In my article on physical (as opposed to chemical and cultural) weed controls (available here) I do mention flame weeders, but any piece of equipment that is this much fun is deserving of a more detailed article of its own! Just to recap, some of my comments from the original article include –
The easiest and most ergonomic way (you don’t need to get down on hands and knees) to control weeds with fire is to use a flame weeder. Unfortunately a flame weeder will be powered by a fossil fuel, in the old days it was kerosene, I still have an old kero powered flame weeder I inherited from my father (see blow), but these days they are powered by butane or propane. They will also require a small to moderate sized cash investment in equipment.
Cheaper flame weeders (<$40 AUD in 2023) are lighter, have a small attached disposable butane gas bottle, but have limited life and limited ability to get to the root of the problem (ie the weeds!). For a small area, small weeds without deep roots and occasional use these may do the trick, but even so you will need to replace the gas bottle regularly, hopefully recycling the empty one (they are single use only) rather than sending to landfill.
My large flame weeder
Larger flame weeders cost more ($250+ AUD in 2023) but have a number of advantages –
- They get hot enough to actually give weeds a hard time,
- They have a refillable gas bottle which is easier, more cost effective and reduces waste, particularly if you have a large area to treat.
Where possible, look for a flame weeder that -
The push button igniter
- Can change from pilot flame to full flame manually (saves gas between weedy areas),
- Has a tube long enough so you don’t need to bend down to get to the weeds,
- Has a push button igniter
- Has adjustable flame control
- Has the correct connection for your gas tank if you have one already.
The two red dials on the bottom adjust the gas supply for pilot and full flame settings, the top lever changes between the two
Strapping the gas bottle to a trolley will help make the setup more mobile so you don’t have to lug the bottle around by hand. A larger weeder will despatch newly emerged and shallow rooted weeds with one treatment but deep rooted perennial weeds may still need multiple (3 to 4) treatments to compete the job.
When using the weeder, weeds need less than a second of exposure to the flame for the flame to kill them by disrupting their cells, they do not need to be incinerated.
Flame weeders are effective in reclaiming some small, moderate of even large areas from the ravages of garden weeds, but there are some points to ponder when using the flame weeder, especially when planning a larger project. Most of the following points will not be an issue if you are just singeing a few dandelions that have come up between your pavers, but all points are worth thinking about BEFORE embarking on mass immolation.
1. Even if you are flame weeding in the pouring rain, always, always, always have a fully charged garden hose or full watering can within easy reach. It is remarkably easy to have things get away from you and having some method to extinguish the resulting conflagration is important. There can be stuff hidden amongst the weeds that can catch fire, like plastic, or a carpet of dead/dried weeds under the overburden you are trying to kill.
A nice long hose is good too!
2. Along with the above precaution, it is good to keep a fire watch on the area you have been weeding for 20 minutes to 30 minutes after finishing, or just drench the area before walking away. Case in point: I was murdering some jasmine (jasminum officinale) a persistent weed, which had come up behind the shed. Having done as much as I could, I sat down to enjoy the sunshine, but after 5 minutes or so I noticed a distinct ‘burning plastic’ smell. I turned around to see flames coming up behind the shed. There was a length of plastic hose behind the shed which I didn’t know about/ had forgotten, which was burning and belching out toxic black smoke. I applied a stream of water from the nearby garden hose liberally which fixed the problem, but I should have been more careful. Also, depending on where you are weeding, remember that organic mulches like hay, straw, wood chips and so forth, while not being flammable, are certainly combustible.
Just sayin'!
3. It goes without saying that if there is a fire ban, it is time to put the flame weeder away until the weather is cooler and/or damper.
4. Be aware that in full sunlight the gas flame may not be very visible. This can lead to issues as to where the flame weeder is being directed. If possible, flame your weeds in the early morning, late evening or other low-light time so that you will be absolutely sure of the extent the flame and you don’t accidently direct it towards valuable plants, flammables, combustibles, friends or family.
5. While it might seem obvious, where possible, make sure any wind is behind you when using the weeder, so that it blows any smoke and fumes away from you rather than back into your face. Also if you are using the flame weeder in longer grass, weeds etc, and they are firing up, the flames can be blown back towards you which is uncomfortable to say the least.
Well, it is a FLAME weeder!
6. Hold the end of the torch about 25cm to 30cm away from the target weeds. There needs to be sufficient space between the nozzle and the weeds for the gas to get enough oxygen to burn efficiently and jamming the nozzle into the weeds (as I have a tendency to do) prevents this from happening.
Not working so well, too close!
That's better!
7. If the weeds are more than 50mm tall, the flame weeder may have trouble getting through to the base of the weeds. If this is the case, a quick whipper snippering to drop them back a bit before using the flame weeder will improve its efficiency considerably.
8. Also, the flame weeder is not guaranteed to incinerate the seeds of the target weeds so using it before the weeds get a chance to set seed is the best idea.
9. Once the weeding is finished, turn the gas off at the cylinder and allow the line to clear out. By this time the fame end of the weeder will be exceedingly hot, so leave it to one side for half an hour to cool down before putting it in the shed, placing in the boot of the car or touching that end. Sounds simple but if you are like me, it is easy to forget. Just sayin’!
The business end: it gets awful hot!
Once all the fun is over (for the time being) and the weeder has cooled off, it is a good idea to put it away somewhere it is lockable (to stop the kids having fun too) and that is away from ignition sources just in case the gas cylinder valve leaks. A shed at least 1 metres away from the house is not a bad idea.
