Best propane weed torches, ranked on the regulator

Every propane weed torch sold is sold on one number, and the number is measured in the wrong units for the job. BTU per hour is a rate of fuel consumption. A 340,000 BTU torch is not a torch that kills weeds 3.4 times deader than a 100,000 BTU torch; it is a torch that burns 3.4 times the propane. Weeds die from heat, and the one maker here that publishes a flame temperature puts it at about 2050 °F — already vastly more than enough, at the lower BTU rating. So the interesting question is not how big the number is. It is what the torch does with the fuel, and that comes down to one component.

The short answer

BTU per hour is a fuel-burn rate

This is not an interpretation, it is arithmetic, and Flame Engineering supplies the numbers to prove it. The company publishes a maximum capacity of 100,000 BTU/hr for the Weed Dragon and a maximum fuel consumption of 4.6 lbs/hr. Divide one by the other and you get the energy content of a pound of propane — about 21,739 BTU. That figure is not editorial; it falls straight out of the maker's own two published specs, and it means the BTU rating and the fuel-burn rating are the same fact written twice.

Which lets us check the maker against the federal government. The U.S. Department of Energy publishes propane's energy content as 91,420 BTU per gallon on a higher-heating-value basis. At 21,739 BTU/lb that implies 4.21 lb per gallon — which is the propane density the trade uses. Flame Engineering's two numbers are internally consistent and consistent with DOE. Good.

So when Flame King rates the YSN340K at 340,000 BTU, it is telling you — whether it means to or not — that the torch consumes roughly 15.6 lbs of propane an hour held wide open. That is the whole finding of this page, and here is what it costs you.

The regulator is the real split in this category

Once you notice which specs each maker publishes, the category stops looking like a BTU ladder and starts looking like two different machines.

The Red Dragon kit contains a U.L. Listed R-700 C regulator and a separate V-334 flame-adjusting needle valve. Because the pressure is held at a known value, everything downstream becomes a publishable number: an operating pressure of 18 P.S.I., a usable range of 5–25 P.S.I., a consumption figure at that pressure, a maximum consumption figure, and a flame temperature.

The Flame King publishes no regulator at all. It runs on whatever pressure the cylinder is making, which is why Flame King cannot print an operating pressure, a consumption figure or a flame temperature — there is no fixed value to print. Instead it publishes the things that stay true regardless: a flame length of up to 28 in, a 32 in torch, a 10 ft hose, 3.49 lb, CSA testing and a one-year warranty.

Neither design is unsafe and neither maker is hiding anything. But it explains the one piece of advice Flame King gives that reads oddly until you understand the architecture: its own documentation warns that cold weather lowers tank pressure and tells you to use a 20 lb tank or bigger. An unregulated torch gets weaker as the cylinder cools. And Flame King markets this torch for melting ice and snow on steps and walkways — which is to say, for use in precisely the conditions that undermine it. If that is your job, our ice melt page covers the chemical route and is a great deal less exciting.

What each maker publishes

Read the "not published" cells as a block and the asymmetry is almost comic. BTU is the only specification both makers print, and it is the one that misleads. Everything that would let you compare these two torches properly is published by exactly one of them.

What flame weeding actually does

It helps to know the mechanism, because it explains why the BTU arms race is beside the point. Flame weeding does not incinerate a plant. Passing a flame over foliage for a fraction of a second heats the water inside the cells until the cell walls rupture; the plant loses its ability to hold water and collapses over the following day or two. The visible leaf often still looks green when you walk away. You are not burning the weed down, you are killing it and letting it wilt.

Two consequences follow, and both matter more than BTU:

• It is a top-kill, not a root-kill. Annual weeds caught small frequently die outright because they have almost nothing stored below ground. Established perennials — dandelion, bindweed, Bermuda grass — regrow from the root and need a repeat pass every couple of weeks. If root removal is the actual goal, our weed pullers page covers the mechanical answer and weed control basics covers why timing beats force in all of this.
• More heat does not mean more dead. Once you are past the temperature that ruptures a cell wall, extra temperature is wasted, and the Red Dragon's published 2050 °F clears that bar by a margin no plant notices. What a bigger flame genuinely buys is area — a 28 in flame clears a wider strip per pass than a 2 in bell, so you walk faster. That is a real advantage on a gravel driveway and an irrelevance in a paver joint.

It also cannot be used on a lawn. A torch does not discriminate between a weed and the turf around it, so flame weeding belongs on hard surfaces, gravel, bare beds before planting and fence lines. For weeds standing in grass you want a sprayer, a puller, or a pre-emergent — see lawn sprayers and crabgrass preventers. For weeds taller than the tool, string trimmers get there first.

The picks

1. Red Dragon VT 2-23 C Weed Dragon — best overall

Flame Engineering is an American manufacturer in LaCrosse, Kansas that has been building flame equipment since the tool was a single farm torch, and the Weed Dragon is its homeowner kit — the company says explicitly that it regulated the flame and BTU down for homeowners who do not need the power of a farm torch, and that it assembled the kit for you. That sentence is the product.

What arrives is a complete, closed system: the VT2-23 torch, a 10 ft U.L. Listed hose, the U.L. Listed R-700 C regulator, the V-334 flame-adjusting needle valve, a hand-tighten excess-flow P.O.L. fitting that Flame Engineering says needs no wrench, and an L2002 spark lighter. Because the regulator fixes the pressure, you get the only genuinely predictable torch on this page: 18 P.S.I., 2.25 lbs/hr, roughly 2050 °F, and by our arithmetic 8.9 hours of work out of a cylinder you can refill at any hardware store.

The honest marks against it. It costs the most here at $74.99 despite being rated for under a third of the BTU. Flame Engineering publishes no flame length, which is the figure that would tell you how fast you can walk. Ignition is a separate spark lighter held in your other hand — a genuine step backwards from a push-button piezo when you are crouched over a path. At 5 lb it is the heavier of the two by 43%. There is a California Prop 65 lead warning on the product page. And no warranty term is published anywhere on it, which is a strange gap next to Flame King's clearly stated year.

One thing worth knowing before you compare prices anywhere else: Flame Engineering's own list price is $134.00. The street price is 44% below the maker's list, so the gap between this torch and the Flame King is far narrower in the shops than the two companies' own pricing suggests.

#ad Check the Red Dragon VT 2-23 C Weed Dragon Propane Vapor Torch Kit price on Amazon — how we're funded.

2. Flame King YSN340K — best for reach and flame size

Flame King's main business is propane cylinders, and the YSN340K is the torch that sells on the number: 340,000 BTU, a published flame up to 28 in long, a 32 in torch on a 10 ft hose, 3.49 lb, a built-in piezo igniter and a blast lever that snaps back to idle when you release it. CSA-tested, one-year warranty against defects, fully assembled in the box, and it will run off anything from a 5 lb to a 100 lb cylinder. At $49.99 it is $25.00 less than the Red Dragon.

For open, rough work this is the better tool, and the reason is the published flame length rather than the BTU. A 28 in flame clears a wide strip of gravel drive or fence line per pass; a 2 in bell does not. Flame King also lists the jobs beyond weeds that the extra output genuinely serves — brush, fire starting, torch-down roofing, charring wood, ice and snow on steps.

The honest marks against it are all downstream of the missing regulator. There is no published operating pressure, no fuel consumption and no flame temperature, so there is no way to know what it will cost to run except by deriving it as we did above: roughly 15.6 lbs/hr wide open, about 77 minutes per barbecue cylinder. Flame King's own guidance that cold weather lowers tank pressure, and that you should therefore use a bigger tank, is an admission that the output is not fixed. It will not take a 1 lb camping cylinder, ruling out the cheapest fuel most people already own. And a 28 in flame is a great deal of flame to point into a 2 in crack.

A buying note we will not pretend away: at the time of writing the YSN340K is out of stock on flamekingproducts.com, and the $49.99 street price is $3.63 above Flame King's own direct price of $46.36. That is the opposite of the Red Dragon's situation and worth knowing before you assume the retail price is the deal.

#ad Check the Flame King YSN340K Propane Torch Weed Burner price on Amazon — how we're funded.

The safety section most torch roundups leave out

A propane weed torch is an open flame — around 2050 °F where the one maker who publishes the figure does — that you walk around your property pointing at dry vegetation. Both makers say outdoor use only and both tell you to wear eye protection and heavy gloves. Beyond that, three things deserve more prominence than they usually get.

1. Never torch poison ivy, poison oak or poison sumac. CDC / NIOSH is unambiguous: "Do not burn plants" that may be any of the three. These plants release urushiol when damaged or burned, and CDC warns that inhaling the smoke can cause "severe allergic respiratory problems". CDC also records that urushiol stays active on surfaces for up to five years and that less than a grain of salt's worth triggers a rash in 80–90% of adults. That guidance is written for outdoor workers rather than homeowners, but the chemistry is the same. Identify the plant before you light the torch.
2. Check your local burn rules, and the day. Many jurisdictions restrict open flame outdoors seasonally or during fire weather, and Flame King tells you to check local burn rules on the product page itself. Dry grass, mulch beds, bark chips and anything resinous will take light from a passing flame and keep burning after you have moved on. Carry water or an extinguisher, and walk the area again twenty minutes later — a smoldering mulch bed is the classic way this goes wrong.
3. Open the cylinder valve slowly. Flame King specifically warns that opening it fast can trip the built-in excess-flow valve, which leaves you with a feeble flame and no obvious cause. Both torches use a reverse-thread P.O.L. connection — turn left to tighten, hand-tight only, no wrench.

What nobody in this category publishes

Worth stating plainly, because every one of these is a figure a buyer would reasonably expect and neither maker provides:

• Coverage rate. No square feet per hour, and no flame width at a stated height, from either maker. The nearest thing available is Flame King's flame length.
• Idle fuel consumption. The Flame King has a lever that returns to idle, and no published figure for what idle costs — which makes its real running cost uncomputable from published data.
• Flame temperature, from Flame King. The one specification that explains why flame weeding works at all is published by one maker out of two.
• How many passes a perennial takes. Neither maker will put a number on it, which is fair — it depends on the species — but it leaves the central question of the method unanswered in the marketing.
• A warranty term, from Flame Engineering. Flame King publishes one year. The Weed Dragon product page publishes nothing.

We also could not transcribe specifications for Flame Engineering's heavier VT 3-30 kits, which sit above the Weed Dragon in its own catalog and would be the logical step up for brush and burn piles: flameengineering.com served one product record and then returned HTTP 429 to five backed-off retries. They are named here unranked rather than quietly omitted, on the same principle that keeps Fiskars off our bypass pruners page.

Which torch, by the job

Verdict

The Red Dragon VT 2-23 C Weed Dragon wins because it is the only torch here that can tell you what it will do. That is not a coincidence of better marketing — it is the regulator. Fix the pressure and every other figure becomes publishable, which is why Flame Engineering prints an operating pressure, a range, a flame temperature and two fuel-consumption figures while Flame King prints none of the four. The Flame King YSN340K is the right buy for open ground, reach and one-handed ignition, and its published 28 in flame is a more useful number than its BTU rating; it is also cheaper, lighter and the only one here with a published warranty.

But the finding worth carrying away from this page is the arithmetic, because it inverts the way the whole category is sold. BTU per hour is a rate of fuel consumption — Flame Engineering's own two published figures prove it, and the Department of Energy's propane data confirms their internal consistency to within a percent. So the 340,000 BTU on the box is not a promise about weeds. It is a promise about propane: 3.4 times the fuel for 3.4 times the number, while the weed, which dies the moment a cell wall ruptures somewhere north of boiling, cannot tell the two torches apart.