But if you prevent weed seeds from germinating, your garden will be weed-free. Here are some surefire ways to keep weeds from growing in the first place.
Shhh! Don’t Disturb the Soil
Weed seeds “sleep” in your soil all the time, just waiting for sunshine to enable them to germinate. Left underground, many weed seeds remain dormant for years. So the less you disturb the soil, the more likely weed seeds will remain asleep.
Avoid high-powered tillers, and go easy on the hand cultivating. Sow your flower and vegetable seeds above the ground in mounds of compost, shredded leaves, or even in bags of topsoil. Better yet, plant seedlings and starts.
Smother Weed Seeds
Another way to keep seeds asleep is to cover your soil with sun-blocking organic or synthetic mulches.
Organic mulches — hardwood mulch, newspaper, cardboard, straw — degrade in a few months and improve soil structure and add nutrients. Synthetic mulches — landscaping paper, plastic — can last several seasons, but won’t help rebuild soil when they eventually degrade.
Heed these mulching tips:
- Wet the ground before you lay down layers of paper, which will prevent the paper from blowing away while you work.
- Scout yard sales for old carpet and wallpaper, efficient sun blocks that prevent weeds.
- Spread mulch 2 to 4 inches deep to suppress weeds and retain moisture.
- Always pick straw, not hay, to prevent weeds. Hay usually contains hayseeds, which will sprout where you’re trying to keep weeds out.
Learn more about mulching with our handy garden mulch guide.
Wage a Chemical Attack
Pre-emergent herbicides prevent weed seeds from germinating, but don’t kill existing plants and grasses.
The exact timing for applying a pre-emergent herbicide is hard to pinpoint because you must spread the herbicide before seeds germinate, which happens underground at different times.
Conventional gardening wisdom says spread pre-emergent herbicides when the daffodils pop or the forsythia wilts. But advance planning is the best way to determine when to spread. Log the date when you see the first weeds in your garden, then subtract three weeks to arrive at the date you should spread the pre-emergent herbicide next spring.
Grow Up Close and Personal
The closer together you plant your flowers and vegetables, the less space weed seeds will have to grow.
If you double-dig — loosen (don’t pulverize) soil at least 2 feet down — you can plant cheek-by-jowl, because plant roots can grow down, not out, to find water and nourishment. If you plant intensively in a diamond-shaped pattern — rather than rows — you’ll avoid barren spots where weeds will grow.
To keep weeds out of lawns, make sure your grass is lush and healthy so weeds have no room to grow. Reseed bald patches; fertilize if a soil test determines nutrient deficiencies; aerate in the fall.
Test your weed knowledge with this slideshow of common weeds.
Need to Kill Weeds?