Something is Growing in the Straw Bales

Inky cap mushroom in straw bale
This one is about to ink-out!

I haven’t planted anything in the straw bales yet, but something is growing! I have a big crop of mushrooms in one bale and a smaller crop of grass popping out of some of the other bales. Both of these are expected events, though still a bit surprising. The mushrooms are “inky cap mushrooms,” which are mushrooms that dissolve into a black goo after a day or so — I noticed the goo pretty heavily on one of the bales.

One bale is covered with mushrooms.

Cornell University’s mushroom blog has an interesting post on inky caps and their tendency to destroy themselves. In addition to sprouting mushrooms and grass, the bales are definitely heating up and I expect to be planting them out within a week or so.

75 thoughts on “Something is Growing in the Straw Bales

  1. I’m excited to follow your adventures in hay bale gardening–I can’t believe the temp was up to 100 degrees. Wowsa!

  2. I’m buying a straw bale today. I’ve had grass growing in some, but not mushrooms. I get mycelium growing in my wood chip mulch though.

  3. Hello again ๐Ÿ™‚ I posted a few weeks ago and thought I would check back in. I finally resolved to cover my 8 straw bales in plastic to help heat them up. I left the plastic on for a little over a week and when I took it off it was steaming. I never had the chance to actually measure their temperature but everything I had read said it would take 10-14 days with the method I used. I didn’t plant them until close to 30 days and finally started planting them this week. I laughed when I read your post though! I had several bales that turned into chia pets with grass like wheat sprouts and when I removed the plastic I had one that looks just like your picture with the mushrooms. I was totally shocked! I will say the wheat sprouts died off with the plastic on them and the mushrooms died in a couples days. (I pulled a lot of them manually too). My boyfriend started seeds this year but they haven’t turned out very well, so, out of of the 4 bales that I have planted so far – 3 have been seeds. I planted lettuce, cucumbers, and green beans with seed. I planted 3 tomato starts in the 3rd. (not sure if that is to many! this is my first attempt) I want to start my peppers from starts so I will probably do that this week. Not sure what I will do with the remaining 3. herbs maybe? Good luck to you! I look forward to reading how it all turns out ๐Ÿ™‚ I will try and post pic’s of mine as they start sprouting. How exciting! lol

  4. Beth — Glad things are moving along. I found that covering the bales with plastic does really fire up the decomposition. I’ve planted some zinnia seeds, a few tomatoes and potatoes in my bales. We’ll see how they do! The biggest advantage I’m seeing so far is that it’s tricky for the rabbits to get at the bales, so they are not bothering them. Good luck with your bales!

  5. I said I would post some pics so I thought I would uphold my promise but it doesn’t look like I can on the reply… ๐Ÿ™ Mine are doing pretty well.
    I hope yours are going well!!! Can’t wait to hear an update. Those darn inky cap mushrooms are sprouting crazy just about every morning when I go out to check on the bales. They are worse on the ones that I planted seed and the ones I have not planted yet. My tomato bales only gets a few!

  6. I am doing my first straw bale garden this year and I too got the mushrooms and the grassy chia pet LOL I wanted to put pictures but can’t seem to figure out how.

  7. Well Im glad to hear that Im not the only one with these nasty gooy mushrooms all over the place. I too get them every morning more and more. Pretty weird. that I only have just now one or two on my tomato bale. Does anyone know if they are ok growing with everything? Should I leave them? Pull them? Ive been doing a little of both. I really would just like to know how to get rid of them. Oh and mine look like chia pets too. But… I have 6 bales and I have watermelon, strawberries, 3 different kinds of tomatoes, pumpkins, 3 different kinds of peppers, cucumbers, red potatoes, peas, green beans, lettuce, carrots, and green onion and they are loving the bales, this is my first time so Im hoping they all turn out great!

  8. Nikki — Don’t worry about the mushrooms. They are harmless to your plants. (I don’t know if they are edible, so don’t eat them.) Just leave them alone and they will die out on their own. The chia pet look may mean you have weeds in your bales or the straw in them is actually hay — clean wheat straw should not produce a lot of weeds. If it really gets out of control, you could trim it, but it shouldn’t harm the vegetables either. Glad the bales are working out for you!

  9. I have grass growing in my straw bales. I was told they were straw, I am afraid that they are hay bales….. any ideas how to get rid of it? Is there a spray that will not harm my veg. plants? Any help is better than what I have. thanks!

  10. Don’t bother to spray the bales — that will do more harm than good. If the bales are really hairy, you can trim the grass off with a shears. Otherwise, leave it alone, follow the protocol for conditioning the bales and plant your plants. They should still do OK. Good luck!

  11. Hi! We have some straw bales that have grass growing in them, which is a new thing for us. I took out some of the grass from the bale, and it looks like it’s growing from a wheat stalk? Does that mean it’s wheat grass? My mother is worried about weeds growing in the garden from the straw; is that something to worry about when we put down a layer of the grass-growing straw beneath the plants? Like I said, this is a new thing for us! It’s fascinating. My horse tried to devour the grass from my hand. Apparently it’s tasty stuff…
    I’ve never heard of straw bale gardening, but it sounds like it’s worth looking into!

    Thanks a bunch!

  12. Katie — If it is wheat straw (that’s the best kind), it could be wheat growing. It also could be a grassy weed. It depends on how clean the straw was when it was baled. Most straw-bale gardeners just cut off or pull out any weeds/plants that are not vegetables you planted. Good luck with your bales — it’s way too cold to plant anything here in Minnesota yet!

  13. Inky caps from what Ive read are edible but sometimes can be poisonous and as always you should not eat mushrooms unless you are experienced in identifying them.

  14. what is the sharpest-or best-hand-held tool for slicing grass out of a straw bale,or for cutting a hole in which to put my plant? i tried pulling out the grass but i could not get it all.many thanks!

  15. what is the most effective tool for cutting a hole in a staw bale,or for removing unwanted grass?many thanks!

  16. I just cut the grass with a scissors or shears. For cutting a hole to plant a plant, a sharp trowel works well. Your bale should be conditioned enough that you can get into it with the trowel. If it is too hard, it may need more conditioning time. Good luck!

  17. Hi, this is my first attempt at straw bale gardening. I have put in tomatoes, carrots, yellow beans, peas, and onions. All are doing amazing! Here is my question and it may be sort of odd but here it goes: I’m celiac and my garden is in barley straw, will I be able to eat my veggies or was this all for nothing? I’m worried my food will be contaminated by the barley that is growing out of my bales with my veggies. Thanks for any advice!

  18. I have same problem with mushrooms in my straw bale garden… They grow like crazy – every morning they surround mu watermelon plants. I’m thinking to cover it with a paper mulch…

  19. Bob — This question is beyond my pay grade, though I kind of doubt the barley would seep into the vegetables. If you live in an area with a University Extension service, I would contact them. Extension folks know a lot of things and they have access to University resources as well. Best of luck with the garden!

  20. This is our 3rd year Straw Bale Gardening, so we thought we would put in a nice size garden. We have experienced mushrooms like the inky caps with out any problem except when they fall over on a leaf and covers it. The last two years of Tomatoes grew great! This year however, the plants are not doing as well ๐Ÿ™ the Tomatoes are all about 1′ tall, flowering and some w/ fruit! All the different veggies we put in are stunted and turning yellow ๐Ÿ™ we use well composted horse manure tea for our fertilizer. How much is too much? Can’t seem to find this info! Help!!!

  21. will gardening in straw bales work in arizona? my soil is too hard to woe
    work so i’d love to try this but i’m wondering if our heat will be too
    much on top of the bale’s own heat?

  22. That’s a good question. I know that straw bales have been used successfully in California. Here’s another southwest gardener who uses straw bales. This person suggests planting your bales where they get some afternoon shade. I think that makes sense given the heat you would normally get. Lots of watering, too! Remember straw bales are basically a container garden, so what you would do with containers would apply here, too. Best of luck!

  23. thank you for the link to the california gardener. very enjoyable write-up and beautiful pictures. I guess all I can do is give it a whirl. I know people are successful with growing vegetables out here so being planted in a bale should not make much difference. I’m originally from wisconsin so this whole desert thing is a brand new concept to me. Thanks again

  24. I haven’t planted my straw bales yet ”still conditioning them” but not happy about all the grass coming out. I was told to pour vinegar diluted w/water on it. Any other fixes?

  25. I’ve heard of this problem before with people planting strawbale gardens. It may be the straw you got had lots of weeds in it. I would not use vinegar. That might change the acidity of the bed itself. You could just cover the bale with plastic to heat it up and smother the grass. Check out Joel Karsten’s website: for more tips.

  26. I bought 11 bales here in Arizona in March with the intention of using them to supplement my three 5 by 20 raised beds.
    I planted two in the shade of Citrus and Oleander for peppers and tomatoes. They are progressing slowly as expected because they only get a little light. But I am hopeful that they will still be slowly growing when it gets up to 120 degrees here.
    Planted two sets of four bales in an I beam configuration in the hottest part of the back yard.. Two side by side and one at each end.
    I have a tomato in each doing OK. Four tomatillo going crazy. Iranian tomatoes doing well from seed. Hopefully they will withstand the heat like the Iranian desert. Have Melons, cukes, watermelons, summer and crookneck squash, and an Eggplant.
    They all started slowly and are doing a lot better since I started sprinkling 7am and 7pm for 15 minutes.
    The eleventh bale is on the south side of the southern most raised bed and is producing lots of Italian ribbed zucchini and basil.
    Trying the bales for the wandering crops to try and avoid the squash beetles that destroyed almost everything apart from the Eggplant last year.
    This is my fourth year of urban farming and we are getting a little better every year. We are fortunate to have SRP irrigation water twice a month now that it is getting warmer.
    I am getting some kind of evil lurgy that grows at an alarming rate until I scrape it off then it goes away. It is like a bubbly soft slime that rises up on top of the bale and will surround any leaves in it’s path, and it spreads about 6 inches a day. Any ideas what it might be and how to prevent it?

  27. Dave, I am completely flummoxed about what the slime might be. Your climate is so different from the one we have in Minnesota that it would be hard to say. If you have a university extension service in Arizona, I would ask them. Many states have a Master Gardener help line you can call or a local extension office that might have the answers. Good luck!

  28. I read some of the comments on the “inky black mushrooms”, but I am still curious if it is okay to pluck them out each day?

  29. I prepped my bales, followed all instructions, got my plants in and now everything is turning yellow. I used compost tea as an early fertilizer, and added some granule garden fertilizer in w/the potting mix. Waited a few weeks and added more granule fertilizer. I don’t want to overdue it. I put so much TLC into my bales. I am so frustrated!

    What have I done or not done properly? I water the bales, and have had mushrooms sprout so I know the bales have composted properly. I have read so many blogs where others have posted the same yellowing stunted grow issue, yet no one seems to have a response on how to fix it. Does anyone have any suggestions? I have worked so hard and really want this to work.

  30. Here’s the response I gave to another commenter with a similar problem:

    Yellowing can be caused by all sorts of issues: too much water, not enough water, too much nitrogen, not enough nitrogen. Have you had a lot of rain? That could cause the manure tea to be diluted. Hereโ€™s a university post on manure that might be helpful:

    My guess, given the prepping process for straw bales, is the problem is more likely to be too much nitrogen or water rather than too little. Have you posted on the main straw bales site? If not, you might want to ask Joel Karsten. He is trained in agriculture/horticulture (I’m a writer and gardener, not a horticulturist). Here’s the contact page for his site:

    Good luck!

    Let me know how the harvest goes.

  31. I have mushrooms come up in my bales basically every day (especially after rain). I know this is a good sign of decomposition, however, some of the small seeds that I had sown (carrots, endive) did sprout and the mushrooms that came up displaced the sprouts and now they are gone. Any suggestions on how to deal with this?

  32. My hay bales have piles of some substance that seem to have been coming up from the inside of my hay bails. For lack of a better description, it looks like purรฉed cat vomit. There are piles spread throughout the tops of my bails. Any thought on what this might be?

  33. That’s a new one, Pam! It could be some kind of fungus or mushrooms but I’m not sure. Are the bales saturated enough or maybe over saturated?

  34. I have that too.
    Just scrape it off very carefully and put in the trash can. Be sure to clean the scraper very well.

  35. Hello,
    I know the best method is to use straw BUT I had ruined some hay bales this year & can’t feed them. Would it be possible to use the hay bales & cover them in weed barrier to prevent the seeds from germinating? I’m afraid that plastic will keep them too hot or do you just use plastic for a short time? Then the seeds will be killed & it’s a done deal?
    Also, would it be worth it to transfer my pepper plants into a conditioned bale? It’s already August here in OH & they have struggled in our soul. Thank you ๐Ÿ™‚

  36. Robin — I used the plastic to warm the bales in spring in Minnesota, so getting too hot wasn’t a problem. Definitely try moving the pepper plants. You might want to add a bit of potting soil to the hole in the bale, too. Good luck!

  37. Hi Guys,
    Just an update on my eleven Mesa, Arizona bales:
    Radishes grow like crazy in the spring.
    Once the heat takes over starting in late May then the plants start to suffer, just as they do in the raised beds. My bales have continued to decompose and are now about half their original height and totally decomposed in the centers.
    I got a pretty good crop of tomatoes out of the bales but not as good as the raised beds. Maybe I should have continued to give them more fish fertilizer.

  38. Dave — Fertilizer is a good idea. You might be able to get a fall crop of something given how decomposed your bales are. Thanks for the report. M

  39. This is my first year for straw bale gardening. I conditioned my bales for 14 days, watering every day, and fertilizing with organic fertilizer every other day. It was difficult to make the hole for bedding plants, but I found a sharp metal trowel at Home Depot that made the job much easier. I do have mushrooms growing out of the sides of the bales, and in at least one spot on top, a goey yellow something or other. The main problem so far is an infestation of tiny little bugs…maybe tiny gnats, as they seem to fly a bit. I sprayed insecticide soap, but ave not checked today to see if it helped. Anyone else have a bug problem?

  40. Little gnats or seem to like the decomposition. I jus sprayed some diluted Diatomaceous Earth on everything so we’ll see if it helps. The plants have a little indication of being eaten but nothing they can’t handle at least as of yet.

  41. My straw bale gardening is going great except for the dang mushrooms! How can I plant seeds when the mushrooms sprout up overnight and push them right out! Can anyone help? I’m afraid to plant my seeds.

  42. We planted before the mushrooms arrived but now we have plenty of them showing up here and there. They don’t seem to be doing too much to the plants that have sprouted, they are here one day and gone the next. They don’t seem to be too strong in their root system and are there in the morning when I check and gone by afternoon. I wouldn’t worry too much about them unless the entire bale is covered with them.

  43. This is our first year trying straw bale gardening. The veggies plants were looking until the leaves started to get this fungi it has destroyed the Casaba melon. Is there anything to prevent and make sure the other plants are affected.

  44. We put our bales up on pallets that are in turn sitting on the ends of cut off telephone poles because I have problems with my back and can’t get down on the ground or even bend over for extended periods and the bales are working for us. Going to plant them this weekend and put up a plastic tent over just in case it gets cold again. It is a bit early here in Maine but this spring has ben so warm already we don’t want to waste the nice weather.

  45. I usually just scrape the fungus off and throw it in the trash. Then clean the trowel very carefully to prevent more fungus spreading. The mushrooms just die in the sunlight with no apparent ill effects.
    With reference to the difficulty planting in the bales – I put my 2016 ten summer bales flat on the long side in two parallel groups of five and separated them with 2x8x16 red pavers. Then filled the gaps with compost. Unfortunately conditioning this set effectively created a huge compost pile that did not cool down for weeks until we got our third flood irrigation. Fortunately the idea paid off in spades as the sixteen one gallon tomato pots were so easy to plant between the bales. I think that the tomato roots spread out into the bales on either side of the bales. The zucchini and squash do well in the middle bales and the watermelon and cucumber do well on the end bales. I am harvesting about ten pounds of tomatoes a day, actually running out of neighbors.

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