Many weed-control methods can effectively eradicate weeds from growing or landscape areas. You may wish to avoid control methods that involve chemicals or back-breaking work, however. Covering weeds with a tarp is an easy way to eliminate and control weeds that does not require the use of chemicals and does not involve strenuous work. As long as you use a thick tarp, prepare the area properly and apply the tarp at the right time of the season, you can effectively eradicate weeds from a growing area using this method, which is also called solarisation.
Mow the weeds and vegetation growing in the area to a height of less than a half-inch.
Use the rototiller or garden spade to cultivate the area for planting. You must perform this soil cultivation prior to laying the tarp and not after removing the tarp because you want to disturb the weed spores and seeds now before laying the tarp. Till the soil down to the depth necessary for whatever planting you plan to do in the growing area. Rake the growing area to make it smooth and level.
Water the soil generously with the garden hose.
Cover the entire area with the clear plastic tarp. Use clear plastic because this plastic will more readily attract the heat from the sun. As this heat accumulates, the weeds, insects and pathogens existing in the soil will die. Place soil around the outer perimeter of the tarp to ensure a proper seal. Add heavy bricks or rocks to hold down the tarp if you think the wind may loosen the tarp.
Leave the tarp over the growing area for at least six weeks. If you have cloudy or windy weather, leave the tarp on for a longer period. You must allow the tarp to stay over the growing area until all of the vegetation beneath the tarp dies.
Remove the tarp when the time elapses or the vegetation dies.
Plant new plants in the growing area as soon as possible after removing the tarp. Do not cultivate the soil down to a depth more than three inches at this time. You already performed the bulk of the soil cultivation prior to laying down the tarp so deeper cultivation is unnecessary.
Try to apply the tarp to your growing area so the tarp covers the area during the hottest and sunniest time of the growing season, for best results. This will create the most effective solarisation conditions under the tarp to kill the weeds. Obviously, this might make it challenging to plant some plants when you remove the tarp. You can plant bulbs and other plants in the autumn but you will have to wait until the following spring for vegetables and some annuals and perennials.