When the trees turn into a blaze of color, something comes out of hiding. It has hibernated behind your lawn mower for the last three seasons, but now it’s hungry to take action and help you winterize your lawn. It’s your leaf rake.
But do you really need to rake that layer of leaves off your lawn and go through the steps of winterizing? Or would it be best for Mother Nature to take charge, allowing the leaves to compost into the grass and help boost its growth in the spring?
“Homeowners don’t necessarily need to rake, but they should mow the lawn and leaves to make clippings and leaf particles small enough to break down in the soil,” says Carrie Engel, greenhouse manager at Valley View Farms Garden Center and Nursery in Cockeysville, Md. “Fall is also the single best time to feed a lawn with fertilizer, and the best time to reseed. The soil is still warm, but the cooler air and chance for rainfall creates nice conditions for the lawn. Because lawns are not ‘natural’, they do require some care and feeding.”
Low temperatures can kill both cool and warm-season grasses. The plant does become semi-dormant in cold weather, but it can suffer damage by ice crystallization. The grass blades and roots are more sensitive to the damage, but as long as the meristematic regions of the plant (the growing points of the plant that produces stems, leaves, or flowers) are not injured, the lawn can recover the next year.
Grass types that recover well from low temperatures:
- Rough Bluegrass
- Creeping Bentgrass
- Kentucky Bluegrass
- Canada Bluegrass
- Colonial Bentgrass
Grass varieties that do not fare well from low temperatures:
- Perennial ryegrass
- Manita grass
- Bermuda grass
- Italian ryegrass
- Centipede grass
- St. Augustine grass
Steps to preparing your lawn for winter
Once your kids have jumped in the piles of crunchy leaves and kicked the rest around the lawn, you have to decide if raking is and discarding the leaves is really necessary. The grass underneath is still green and is trying to use as much light as possible to prepare for the winter months. They, like bears, pull in as many nutrients as possible before hibernating over the winter. Removing the leaves allows light, water, and air to get to the plant. Leaves tend to pack down and do not make an ideal mulch for perennial flower beds, either.
But, says Engel, if you mow and mulch into tiny compostable bits, the leaves can help your lawn. “The leaf matter adds organic matter to the soil; that is always a good thing. If there are a lot of leaves, and you are planning to reseed over the fall, move the shredded leaves into the garden to add good, organic matter there.”
Check the pH levels
Before adding any fertilizers to your lawn, have your soil tested at your local extension service, or test it yourself with a home tester.
Your lawn can begin to thin out after a summer’s use, so checking soil pH levels is important to maintain healthy grass.
Remove any weeds or invasive plants.
If you fertilize, the additional nitrogen can increase weed growth. Those pesky weeds will wait for a chance to take over thinning or weak areas of the yard, so attend to them now before the snow arrives. Take advantage of the late rains and pull weeds out by the root while the ground is soft.
Lawns grown on sandy soil or in areas with heavy rainfall may need potassium applications. Soil tests will tell you if you need to fertilize. If you have adequate potassium levels, you probably don’t need to break out the spreader and apply lawn fertilizer.
The garden stores fill with winterizer fertilizers as early as late summer. Most of these products contain high doses of nitrogen. However, grasses are different, and some may not appreciate this feeding. Warm-season lawns could be damaged by too much fall fertilizing. The added nitrogen could promote shoot growth while the plant is trying to slow its metabolism, depleting carbohydrates and causing stress. But cool-season lawns might enjoy a fertilizer containing nitrogen and potassium.
Putting too much fertilizer on a lawn could upset the balance of nutrients that your lawn may need, or cause burning. If you are using granular fertilizer, make sure you apply it to dry grass to avoid the problem of salt burn. Again, follow directions based on your soil test results to grow a healthy lawn. “Organic lawn foods are available in garden centers for those that are concerned about synthetic fertilizers,” says Engel.
Soil temperature over the winter can affect grass health and recovery more than the temperature of the air. The crown tissues of the plant need to be protected to allow them to begin the new growth process in the spring. A compacted soil stays colder than a well-drained or looser soil, so you can help start a lush lawn by aerating the soil in the fall.
“Compaction takes its toll on a lawn. Enlisting a lawn service or renting an aerator is a great way to improve the root zone of the grasses in the lawn,” says Engel.
Raise the mower deck and cut high in the fall, leaving longer blades to protect grass structure and reduce direct temperature kill of the plant. Mowing at a length of 2 to 3 inches is recommended.
Once your grass goes dormant, stop mowing until spring. Mowing the lawn in winter, especially when there’s snow or frost on the ground, could do irreparable damage to your grass.
Overseed for Spring
In the fall, the soil is still warm from summer. The temperate autumn days and cool weather at night can encourage germination and establishment of grass seed. So now is an ideal time to broadcast cool-season grasses. Cool-season grass seed will germinate best in soil temperatures between 50 and 65 degrees – a soil thermometer will help you determine if your soil is within those guidelines.
Plant cool-season grass seed about 4 to 6 weeks before the scheduled frost date. Contact your local extension agent for ideal times in your area. “Use quality seed recommended for your area,” Engel suggests. “Most of us in the mid-Atlantic and Northeast do best with turf-type tall fescue grass seed mixes, not bluegrass.
Engel suggests leaving the seedheads of daisy-shaped flowers in the beds over winter. “Their seed heads are very attractive to our feathered friends. Add organic matter (including the shredded leaves you have raked from your lawn!) to the beds as a top dressing. Keep the stems and crowns of perennials, trees and shrubs free from mulch.”