How can I kill the grass in unwanted areas?

I want to kill the grass in some unwanted areas.  Specifically, grass that's growing up over the gravel driveway, and grass that's growing up between the bricks that make up the front walkway.  Obviously, I don't want to use any modern chemical herbicides.  Any old lore or forgotten wisdom that I could try here?

Hi Creighton,
For the gravel, the idea would be to disturb it frequently. There are tractor implements that will skim just below the ground level and disturb the ground and maybe cut roots off plants. Getting the roots above ground will kill them. I'm sure for small area you could also use a garden rake or hoe. If the gravel is compacted already and/or you don't want to disturb it, see my answers for the brick walkway.

Two things come to mind for the brick walkway. Horticulture strength white vinegar. This is not your grocery store vinegar, but still is relatively innocuous. The other option would be a flame weeder. You don't need to burn them up, just heat enough to rupture the cells and the plant will die. Something like this one from Johnny's.

https://www.johnnyseeds.com/tools-supplies/weed-control/flame-weeders/red-dragon-backpack-flame-weeder-9758.html?cgid=flame-weeders#start=1

Thanks Mat.  I asked my wife about the weed burner before posting, and she's afraid that it would discolor the brick.  But I will definitely try the vinegar.  Any suggestions as to where I should look for such a strength of vinegar?

the flame weeder is probably the way to go for the driveway.

Another possibility is to use glycerol. if you know anyone with a biodiesel maker you could probably get as much as you could ever want on the cheap. It's a byproduct of the chemical reaction that converts vegetable oil into fuel. It's not pure glycerin though so I don't know how "organic" the impurities are. Glycerol itself though should be perfectly safe as its been used in food, cosmetics, and even fed directly to pigs. A little bit of dilution in water and you should have a very effective weed/grass killer. Just don't over do it or spray it anywhere that you might want to grow something in the future.

Pouring boiling water especially if high or low pH works. After boiling my pretzels, the baking soda water gets poured on weeds. Same thing with any leftover pickling liquid.

A squirrel chewed a line on my vegetable oil filter and it leaked some on the ground.
Couldn't grow grass there for a couple years.
Makes kind of a hard shell.

Hi Creighton,
Most of the examples I have seen for agricultural vinegar are about 20% concentration of acid. Grocery store stuff is like 5%. I have heard of higher concentrations... but I don't know if that much is needed. I'm not sure where you are, but I know that Amazon, Home Depot, and Walmart all sell it. Some are pure vinegar, and some are vinegar based products, so make sure to read the label. There might be a good vinegar based product that makes it easy... but there could also be a vinegar based products that still contains things I wouldn't want to spray. I'd imagine most smaller hardware or feed stores would also have it, or be able to get it. Just tell them you want the 20% concentration for weed killing.

Here is my disclaimer... too much of even a natural thing can cause unwanted problems, so I don't recommend dumping a whole gallon on one weed :), I'd get a spray bottle for small areas or a small backpack sprayer for larger areas.

Having said all that, there is a chance the vinegar will cause discoloration on the bricks. I would see if you can pull up 1 brick and try the vinegar on the side before using it across the whole path.

About the torch discoloring the bricks... I doubt it would be a problem, but I've never tried one on bricks, so I don't know for certain. It is a propane based torch, so the burn is quite clean. I doubt there would be any soot left behind. Maybe the heat would discolor it? But unless you are leaving it on one place for a long time, I doubt the heat would be a problem.

PS - most of the things I see on amazon right now are 30%, 45%, or 75%. Personally I would be wearing gloves and dilute it down to 20%. It also seems to be marketed on Amazon primarily as "concentrated vinegar". So if "agricultural vinegar" doesn't get you anywhere, try concentrated vinegar.

I have a little electric kettle just for this sort of spot killing weeds.  I feel a little bad for the collateral damage of whatever insects are down there too, but it's a cost/benefit analysis.  I use it on driveway cracks,  between bricks in my work walkway, and along the concrete edge of my house between the house and driveway.  

For bigger areas, I solarize (although I just learned that is occultation when it's opaque lol)  with a large heavy rubberized black tarp; the kind they cover tractor trailers with.   I'm about to do my whole side yard to get rid of the grass on the side of the house where I plan to wood chip and then put a greenhouse.  

Thanks all. I've ordered a gallon of 30% vinegar from Amazon that comes as it's own backpack sprayer. It's advertised as a weed killer also. I will report on my outcomes.

Instead of a purpose built flame weeder, a tiger torch also works. Just put a 20lb propane bottle in wagon and pull it along while you use the torch to scorch the weeds.

dissolve 1 cup of salt in hot water,  combine with 1 gallon white vinegar, add a tablespoon of dish soap like dawn.
mix it up and you can put it in a sprayer and spray it on your weeds

bruce Fine wrote:dissolve 1 cup of salt in hot water,  combine with 1 gallon white vinegar, add a tablespoon of dish soap like dawn.
mix it up and you can put it in a sprayer and spray it on your weeds

Would this work to kill the weeds in my garden pathways?

Vinegar should never be mixed with hot water!

The vinegar can evaporate (and thus dilute so even less reasons to do it) and that stuff is really not good to breath in. It can really irritate the airways.

I have not used vinegar for weeds, so I don’t know what will work. I just wanted to add the warning to this conversation so people can stay safer!

I agree that hot water and vinegar is probably not a good combination.

However, vinegar in and of itself, if it is more concentrated than the grocery store stuff would work fine to kill weeds. Since I posted back 8 months ago, I have learned that amphibians are extremely sensitive to vinegar. They can be hurt or killed by it easily. So make sure you check the area before spraying. You want frogs and salamanders and whatnot around.

Naturally they would be hurt or killed by the flamer weeder too... but once the flame weeder is gone, it's gone. The vinegar can stick around for a while.