GardenLine | Yard & Garden | Getting a Head Start: Lawn Cre for Late Winter and Early Spring

The writer is a past professor of horticulture with the Department of Horticulture Science. This column is offered as an extension service by the Division of Extension and Community Relations and the Department of Horticulture Science, University of Saskatchewan.

We continue to receive many inquiries at Garden Line about care of lawns. In response to requests, we are re-running articles on lawn care, maintenance and fertilization that last appeared in 1987.

Green lawns evoke images of summer, but much can be done during late winter and early spring to give lawns a head start for the active growing season. For example, consider pathways. In winter it is wise to prevent pathways across lawns. This is particularly important in late winter, when tramped, slushy snow can cause severe crown damage to the grass. Although very hardy, with the ability to withstand our dry, cold conditions, turfgrass can be killed when the crowns are surrounded by ice-cold water.

Here are some other things you can do to help get your lawn off to a good start.

Snow Mould Diseases

Snow mould fungal diseases cause less trouble when snow melts relatively rapidly and at an even rate. Significant damage from snow mould can be expected when snow is deep and melts slowly, particularly when a receding snow drift remains stationary for a few days. Snow mould diseases will often grow rapidly on the honeycombed face of a stationary drift, causing severe damage to the grass.

There is no chemical licensed for home use to control snow mould diseases, so other preventive measures must be taken. In late winter and early spring, break up large drifts and snow piled during winter shovelling and spread the snow over bare patches of the lawn. Continue this operation periodically until the snow has disappeared. This practice should help to break up the fungal growth (mycelium web) and minimize damage from snow mould diseases.

Raking and Thatch Removal

After the snow has melted, the lawn can be raked to clear off debris accumulated during the winter. This should be done quickly because as little traffic as possible should be on the saturated lawn at this time.

A more thorough raking to remove thatch can be done when the lawn is dry. Thatch shows up as a light brown layer of decaying vegetation, mostly old leaf sheaths and clippings from previous years. The clippings serve as an effective mulch, but too much thatch can adversely affect a lawn. Grass develops fine feeding roots in the thatch layer, which is rich in organic matter and contains many humid air cells that promote root growth.

Thatch therefore encourages shallow rooting, which makes turf management difficult during the dry periods. The shallow roots cannot reach the reserve moisture in the soil, and so the lawn tends to dry out quickly. The dried-out thatch is difficult to moisten. It forms a water-resistant layer that prevents water from reaching the soil.

Before raking, determine the amount of thatch present by slicing down with a spade and examining the cross section. If the thatch layer is greater than 1 to 1-1/4 cm, the excess thatch should be removed. Rake the lawn with a dethatching rake (solid construction with v-shaped teeth). This will bring the less decomposed vegetation to the surface so that it can be removed. If a thick layer of thatch has developed, it may be wise to rent a power rake and vacuum for this operation.

Power raking need not be done annually -- every third or fourth year will suffice. A word of caution. Power raking should only be carried out on healthy, solid turf. It is too rigorous a treatment for turf damaged by winter diseases. Whole patches will lift, and this will severely delay recovery.

Mowing

To promote early greening of the lawn, cut off the dead leaf blades when the lawn is dry enough to mow. Adjust the lawn mover to the lowest setting. The clippings should be raked off and removed.

After the initial mowing, mow the lawn as necessary to a height of about 4 cm. No more than one-third of the leaf blade should be removed in any mowing. Clippings of this size can be left on the lawn. The mower blades, whether rotary or reel, should always be sharp to avoid torn ends on the grass. The brown, ragged ends are unsightly, and grass blades with torn ends tend to lose moisture more rapidly than intact blades.

Fertilizer

Many people are anxious to get at their fertilizer program in order to have a green lawn early in the spring. In most years, however, it is not advisable to apply fertilizer before mid-May. Nitrogen carried over in the plant from the previous year should be sufficient to produce greening in the early spring. We will devote an article in this series to fertilization before mid-May.

Aeration

The main purpose of aeration is to reduce compaction so that moisture and air can be absorbed into the soil. There is little need for aeration if a home lawn has been well prepared and does not have a traffic problem. Aeration should be considered when stress patterns appear in the lawn from poor water penetration or wear. In contrast to home lawns, aeration is a routine practice on golf courses, where there is a great deal of compaction due to the heavy traffic.

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Sustainable horticultural information, offered free of charge to the public with the support of the University of Saskatchewan Extension Division, the Department of Plant Sciences and the Provincial Government.