Flame Weeding and Garlic
Updated: Feb 13
Fire is Awesome. Flame Weeding is Awesome. It adds FUN to growing garlic.
Fire is the visible effect of the process of combustion. It can appear as flickers of orange, red, yellow, blue and green. Fire is a special type of chemical reaction. It occurs between oxygen in the air and some sort of fuel. The products from the chemical reaction are completely different from the starting material These flickers of heat rippling in the air, require oxygen, heat, and fuel. This is considered the "fire triangle." Add in the fourth element, like nasty weeds, and we have a sweet chemical reaction, Whew! and you actually have a fire "tetrahedron."
Growing Garlic is a rewarding experience, though it can be a lot of work. Dealing with weeds in a dedicated garlic patch can surely take the fun out of growing garlic. Arggg! Flame weeding is a viable solution to remove many weeds that compete for and attempt to steal precious nutrients from your prized garlic plants. Essentially, Weed Flaming uses heat to destroy the cell structure in the plant's leaf and core structure. The weed will no longer put energy toward growth (photosynthesis). If the weeds or forbs are flamed when they are small and young, often this process will kill the entire plant including the root system.
CRITICAL AND IMPORTANT INFORMATION: If you decide to use a weed flamer to irritate weeds, it is critically important you wear a mask or respirator to prevent any dangerous smoke from getting into your lungs.
Using Flames and Heat to Destroy Weeds
At GroEat Farm, we use a propane tank roughly the size of a beer keg, strapped to a backpack (or pulled in a wagon) and a flame-throwing wand. 300,000 BTUs of heat thrown at weeds, allows us to cook to death these weeds, instead of spraying them with nasty chemicals.
Flame Weeding involves "throwing a hot, brief flame" onto a weed plant to briefly heat the plant's sensitive plant tissue, just enough to explode the chloroplasts and kill the plant. The leaves of the weed often turn a lighter green color and the plants then have a slightly wet appearance. The plant's cell membranes is disrupted by the heat. Flame weeding often called “flaming,” is just one method for natural weed management. After the heat is applied to the plant tissues just enough to kill them, the plant's leaves will start to look dull and wilt a bit. The method isn’t appropriate for every situation.
“Flaming is just one of the tools we use to remove weeds from our garlic patch. Flaming works really well in certain situations,” said Jere Folgert, owner and farmer at GRO Eat Farm near Bozeman, Montana. “Flame Weeding can work really well on young weeds, that are not right next to the garlic plant. Flaming also works well to destroy the seeds on weeds, essentially eliminating next year's weeds." Jere also warned that "If your garlic patch includes mulch such as straw or dried leaves, definitely do not use this method to kill weeds. We no longer mulch our garlic field and have had excellent results." Flaming is nearly 100% effective at killing very young weeds that are just emerging from the soil, whereas weeds over 3+ inches are more difficult to kill without multiple flamings. Repeat applications combined with hand-pulling of weeds will usually do the trick. For best results, increase exposure to the heat if weeds are wet from dew. Thistles often require more exposure to the heat given their dense leaf structure. Water on the leaves acts as insulation and decreases cell damage unless exposure time is increased. Jere Folgert stated: "It is important to remember when flaming in and around desirable plants, such as garlic, the heating process can cause damage to the garlic plants as well. Fire does not know the difference between desirable plants and undesirable weeds. Be careful around the sensitive garlic leaves, especially early in their growth cycle. We use a small, light-weight aluminum snow shovel that is placed between the flame and the garlic plant. It is a little extra work, and it allows us to zap weeds growing close to the garlic plants."
The goal is not to completely burn up the weed (although this is a truly satisfying experience), but to destroy plant tissue so that the weed dies. Flame weeding kills the above-ground portion of the weed, but it doesn't necessarily kill the roots. Starving the roots of energy provided by the leaf structure has the potential to kill the weed. Another big benefit of Flame Weeding is it can be used to incompassatate or kill seeds that are on weed plants. The heat and flame zaps viable seeds from Dandoline, Broadleaf Plantain, Chickweed, Lamb's Quarters, and Pennywort.
We believe Flame Weeding is most effective when it is used as one tool in our arsenal, integrated with other management tools, such as picking weeds by hand (plant and root), tilling, and mowing. Flaming is rarely utilized as the sole tool in a garden. Flaming is less effective when used on perennial weeds, which have below-ground root systems from which new weeds can emerge.
WARNING: Poison ivy, oak, or any poisonous plant should not be burned! and should be avoided. The vapor/smoke from flamed leaves can cause a rash on your skin, eyes, and lungs. Some weeds are a poisonous members of the nightshade family, and are difficult weeds to eradicate since they resist most attempts at control. Climbing Nightshade - Solanum dulcamara is one example. Tilling the soil only makes it worse because it brings seeds to the surface where they can germinate. Flame weeding doesn’t kill the weed either because of the penetrating roots. Ideally, wear a respirator when weed flaming. Also, be aware of the wind direction. Let any smoke or residue blow away from you. Wear proper feet and leg protection. Don't use a weed flamer in dry, hot and windy conditions. Have a garden hose close by just in case you need to distinguish any flames. Don't use a flame weeder if you have mulch in your garden, such as straw or leaves.
DON'T START A WILDFIRE: Anything with an open flame has the potential to be dangerous. The risk of fire is always there when using a flame weeder. Dried and brown material (dried grass) is flammable. Flame weeding too close to structures poses a risk. Flame weeding during exceptionally dry weather conditions is not advisable. Don't use this tool if windy conditions exist. Don't become a pyromaniac.