TURF WEEDS

MEET THE PEST

Any plant which is growing in an area where it is not wanted can be considered a weed. Weeds seem to flourish in lawns, gardens and recreational areas and are a constant battle for many people. Because they contain a large number of seeds, control is sometimes difficult. Most people strive for the green, weed-free lawn, but this is next to impossible to achieve if the lawn is not healthy and vibrant or unless pesticides are used. Although difficult to control completely, weeds can be kept to a minimum with a little extra work. Turf management is the best way to produce a healthy lawn which will provide the best protection against weeds.

Dandelions are the most recognized and most common of the weed problems. They have very deep roots and grow just about anywhere! Dandelions produce many seeds which are easily spread to other parts of the lawn and to neighbouring properties. However, dandelions can also be beneficial. They attract pollinating insects such as bees and butterflies which use the dandelion as a food source. Some people also eat dandelion.

LIFE CYCLE

It is important to determine what type of weeds are present in your lawn and garden. There are three classifications of weeds: annual, biennial and perennial. Annuals complete their life cycle in one year and produce many seeds. Biennials complete their life cycle in two years - the first year is for vegetative growth, and seed is produced in the second year. Perennials live the longest of the three - more than two years. Because they produce seeds from the second year onward, their potential for spread is greater.

By identifying weeds, control will be more effective because information on the weed classification, potential damage and management options can be obtained. This information will identify what conditions must be changed and help in determining the appropriate control measures.

CONTROL

Physical

Proper lawncare/turf management is the most effective method of controlling weeds. While this may take extra effort and time, the results will be very pleasing. Good lawncare includes: healthy soil, fertilizing, mowing, watering, aerating and other physical control measures. In addition to creating a healthy lawn, these activities help you achieve a healthy mind and body. Many people are coming to realize the therapeutic benefits of caring for lawns and gardens.

SOIL AND NUTRITION

Turf management provides your lawn with the tools it needs to successfully compete against weeds. You should also learn to tolerate some weeds. Although they compete with grass for necessities such as water, sunlight and nutrients, if kept managed, problems with weeds should not be too severe.

Turf management begins even before the lawn is planted. Begin from day one to achieve a healthy lawn. The first step is to create a good soil base by removing large rocks, tree stumps and other barriers to water movement. A minimum of six inches of good quality soil is needed. Future problems with drought, compaction and nutrient deficiency can be reduced if healthy root growth is promoted. When seeding, it is important to choose a good quality seed. Shaded areas of the lawn should be seeded with varieties of grass which do not require full sunlight.

Have the soil tested to determine the pH level and the fertility. A pH level of 6.5 is optimum. If the soil is too acidic (the pH level is less than 6.5), the addition of limestone may be necessary. A soil-testing lab can provide suggestions for the amount of limestone to add, and fertilizers to use for optimal plant growth. Have soil analysed every two to three years, and the pH level tested every year.

The nutrients which are vital to plant growth are most readily available when the soil has a pH level of 6.5. Lower pH levels are natural in Eastern Canada. At these lower levels, nutrients remain tied up in the soil, limiting access to the plant. Limestone is best applied in the fall or early spring. It should be added regularly - first, to bring the pH level to 6.5, and then, to maintain it at that level. Limestone also contains large amounts of calcium and magnesium (nutrients required for good plant growth).

Fertilizers contain nitrogen, phosphorous and potassium (N, P and K). All are vital to plant health -nitrogen aids leaf formation and colour, phosphorous helps achieve strong roots and potassium makes the plant stronger and better equipped to fight pests and disease. Adding organic matter or compost to your soil will also improve soil quality. Although most composts contain nutrients, compost alone will not provide adequate nutrient levels to sustain a lawn. A healthy soil will produce healthy turf and reduce pest problems.

In the fall, fertilize the soil using a fertilizer with a low nitrogen. (This is also a good time to aerate and re-seed damaged sections of the lawn!)

MOWING

If grass is already present, proper mowing techniques will help control weed problems. Grass should be mowed to a height of two to three inches (5 to 7 1/2 cm). Mowing to levels shorter than this will reduce plant vigour and give weeds and insects a better opportunity to flourish. Mow frequently to minimize plant stress and use lawn mowers with sharp blades which will not tear the grass. Leave the clippings on the lawn to serve as a natural fertilizer. Long lengths of grass clippings left on turf may increase problems as it will shade the grass from the sun.

WATERING

Proper watering techniques are helpful in the control of weeds. Make sure watering is necessary and only done when the lawn is under drought stress. Water grass early in the day or in late evening (when the sun is not at its peak). It is important that water reaches the root zone, but overwatering helps weeds flourish. Frequent watering for short periods of time each day promotes shallow root growth. A single, heavy watering once a week provides sufficient water to the lawn, and promotes the development of deeper roots.

AERATION

Compaction of turf provides favourable conditions for many species of weeds. Heavy traffic and poor drainage cause turf compaction. It may be necessary to use an aerator to reduce compaction and increase air circulation in the root zone of the turf. This simply involves pushing the aerator down into the soil at an angle to remove soil cores (leave them on the lawn).

OTHER OPTIONS

Adding a layer of mulch may be beneficial to your lawn and its ability to fight weeds. Mulch improves root growth and prevents the germination of weeds. Hand picking or removing weeds and their roots with a screwdriver or root-puller is another control option. This roguing-out of weeds will reduce numbers, especially if it is done before seeds are produced. Destroy the removed plants or use them in the compost pile. Another option is to hoe during peak sun as the heat will cause the weed to wither and die.

Chemical

If physical control measures are not effective, use a pesticide which will have a minimal impact on both you and the environment. The first step in controlling weeds is to identify what type of weeds are growing in your lawn. Weeds are indicators of problems, therefore, it is important to find out why they are growing and fix the problem. Remember herbicides do not offer permanent protection against weed regrowth.

If the above measures are not effective, consult with an expert at a garden center for herbicides available. Before using pesticides, consult the Backyard Bug Brigade Brochure which contains information on safe pest control. Spot treat by applying a herbicide only to the weedy areas.

Always use a registered domestic class pest control product labelled for weed control and carefully follow the label directions.