Most of us have now survived our first threat of fall frost, but there are cooler nights forecast and the days are becoming appreciably shorter. But it’s not too late to take some steps to help your lawn survive the coming inclement weather.
1. Watering – If you haven’t already done so, now is the time to let your grass stop growing, so minimal watering if any. Some lawns still look lush and green, and they definitely need to cease producing soft leaf tissue that is very susceptible to frost. Many lawns are already brown, having endured such a warm dry summer. Once the leaves have begun to fall, give the lawn a thorough soaking prior to winter.
2. Cutting height – The above ground parts of the grass dictate the depth of the root system. The taller the grass, the greater its photosynthetic surface, and thus the deeper its roots. A well-developed, deep root system is what your lawn needs to survive the cold of winter. Raise your cutter height to 3 inches (7-8 cm) if you are currently cutting shorter than this. One pass in the next few weeks is all that’s required.
3. Fertilizer application – I am “old school” and was taught not to fertilize the lawn after mid-August. In particular, do not apply any nitrogen as fall approaches, as this will encourage green, lush growth - definitely not a good idea heading into fall. Nowadays, it is common to be advised to “winterize your lawn” by the addition of fertilizers that are high in potassium, which encourages strong root growth. “Winterizer” fertilizers contain lower levels of nitrogen than early-season fertilizers (for example, an N-P-K of 15-0-30), and are designed to help your plants through the winter. If you decide to use them, they should be applied evenly at the recommended rate. Do not over-fertilize as this can damage the lawn. However, most prairie soils already have adequate amounts of potassium and if you’ve been feeding your lawn with balanced nutrients all season, there should still be plenty of potassium available in the fall.
4. Re-Seeding – Fall may also be a good time to deal with bare lawn patches. Rake to loosen the thatch and then reseed with a grass seed mixture suitable for prairie conditions, covering with a light layer of potting soil or compost. This is something often better done in the spring, but is worth trying in the fall if the patches are not too extensive. Bare patches caused by dog urine should be well-watered before reseeding, to dilute the urine which is high in nitrogen.
5. Removal of leaf litter – Again, there are conflicting viewpoints on this. One recommendation is to rake off the leaves and any thatch so that the grass is not covered by a damp layer of leaves the following spring. Their removal allows water and nutrients to reach the roots more easily. Raking up piles of leaves can be a fun family activity on a sunny fall day, with the kids enjoying jumping into the piles. Halloween bags of leaves are also useful as decorations for Oct. 31. The leaves you have removed are a valuable addition to compost and can also be used to mulch roses and other tender perennials. Altenatively, you can leave the leaf litter on the grass as a protective layer. In this case the leaves should be pulverized with a mulching mower so the layer is not too dense. The leaves will break down and the newly emerging grass in spring will be able to poke right through it. If you run out of time before snowfall and whole leaves remain on the lawn through the winter, they can be raked off in spring to give the grass an earlier start and to discourage snow mould.
6. Removal of perennial weeds – Perennial weeds, such as dandelions, will compete with the grasses in your lawn for space, moisture and nutrients. Fall is a good time to get rid of these weeds.
Jill Thomson is a plant disease specialist (retired) who enjoys gardening in Saskatoon with her family, including the dogs.
This column is provided courtesy of the Saskatchewan Perennial Society (SPS; firstname.lastname@example.org). Check our website (www.saskperennial.ca) or Facebook page (www.facebook.com/saskperennial) for a list of upcoming gardening events.