John Burnap asked:
I have some rather nasty weeds in the yard and I don't want to use chemicals. Is it possible to electrocute the weeds?
Sarah - It’s very noble of him to not want to use chemicals. I think the important point here is, yes, you could but not in the same way that you would electrocute a human. So the reason that we would die by being electrocuted is because it will stop the heart because the heart is full of little tiny cells called myocytes that have their own electrical rhythm and then if you zap them electricity, they start just firing madly and don't beat in rhythm. There's the synoatrial node which keeps them beating at a regular time, keeping the blood going around your body. But if you have a load of electricity going through, that stops happening. But obviously, plants don't have that so they can survive.
In fact, if you get a tree that's struck by lightning – this is one of the reasons that you shouldn’t stand by a tree in a lightning storm –they can actually explode! The sap inside the cells boils with the heat of the lightning and can make part of the tree blast out. But depending on the extent of the damage, the tree can actually survive that and you do see “scars” down the side of trees that are still living, and then they just sort of healed over. So you could kill the cells by frying them with electricity so that they got so hot that they died, but you'd be more likely to accidentally kill yourself, in the process, than the plants. So I think if you're going to heat them with so much heat that they die, you might as well use a flame thrower.
Chris - Or even a garden spade and fork, better still. That might be a better idea.
john burnap asked the Naked Scientists: I have some rather nasty weeds in the yard and I don't want to use chemicals. Is it possible to electrocute the weeds? John Burnap What do you think? john burnap , Thu, 20th Jan 2011
Well, lightning certainly fries a plant, but that's more down to heating that any specific electrical impact.
Thank you for the reply! We have some very large weeds, including some Arundo Donax (something like Bamboo). The root system of the Arundo is rhizomal and it can regenerate quite rapidly from a single piece of root. I was just considering tapping some metal electrodes into the rhizome, say a pair of nails, and attaching them to a car battery for a while. I presume that the rhizome will not get very hot, but hopefully it will suffer some fatal electro-chemical imbalance. Will the electricity pervade the entire rhizome? How are plant cells affected by electrical current? Perhaps I should do some Kitchen Science!
As Chris has said, it is the heat rather than the electrical current which frazzles plants in a lightening strike. Connecting your unwanted plants to even the most powerful car battery is unlikely to have any effect whatever.
Some trees can survive lightening strikes, although I like the idea of affixing a lightening rod to your plant :)
Roofing torch=flame thrower Travis, Sat, 27th Aug 2016