Weed seeds need light to germinate
To shade the soil around your plants, keep it covered with organic mulch, black plastic or paper mulch, layers of wet newspaper, or a geotextile weed mat.
Build a shield
Use edging materials like bricks or underground barriers of metal or plastic around garden beds. This will keep lawn grass and perennial weeds from creeping into flower beds and vegetable plots.
Let the sun help you
Solarizing the soil means letting the sun do the weeding work for you. Till up the soil and water it. Lay a sheet of clear plastic over the area, anchor the edges with stones, and wait four to six weeks: The sun’s heat will “cook” weed seeds. If any weeds are found after you lift the cover, rake them up lightly without disturbing the soil.
Till the soil the first time to bring buried weed seeds up to the surface, where they can germinate. Wait two weeks. Till again, this time with the tiller at a shallower setting. The second tilling will chop up the weeds without exposing more seeds.
Be careful with compost
Toss into the pile any weeds that have not yet bloomed; they have no seeds to spread. Add weeds that have set seed only if the pile heats up to 200 degrees F—the temperature needed to kill seeds. Or start a separate compost pile for weeds; use this compost only in deep planting holes, where seeds can’t germinate. Here are more tips on starting a compost pile.
Keep soil covered
Don’t let soil remain bare for any length of time—weeds will move right in. If you regrade or remove plantings, blanket the soil with a cover crop, ground cover, mulch, or grass.
Don’t mow too short
Letting grass grow to the recommended height shades out weed seeds. It also spurs root growth, which crowds out any emerging weeds.
Try elbow grease first
Don’t automatically reach for the sprayer to treat lawn and garden weeds. A combination of elbow grease, ingenuity, and tools will usually do the job.
Buy a dandelion digger
It has a sharp, notched end that will pry up stubborn weeds with taproots. You can also buy weeding tools with hoelike blades and short handles; they’re good for slicing weeds off below the surface.
Water before weeding
Weeds are easier to pull with their root systems intact if the soil is moist. Also, neighboring plants are less likely to be disturbed or damaged.