If you need a cost effective way of keeping your garden weed free, then these remedies use things you can find around your house.
1. Boiling Water
Boiling water is an extremely effective weed killer, even more effective than many of weed killers that can be bought in stores. All you need to do is heat up water until it is boiling then carefully pour it onto the weeds you wish to kill. This technique is great for clearing out large amounts vegetation on areas such as driveways and pavements. However, boiling water is not selective, it will cook and instantly kill any plant it comes in contact with and this includes underground roots of nearby plants.
Place some bleach in a spray bottle and spray on the weed you wish to remove. The bleach chemicals will evaporate or dissipate in about two days, making the area safe for planting. Again, bleach will kill anything but if you do get some on a plant you want to keep, just wash the plant off.
Vinegar is a great organic homemade weed killer. Vinegar will kill back (kill the leaves but not the root) any plant but works best on young plants because they do not have enough energy stored in the roots to regrow their leaves. If vinegar is applied to more established weeds enough times, the plant will eventually deplete its stored energy reserves and die.
On a small scale, you can drop a small pinch of table salt at the base of the undesirable plants. It will kill the plant and after a few rainfalls, the salt will dilute down making the soil good for use. On a larger scale, you can cover your gravel driveway with a good amount of salt and nothing will grow there for months.
5. Rubbing Alcohol
Spraying rubbing alcohol onto weeds will draw the water from the plant and quickly kill it. However, be carefull as rubbing alcohol is non-selective and will kill any vegetation it comes contact with.
6. Corn Meal
Corn meal doesn’t really kill weeds, it just stops the weed seeds from ever developing. Corn meal scattered around an area will keep any seed in that area from growing into a plant, including weed seeds and desirable seeds. This method is a good option for areas that you plan on planting grown plants in.
Laying down a layer of newspaper at least 4 sheets thick (the more the better) will go a long way towards killing the weeds underneath. The weeds that are already there will die from lack of sun and the weed seeds will not be able to sprout because they are not getting any sun to start with.