [00:23:47]:
You may consider adding a mulch to the top, which kinda sounds weird when it's usually the straw we're using as a mulch in the garden, but it will preserve that moisture early on. And then just check the moisture level of the bales regularly. Do the same thing you would if you were planting into soil. Stick your fingers down into the straw to feel for moisture. If it's dry several inches down, then it's time to water, just like in a raised bed or in an in ground garden. Now as the straw bale decomposes, it's going to release nutrients to your plants, but that doesn't mean that those plants won't deplete the nutrients that are available to them. So keep an eye on your plants for signs of nutrient deficiencies. We do that initial feeding with the nitrogen in order to get the bales to start breaking down, and we do that single feeding of a balanced amendment at the end of the conditioning.
Karin Velez [00:24:44]:
But don't be afraid to feed those plants a balanced fertilizer or amendments for specific deficiencies the same way you would any others in the garden. Just adjust your feeding schedule accordingly to ensure that you have healthy plant growth. Now, what do you do with those bales at the end of the season? By late fall, those bales are likely going to be kind of falling apart. So it's not like you can reuse them again the next year. But you've conditioned that straw and watched it decompose all year, which means it is now the perfect addition to your garden. Use that straw as mulch in the garden, or add it to your compost pile for the next season. Or do what I plan to do. Tear apart those bales, pile them into a nice thick mound, and plant potatoes in them the following spring, replacing them with new bales to start the process all over again.