back to article Boffins develop microwave weed-zapper

Reg readers frustrated by the never-ending presence of weeds in their veggie patches may find salvation in the next few years in the form of a microwave device that can pick out garden invaders and blast them into mulch. The device is the brainchild of Australia's Rural Industries Research and Development Corporation , which …


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  1. moiety

    I can see it as a between-rows blunt instrument. Using it to "prepare a veggie patch before planting" would also fry earthworms; beneficent micro-organisms and all the stuff that makes soil soil. Can't see that ever working.

    1. easyk


      You are not going to penetrate very far into the soil. Even if you did it is trivial to toss down a box of worms after the radiation. One way the device could work is you microwave an area to kill the existing plants and seeds and then till the soil.

      1. Electric sheep

        Re: depth

        " Even if you did it is trivial to toss down a box of worms after the radiation"

        Sadly that sort of cavalier attitude is what screws so much up these days.

        Hey, lets have to kids then we have a spare if we brake one.

        1. Anonymous Coward
          Anonymous Coward

          Re: depth

          "Sadly that sort of cavalier attitude is what screws so much up these days"

          Maybe, But presumably earthworm casualties from spades and forks are "organic", and don't count?

      2. Ole Juul Silver badge

        @easyk Re: depth

        Seeds don't contain much water because they have evolved to survive in a dormant state. I recommend you do a bit of testing with microwaves on seeds to compare their resistance referenced to seedlings. While you're at it, do a cost estimate for raising worms on a scale suitable for a thousand acres (or even just a few hundred), then add the fuel cost of running a tractor for the amount of time that would take. Don't forget the salary for the guy who tends the worms and distributes them. Oh, and what building that isn't already in use do we use for the worms?

        What you have said is like suggesting you run a computer on a higher voltage to get more power out of it. BTW: have you spent much time in agriculture?

        1. moiety

          Re: @easyk depth

          For the sake of argument, let's say that all the action is in the top three inches of soil and also for the sake of the same argument that the microwave can both get that far down and be targeted.

          You need a machine that can scan 3" down; identify things down to pretty well virus level; and in realtime target and destroy the nasties while being bounced around on something being dragged behind a tractor. If we had that kind of shit; we could lay cancer sufferers down in the furrows and sort them out in the same pass.

          Not saying it's impossible; just saying that it may well not happen in 2013.

  2. Herby Silver badge

    2KW of power...

    Isn't very portable. You need probably 3HP of engine just to power the microwave horns, and a bit more to move it all along. If you DO decide to plug it in, make sure your home service isn't limited to 1.5kW (see yesterdays story) and don't plug it into a USA domestic outlet as they are only good for 1800 watts or so (at the outlet, less at the other end of the cord).

    Alternatives that might work are playing music, as I've heard it does effect the growth of plants, I just don't remember which way it does it.

    Otherwise, zap away. Don't forget you shouldn't look at the microwave emitter as it can cook your eyes if you aren't careful!

    1. This post has been deleted by its author

    2. Androgynous Crackwhore

      Re: 2KW of power...

      Alternatives that might work are playing music, as I've heard it does effect the growth of plants, I just don't remember which way it does it.

      I hear that classical is the best for making them flourish. Something like Agadoo or The Birdy Song should be enough to quickly eradicate even the most pernicious nettle patch... but wouldn't it be difficult to confine between the rows? You could turn your entire garden into a wasteland as well as exposing yourself and your neighbours to mortal risk. Just imagine your ear defenders came loose!

    3. AdamT

      Re: 2KW of power...

      Yes, in a domestic environment it does seem kind of dangerous doesn't it?

      Of course on a farm where the living things are be-spiked, be-hooved and/or large and cross all the time and the machinary all seems to involve Spinning-Blades-of-Death (tm) and/or Crushing-Wheels-of-Misfortune (tm) it probably doesn't add much to the overall risk levels. Not forgetting the Unpleasant-Pit-of-Sh... well, anyway, you get the picture

    4. annodomini2
      Thumb Down

      Re: 2KW of power...

      I see this being of greater benefit in a commercial environment, reduction of pesticide usage.

      2kW from a tractor engine (may need a bigger alternator) is not a major challenge.

      Secondly, if it were for home use, getting 2kW out of batteries for the few minutes it's used wouldn't be a major issue. May need a capacitor or 2, as the article states it only needs to operate for 1 second on each weed.

      Getting it CE marked however would be an interesting challenge.

      1. Suricou Raven

        Re: 2KW of power...

        My Mad Science group have been considering hooking our multi-megawatt cap bank up to a magnetron. We're just waiting for warmer weather so we can move the equipment outside.

        Other plans include a steam cannon. Flash-boiled water launching a projectile.

  3. Martin Budden

    Can they make it zap mozzies?

    It might be an alternative to the mosquito laser, which works well but still hasn't been commercialised.... come on Intellectual Ventures pull your finger out!

    Safety goggle icon to prevent cataracts.

  4. This post has been deleted by its author

  5. Androgynous Crackwhore

    So Aussie BS knobs go all the way to eleven too!

    I can (sort of) see the potential appeal to farmers: If you're trundling around in a tractor anyway then what's a few extra kW here and there?.. and offset by agrochem savings too. ...and I suppose exploding wildlife on the spot could be kinder than dousing it with some Nazi nerve toxin and leaving the survivors to creep off to get cancer... but...

    A home version??!?! lmao

    Other than...

    1. Providing young boys with an excellent new way to do unthinkable things to wildlife and pets

    2. Doing wonderful things for the utility corporations' bottom line

    3. Providing A&E staff with a whole new class of amusing "the fuckwit had assploded his foot!" anecdotes is this better than a hoe?

    1. Anonymous Coward
      Anonymous Coward

      Re: So Aussie BS knobs go all the way to eleven too!

      Bros before hoes.

      That is all.

      1. Anonymous Coward
        Anonymous Coward

        Re: So Aussie BS knobs go all the way to eleven too!

        My hoe does all the weeding.

        1. Thorne

          Re: So Aussie BS knobs go all the way to eleven too!

          "My hoe does all the weeding."

          And that would make you the pimp?

          1. Euripides Pants Silver badge

            Re: So Aussie BS knobs go all the way to eleven too!

            "And that would make you the pimp?"

            Only if its spelled "ho".

    2. Peter Ford

      Re: So Aussie BS knobs go all the way to eleven too!

      " is this better than a hoe?"

      A hoe has difficulty weeding my patio: this sounds ideal as long as I don't point it as the fish pond...

      1. Anonymous Coward
        Anonymous Coward

        Re: So Aussie BS knobs go all the way to eleven too!

        My hoe weeds the patio with an old knife.

        1. Montreal Sean

          Re: So Aussie BS knobs go all the way to eleven too!

          You owe me a new smartphone keyboard!

    3. Intractable Potsherd

      Re: So Aussie BS knobs go all the way to eleven too!

      Yep, and that fire ought to be banned too - lots of ways for children to harm things and many A&E visits per year as a result of it.

      Precautionary principlists are the bane of civilisation.

  6. Allan George Dyer Silver badge

    Deadly weapon!

    OK, the power cable might be a bit limiting, but plenty of scope for in-the-heat-of the-moment manslaughter, or meticulously pre-planned homicide.

    Also an open invitation to Darwin awards for anyone close enough ("it really warms you up if you stand here").

  7. Anonymous Coward
    Anonymous Coward

    Old news ..

    I thought there was a number of electro-static weed zappers on the market by now ...

  8. Magani

    No thanks.

    I'll keep relying on my favourite gardening tools : my chainsaw and a flame thrower.

    If SWMBO wants a garden bed weeded, she only asks me if she wants a replica of the scorched earth policy on the Eastern Front.

    1. Intractable Potsherd
      Thumb Up

      Re: No thanks.

      Yep - prune hard, prune often!

      (I don't get asked to do much in the garden I don't want, either ...)

  9. DougS Silver badge

    "Far happier are those who worry about the prevalence of pesticides"

    Probably not. I'm sure some of them will claim that this is worse because a few stray microwaves will get into the leaves of the food crop and cause horrible mutations making it worse for you than pesticide laced or GMO crops, or worse will mutate insect larvae creating giant mutant aphids able to eat an entire corn plant in a single mouthful. See, the B flick is already writing itself...

    There is a certain segment of the green movement that isn't interested in any form of technology to solve the problems of other solutions technology has come up with. Because technology hasn't been 100% good it should not be considered any sort of solution. So when it comes to curbing the worse abuses of factory farming or fossil fuel wastage, they believe the only proper solution is that society be brought back to an 19th century form of existence. Luddites in new garb, essentially.

    At least I don't know what else to consider people who think wind power is bad because it kills birds, solar power is bad because it shades habitat, hydro power is bad because it hurts fish, wave power is bad because it disturbs sea life, biofuels are bad because, well, I can't really remember but I'm sure they had a good reason why it has no place and we shouldn't go beyond horse power and whale oil for lighting. Oh wait, scratch that, whale oil is also bad.

    1. Ian Yates

      Re: "Far happier are those who worry about the prevalence of pesticides"

      Dear $DEITY! Save us from this microwave RADIATION! (etc., etc., etc.)

  10. Ole Juul Silver badge

    This isn't particularly innovative

    They've been using flames commercially to weed between rows in fields on large farms for years now. The trick is to get the timing and duration just right. The actual crops are bigger and absorb less heat, and the weeds are only allowed to grow to a small size, and are thus tender and immature, and very vulnerable. It is this mass and hardness differentiation that allows the heat to only kill weeds and not crops. I don't see the use of microwaves to be materially different. As for the power requirements, the flame technique is used on equipment attached to a tractor. Getting a few extra kilowatts from an 80hp (possibly much more) tractor is not a big deal.

    1. hplasm Silver badge

      Re: This isn't particularly innovative

      I dunno- 80hp tractor wielding a +2500 microwave mace should be good in a melee against the Weed People...

    2. Euripides Pants Silver badge

      This isn't particularly neccessary

      An organic farmer I know doesn't really worry about the weeds once his crops get sufficiently established. In fact, he finds their presence useful as a way to determine the condition of the soil.

  11. g e

    Anyone have a video?

    Of what happens when a bird flies through the beam?

    1. annodomini2

      Re: Anyone have a video?

      Surely there's plenty of videos of people having lunch on the net?

  12. dlymn

    micro brainwaves

    In Popular electronics over 20 years ago they ran an article on a make it yourself microwave shaver! I was tempted just as I was to make the 3kv mouse killer which was constructed on a tray; so accessible by mice and any living thing . Mad inventors even madder readers.

    1. Suricou Raven

      Re: micro brainwaves

      I'm curious exactly how, as producing high-power microwaves requires quite exotic components. Either very high-power high-frequency transistors (Or tubes!) or a magnetron, which cannot function without hard vacuum in the cavity.

  13. Dragon Leaves
    Thumb Down

    Microwaves do wonders to DNA, yay!

    GMO are often a byproduct of microwaved lifeforms. Isn't that just great?

    1. KjetilS

      Re: Microwaves do wonders to DNA, yay!

      Source please?

  14. Anonymous Coward

    I am curious as to why....

    They have not confined the beam to a narrow directional appature, at the microwave's width wide and say 5cm long.

    Also you don't need to detonate the plant, merely heat it enough.

    Satan - because she loves a hot horn.

    1. Minophis

      Re: I am curious as to why....

      ' you don't need to detonate the plant, merely heat it enough'

      True but there are advantages to detonating the plant: -

      1. It gives a clear visual indication that the plant has absorbed sufficient microwave radation to kill it.

      2. It's probably quite funny for the first few goes.

  15. Anonymous Coward
    Anonymous Coward


    Come on, well all know Triffid guns should be metallic and shoot fast, rotating, triangles to lop their heads off.

  16. TRT Silver badge

    Accidental operation...

    On a field of corn might be fun.

    "I realised with horror that my home was now within range of the Heat Ray"

    1. VeganVegan

      Re: Accidental operation...


      Guinness Book of Records: The biggest batch of popcorn, EVER!

  17. S4qFBxkFFg

    ...but is it cheaper than a robot lawnmower?

    I am wondering if the beam is accurate enough to fire horizontally at a certain height (say 3 inches). It could then be situated where it has a clear view of the whole lawn mounted on a rotating platform.

    It would probably only need a few minutes a day, but might mean the grass has perpetual brown tips though.

    1. Blofeld's Cat

      Re: ...but is it cheaper than a robot lawnmower?

      To do this you would need a lawn "like a billiard table".

      Actually turning the power up a bit could create a lawn "like a billiard table" - i.e. no grass anywhere and full of holes.

      1. S4qFBxkFFg

        Re: ...but is it cheaper than a robot lawnmower?

        Indeed - however, you could just set the device height to the height of the biggest bump + desired grass length - bumpy ground, flat lawn.

        1. TRT Silver badge

          Re: ...but is it cheaper than a robot lawnmower?

          Yeah, but you'd need to mount your lawn on a rotating turntable and leave the security light on.

    2. Anonymous Coward
      Anonymous Coward

      Re: ...but is it cheaper than a robot lawnmower?

      Also at just the right height to zap moles...

      1. TRT Silver badge

        Re: ...but is it cheaper than a robot lawnmower?


        Is there an icon for an avid Duncton Wood fan?

  18. Anonymous Coward
    Anonymous Coward


    I just hope it has a safety cut-out so it only works pointed downwards :)


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