The Non-Toxic Way I Killed All My Grass (On Purpose!)

how to kill grass without spray

Most people don't set out to kill their grass. I, on the other hand, was on a mission.

Our neighborhood doesn't have much in the way of sunshine because the houses are built so close together. As a result, I grow things in a community garden plot so I can keep the fresh veggies coming all summer! 

For the last two years, I've been growing in a community garden was about 4.5 miles from my house and up a HUGE hill - which I would ride with my 3 year old in a bike trailer. My city recently finished building a new community garden that is a lot closer to my house - close enough that I can walk to it. Which is perfect since new babies can't go in bike trailers and I'll be having one of those pretty much any day now! 

The location was great. The price was great. 
There was only one problem: GRASS

The city had built raised bed quadrant plots for us, filled them with good quality dirt and then over the winter grass took hold. And not like grass here and there. Like, a rich, thickly rooted lawn grew on top of the raised beds over the winter. When I was ready to start gardening in April, I was faced with a 20' x 20' plot of this:

non-toxic way to kill grass

YIKES!

My friends in the plot next to mine painstakingly flipped their 20 x 20 plot shovelful by shovelful to turn the grass under. Being 8 months pregnant, however, I was NOT interested in so much back breaking labor - and really felt like it wasn't fair to ask my husband to take on such a big task on his own. Especially since I wasn't sure I'd even do that much labor without being pregnant.

After some research I developed a great plan to destroy the grass in my plot without chemicals and without a lot of backbreaking labor. 

Here is what my plot looked like 4 weeks later:

how to get rid of grass


Beautiful black dirt with just a couple plants to pop out here and there. And it was EASY! Let me show you what I did...

How to Kill Grass the Non-Toxic Way



how to kill grass without spray or poison

Supplies

  • LARGE pieces of cardboard - check at mattress and appliance stores. 
  • Hose and spray nozzle or sprinkler
  • Rocks or water filled jugs to help weigh everything down


Directions

Step 1: Cut the grass short
You can leave the clippings on top of the plot - no need to rake or bag it up. The goal is to get the grass short so the cardboard is less likely to "float" on top of tall tufts.




Step 2: Soak it
Get your hose and drench that sucker! Or turn on your sprinkler and walk away for a while. Make it very very wet.


Step 3: Lay the cardboard out on top
Get large pieces of cardboard and lay them out on top of the grass you want to kill. HUGE pieces do best. I had a few largeish boxes and they were too small. I'm talking ginormous - like boxes for mattresses or refrigerators. Be sure to overlap the edges so no sunlight in sneaking around the sides.
how to to kill grass without roundup or spray
Step 4: Soak and weigh down the cardboard
Get your hose or sprinkler back out and drench your cardboard. This will take a while the first time you do it and your sprinkler (if you have one) will be your best option.

Once your cardboard is absolutely drenched, weight it down in different spots by placing large rocks or empty milk or laundry jugs filled with water on top. This will help keep the corners from blowing up if the cardboard gets dried out.

Step 5: Water the cardboard occasionally
Be sure to pop over to your garden and water your cardboard every day or every other day if it isn't raining. Part of how this method works is by both smothering and blocking light from getting to the grass so keeping it damp and weighed down is critical.

Step 6: Clean it up
After about 3 weeks you can start to check your progress. Pick up a corner and peek underneath to see how the progress is coming along. I ended up leaving my cardboard on for a full month before removing it and it looked AWESOME!

I raked it lightly to get up any dead grass chunks. I also dumped used coffee grounds over the top to use as a mulch (just pop into your local Starbucks and ask for "grounds for your garden" and they will give you a whole trash bag full of used espresso grounds).
non-toxic way to kill grass


So that's my story! Now it's ready for planting!

(Don't forget to pin this post to save it for later!)

Nontoxic way to kill grass


Some questions I've been asked about this project:

Some people have been asking me WHY I needed to kill grass to plant a garden. Why not just put dirt on top?
Well, I could have put dirt on top. But in my particular circumstance this seemed silly. First, my city was providing me with free, awesome dirt. Second, buying that much high quality dirt is expensive! Also, because I was not building a raised bed on top of my lawn - where laying cardboard in the bottom and then filling with dirt would have worked awesome - I needed to do something different. I already had a raised bed filled with  good dirt - it just had a lawn growing on top of it!

I also heard this a lot: "Just spray a mix of vinegar, soap and salt on the grass to kill it. "
If you are planning to grow anything in the space you are treating, DO NOT DO THIS! I, too, use a non-toxic Round Up alternative to kill weeds (get my recipe here). However, you should never NEVER never use salt to treat weeds in dirt that you want to grow healthy plants in later. It takes forever to wash away (depending on how much you use) and will most likely poison anything you want to grow there in the future. 

If you have a question about this process (or why I didn't do something else instead!), let me know in the comments!


Carissa Bonham

About the Author:

Carissa Bonham is a lifelong crafter and mom of two creative boys. The owner and lead writer at Creative Green Living, she won the Craftys Award for the "Best Craft Blogger" category in 2016 and the ShiftCon award for "Best DIY Blogger" in 2018.

Her goal is to empower families to make easy projects and healthier choices that are beautiful and delicious! She is also the author of the hardcover cookbook, Beautiful Smoothie Bowls (Skyhorse, 2017) and Proven Techniques for Keeping Healthy Chickens (Skyhorse, 2018). 

Her projects have been featured in magazines like Kids Crafts 1-2-3, Capper's Farmer and Urban Farm Magazine. Follow her on PinterestInstagramTwitter or join the Creative Green Living Tribe.
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29 comments

  1. Your dirt looks beautiful! Nice and rich looking!

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  2. This is how I kill grass too but I use wood chips on top which end up decomposing to add to the soil. I usually do this in the fall so in the spring I have dirt!

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  3. Does this keep weeds from growing all season or do weeds still grow?

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  4. This will kill anything that was growing at the time you laid down the cardboard. It will not prevent new weed seeds from landing on your soil and germinating so you will still need to do some weeding. You can reduce the new weeds by applying a mulch once you remove the cardboard

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  5. I'm trying to figure out how you had dirt at the end and not just 400 square feet of dead grass.

    I guess I need to try this next year, leading up to planting season. (I tried with newspapers, but they were too thin - they dried out too fast.) I spent lots of time - and money! - trying to prep my soil last year, with straw and compost and the like. And it's full lawn this year, too.

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    Replies
    1. The grass died and then decomposed. If you check on it and you just see dead grass, it needs more time.

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    2. he said in the article that he raked up the dead grass and then added coffee grounds.

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  6. Good to know! I guess we've never had any blocked for quite that long.

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  7. Doing this now. My dad thinks I am nuts. :-)

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    Replies
    1. My dad thought I was nuts, too. As did my husband. And my garden neighbors. But it worked and was easy. I could also rename it "the lazy girl way to kill grass"

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  8. I'm so glad someone commented on this again so I got the notification. I was wracking my brain trying to remember who had posted this! I'm about to pull my hair out over trying to get this method to work. I've been saving boxes for months and planning ahead to do this. And I cannot get the cardboard to stay down for anything. I soaked all my boxes the first time and I swear within 2 hours they were bone dry again. We now have half our lawn furniture on top of them and they STILL blow up. Mine have been on (sort of) for almost a month and I still just have a half-crumpled mess of cardboard. :/ I wanted to come by and see if I'd missed an important detail! I guess we just have a LOT of wind.

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    Replies
    1. It sounds like you might be using fairly "standard" size cardboard boxes. The first week I wanted to do this, I tried a combo of brown paper bags and fairly large boxes - and I had the same problem. The cardboard dried out too quickly and I ended up with what looked like the remnants of homeless camp.

      This method was only successful for me once I got HUGE boxes - like the kind that a queen size mattress comes in (so think: It's twice the square footage of a queen size mattress in one piece of cardboard). Try calling around to mattress stores or appliance stores to ask about refrigerator boxes.

      I also weighed down the cardboard at the overlaps with huge rocks or jugs filled with water.

      Lots and lots of water is a key ingredient to making this work, so if you are having a hard time getting the cardboard to stay soaked, you might want to try putting the hose under the cardboard to flood the area under that cardboard as well as water on top of the cardboard.

      I hope those tips help!

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  9. My boxes might not have been quite that big, but they were pretty big. Amazon sends us cases of diapers and wipes, and they put them IN boxes -- like, multiples cases of diapers in one shipping carton -- so they're pretty big. But I didn't think of wetting UNDERNEATH; that's a really good idea!

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  10. Good job! What did you plant?

    My husband built me 2 beautiful raised beds to start our garden in (first year, starting off small...there's room to GROW next year...LoL)

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    Replies
    1. I had about 20 tomato plants, 4 massive zuc hini plants, peppers, cucumbers, basil and some poured blueberry plants. It was glorious!

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  11. This thread is a bit old, but if you know anyone who works computer or IT, ask them for boxes. The computers come in extra heavy duty hard to open boxes. They are smaller, but heavier than the standard every day moving box.

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  12. Has anyone run into issues with neighborhood associations or cities taking issue with the "nutso" look of this? I would like to take part of our front yard out of grass and this makes more sense than paying $$ for a service to rip it up.

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    Replies
    1. I didn't have an issue but that was probably because it was in a dedicated garden area.

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    2. I didn't have an issue but that was probably because it was in a dedicated garden area.

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  13. Thank you for sharing! What time of year do you think would be best if I'm planning on planting a spring garden? I live in the Midwest and was thinking early spring but I saw someone comment about doing in the fall. Any suggestions?

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    1. I did it in April for a garden I planted in May. It would work any time of year. I would start working to kill the grass about 5 weeks before planting.

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  14. Hugh boxes are essential. The more overlaps, the more opportunity the grass or weds have to find their way in between the cracks (these plants really try hard to live). If your soil is either bit acidic, PH<7 sprinkle with horticultural limestone (organic) before applying the cardboard. Also, it's a good idea to sprinkle a healthy amount of blood meal (organic) under the cardboard, because the decomposition process uses a lot of nitrogen. BTW coffee grounds are the best.
    Master Gardener

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  15. Good post. I am bookmarking this!

    http://www.thetravelingdyosa.com

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  16. I did that while ago to kill the grass to make a bed garden it did kinda work but the grass will come back a few months later so is more like temporary. My husband though I was nuts when I did mine too ��

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    Replies
    1. My husband thought I was nuts as well!

      You're right that it is not a permanent solution to keeping the grass away. BUT it does give you enough time to plant other ground covers or establish a garden that you keep up with on a regular basis without having to manually remove all the grass.

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  17. Thank you! I'll be using this method on my garden as it's laid fallow for 2 years due to my partner and I being ill

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