Using a flame weeder or ‘weed burner’ kills the foliage immediately, however not the root system immediately , so it will kill some weeds, and not others.
- Annual Weeds
Flame weeding will kill many annual weeds permanently, however it depends when you use it, you need to weed before they seed. - Perennial weeds.
Especially those perennial weeds with long tap roots, you just need to flame weed regularly, from when they first appear until when they stop growing. Continually killing the foliage saps energy from the weeds and eventually they die. Again, you can not afford to let them set seed.
Types of Flame Weeders
Most flame weeders have a flame head designed to concentrate the heat into a small area, like a blow torch rather than a flame thrower. The have an on/off handle, and some are manual lighting others auto lighting.
- The smaller ones, the type you can but for around $50 that have a small disposable butane or propane gas tank and are light weight.
- Larger flame weeders have a more powerful flame, larger refillable gas tanks and more control over the flame, however are heavier
How do Flame Weeders work?
Most flame weeders have a flame head designed to concentrate the heat into a small area, like a blow torch rather than a flame thrower. The have an on/off handle, and some are manual lighting others auto lighting.
All of the models we have used work on gas, and different models have different gas tanks. The lightweight ones look easy, however the gas bottles that they use are not refillable and can end up being costly. These may suit occasional use in a small yard, however for serious weed destruction, you might be looking for a bigger tank and something more cost effective.
Do Flame Weeders work ?
Yes flame weeders do work, they destroy the above ground cellular structure and the weed dies back. At least the top part does, and so do very shallow rooted weeds and small weeds. The deeper rooted weeds and those with long tap roots will come back. Usually 3 – 4 flame weeding efforts will get rid of them.
The theory is that you do not actually BURN the weeds, you just blast them until the begin to give off steam. This is when the cellular structure is destroyed.
However, on a large deep patch of weeds, this approach is problematical, you may get the same results from using a brush cutter, cutting back to ground level and them raking up.
Which weeds do they work on?
Where the flame weeders are efficient are on weeds such as Tradescantia fluminensis, commonly called Wandering Jew. This is a very shallow rooted weed, and these weeders work well on it.
Bulbous weeds are another thing, Onion weed, Oxalis and similar bulbous weeds will be knocked back, however they will come back. Repeated flame weeding may kill them, you just have to keep destroying the foliage above the ground.
Flame Weeders Explained
The smaller flame weeders with disposable gas tanks.
The smaller models come with some interesting instructions, including that they can be used to lite barbecues. And they are good at this.
What they are really not that good at is destroying larger weeds. And their is one simple reason for this, they are simply not powerful enough. The flame is not hot enough to kill any but the smallest weed in a pathway.
We have tried to a few models, and although they are promoted by ‘gardening’ companies and some of the big boxes, we get the feeling that they may not have actually used them, although they do sell them.
Should you buy one?
Only if you have a very small area and are looking at very small weeds. You also need to be fairly patient as they are slow. The cost of the refillable gas bottles also builds up over time. If you are looking a weeding between pavers, they will knock the weeds back but will not kill the root systems in most cases, so you may as well use a line trimmer or brush cutter with a nylon line.
- The larger models that run on refillable propane tanks.
If you seriously want to use a flame weeder for larger areas, then you need one that works. You need to look for one that has these features :
- A model that will generate heat at 2000F
- A handle that island enough so you do not have to bend.
- One with a squeeze handle that changes the flame from pilot to full flame
- A method of transporting the gas tank, you can get back packs as well as trolleys.
- One that comes with the right connection for your gas bottle.
The squeeze handle means that you can do spot weeding without having to earth waste gas or relight the weeder.
These will indeed knock the weeds back to the ground, and for newly emerging weeds, and shallow rooted weeds such as Tradescantia flumiensis, they can actually kill them. Deeper rooted weeds will come back, and you will need to repeat the process a number of times.
Should you buy one.
We do use one, and we think its worth it, it is used for larger areas and a long driveway. If you knock back the weeds regularly, most will die off. However you can’t just leave the ground bare, weeds will come back and bare ground is a favourite place for them.
The ideal way to use it is as the weeds emerge. On larger weeds, it works, however it does tend to incinerate them, so have a hose handy.
The one we use is called a Weed Dragon, and the gas bottle is mounted on a trolly…..
Safety.
Be aware that the flame of these weeders is HOT, and will shoot out to around 10 -15 cms (4 -6 inches) so be careful with surrounding plants, any underground pipes, buildings and in fact anything that could burn or be damaged by the flame.
Gas bottles need to be properly fitted and secure and safe. Take care of any gas hoses and make sure you keep clear of others when using. Follow the safety instructions that come with the appliance, gas bottles and hoses.