Cornstarch: your friend in the garden

Just like last year, I planted a bunch o’ tomatoes in the garden in the back yard. Unlike last year, my tomatoes this year came under attack (ATTACK I say!) by bugs. First it was worms (tomato worms? Hornworms? I don’t know. Icky worms). Then came the stinkbugs. All my tomatoes were being eaten and rotting before they even started to ripen and I hadn’t gotten a single tomato for me to eat.

I wanted to evict the bugs, for sure, but I didn’t want to do it with a bunch of chemicals — sort of defeats a large part of the purpose of growing them in the back yard, you know?

Enter: cornstarch. Seriously! Now my garden looks like this:

I use a powdered sugar shaker full of cornstarch to cover the leaves, the tomatoes, and the ground around them. The plants look ridiculous, sure, but guess what? The tomatoes are MINE again!

I’m not sure exactly why this works, honestly — I don’t know if it kills off the bugs or if it just keeps them away; as long as I’m the only one eating the tomatoes, I’m good. It even deters Vinny the squirrel a bit which is an unexpected bonus. A quick wash in the kitchen sink removes all the cornstarch and I’m good to go. Tomato sandwiches for everyone! 🙂

101 thoughts on “Cornstarch: your friend in the garden

  1. So glad to know this trick is also keeping squirrels away!! That has been my big problem the past couple of years, so I finally gave up and didn’t plant any tomatoes this year. Next year I will, and I will use this tip!

    • It kills weed seeds too. Any corn gluten, pig feed corn. I like the feed stores most ground up 50 lb bag, which you apply to soil especially prior to the seasonal cooling and rains after summer heat. Let it rain on. The corn and it kills seeds. I do not know for how long but it works o mine. Cheaper than pre-emergent.

  2. My! I learn something new every day. Thank you for this handy, inexpensive, eco friendly tip. I love squirrels like I love home-grown veggies. This will come in handy.

  3. This is such a great tip! I sprinkled my tomato plant and herbs with cornstarch on your suggestion and hooray no more worms gnawing on my plants! It is fantastic! My deck looks a little crazy covered in powder, but it works!

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  5. Awesome! I am going to try this! I got chipmunks, squirrels and fire ants all eating my tomatoes. They don’t eat basil, mint or peppers though, just my tomatoes. Tomorrow, 1st stop in the grocery store, Corn Starch!

  6. I have tried the cornstarch now, but I’ve got a bad aphid (or maybe stink bug?) problem and now the grasshoppers have showed up. At first it was just on one plant and I was happy to let them have that one and leave the others alone, but now they all have it, even with the cornstarch. Oh well, I had a good run at the beginning of the season. Next year, I’ll start with the cornstarch before the bugs even hit and keep re-applying! Here’s hoping!
    Re-applying is definitely key! I have to head back out there after it rains (you know, both times it rained this summer) and cover them again or the stinkbugs are back way too soon. Here’s hoping for bug-free tomatoes for all of us next year!

  7. So far none of above problems for our tomatoes ( 50 plants a year ) but wind is big. I am going to try this on Broccoli, Cauliflower and Cabbage and if it works, it will be super big for us. Right now after 2 cuttings we need to remove the plants and burn them for the worms.

  8. My garden group has a couple of questions regarding this idea!
    How does it effect photosynthasis regarding the plants and does it wash off in rain or cluster?

    • I am POSITIVE that y’all know more about gardening than I do. 😉 It just washes off in rain (or if, say, your five year old is watering the garden with a hose… just for example), and I haven’t noticed any ill effects photosynthesis-wise.

  9. It’s not beyond reason to think that the Monsanto BT gene product that is in corn to prevent corn borer worm and other insects eating the corn is still present in the cornstarch… and killing the caterpillars that are eating your plants. GMO is everywhere and pervasive. The BT gene has spread on the wind to non GMO fields.

  10. Im trying this today on my toms which are being ravaged by cabbage moth caterpillars. And Im in Australia using non GM modified cornflour, so we shall see if the above hypothesis has any merit.

  11. you can make a beer trap ~ use a babyfood (or similar size jar)place some stale beer in jar and lay on it’s side in the garden the earwigs crawl right in. you can also use the tuna can and bury the can about half way into the soil. we have found this works on the slugs that attack our tomato plants

    • I used plastic cups with low alcohol beer dropped down into the soil to control slugs…I watched the darn slugs turn around and head right for those cups and they go in and drown…much easier on me than squashing them…I had them spread throughout my gardens and saw a drastic drop in the population. One can was used mixed with a little water and it did several bait cups for a week and then I topped up the cups with more…didn’t even take out the dead ones and they were dumb enough not to heed the warning the other dead ones were giving out

  12. Defintely gonna try this..I have problems with all of those critters an bugs you are all mentioning an I really dont want to use any chemicals..Will let you know how it works..Thanks for the tips..Yes we do learn something new everyday!!!

  13. Thank you everyone for the very helpful information. I live in North Carolina and my tomatoes and compost have been invaded by fire ants.

    • I realize this is a very old post, But so am I…lol I live in Florida where the fire ants stay on vacation year round. I have a huge piece of property and 120 billion plants in pots as well.lol The fire ants decided to build colonies in each pot. I had ZERO intention of repoting 120 Kazillion. …..or was that a billion. ..lol. Nor will I use chemicals. Soooo I decided to use cinnamon. Just a little tab on top of soil. Then the fun began. Pulled up a chair and watched them run up and grab up some, Like a thief in the night.They must of thought Whoop-Whoop ParTee.While Each little worker ant was thinking, The queens gonna love this!-I’LL now be her favorite little worker.
      Their gone now, Lets have a moment of silence. RIP you little..% ₩¥£.&^/$#(!! Now who’s saying Whoop-Whoop ParTee.

  14. I don’t have a problem with bugs eating my tomatoes but I have a problem with rabbits eating my bean plants before they begin to flower. Any ideas on a natural way to keep them away? I do use soap to keep the deer away and that does work but it doesn’t seem to work on rabbits.

  15. Try cayenne pepper for squirrels and rabbits. Or puree a habanera pepper, add some garlic, and mix it in an old gallon milk jug. Spray over plants that are frequented by squirrels and rabbits.

    • Please rethink the hot pepper treatment: ANY bird or animal (or child) that gets this into their mouths or eyes are absolutely miserable with pain! And the fiery oils are also transferred to their babies when they feed or touch them. Remember, ALL wildlife, children or pets in contact with the treated area will be affected. I believe there are more humane ways to deter these pests, hope you find one that works!

  16. Out of desperation, I put a whirly gig in my tomatoes to get rid of rabbits. It worked!! It is a metallic one. Don’t know if it is the motion or the reflections from the moon.

    • Were did you get such a gadget. I’ am interested in anything that might be useful. Did it work for you? We put up a fence to keep out peter rabbit but this might be useful for other things as well. We have had so much rain here in North Carolina. My poor tomatoes!Been dealing with early blight and sephoria all morning!

  17. I also tried Zest Bar Soap . Used potatoe peeler to make shavings and put around ur garden. As i had pots,i did sovaroundpots. It worked kept intruders out.

  18. My grandma used to tie a string around and through her garden with tin pans tied onto the string. They flutter in the wind and make noise plus reflect the light. She was critter free.

  19. Most all corn products, unless organic, are GMO. Bugs are smart,they knew not to come near the plants, since it was full of GMO residue. Using Irish Spring or Zest soap, highly toxic, artificial fragrance and chemical soap product is not good for plants, people, soil, ground water, fish, intruders, whatever. Please think about what you are using on your food and how it affects the environment and beneficial critters.

    • Peggy… Seems like you entered into the SJW phase rather early. Would you rather eat or starve?

  20. I will definitely try the cornstarch this next summer, but I also plan to spray with doTERRA Peppermint Essential Oil spritzed with water. It works as a pest control for many bugs and probably animals too! Very strong aroma, but 100% CPTG Natural alternative.

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  22. Go to your local hunting store or a Walmart and purchase bobcat or cougar urine. It repels ANY type of wildlife. I use it on my chicken and duck pens and garden. Well, it doesn’t’t work on birds because they can’t smell LOL

  23. The cornstarch idea is definitely something I will use this year for my tomatoes but in regards to the soap, I have all raised beds and for the pesky rabbits eating all my salad stuff, I’ve been using Ivory bar soap (3/$1.00 at dollar store)shaved with a cheese grater outside of my beds on the ground for years and you can watch those rabbits walk right up to the beds and turn around and walk right away. Works great and no worries to my food or soil. Don’t put on wood of raised bed though as the first year I did and it did bleach it a bit….ooops

    • Every year our grape vine is loaded with grapes but right before they get ripe enough to pick them, the birds come in and in ONE day every single grape is gone.. The past 2 years we have put up netting to no avail. The first year only one net, birds got the grapes anyway so last year we put up two nets, one on top of the other… guess the nets killed the vines. SOOO, this year we are cutting them down and digging up the grape root. sigh

    • I’m not sure if this will work on your grape vines, but I know that the orchards around here tie tin strips in their trees to keep the birds out. There is something about the way the light hits the tin that scares the birds away.

  24. I live in Northern California and all the wineries in the valley and hills use shinny long silver and colored eflective strips. They attach them all along their grape vine wires and stakes. They also attach them to tall polls. This defently keeps the birds away.

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  26. How about squash bugs on pumpkin and gourds? We live in North Missouri and we have more trouble w/those than anything else in our garden.

  27. ok so if I missed the tip forgive me in advance but 1. Will this work on flowers as well as foods? 2. will the cornstarch hurt dogs? They for some reason like to munch on the grass where i have my flowers (go figure.. I have 2 acres of grass and they want to eat it right by my flowers lol ) 3.DAFFODILS planted in with your vegies and such will keep deer away.. the Daffodils are poison to deer and they know it…

  28. Hi Peggy! I don’t know why it wouldn’t work on flowers as well — worth a shot! I have NO CLUE about the cornstarch hurting dogs or not; that might be worth a phone call to a vet or something. I don’t have any animals right now (unless you count my children) so I’m not sure.

    Daffodils!!! I’m going to remember that one. Thanks!

  29. Love all the tips on here. I use crushed egg shells to keep slugs off my plants. The rain doesn’t wash it away and they won’t crawl over the harsh shells. Just lay a ring around the plant. Good for anything that slugs want for dinner.

  30. Has anyone tried this on zucchini plants for White Flies. We always get hit hard with them every summer and most of our squash plants never get to produce much after an attack. Thanks much.

    • yeah I was wondering that myself.. Also how in the world do you get rid of ladybugs in the house? I know totally off topic but still LOL…

  31. I live in Ottawa. I put up a 7 foot bird netting around the garden. That was successful for squirrels but not for chipmunks which are now taking the tomatoes. Outside the bird netting I have a wire fence to keep groundhogs out.
    I am trying a mix of castor oil and detergent 1:1 for chipmunks. So happy to find the cornstarch solution. That will be next.

  32. We have moles eating our tomato plant roots which kills them.I actually shot some powder (cornstarch) down several holes. Don’t know it this will help. Is there something else I can do to get the moles to leave?

  33. I wonder if the cornstarch will work to keep the worms off of my cabbages? I am going to get me some cornstarch and try it.

  34. Cabbage worms and bugs decimated my cabbage, broccoli and some tomatoes last year. Thanks for the cornstarch tip. Will try it this year and give updates later.

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