Mike from Big Bear City, CA
Mike,
I'm not aware of any home remedies you can make to kill weeds selectively over a large area. For weeds growing up through the gravel you can try spot spraying them with vinegar (vinegar is not selective though, so be careful). You need a hot sunny day for this for it to be really effective. You could also burn weeds with a propane torch. This method seems to work really well for weeds in gravel driveways or paths. Pouring straight Epsom salt on some weeds will turn them black and kill them over the course of a few days. Another strategy is to prevent weeds from germinating by applying corn gluten meal to the area. This is a natural corn by-product (usually used in animal feeds) that provides pre-emergent weed control by interfering with root development. You should be able to find it at feed stores and some garden centers. Corn gluten meal is also non-selective, so you need to time application with when your weeds normally germinate. It won't harm already planted grass or bulbs (in fact it's a great lawn fertilizer), but if you planning on re-seeding your lawn or planting flower seeds in the area you'll need to wait 6 weeks. It's usually applied at a rate of 2 lbs per 100 square feet and provides 6 to 8 weeks of control.
Good luck!
Ellen