Weed control should be a carefully planned and coordinated program instead of a hit or miss operation. A weed is any plant that is unwanted or growing out of place. Most weeds possess a vigorous capacity for growth and survival under adverse conditions. Whether grass, broadleaf or sedge, the proper identification of weeds—and some understanding of how and why weeds are present—are important in selecting the best control strategy.

Knowledge of whether or not weeds were previously present in a particular area will also help prepare for control procedures in the future. Weed control should be a carefully planned and coordinated program instead of a hit or miss operation.

Weed Life Cycles Dictate Treatment

Understanding the life cycle of the weed is important for developing an effective weed management program.

• Annual weeds germinate from seed, grow, flower and produce seed in less than one year. Summer annuals germinate in the spring and mature in the fall, whereas winter annuals germinate in the fall or late winter and mature in late spring.
• Perennial weeds have a life of more than two years, though new seeds may be produced every year.
• Biennial weeds have a life of two years, generally storing up food reserves in the leaves and roots the first year and producing seed in the second year. The biennial weeds often are grouped with perennial weeds since control is similar.

Turfgrass Management as Weed Control

The best weed control is healthy, well managed turf. When turfgrasses are properly managed, they are quite capable of out competing weeds. Good turfgrass management programs should include proper use of cultural practices like mowing, fertilizing and irrigation, as well as chemical weed control when needed.

1. Set mow levels to ideal height for your turfgrass variety.

Mowing itself is a weed control, as only plant species that are specially adapted to defoliation can survive as weeds in turf. But mowing below the ideal height for the type of turfgrass can stress the turf and make it less competitive, and weed populations will increase.

2. Establish a fertility program based on type and timing.

Fertility programs can affect weed infestation, but this requires knowledge of both the turfgrass type and weeds to be controlled. The timing of fertilizer application should be made to favor the growth of the turf and work against the weeds.

3. Irrigate appropriately.

Irrigation is also an important part of a good weed control program. Applications to established, mature turf should be deep and infrequent. This practice allows the soil surface to dry between waterings, which can reduce the survival of germinating weeds.

Sometimes more is needed than good turfgrass maintenance practices. Chemical applications are sometimes needed to combat weed control. I’ll talk about the various types of herbicides available in a future blog post.