Green Lawns and Gardens Tips: Non-Toxic Weed Control

Herbicides, whether applied by themselves or in the form of weed and feed products that combine fertilizer and herbicide in one application, can easily run off into streams and lakes and can migrate into groundwater supplies in areas of porous soils.

Preventing Weeds in your Lawn

Weeds move into lawns when conditions favor their growth over that of turf grasses. A healthy lawn will be able to endure drought, diseases and pest infestations better than a stressed lawn. Healthy grasses can also compete better with undesirable weeds.

Promote lawn health by mowing and watering properly:

  • Mow at a 2.5 -3″ height. Taller grass develops deeper roots, an advantage during dry spells
  • Water deeply once a week. Lawns need about an inch of water a week. Supplement with irrigation only when necessary
  • Water early in the morning
  • Water at a rate that the soil can absorb

To control the spread of broad-leaf weeds, try using corn gluten, a non-toxic corn by-product. Apply at the suggested rate in the spring (when forsythia is blooming). Corn gluten will not kill existing weeds, but will prevent new ones from germinating each year that it is applied, and it adds some nitrogen to the soil as well.

Preventing Weeds in Garden Beds

For newly planted beds a two to three inch deep layer of mulch will help keep weeds down until the plants grow and shade the ground. Take care to keep mulch away from the trunks of trees and shrubs as this encourages certain pest problems. Shredded leaves can also be used as a temporary mulch. They will decompose and enrich the soil.

A “living mulch” of ground covers and/or low perennials planted beneath trees and shrubs will add beauty and shade out annual weeds.

Help for Tough-to-Weed Areas

Weeds often take root in between pavers or stones used for walkways and patios, as well as in cracks in asphalt or concrete. Manage weeds in these areas with a highly acidic spray to kill the above-ground portion of the plant.

The commercially available sprays are typically made with vinegar or lemon juice either alone or in combination with herb or citrus oils such as thyme and orange. These sprays work well on annual weeds. Pouring boiling water over the weeds is also an option. Killing perennial weeds with either method will take repeated applications to exhaust the nutrients stored in the root.

Reduce Pesticide Use with Smart Plant Choices

Head off pest and disease problems by choosing plants that have built-in disease and insect resistance.

  • Cool season grasses such as tall and fine fescues, kentucky bluegrass and perennial rye grass are appropriate for the Northeast. Choose fescues for shadier areas. Pick grass seed mixes with more bluegrass for areas that are sunny and will receive a lot of use.
  • Crabapples are a popular tree with multi-season interest. Choose varieties resistant to rust, scab and fireblight – three very common diseases.
  • Roses are susceptible to black spot, but there are some resistant varieties. Or try the hardy “landscape roses” which offer beautiful flowers, excellent cold-hardiness and are disease resistant too.
  • White-barked birches are extremely popular, but plagued by the bronze birch borer. Choose the ‘Heritage’ river birch over the European white birch.
  • Phlox, bee balm and certain asters are susceptible to powdery mildew. Newer cultivars and hybrids such as Phlox ‘David,’ or ‘David’s Lavender,’ New York Aster, and the beebalms ‘Raspberry Wine,’Coral Reef’ and ‘Marshall’s Delight’ are less prone to mildew.
  • Lilacs are also mildew targets. Try ‘Miss Kim,’ the Meyer Lilac, little-leaf lilac or the cultivar ‘James McFarlane.’