Why should you overseed your lawn? Nature loves diversity. On the flip side, it hates a monoculture. Our efforts, as 21st century American homeowners, to create a monoculture in our lawns goes directly against what nature wants. So, left to its own devices, your lawn is going to have a lot of diversity popping up. You might better know this diversity as "weeds." You don't want weeds (and you don't want to use herbicides)? Put down grass seed and over time, it will push out the weeds.
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Now you've got three options when facing the idea of lawn diversity:

1) Let it happen. Just unconditionally accept the diversity popping up in your lawn and love it as you would love a pasture growing wild in the countryside.

2) Drop chemical herbicides onto it. This is how golf courses and baseball fields roll. They put down chemical herbicides to both prevent and kill weeds. It's also how most Americans have been conditioned by the chemical lawn industry to approach their lawns. ("Weeds are BAD!") 

Or (our favorite choice) 3) Employ better lawn management practices. This means fertilizing with an organic fertilizer to get richer soil that turf actually wants to grow in. It means watering deeply a couple times a week to encourage deeper roots. It means setting your mower to its highest setting. And it means overseeding your lawn once, and maybe even twice, every single year. The importance of overseeding comes from the fact that weed seeds can find even the smallest gap in your lawn to germinate and establish roots. If you can put down grass seed before the weed seeds can germinate, you'll have grass growing there instead of something you don't want

Now, if you're going to opt for an organic lawn, you're going to have to accept Option 1 to a certain degree. Going organic, you should always expect (and even strive for), at minimum, 10% diversity in your lawn. Anything less than that just isn't healthy. If your lawn is more than 90% grass, you're opening yourself up to pest infestation, fungal infection, higher water bills, etc. But allowing some other stuff (clover, dandelions, violets, etc.) to find a home on your lawn will help keep things balanced and healthy. And telling yourself that some diversity is good for your lawn will even help you relax a bit and enjoy your lawn more, without the stress of striving for perfection weighing you down all summer.

We only recommend Option 2 (chemical herbicides) as a very last resort, and as an organic lawn company, we don't make specific chemical recommendations. But if your yard has become more than 50% weeds, and you're not happy with how it looks, we'd advise researching ways to start over by killing off what's there, and doing a complete re-seed or re-sod. If you've just got areas that are becoming infested with weeds (creeping charlie, for instance), at the very most, spot treat with an herbicide to kill off the stuff in that area, then re-seed. Again, these are last resorts. Pulling up weeds and overseeding is a much more sustainable option

But keeping weeds out isn't the only reason you should overseed. Does your lawn do better in certain parts of your yard than others? Maybe your shady backyard is thick and lush, while your sunny front yard is looking thin and brown during the hot summer months. Maybe the grass under the shade of a tree looks good, while the grass that doesn't receive shade looks terrible. If so, there's a chance your yard was initially seeded or sodded with the wrong type of grass. If a shade-loving grass was put down in an area that never gets shade, it's always going to struggle. Likewise, if a sun-loving grass gets put in a shady area, it's not going to thrive either. To fix this problem, you should overseed with a sun/shade grass seed mix.

What type of seed should you overseed with? We recommend using a sun/shade mix of grass seed. You can buy this type of mix in most stores. You can also buy it right on our website; this is what we've been recommending to our customers for years. Don't waste time trying to figure out if you need fescue or ryegrass or bluegrass. Just put down a sun/shade mix over your whole yard, and let nature sort it out. The shade-loving varieties will germinate in the shady areas, the sun-loving varieties will germinate in the sunny areas, and it will blend nicely with your lawn, giving you thick and beautiful turf..

We're also a big fans of Dutch white clover, and you should be too! You can put down some clover seed to fill in gaps where grass struggles to take hold. We sell that too.

We also work hard to keep things like seed affordable, so we've introduced a Seed Club. Once you pay the one-time membership fee, you're a member for life. Membership benefits include 50% off all of our seed for life, plus each year you buy seed from us, we'll give you a $100 discount on organic lawn fertilization. Click here to join!

How should you overseed? When overseeding your whole lawn you should follow these practices:

1. Mow your lawn the day of or the day before you overseed, and set your mower a notch or two lower than you normally mow at (not the lowest or second-lowest settings; you'll scalp your lawn). You should also either bag the clippings or rake up as many clippings as you can before putting the seed down. Now both of these practices (mowing shorter and removing the clippings) go against our normal recommendations, but there's a reason for it. Mowing the grass shorter than normal allows the seed to move down to the ground easier. It also allows you to go a little longer before you need to mow again so you're not sucking up the baby seedlings. Removing the clippings from the lawn before overseeding also helps the seed work their way down to the soil easier.

2. Using a push spreader or hand spreader, apply the grass seed mix just as you would fertilizer, in even rows, in a snaking motion across your lawn. It's best to do it on a calm day, when the grass is dry.

3. Water immediately for 20-30 minutes. Then for the next 14 days, water daily for about 10-15 minutes in the morning. If it's an especially warm day (80-degrees or more), you might want to do another 10-15 minute watering in the evening. Short daily waterings aren't normally recommended for your lawn, but think about these seeds as babies-- they need constant help from you until they grow roots and can find water on their own. Until these seeds germinate and grow to about 1/2-inch tall, you need to give them water every day. The soil must remain damp for the first two weeks, or the seeds won't sprout, and if the new seedlings have sprouted, they'll whither and die.

4. After about 14-20 days, feel free to mow again. This may mean letting your lawn get a little shaggier than it normally looks, but tough it out so that your new grass has a good chance to germinate, take root and begin its new life on your lawn. Basically, go as long as you can before mowing again.

But what if you've got larger patches in your lawn where grass just doesn't seem to do very well? You've tried seeding there before, only to have it not germinate or, if it does germinate, die off shortly after. Or maybe you've got areas where pets have killed the grass with their urine. This could mean you've got bad soil there. I'd recommend putting down some organic matter-- a compost/topsoil blend would be good. Once you've put down some organic matter on the area, you can overseed as recommended above. Boosting organic matter in your soil is key to growing a natural lawn.

When should you overseed? The short answer: either the spring or late-summer/early-fall. Late-summer/early-fall is ideal, however.

The longer explanation is that the grass that grows in Michigan is called "cool weather turf." That means it grows best in cool temps-- when daytime air temperatures are between 60 and 75 degrees. (I like to call this "open window weather," when you need neither your furnace nor air conditioner to make your house comfortable.) When temps drop below 60 for an extended period (late fall & winter), the grass goes dormant. When temps rise above 75 for an extended period (summer), the grass also goes dormant. Winter and summer are terrible times to put down grass seed in Michigan; the seeds just will not germinate.

So the ideal time is to put down seed in the late-August to mid-September. This is when the nighttime temperatures start dipping into the 50s again, which will help lower the soil temp to an optimal point for seed germination. Fall is also a great time to overseed because of the life cycle of annual lawn weeds. Annual lawn weeds germinate in the spring, drop their seed in the summer, and typically die off in the cooler temps of fall. If you can put down some grass seed in late summer or early fall, it'll have time to germinate before winter. This will help fill in gaps in your lawn, so next spring when those weed seeds are looking for a place to sprout, you'll already have grass growing there.

While fall is ideal for overseeding, you can also do it during the spring growing season (typically late April to late May). The competition for nutrients, water and space is just a bit more fierce in the spring.

Fall and spring are also the time to pull up weeds (or, if you absolutely must, put down an herbicide). If you're removing weeds from your lawn, you're typically opening up a space on your lawn as well. Now is the time to do the overseeding, so that grass will fill that gap instead of a new weed. Something is going to grow in that gap-- let's make it grass.

If you're going to core aerate your lawn, spring or fall are the times to do it. Over-seeding after a core-aeration is very important. You're opening up holes in your lawn, and if you don't want noxious weeds filling in those holes, you need to put down grass or clover seed. But typically, once you've been working on growing a natural lawn for a couple of years, core aeration isn't necessary anymore.

Where should you overseed your lawn? It doesn't take much space for a weed to sprout. Nature hates any empty space, so if there's a bit of soil showing, there's a good chance something's going to pop up there. You may not even see that empty space-- it could be as small as a nickel on your lawn-- but it's there. That's why it's important to overseed your entire lawn, every single year-- especially if you're growing an organic lawn. Cover it, from corner to corner, with a sun/shade mix of grass seed.

Follow the application instructions on the bag; don't put down more than the recommended rate (typically, for our sun/shade mix, 2.5 pounds for 1,000 square feet of turf). If you're patching a bare spot, don't cover the entire space with seed, sprinkle it like you're seasoning a steak. Remember that grass spreads and more isn't better when it comes to grass seed.