Ever Had What Looks Like Grass Sprouting in the Garden from Straw Mulch?
In 40 years of gardening I’ve had it happen to me twice (maybe three) times.
The good news is that it’s NOT grass.
What is Straw?
Straw is a by-product of growing grain. It’s usually the stems of either wheat, oats, rye or barley. So those sprouts that look like grass are one of those grains.
Why Does It Have Seed In It?
Seed of grain in bales of straw can be a result of it not being harvested properly. Or perhaps the grain head on the harvest machine was not set right.
Another reason can be the use of older combines that leave grain in the field that are then picked up by the baler (machine) collecting the straw.
There are probably other reasons that are beyond the farmer’s control.
Know Your Source If Possible
If you buy straw from various sources and/or big box stores you have no way of knowing the origin. There’s no way to even take an educated guess at what your chances are of getting seed-free straw.
I’ve gotten my (wheat) straw from the same family for 40 years. They know what they’re doing when it comes to proper harvesting, but in spite of that I’ve had seed sprout in the garden at least 2 or 3 times over 40 years.
What To Do When It Sprouts
It pulled out easily and I took out a little each day until it was all gone.
As long as you don’t let it form seed you can just pull it and leave it on top of the bed to decay.
Another Way to Handle Things
I’ve read that folks who raise rabbits often cut these clumps which encourages more growth. Each time they cut — that’s free rabbit food.
And while it continues to grow the roots mine nutrients from the soil.
Will Covering Them Kill Them?
In a recent comment left on this post, friend and reader Susan also asked if covering the clumps would kill them.
Probably would if the mulch was deep enough to smother it. The main thing you don’t want to chance is having it continue to grow and set seed. My preference would be to pull it.
How About Using Pine Straw?
I had a brief email conversation with Susan right after she left her questions which included “should I consider using pine straw this summer rather than straw from Lowe’s?”
Pine straw makes an excellent mulch. When Bill was alive he would go to a forested area and rake up as many pine tags (a/k/a pine needles or pine straw) as could fit in the back of the truck. Over the years they’ve always been my favorite mulch.
If anyone has more questions about straw mulch (or any other kind of mulch) feel free to ask.
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Pine straw is an excellent way to add acidity to the soil.
I appreciate this post as I have had the same with quite alot of growth, way too much to pull out. I was wondering, did I get hay vs straw or what? Do I need to find sterilized straw or does that even exist? So perhaps I need to make some calls ahead of purchasing and hopefully be assured there aren’t a lot of seeds in what I buy ….
Graham, the notion that pine needles make the soil acidic has been around for a long time. It’s not accurate. It is true that pine needles are acidic when they fall from the tree, but when you lay them on the soil the soil life neutralizes them.
In all the years I used pine for mulch I NEVER had it turn my soil towards acidic. The pH always runs around 6.8.
I addressed this in my book on Organic Gardening on page 167.
“When organic materials are added to the soil and decay, the resulting organic matter tends to change the soil pH towards neutral.”
Cathi, indeed you may have gotten hay instead of straw. One indication of hay would usually be a variety of different plants sprouting. With straw — it will be the one plant (wheat,oats,or whatever grain it’s from).
I don’t know that there is such a thing as sterilized straw.
Calling ahead may help to one degree or the other. Depends on your source. I would call and ask as many questions as they’ll answer.
My situation is an example of what can happen even with folks who don’t intentionally mislead you:
As you and I know — once this sprouting event happens to us, we get rather paranoid about straw.
I addressed it with the farmer from whose family I’ve bought straw for 40 years. He is very emphatic about it not happening with his straw BUT the fact remains that it has and did happen 2 or 3 times over 40 years.
All we can do in any of life’s situations is “the best we can”. Do our homework and everything we can to make sure it turns out ok. That increases our chances of a good result, so most of the time things will be fine. But there always a possibility – even if small – that things won’t go according to plan. When that happens there’s nothing else to do but work through it.
I hope you’ll keep me updated on what happens. If you have more concerns as things progress, just email me with questions.
I’m so glad you mentioned that pine needle mulch does not contribute to a lower pH. This year I had been neglectful about my asparagus bed so after cleaning it up I used left over pine needle mulch on top. Then I worried because I read that asparagus prefer a higher pH. Your information has eased my plant conscience. Thank you.
I was JUST dealing with this on Sunday. I’m thankful it pulls out easily. I looked at the bright side of the problem being happy it wasn’t crab grass.
About 30 years ago before I knew better I bought hay instead of straw to put on my garden.
You are doing a great service to your readers. Thanks
Thanks for the response and I feel better somehow knowing I’m not the only one perplexed about this topic. I have considered using the kind of pine bedding around my garden beds that we put in our chicken coop. But that could get pricey and I worry it might just blow all over the place once I spread it….
So is there really any cost effective way to avoid all the weeds that sprout up everywhere short of building a boardwalk? (Which isn’t a bad idea except for the cost and labor.) Sand maybe? We’ve used free mulch in the past but are so done with that by now. Eventually there are sticks everywhere! (And weeds… ) : (
With my native landscaping ( in Colorado) I fight weeds pretty successfully with ground cover and prairie grasses. But of course around garden beds there would be too much foot traffic for most of those.
Thanks Theresa. It will be easier to throw the straw grass on top of the garden than to put it into a trash can. I just hope I can get to all of it before it goes to seed. I was anticipating a heavy rain this past weekend so I could cover my “de-strawed” garden with pine needles but it didn’t happen. Heavy rain is forecast again for this Friday so hopefully, I’ll get to put down the pine needles. Also, now that I know what to look for, I found a garden center that not only has pine straw but also seedless straw AND it also looks a bit chopped up. Yay!
I’ll keep you posted on how things go and I hope to get some things growing soon.
Christine, your asparagus will love the pine mulch. Glad the topic came up so you can rest easy.
Patricia, you’re right – that’s the bright side. Definitely not crab grass.
I did the same thing those many years ago Don. Hopefully I’ve been able to help others avoid that mistake.
Cathi, my reply – with several suggestions — is a bit long for the comment area. I’ll try to get a post up within a day or so. (See update in comment below this one.)
I want to mention here however, that sand will not stop weeds. Neither will gravel.
It’s excellent that you are fighting weeds with ground cover and prairie grasses.
Susan, what great news that you found a garden center with pine and also seedless straw!
Hope you didn’t get rid of your straw that was in garden. Assuming you still have it (I hope so)
rake it to one spot and the seed will germinate and can be easily pulled. Then you can use the straw.
Hope you’ll get that nice rain so you can get your pine down.
To Cathi and everyone —
I started writing about all the things to do in order to have very little weeding and it can easily be a major piece — so I’m not going to try to do it now when I have so little time.
Cathi, if you have access to wood chips (not chips of bark, but actual wood that has been put through a chipper) it makes a good mulch. And even better once it’s been aged. It works better than almost anything for border edges. It can have big chunks of wood in it, but for flower borders that’s usually not a problem.
Last year, I bought what was labeled…I think, 94% weed free straw to mulch my vegetable garden. It was fantastic. This year, I was not able to find the same brand or type of straw and bought something else. I was assured it would not sprout. I had my doubts but bought it anyway. It took a couple of weeks to start sprouting. Marone! Do I have my work cut out for me. Be careful about what you buy. Thanks for allowing me a place to vent.
Thank you for this thread! I’ve spent a week spreading what I hope is not hay…. but little grass sprouts are popping up all over my raised beds. It’s all the same sprouts, and I do see a lot of seed from something in this straw/hay.. should I pull it off my raised beds immediately?
If it all looks the same David, you probably have straw that had seed in it. I’ve received numerous emails from folks having this same problem.
Pulling them up when they’ve just sprouted would be what I would do.
Also, reader Kathleen’s questions and my reply to her on June 5, 2020 might be encouraging to you. Read them in the comments section of this post: https://tendingmygarden.com/hay-or-straw-which-to-use-for-mulch-2/
Let me know how you do.
Dorothea, thanks for “venting” here. It will help others to know they’re not alone with this.
And welcome to TMG.
I also have what is supposed to be a straw bale, with lots of partial seed heads in it, which are cheerfully sprouting. Looks like wheat to me. I read a suggestion somewhere that you should deliberately saturate the bale with water and let it sprout, before you use it as mulch. Sounds like a clever idea, but I was concerned about it getting moldy, and triggering allergies. What do you think about that?
At this point I’ve only put it over potatoes. I’ve been pulling some of the sprouts, but then I thought, I’m going to dig them up anyway, then I can add the wheat grass in the compost. I’m new to vegetable gardening. I’d like to use the straw elsewhere, but read that you shouldn’t put it over new seedlings. Is this your experience?
I also have a problem with slugs – I’m on the Oregon coast. I thought straw would interfere with hunting for slugs, but it’s pretty easy to pull it up and put it back down.
Thanks for your suggestions.
Others have also written to me about the possible solution of soaking the bale with water and letting it sprout. I think your concerns are ligitimate and you sure don’t want moldy stuff. If you go that route, at some point you need to loosen the straw and let it dry out.
And yes, you can add the sprouted wheat to your compost pile if you want. Just don’t let it go to seed unless you know the pile is hot enough to kill the seed.
That being said, pulling and dropping the new sprouts on the bed is the easiest way. (That’s what I did when it happened to me.)
Good luck Margaret!
My straw bales (all 100, being used in straw bale gardening) sprouted. Uggg. I put them in in the fall for the next spring, and they sprouted them. I was hoping the winter would kill them and I could have “weed free” bales for the spring season. I think they sprout or don’t sprout, depending on the age. Old bales sprout a lot less or not at all. Mine were from that fall season, so are hairy green things.
I’m debating spraying a very weak bleach solution on top to kill the new sprouting straw, but not permanently damage the beds for the transplants I put in. Thoughts?
Kathryn, sorry to hear about all 100 bales of straw sprouting.
As I mentioned in the post seeds being in straw can be the result of not being harvested properly. Also older combines can leave grain in the field that are then picked up by the machine collecting the straw.
For 42 years, I’ve bought my straw from the same family. Two or three times over that period I’ve had seed in the straw that sprouted. Thus, I know it can happen that even if the farmer knows what he’s doing (and this family knows what they’re doing), there could be circumstances beyond his control.
You mentioned you were debating spraying with a bleach solution. My gut feeling would not allow me to do that.
If the straw was mine — the first thing that would come to mind for the future would be to use a different farmer as a source of the straw.
Then I would open up these bales and as the wheat got some length to it (to make it easier to remove), I’d pull it and throw it in pile to die.
After that process was complete, I’d spread the straw where I wanted it.
I’d be interested in knowing what you decide and what the results are, Kathryn.
This has just happened to me in my vegetable patch. All the same looking grass popping up through my straw. I was wondering can I collect them and eat/juice them?
Chris, I can’t advise you because I’m not there to see exactly what’s happening.
If it were in my garden which is as free from chemicals as I can possibly get and I knew
exactly what it was, AND I needed the nutrition and/or liked wheat juice – then I would
feel free to juice it.
Hope that helps.
I have this happening right now. I thought the crab grass I was trying to kill was growing through and I pulled it out and it’s seeds with little sprouts off the end. It did come up pretty easily. Are you saying to just keep doing that and then the rest of it should be fine? Or since I saw a seed, that’s bad… I have 3 more bales of this and now I’m afraid to use it
If wheat is coming up from the straw, it is probably still too early for the seed to be “ripe”.
But yes, keep pulling it up.
If you have 3 more bales of straw just like the one that seed sprouted from, you’ll have the same problem with those.
In order not to waste the straw, you could open the bales and leave in one place and allow the seed to sprout. Pull those up. And then use the straw in a “controlled” area that you can keep an eye on.
There is a method of pasteurizing straw used by mushroom farmers that uses lime water to control mold. I can tell you it works a charm against rot and mold.
However, it does nothing against sprouting. It was the reason I came to this site. A whole almond agaricus/herb garden sprouting like a lawn.
Hi! I’ve made this mistake and it’s sprouting like mad. Can I just cut it down with a weed whacker before it goes to seed or do I need to pull it? There so much! Thanks
Keely, you can cut it with a weed whacker to give you more time before it seeds.
Then little by little as you see it growing again, you can pull it up and just leave it on your beds to die and decay.
You’re in good company! Lots of us have been through this. Good luck!
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How to Start a Straw Bale Garden
Kerry Michaels is a container gardening expert with over 20 years of experience maintaining container gardens in Maine. She specializes in writing and capturing photography for gardening and landscape design for print and broadcast media, including the Discovery Channel, Small Gardens, and Disney, among others.
Kathleen Miller is a highly-regarded Master Gardener and Horticulturist who shares her knowledge of sustainable living, organic gardening, farming, and landscape design. She founded Gaia’s Farm and Gardens, a working sustainable permaculture farm, and writes for Gaia Grows, a local newspaper column. She has over 30 years of experience in gardening and sustainable farming.
The Spruce / Steven Merkel
- Working Time: 3 hrs
- Total Time: 1 wk
- Skill Level: Beginner
- Estimated Cost: $4 to $9 per bale
Any kind of raised bed makes for an easy, convenient garden, but one technique that is especially effective is straw bale gardening. Sometimes known as bale gardening, or hay bale gardening, a straw bale garden uses ordinary farmer’s straw as the principal growing medium. Conditioned with a small amount of potting soil, compost, and fertilizer, the straw itself breaks down gradually, providing its own nutrients over the course of the growing season.
What Is a Straw Bale Garden?
A straw bale can make a great growing medium, and a straw bale garden is a raised bed in which the potting soil, compost, and plants are all housed inside the straw bale.
Straw bale gardening is a great way to grow herbs and vegetables, and can also be used to grow ornamental plants. It’s economical, easier on your back, and is great for people with mobility issues.
Consider the pros and cons to determine if straw bale gardening is right for you.
Tips for Straw Bale Gardening
For effective straw bale gardening:
- Use straw, not hay. Hay is made from alfalfa and grasses that still have the seeds attached, and these seeds will turn into weeds when they germinate and sprout. Straw, on the other hand, is comprised of the leftover stalks of grains such as oats and wheat—after the seeds have been removed through harvesting. Hence, straw is virtually weed-free, which makes for an easy-care garden.
- Locate the garden near a water source. If you can, put your straw bale garden near a water source. Any garden takes a fair amount of water, and it’s helpful to be right near a hose.
- Solarize the bales. If you solarize the bales by wrapping them in black plastic for several weeks before you plant them, the heat will kill any remaining seeds that might otherwise sprout. It also speeds along the process of breaking down the straw into nutrients the plants can use. Remove the plastic before you begin planting.
- Use short plants. Corn, sunflowers, tomatoes, and other upright plants may grow too tall to be supported by the straw bales. And stakes are difficult to use in straw bales unless you can drive them down through the bales and into the earth. You can either grow smaller varieties of tall plants like tomatoes or keep them pruned to train on wider, shorter trellises.
- Plant in full sun. Nearly all herbs and vegetables prefer full sun locations—defined as six to eight hours per day or more. If you have only part shade locations, make sure to use plants suitable for that exposure—such as lettuces and other leafy vegetables.
- Avoid pooling water. Don’t position the straw bales in low-lying locations where water pools. Too much standing water can cause the bales to rot, and it can even drown plants.
What You’ll Need
Equipment / Tools
- Garden trowel
- Straw bales
- High-nitrogen lawn fertilizer
- Potting soil
- Plant seedlings
- Wire fencing (optional)
- Balance water-soluble fertilizer
The Spruce / Steven Merkel
Configure the Straw Bale Garden
Once soaked with water, straw bales are very heavy, so plan the position of your straw bale garden first, before planting. The most important criteria is to have a location with plenty of direct sunlight—at least six to eight hours daily for most vegetables.
The bales should be postioned on-edge so that the sheared ends of the plant stalks are facing upward and the bands of twine are along the sides.
Arrange the bales in whatever configuration is convenient for your style of gardening. Some people like to arrange the bales in a straight row, others arrange them in an L or U configuration. The bales can also be abutted against each other to form a larger raised bed, but make sure you can still reach to the center of the garden for tending the plants.
Be aware that as the bales decompose they shrink so the spaces between the bales will get larger. Some gardeners fill these spaces with additional compost/soil mixture as they appear.
The Spruce / Steven Merkel
Prep the Bales
Prepping straw bales (sometimes called conditioning) involves starting the decomposition process before planting. Proper prepping requires a week to 12 days.
After the bales are arranged in your chosen configuration, spread a generous layer of high-nitrogen fertilizer on top of the bales. Water in the fertilizer, making sure to saturate every bale, every day for several days. Add more fertilizer every couple of days, spreading it generously, then soak the bales each time. A high nitrogen fertilizer, such as that used for lawns, is the best formulation to use for this conditioning stage.
After you notice the straw beginning to get warm and decompose, spread a mixture of potting soil and ordinary compost over the top of the bales in a 2- to 3-inch layer. When placed over straw that has begun to decompose, this is the only growing medium you need.
The Spruce / Steven Merkel
Plant the Garden
To plant seedlings in a straw bale, simply take a sharp trowel and stick it down into the straw, wiggling it back and forth to make room for the seedling. As usual, make sure to plant seedlings no deeper than they sit in their nursery pot. Also, try to place taller plants toward the back of the bale, so that when they grow, they won’t shade the smaller plants.
If you are staking taller plants, make sure to use long stakes that can be driven all the way through the straw bale and into the ground.
Seeds can be planted directly into the soil/compost layer, then watered in. Make sure to keep the soil constantly moist until the seeds have sprouted and are well established.
Some types of edible plants will also grow in the sides of the bales if you create pockets of potting soil and compost. Strawberries and potatoes are especially effective when planted this way. Or, you can use the sides to plant ornamental flowers, such as marigolds or petunias.
The Spruce / Steven Merkel
Tend the Garden
Like most raised gardens, straw bale gardens resist many common garden pests. But there are several critters that will not hesitate to scale your bales and eat your entire harvest. A fence may be mandatory to prevent pest such as groundhogs or rabbits from decimating the harvest. An inexpensive wire fence may discourage these pests. Serious vegetable gardeners may want to invest in a large fencing structure constructed of chicken wire and stakes to surround the entire garden.
Water regularly to keep your straw bales moist. Like any raised garden, straw bale gardens consume a lot of water. In the heat of the summer, this may mean watering every day. It’s best for plants to water in the morning, making sure to water the bale, not the leaves. Excess water will drain out the bottom of your bales so your plants don’t sit in water. Plants are much less susceptible to drowning in a straw bale garden.
Even though plants will get nutrition from the internal decomposition of the bales, you still need to fertilize them, though it’s required less frequently than with in-ground plants. A monthly application of a balanced water-soluble fertilizer is sufficient. At the end of the season, you can let the bales decompose, using the remnants the following season as mulch. Harvesting root vegetables such as potatoes, carrots, and onions often means breaking apart the entire bale—which is largely decomposed by this time—to extract the vegetable roots.