How do organic farmers get rid of weeds? #NonDairyCarrie


Last week when I was writing my post about spraying our crops for weeds with a helicopter, my friend Carolyn was sharing how she and her husband Jonathan, take care of weeds on their organic crops. I’ve never seen this method in person but I thought it was pretty cool so I asked her to write a guest blog for me.


Carolyn and Jonathan OlsenJonathan grew up in the house that he and Carolyn moved to in 1998. Carolyn grew up in the suburbs of Minneapolis, but happily became a farm wife on August 20, 1988. They have three daughters, ages 22, 21, and 19.  They celebrated their farm’s 100th Anniversary in June.

Jonathan and Carolyn have grown their farm to 1100 acres of cropland. They also conventionally finish 7000 pigs a year for a neighbor.  Jonathan is active in their church, is a past Soil and Water Supervisor, and a past winner of the Minnesota Farm Bureau’s Achievement Award.  Carolyn is also active in their church, is the current president of their county Farm Bureau, and sits on the University of Minnesota’s Tools for Transition Advisory Task Force, and the Minnesota Department of Agriculture Organic Advisory Task Force. 

Flame Weeding? What the Heck is That?

When we first decided to transition into organic farming in 1998, weed control was our biggest worry. It still is. We have tried many methods of weed control over the past 15 years, and have settled on a system that works pretty well for us. Like everyone else, though, Mother Nature can wreck your best laid plans in a hurry!

Like many of our neighbors, we are row crop farmers. We grow corn, soybeans, and small grain.  We have roughly split our fields so each crop is 1/3 of our acres. This spreads out the work load, and creates a good crop rotation to stop pests like corn rootworm. The 3 year rotation also means each year we are doing different types of weed control on each field in a rotation as well.

We hire a crew from Texas to come and walk our fields in the summer. They have jobs in Texas in the winter, because they don’t really like Minnesota winters. They come here in the summer to work in the fields, because they don’t really like Texas summers. The main family that comes up has been working for us for about 8 years.  We converted a shed on our other farm site into an apartment for them after a former landlord treated them very badly. We wanted to make it nice and easy for them each summer to find housing close by.

The crew will walk the small grain fields first, usually about the time the grain is forming heads (heading out). They hoe thistles and will pull some weeds that they carry out in bags, so the grain will be clean enough to pass inspection for seed production.

The soybean fields get walked as well. There, they will use a heavy duty garden hoe to cut the weeds off at or just below the ground. The idea is to prevent the weeds from going to seed. Some years, the weeds may get ahead of us due to weather, and the fields will look ugly. We don’t like that anymore than the neighbors who tease us about it. The soybeans are also raised for seed, so the fields need to be as clean as possible.

We do not grow corn for seed, but we still want the fields to be as weed free as we can get them. To accomplish this task, we harrow, rotary hoe, cultivate, and flame weed. What the heck is flame weeding? It is the most wrong thing, and most cool thing we do on our farm. The wrong: pulling a large LP tank behind 36 burners. The cool: playing with fire!

The first thing we need to do is call the Co-op to come and fill our LP tank. Rich arrives and unwinds the hose and nozzle, hooks it up to the tank, and transfers the LP. Jonathan and Rich will chat about whatever during the 10 minutes it takes to fill.

Propane fill

On farm propane delivery

Jonathan uses a torch to light each burner’s pilot light, and then jumps in the tractor to get going as soon as he can. Even when the burners are flaming a little, they are putting out enough heat to do a little damage.

Flame burning weeds

When the burners are going full force, they put out quite a bit of heat. In this photo, you can see the heat waves behind the tractor.

Organic weed control

Jonathan goes between 2.0 and 3.5 miles per hour, depending on how many weeds are in an area.  He also uses GPS technology so we can stay in the same wheel tracks for everything we do in a field. The AutoSteer is really nice when you are trying to watch what’s going on behind you!

Tractor with GPS

The next three photos show what it looks like from inside the tractor cab. Each burner is pointed towards the base of a row of corn. The whole point of flame weeding is to clean up the weeds in the row where the cultivator cannot go.  If there are too many weeds or grasses in the row, they compete with the corn for nitrogen and moisture.

Organic crop weed control

Burning weeds

Weed control for organic farms

After the flame weeder has gone through the corn, you can check to see if the burners are doing their job by squeezing the leaf of a plant between your thumb and forefinger. If you can leave a mark, that means the water cells have burst, and that leaf will die.

Corn the has been burned.

The corn fields look pretty ugly after they have been flamed. It smells like a corn roast when you drive by.

after the corn field has been burned.

The weeds should be toasted or wilted like they are here.

Dead weeds

Weeds after being burned off.

Unlike the broadleaf weeds, the corn’s growing point is protected in the center of the plant.  The cool thing is, in about 7-10 days, you won’t know the corn leaves were burned off. The corn will continue to grow where it left off.

A growing corn plant

Every farmer out there needs to make a decision on how they want to manage their farm.  Becoming certified organic farmers is what worked for us, and we really like farming this way. Remember, not all methods of farming are for everyone. Please consult your Farm Business Management Instructor to see what method of farming is right for you. Please farm responsibly.

Check out Carolyn’s super cool video of the weed burner in action HERE on her blog.

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15 Comments on How do organic farmers get rid of weeds? #NonDairyCarrie

  1. michele der
    July 1, 2013 at 9:51 am (6 years ago)

    This is very cool, would this work on a smaller scale in a backyard garden?

    • dairycarrie
      July 1, 2013 at 10:20 am (6 years ago)

      If you were very careful to only hit the weeds with the heat it might work but I’m not sure.

      • Raymond Person
        July 1, 2013 at 12:05 pm (6 years ago)

        A small hand-held flamer can work well in the home garden, but only in certain circumstances–for example, since carrots take so long to germinate, you can kill the weeds that germinate so much faster before the carrots are up.

        A good friend farms corn, soybeans, and wheat organically and he uses a backpack sprayer with vinegar to spot kill his weeds. He buys vinegar with a higher acidity and the acidity of the vinegar will kill whatever it is sprayed on.

        • Warren Levang
          October 10, 2015 at 9:16 am (4 years ago)

          Hi from Montana,
          my name is Warren and I own a farm in Montana where we grow wheat.
          I am considering an alternative method of weed control . I was AMAZED by your idea of using VINEGAR TO KILL WEEDS.
          I would like to use something that isn’t a Herbicide spray so I can cut costs and also grow Peas and Lentils. ( they are more adversely sensitive to sprays).
          I would APPRECIATE any of your thoughts??


  2. carolyncares
    July 1, 2013 at 12:15 pm (6 years ago)

    Thank you so much for giving me the opportunity to share how we do things on our farm!

  3. Jennifer
    July 1, 2013 at 12:21 pm (6 years ago)

    That’s awesome! I had the same thought as Michele “I bet I could burn stuff in my garden…” Something tells me I might not be canning so many tomatoes this year if I tried that though…

    Serious question for Carolyn – are there alternative methods used during dry spells or drought? Or maybe drought isn’t a big concern in Minnesota. I know last year our weeds were growing in full-force while everything else was dry, and it seems like flames for weed-control would’ve been a big risk.

    • carolyncares
      July 1, 2013 at 1:57 pm (6 years ago)

      So far, the droughts have come after the window for flaming has passed. That is where it is pretty easy to see the benefit of removing the competition for moisture. If the corn leaves are curled, or getting dry due to drought, we probably would not use the flame weeder.

      There is a point when the corn gets too tall, and we do more damage with the equipment than the good we are doing with the flamer. Usually those are the rainy years when the fields are too wet for too long.

      • Jennifer
        July 1, 2013 at 10:18 pm (6 years ago)

        Thanks for the response. So interesting; I’ve been around farming my whole life and never seen or heard of that!

  4. Jim Turner
    July 1, 2013 at 1:23 pm (6 years ago)

    This gives a whole new meaning about fighting something with Fire I guess.

  5. NickB
    May 31, 2015 at 3:33 pm (5 years ago)

    I though organic was a way of being more environmentally friendly, amongst other things. It seems I should reconsider.

  6. Hank McClenning
    July 28, 2015 at 6:58 pm (4 years ago)

    I seen flaming in action, it does work, but hurts the crop some. I have discovered a way to
    control weeds but no one wants listen for it calls for the end use of chemicals. Hank McClenning ex-ag teacher..

    • Warren Levang
      October 10, 2015 at 9:26 am (4 years ago)

      Mr. McClenning,

      I am Amazed and Intriqued about your idea of controlling Weeds without Chemicals.
      I own a farm in Montana where we grow Wheat. I am searching for a method of killing/controlling weeds without chemicals so I can grow Lentils and Peas on a Rotation System. they are Much More Sensitive to Chemicals than Wheat. I would Appreciate Your Advice and Ideas. And I would Supply you with any reports and Data after we try it.

      I am currently working with an Ex-ag Teacher as my consultant too.