Flame weeder seeds
The flame weeder is run over the beds of slow-germinating crops such as beets, carrots, onions, parsnips, etc. just before the seedlings emerge from the ground. By using the flame weeder just before the plants come up, the fast germinating weeds are destroyed, and the carrots or other crops emerge into an essentially weed-free bed.
The best thermal weed control is achieved with a “stale bed”. This means that the soil is prepared and the rows marked for planting approximately 2 weeks before the crop is planted, to let the weeds start to germinate. In dry climates water should be applied to promote weed germination. Floating row covers can be spread over the beds to further speed up the germination of the weeds if the beds have not been prepared far enough ahead of time.
Then without tilling the soil again you plant into the “stale bed”. Plant either by hand or with a planter, trying to disturb the soil as little as possible. In this way, by the time the carrots are starting to germinate, the greatest number of weeds are already up to be killed by the flame weeder.
With some close observation one can find the right timing. A pane of glass placed over the row and sealed around the edges will create the greenhouse effect and cause the carrots in that part of the row to germinate more rapidly. When you see the carrots coming up under the glass you know that the rest of the row is about to emerge from the soil. When you think the crop is about to come up, it is good to dig several places in the row and inspect the sprouting seeds to be sure to get the right timing. We tend to plant the crops for flame weeding slightly deeper than usual, so that we have more leeway from germination to seedling emergence. First the seed starts putting down a root and then the seedling leaves start pulling out of the seed coat as the plant moves up toward the surface of the soil. This is the time to flame – just before emergence. It is better to flame a little too early than too late. With a little experience the right timing can be assessed quite easily.
WARNING: If you are one day too late and the carrot seedlings have emerged, the flame weeding will kill your carrots as well as the weeds.
Flame weeding can also be used for faster germinating crops, like spinach, radishes, salad mix, etc., if they are planted into an approximately three-week old stale bed. This way weeds are up before the crop is planted and can be flamed almost immediately if need be, as in the case of radishes and spinach.
Move the flame weeder down the row at a slow walk. It is not necessary to burn the weeds. The flame only needs to overheat the tissues and cook the protein of the plants. They will have a glassy look and wilt in a few hours. You can try different speeds and see what is effective for the size and type of weeds you have to deal with. Try to avoid using the flame weeder when the weeds are wet from rain or heavy dew, since the moisture will keep the flame from killing the weeds. Moisture on the plants requires a slower speed.
Click here for Growing for Market article on flame weeding: Fire Your Weeds!
What Is Flame Weeding: Information On Flame Weeding In Gardens
If the idea of weeding using a flame thrower makes you uneasy, it’s time to find out more about using heat to kill weeds. Flame weeding is safe when you use the equipment properly. In fact, in many cases, it’s safer than using harsh chemicals that can contaminate groundwater and leave toxic residue on your garden vegetables. Read on to learn how to use flame weeders and when flame weeding is suitable.
What is Flame Weeding?
Flame weeding entails passing a flame over a weed briefly to heat the plant tissues just enough to kill them. The goal is not to burn up the weed, but to destroy plant tissue so that the weed dies. Flame weeding kills the above ground portion of the weed, but it doesn’t kill the roots.
Flame weeding kills some annual weeds for good, but perennial weeds often regrow from the roots left in the soil. Perennial weeds require several treatments at two to three week intervals. As with any weeding method, if you kill back the tops often enough, the weeds eventually give up and die.
The problem with flame weeding in gardens is that it’s hard to expose the weeds to the flame without exposing your plants as well. In vegetable gardens, use a flame weeder to kill weeds that emerge after you sow seeds, but before the seedlings emerge. You can also use it to kill weeds between rows.
How to Use Flame Weeders
A flame weeder setup consists of a wand connected to a propane tank by a hose. You’ll also need a dolly to carry the propane tank, and a flint igniter to light the flame if the wand doesn’t have an electronic starter. Read the instruction manual completely before using a flame weeder.
Weeds only need a 1/10 second exposure to the flame, so pass the flame slowly over the weed. If you are weeding rows in a vegetable garden or along a fence line or drainage ditch, walk slowly, about 1 or 2 miles per hour (2 km. per hour) along the area you want to flame. Be careful to keep the flame away from the hose that connects the propane tank to the wand.
Once you have passed the flame over the weed, the leaf surface changes from glossy to dull. If you are concerned that the weeds aren’t dead, allow them to cool and then squeeze a leaf between your thumb and finger. If you can see a thumbprint in the leaf, the flaming was successful.
When is Flame Weeding Suitable?
Flame weeding works best on annual weeds that are 1 to 2 inches (2.5-5 cm.) high. Use flame weeders to kill weeds that grow around garden barriers and fences. They excel at killing weeds in sidewalk cracks, and you can even use them to kill stubborn, broadleaf weeds in lawns because mature lawn grass blades are protected by a sheath. Once you have a flame weeder, you’ll wonder how you ever got along without it.
You’ll need to take a few safety precautions. Don’t weed during dry spells, and keep the flame away from dead or brown material that might ignite. Some areas have bans on flame weeders, so check with your local fire department before investing in the equipment.
Using Flame Weeders for Garden Weed Control
Nadia Hassani is a gardening expert with nearly 20 years of experience in landscaping, garden design, and vegetable and fruit gardening. She became a Penn State Master Gardener in 2006 and is a regular contributor to Penn State Master Gardener publications. She gives gardening talks about growing specialty produce for ethnic cuisines, authors two gardening and growing blogs, and created the taxonomy for the plant encyclopedia for Better Homes & Gardens.
Barbara Gillette is a master gardener, herbalist, beekeeper, and journalist. She has 30 years of experience propagating and growing fruits, vegetables, herbs, and ornamentals.
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Even in the best maintained, well-mulched, and densely planted yard, weeds are a constant reality. If you are tired of pulling weeds mechanically, or you want to avoid using herbicides, a flame weeder can come in handy. Before you light the torch, though, you should know that flame weeding has its limitations both in terms of the locations where it can be used as well as the types of weeds it kills.
What Are Flame Weeders?
A flame weeder briefly exposes weeds to extreme heat up to 2,000 degrees F, just long enough to damage the plant tissue so that the plant dies. The plant is not burned in the process.
The tool consists of a torch or wand that is connected to a propane tank by a hose. There are different systems for the propane tank: torch flame weeders that can be hooked up to any refillable propane tank include backpack-style flame weeders, and rolling flame weeder where the tank is installed on a dolly. Flame weeders for home gardeners vary in BTUs between 40,000 and 100,000.
Are Flame Weeders Effective?
Flame weeding is most effective on weeds no taller than one to two inches; the smaller the weeds, the better they work.
It kills only the above ground part of a plant, not the roots, which is why it is mainly effective for annual weeds. Perennial weeds can regrow from the leftover roots in the soil and usually require repeated treatment in order to be eradicated. Repeat the flame weeding every two to three weeks, or when the weeds have regrown, which will weaken them to the point where they won’t grow back.
What Are the Benefits of Using Flame Weeders?
Using a flame weeder is physically easier on your body than mechanical weeding because it saves you from bending down and pulling or digging. It does not disturb the soil which means dormant weed seeds are not brought to the surface where they will start to germinate.
Unlike non-organic herbicides, a flame weeder does not contaminate; it is environmentally safe because it does not expose humans, pets, wildlife, ornamental plants, your vegetable garden, groundwater, and soil to toxic substances.
A flame weeder is particularly useful for weeds that grow in sidewalk cracks and between patio pavers, as well as on gravel. For weeds that grow into garden fences, whether you can use a flame weeder depends on the flammability of the fence material. Non-coated metal fences such as chain-link or welded wire mesh can withstand the heat but wooden or vinyl fences won’t.
Before using the flame weeder on any fences or barriers, check the manual, as flame weeders vary in their BTUs (the amount of heat they emit).
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What Are the Cons of Using Flame Weeders?
The biggest downside of using a flame weeder is that, although the torch enables you to aim and target the unwanted plant, it is difficult to avoid singeing desirable plants as well, especially in densely planted areas such as a vegetable garden or a flower bed.
If used properly, a flame weeder is safe for the person who operates it. However, it can still pose a danger for pets or children running about, which is a safety issue as you consider when and where the weeder can be used.
When Not to Use a Flame Weeder
Never use a flame weeder during a drought or in dry conditions, and keep a safe distance away from any dry, dead, or brown plant material that could catch fire. Also, stay away from houses and other structures that could catch fire.
Also, the municipality where you live may have issued a flame weeder ban. Before purchasing and using a flame weeder, make sure to check with your local fire department.
How to Use a Flame Weeder
Wait until after a rain, or, if the soil is dry, it’s a good idea to irrigate the area where you want to use the flame weeder; this will reduce the risk of ignition.
Follow the manual to ignite the flame of your flame weeder. Run the torch over each weed in a sweeping motion and make sure to stay at a safe distance from the trailing hose between the tank and the torch.
Touching the flame to each weed only for a split second does the job. If you aren’t sure you killed the weeds, wait until they have cooled down; the leaves will have turned from glossy to dull.
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Does Flame Weeding Kill Seeds?
If you use a flame weeder properly—only on short weeds no taller than two inches—any weed seeds on the soil surface will also be directly exposed to the high heat from the torch and won’t be able to germinate.
On the other hand, if you are applying the flame weeder on weeds that have gone into seed, it will not necessarily kill their seeds.