Weeds are often just unwanted plants that grow spontaneously, but some weeds are invasive and aggressive, growing quickly and taking over an otherwise pristine garden. Gardeners want to first prevent weed growth, then stop it when it occurs without damaging the surrounding plants. This requires persistence to avoid using chemicals, but weeds can be effectively eradicated naturally, which will benefit the whole garden.
Preventing Weed Growth - Taking a preemptive strike against weed growth will save you the hassle of removal. When first planting a garden, lay 3 inches of mulch over bare soil in the spring. Bark chippings, well-rotten manure or leaf mould prevent weeds from taking root and sprouting, and they help the soil maintain moisture, benefiting the other plants in the garden. Maintain this layer of mulch periodically to keep weeds at bay. Cover large patches of unused ground with plastic or landscaping material in lieu of mulch to prevent weed growth.
Removing Existing Weeds - When weeds first sprout, eliminate them immediately to prevent further growth. Sever the growth from the root if you cannot remove the root system itself. The remaining roots will continue to sprout over the course of months, but be persistent in removing the growths. This process is tedious, but it will eventually exhaust the roots, causing the weeds to die. Don't confuse weeds for flower or vegetable seedlings.
Killing Weeds - Once weeds have begun to grow, they produce seeds and spread. If it is too late to exhaust the root, then kill the weeds individually rather than spreading chemicals that can damage other plants and degrade the quality of the soil. Use an herbicide gel by brushing it directly onto the leaves of the weeds to kill just the intended weed. Another tactic is to use a small torch to burn the weeds. The singed nubs are unlikely to grow back.
Spreading Chemicals - Applying an herbicide should be a last resort to eradicate a serious weed infestation. Herbicides can damage surrounding plants and degrade the soil. They also promote weed resistance when used too often, leading to the need for stronger chemicals to kill the same weeds. Herbicides have been linked to fungal root disease in healthy plants in preliminary studies.