Steam and hot water are chemical-free, ecofriendly ways to kill weeds in your lawn and garden. Both methods produce the same effects; killing the weeds by causing cell walls within the weeds to rupture. Once the cell walls rupture, the plant quickly dehydrates and dies. Steam machines can be bulky and expensive and the steam technique is best suited for young perennial weeds. Hot water requires boiling, but works well on well-established weeds. The one you choose is strictly personal preference.
Pour tap water into a hand-held steamer. Unlike hot-water weed killing, you do not have to pre-boil the water. Lukewarm tap water will do.
Plug-in your hand held steamer. Now this is where it may get tricky. Unlike the hot water method, you need to consider distance. Since hand-held steamers run on electricity, you may need a long extension cord to get to the weeds you are targeting.
Turn-on the steamer, let it warm up, and blast the weeds. Two or three blasts of steam is all that is necessary before you notice the weeds beginning to shrivel. This is a sign that the dying process is starting. The weeds will slowly begin to turn brown over the next few days as they die off.
Bring a kettle of water to a boil on your hob. The bigger the kettle, the more hot water you will have to pour over the weeds.
Turn-off the burner on your stove and carry the kettle by its handle, out to the weeds. Unlike steaming, you can only carry so much hot water out to the weeds. So, you will need to weigh the positives and negatives yourself.
Pour the hot water over the weeds. Just like steaming, the weeds will shrivel and eventually turn brown and die. Now this is where another disadvantage of hot water weed killing may come into play. Unlike the steamer that does not require boiling water for use, you will need to run back inside and boil more water if you do not have enough for every weed.
If you are only dealing with a few weeds, you can simply heat-up a small pot of boiling water and throw it right over the weeds.
Be careful when working with steam or boiling water. Do not allow the steam or hot water to touch your skin. Both the steam and the hot water can cause serious burns that may require medical attention. Keep in mind that both steam and hot water will kill any plant life it comes in contact with, so make sure you restrict the process to weeds only and not your prized flowers.