Lawn and Garden Tips – Weed Control

How To Look After The Lawn and Garden

Using 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 on 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 6 – 6.5cm 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 five to seven centimeters 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 a built-in disease and insect resistance.

Cool season grasses such as tall and fine fescues, bluegrass and perennial rye grass are appropriate for the Southeast. 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 spots, 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 they are 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’, 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, the little-leaf lilac or the cultivar ‘James McFarlane.’

Controlling Lawn and Ornamental Pests Naturally

There is an array of natural alternatives to pesticides for controlling insects on your lawn and on your ornamental plants. For example, parasitic nematodes can be applied to the lawn to control grubs before they turn into Japanese and other beetles that eat our plants. Suppressing grubs will also help with mole problems.

Lawns: The Best Way to Fertilize

Over-fertilization or applying fertilizer at the wrong time can harm your lawn. First, determine if there is a nutrient deficiency that needs to be corrected. A soil test can determine this and also give essential information about soil pH. Adding fertilizer will not solve a pH problem. Too much nitrogen decreases root growth, increases susceptibility to disease and decreases tolerance to environmental stresses.

Is the pH Correct?

Turf grasses grow best in soil that is neutral to slightly acidic (pH 6.5-7). Soils in the southeast often need lime to make the soil less acidic. It is best to apply a high-calcium or calcitic limestone rather than dolomitic limestone to avoid adding too much magnesium to the soil.

Adding Nitrogen

Most lawns that are kept green all summer will need extra nitrogen. Nearly 50% of this can be supplied by leaving clippings on the lawn. The best time to apply the other 50% is in autumn (mid to late October). Instead of raking leaves, use a mulching lawn mower to shred the leaves and leave them on the lawn. By spring they will have decomposed, adding nutrients and organic matter to the soil.

Lawns fertilized in autumn will stay greener longer, green-up earlier the following spring, and have higher energy reserves through the summer. This stored energy helps keep turf grasses healthy and more drought resistant. If you fertilize an existing lawn in mid-summer, you’re feeding the weeds.

Broadcasting up to 12mm of finished compost on an established lawn provides nitrogen and other trace nutrients and builds organic matter in the soil.

More serious nitrogen deficiencies should be corrected with a slow-release, organic source of nitrogen such as blood meal, cottonseed meal or fish meal. Apply in the quantities indicated by your soil test while soil temperatures are above 18.33 degrees Celsius.

How Much Lawn Do You Really Need?

Lawns are often the default landscape, used for “something green” and perceived as low-maintenance. In reality, lawns are one of the most high maintenance and high cost elements of the landscape. Think about how much lawn your lifestyle requires and if there are areas of your yard that could become a garden of perennials and grasses, a mixed shrub border, or a grove of trees with groundcovers beneath.