Seasonal Guide: Overseeding your Lawn in Fall, Summer, and Winter

Seasonal Guide: Overseeding your Lawn in Fall, Summer, and Winter

Getting a perfect lawn is a goal shared by many homeowners, but maintaining grass health is so difficult that few lawns ever reach their full potential. Most people simply accept that they’ll have weedy and thin patches in their lawns no matter what they do.

It just takes too much work money to dig up and reseed large areas. This may be exactly how you feel about your lawn right now… But what if it didn’t have to be that way? What if you could improve those bad areas without a muddy, expensive reseeding process?

We have great news for you. You can actually add grass to your lawn through a renovation process called overseeding. If you’ve done it before, we’ve got some tips on how to improve. If it’s a new idea to you, you’ll love having the chance to make a more straightforward, more affordable upgrade.

As we’ve already noted, overseeding avoids the messy and expensive process of reseeding the entire lawn. An effective reseeding process involves using chemicals to kill existing weeds, tilling under the entire lawn, spreading seed, then mulching with straw and watering every day for months.

The result is a long period during which you cannot use your yard, the expense of renting or hiring equipment and the environmental impact of using herbicide. This is all with no guarantee of a yard that’s any better than what you already have. Your other option is purchasing and installing sod, which will give you an immediate lawn but will require a substantial financial commitment and a lot of time watering. But again, with no guarantee of success.

Overseeding a lawn with weeds is much safer and cheaper than reseeding or using herbicides to fight off the weeds. You can isolate the overseeded areas from foot traffic for a couple of weeks while continuing to use the unaffected areas.

You can overseed at almost any time of the year for a fraction of the cost of a complete reseeding. There is no risk of erosion from sudden downpours, and it’s faster, neater, and less expensive than starting from scratch.

The process of overseeding is not complicated. It merely involves clearing away obstructions, preparing the soil, adding grass seed, and then supporting that new seed appropriately with watering and mowing.

So What Happened To Your Lawn Anyway?

Wear and Tear

Before we get too far into the actual process of overseeding, let’s review why it’s necessary. How does a lawn reach a point where it’s weedy or thin and requires some repairs? There are several factors involved, but the most common ones are how we use and care for our lawns.

First, there’s foot traffic. Are there areas of the lawn where we or our pets frequently walk over again and again? Think about spaces where kids play, such as swing sets and trampolines. As they walk from one activity to another, they wear down the grass. In time, it is so thin that soil is exposed and weeds can move in.

Improper Mowing

Another big factor is mowing. Mowing at the correct height is essential. If you lower the deck too far, you can “scalp” the lawn. This allows sunlight to reach exposed soil where weed seeds are waiting to germinate, and it cuts off the critical energy stores in the lower portions of grass blades. Exposed dirt and weakened grass adds up to the perfect recipe for a diminished stand of grass–and a surging population of weeds.

The Lawn’s Beginning

One final element is the quality of the initial turf. If your lawn was not well-seeded, to begin with, it will never fill in correctly without some further intervention. Creating a thick, full lawn is not a one-step process. It requires the initial establishment with repairs made as needed, usually through reseeding.

When is the Best Time to Overseed?

The need for it often drives the timing of grass establishment. That is, if you have had to dig up your water line for repairs, it makes no difference what time of year it is. You should apply some grass seed right then, with the understanding that you’ll need to do more work to it later. When you have a choice in the matter, though, you’ll have better results in certain seasons.

Forget the Spring

Overseeding is a little different. Contrary to what many big-box stores would have you to think, overseeding in spring is not the ideal technique. Stores stock those items during the spring when everyone is ready to get outside and do something, but overseeding in spring often fails due to weed competition and rising average temperatures. Cool-season grasses like fescues perform much better when established in any season other than spring, so let’s review the other three.

Summer Overseeding

Summer can provide some excellent opportunities for overseeding. First, the existing grass has begun to slow its growth a little bit thanks to the hotter temperatures. That reduces the competition for new grass, giving it a chance to push through the canopy and grow. Weeds are also slowing down, reducing their impact on your new seedlings.

For summer overseeding, cut the grass shorter than usual. Cool-season species are dormant at this point anyway, so you won’t have a problem with that lower height. Apply a good lawn fertilizer, then rake and dethatch the area to remove obstructions between the seed and soil.

Remember, the seed will not germinate anywhere but in the soil, so any seed that fails to get through other material and hit the actual earth will never grow. You’ll also want to rake the exposed soil to create nooks and crannies where seeds can settle in and have good contact with the soil.

Next, you’ll toss your seed into those exposed areas and water it immediately. Keep the soil moist at all times until the seeds begin to germinate, then slowly reduce the frequency and depth of watering. If you water too much, the grass will become too shallow-rooted and will die if you stop watering.

This is an excellent time to mention how to overseed lawn without aerating. Homeowners often wonder how to overseed lawn without aerating, and if it’s a good idea. The answer is that you can overseed effectively without aerating. As we’ve just mentioned, it’s all about seed-to-soil contact. You can get good results without aerating by simply clearing and raking the soil before applying seed.

Fall Overseeding

Many homeowners find that overseeding in the fall works very well. Cool-season grasses germinate best when daily temperatures are gradually moving downward as they do in fall, so it can be a great time to overseed without the pressure of summer’s dry, hot conditions.

The techniques are very similar to summer. You’ll need to remove dead plant debris and prepare the soil mechanically (that is, with some raking) and with fertilizer. Aeration is optional, but it may not be practical in smaller spaces. If you do choose to do it, utilize a core aerator (which removes plugs of soil and distributes them on the soil surface) as opposed to a spike aerator (which creates holes by further compacting the soil around them).

Next, you’ll apply your seed and maintain a good watering program. This should be easier in most parts of the country due to increased precipitation and lower temperatures in fall, and if you live in an arid area where water rationing often prohibits irrigation, the fall can be an even better time for overseeding.

When you do your overseeding in the fall, you should know that the fertilizer will have two effects on your lawn. First, the new grass will stay greener than the existing grass, assuming your fertilizer is only in the overseeded areas. Second, that extra nitrogen will keep you mowing a little later into the fall or even into the early winter. On the plus side, though, the nitrogen will help create stronger roots for all the grass, enabling it to withstand dry conditions next year.

Winter Overseeding

Wintertime might be the last season that you think you would work for overseeding lawn with weeds, but it can be surprisingly effective.

First, the underlying causes of your poor lawn quality are not part of the equation in the winter. You aren’t mowing, the kids aren’t playing, and nobody is gathered around the grill. It’s the most restful time of year for your lawn, and that makes it an excellent opportunity to do some reseeding.

Second, your biggest enemies–the weeds–are also out of the picture. There are a few winter annual weeds that you might see, but they’ll vanish in warm weather without being a significant disruption. You’ll also have the added advantage of freezing and thawing, but we’ll come back to that shortly.

Reseeding a lawn in winter follows most of the other seasons pretty closely. You will need to get your mower warmed up and running to cut back on the obstructions, just as in summer and fall. Fertilization will play an important role as well.

What will be drastically different is the temperature, of course, and this can work to your advantage. Now is when freezing and thawing becomes relevant. We know that water expands when it freezes, so the frozen soil actually swells up and breaks apart. When it thaws, the soil is more aerated and is broken apart.

This is a perfect place for grass seeds! When they land on this broken-up soil, the further freezing and thawing just works the seeds deeper into the upper layer of soil, giving them a better chance to be surrounded by aerated soil and ready to germinate. Ready to germinate–but not actually germinating. That comes a little later, when temperatures warm up.

This approach is linked to a common agricultural practice known as “frost seeding.” Because pastures and hay fields can be muddy during optimum seeding times, farmers simply wait until the ground is frozen in late winter before driving tractors on their fields to spread seed. The existing crop is short thanks to grazing or the cutting of hay, and the seed remains dormant until temperatures are high enough for germination. In the meantime, the freeze/thaw cycle–and maybe even the compression of a snowfall or two–helps improve seed to soil contact. Sounds exactly like our plan for the yard!

The Big Picture

We’ve covered a lot of ground in our discussion of overseeding lawns. It’s a lot of information to absorb, so let’s sum it up with a few brief points.

1. Ordinary lawn use and maintenance can lead to thin or weedy areas.

2. It’s not necessary to reseed the entire lawn. Overseeding can correct the problem.

3. Spring is not the best season for this job, thanks to weed and weather issues.

4. Summer reseeding should allow for appropriate irrigation to get grass a good start.

5. Fall work could be your best choice, thanks to temperatures and precipitation.

6. Winter is not out of the question for reseeding, and it has some real benefits.

7. Whatever season you choose, you should cut your grass short, remove debris, and create a clear path to the soil for your seed.

8. New seed must be watered regardless of the season, and excessive watering can lead to weak, shallow roots.

Finally, don’t forget that despite your best efforts, you may not get an ideal stand from your overseeding. If you don’t, you can repeat it as often as needed until your lawn is full and healthy and ready to enjoy.

Sara Butler

Sara Butler has written scores of articles for Lawn Love -- everything from how to revive your dead lawn to how to start to lawn care tools every homeowner should have.