Category Archives: Seed

Managing Pesticide-free Home Lawns: Post-renovation cultural practices

Spring roto-tilling resulted in annual weed infestation—one month after renovation—that were eventually mown out of the sward by August. Photo courtesy Kathleen Dodson


By Kathleen Dodson, MSc.

The effectiveness of the cultural practices implemented in this study varied between years. For instance, spring power-raking effectively reduced/maintained low weed populations when moisture availability was ample in 2011. The spring of 2011 was a more typical spring where there were reliable rains during the month of May, which was during the recovery period of the turf swards treated with power-raking. However, May 2012 was very hot and dry, causing rather different results.

Spring power-raking resulted in the lowest turfgrass coverage and the highest bare-ground coverage. This suggests the drought conditions during May after the power-raking was performed resulted in poor turfgrass recovery. Although the plots received weekly supplemental irrigation of 25 mm (1 in.) of water, the hot, dry atmospheric conditions were not favourable for cool-season turfgrass growth.

Broadcast overseeding in the spring and fall did not have an effect on the weed population of the sward, but did increase turfgrass density. This may be due to the method of overseeding the researchers at GTI chose. Broadcast overseeding has been shown to work well in athletic field environments where the athletes are ‘cleating-in’ the seed to ensure seed-soil contact. However, in the home lawn environment, there was very limited traffic. This lack of traffic may not have ensured a good establishment rate of the seed added into the sward.

Future studies into the best method of overseeding in home lawns would be useful. However, results showed an increase in turfgrass density, which suggests at least some of the seed added successfully germinated and established. Previous work done by Evan Elford and colleagues found overseeding did not affect the weed percentage in the field, but did decrease the weed’s overall influence in the stand because the weed sizes were smaller due to increased competition from more turf coverage.

Read the full article: Managing Pesticide-free Home Lawns

The Increasing Need for Organic Matter: Landscape mulches

Shredded pine mulch installed in a new parking lot tree island. Photo courtesy Gro-Bark


By Chelsea Stroud, B.Sc. Agr. (Hort.), GRP

Landscape mulch conserves moisture by acting as a physical barrier as it slows down evaporation and wind desiccation. Aside from its moisture-holding properties, mulch suppresses weeds and provides nutrients as it adds organic matter to the soil over time. There are many types of mulches used, including:
● shredded pine bark;
● hardwood bark;
● cedar bark;
● composted pine bark;
● wood chip; and
● compost.

If installed at 80 to 100 mm (3 to 4 in.) deep, shredded bark mulches have greater moisture retention than wood chip mulches.

Read the full article: The Increasing Need for Organic Matter

Managing Pesticide-free Home Lawns: The experiment

The percentage of turfgrass and weed coverage. Least square (LS) means were calculated using analysis of covariance (ANCOVA) where the pre-treatment population percentages were used as the covariate to correct for variance in species population between plots before treatments. Bars with different letters are shown to be different at the P<0.01. Image courtesy Kathleen Dodson[/caption] By Kathleen Dodson, MSc.

An examination of cultivation practices in a home lawn environment for the purposes of weed control was conducted at Ontario’s Guelph Turfgrass Institute (GTI). The two objectives of the study were to evaluate:
● four methods of turfgrass renovation in a context of a herbicide-free environment; and
● post-renovation cultural practices and their effects on sward composition.

Research was conducted on four separate plot locations at the GTI—two having fall renovations and two with spring renovations. The research plots were arranged in a randomized complete block 4 x 5 x 2 factorial design with four replications. The research plots were renovated on May 26 and September 28 of 2010, and June 3 and September 26 of 2011. Visual ratings of the percentage of turfgrass coverage and weed populations were taken monthly, and population point quadrat counts were taken in June and September of 2010, 2011, and 2012.

Read the full article: Managing Pesticide-free Home Lawns

Managing Pesticide-free Home Lawns: Turfgrass renovation

A fall renovation picture taken on September 28, 2011 before the plots were seeded, while the site was still being prepared. Photo courtesy Kathleen Dodson


By Kathleen Dodson, MSc.

Renovation is a cultural practice used to increase turfgrass population in weedy turfgrass stands. Turfgrass renovation typically occurs when there is less than 40 to 50 per cent desirable turfgrass coverage. Renovation is different than establishment because it is assumed the soil grading is sound, and you are just going to change the plant population through reseeding. Before the implementation of the pesticide ban, the steps for renovation included:
1. Chemical kill of old turf.
2. Tillage (roto-tilling for a complete renovation/reestablishment or power-raking/core cultivation for a renovation).
3. Improve soil.
4. Reseed.
5. Two weeks of post-reestablishment selective herbicide.

Without using herbicides, steps one and five cannot be performed, suggesting a need to investigate chemical-free home lawn renovations. Most literature suggests timing the renovation for late summer to early fall, so there is adequate moisture and reduced competition from annual weed establishment. However, annual weeds cannot tolerate the practice of regular mowing, so perhaps changing the renovation time to the spring may actually reduce the overall amount of weeds in the newly renovated lawn over time.

Read the full article: Managing Pesticide-free Home Lawns

The Increasing Need for Organic Matter

Photo courtesy Sean James


By Chelsea Stroud, B.Sc. Agr. (Hort.), GRP

Unexpected weather has become the norm over the past decade, and last summer was no exception. In 2012, Environment Canada reported parts of Ontario saw up to nine days above 30 C (86 F) in June, and areas across the country showed temperatures that were among the warmest 10 summers on record.

In terms of precipitation, Environment Canada reported Canada as a whole experienced wetter than normal conditions last summer. Although in Southern Ontario, precipitation was down approximately 10 to 20 per cent from historical norms.

As climate continues to be out of control, we are becoming more aware of our depleting natural resources. Years ago, Canadians would turn the air-conditioning up on warm days and water turf and gardens excessively throughout drought. Now, we know our fresh water is precious and needs to be conserved and protected. The question is, how do we maintain healthy plants with less water and warmer temperatures?

Read the full article: The Increasing Need for Organic Matter