Why late August is the spot repair window, not September
The reason late summer beats spring for fixing bare spots is the split between warm days and cooling nights. The soil is still holding all the heat it stored through July, so seed germinates fast. Meanwhile the nights have started dropping, which means the seedlings that come up are not getting cooked every afternoon and then baked again at night. That combination is what makes late summer into early fall the strongest seeding window of the year.
The usual guidance is to seed while the soil temperature at 2 inches is falling through 60 to 70 degrees F, with air temperatures running 60 to 75 degrees F. In most cool season areas that lands in late August and runs into early fall. If you have a soil thermometer, use it. If you do not, the practical read is whether your nights have started cooling off and whether the lawn has stopped looking stressed by mid afternoon.
Seeding at the front of that window rather than the back matters more than people think. Every week you gain is another week of root growth before the first hard frost. A patch seeded in late August goes into winter with a real root system. The same patch seeded at the end of September goes in as thin grass with shallow roots, and it is the one that gets heaved and thinned out by freeze and thaw.
Two cautions before you buy anything. First, if your lawn is a warm season type like St. Augustine, this whole approach does not apply. Those grasses do not fill in well from seed, and bare spots are a sod or plug job rather than a soil and seed job. Second, if the area got weed and feed or a broadleaf weed killer recently, seed will not establish in it. The standard advice is to wait five to six weeks after application before seeding. Trying to beat that wait is how people end up buying seed twice.
Walk the lawn first and sort patches by depth
Before you order a single yard of anything, walk the yard with a rake and sort the bare areas into two piles in your head. Almost every homeowner has two genuinely different problems sitting in the same lawn, and they need different amounts of soil. Getting the sort right is what keeps the order from being wildly wrong in either direction.
Shallow dead patches
A shallow patch means the grade is fine. The ground is flat and level with everything around it, and the grass is simply gone. Drought stress from a hot stretch, a dog spot, a worn path where everyone cuts the corner, or a fungus patch that browned out in July and never came back. Put a straightedge across it and it sits flush with the lawn.
These need a thin layer of soil to hold moisture and press seed into contact with the ground. They do not need fill. If you dump 3 inches of soil on a flat dead patch, you have just built a mound that scalps under the mower next spring.
Actual low spots and divots
Low spots are the sunken areas where water stands for a while after rain. Also in this category are old divots, settled utility trenches, the depression where a stump got ground out two years ago, and the dip along a walkway edge. Step on them and your foot sits lower than the surrounding turf.
These need real fill volume to come back up to grade, and that volume is where nearly all of your soil order is going to go. Measure them. Length, width, and roughly how many inches down at the deepest point.
Our topsoil calculator does this math for you. Enter the area and depth and it returns cubic yards to order.
One more thing that matters more than any soil decision. Figure out why the patch appeared. Shade that is too deep for turf, compaction along a route everyone walks, or a downspout dumping onto one corner of the yard will produce the exact same bare spot next August no matter how good the soil is. Fix the cause first where you can. Then, in each patch you are going to seed, rake out the dead thatch and debris so you are putting fresh soil onto actual soil rather than onto a mat of dead grass.
Screened topsoil or a topsoil compost blend
This is the decision the general lawn repair articles skip, and it is the one you actually have to make at the order screen.
Screened topsoil is locally stripped and screened native soil. That is worth sitting with for a second, because it means the product is regional. Topsoil in one state can be a heavy reddish clay loam and topsoil two states over can be a gray brown sandy loam, and both are legitimately topsoil. Color and texture vary by region. If you have seen a neighbor's delivery and it looked different from what you expected, that is normal.
The honest description is that screened topsoil is a base, not a finished growing medium. It has real structure and mineral content. What it does not have much of on its own is organic matter or nutrition. That is not a knock on it. It is exactly what you want when the job is volume.
So for filling low spots, divots, and settled trenches, screened topsoil is the right call. It is the cheaper material, and it will not keep shrinking on you the way a heavy organic mix does as that organic matter breaks down over a year or two. You fill a depression with it, it stays filled.
A topsoil compost blend is the better material for the thin surface layer. The extra organic matter holds moisture noticeably better through the first two weeks after seeding, and those two weeks are where homeowners actually lose seed. A quarter inch of dry mineral soil on a windy sunny day in early September gives up its moisture fast. The same quarter inch with compost worked into it stays damp longer between waterings, which forgives the afternoon you forgot.
If you have both problems, and most people do, the practical answer is a hybrid. Fill the depressions with straight screened topsoil to within about an inch of grade. Then finish the top inch of every patch, deep and shallow alike, with the blend. You buy the cheap material in volume and the richer material in the small amount where it earns its keep.
What does not work is straight compost as a patch fill. It holds water beautifully, which is why it is tempting, but it settles. A pure compost layer dropped into a sunken spot will be a sunken spot again by spring, and you will have done the work twice.
How deep to fill each patch
There are two different depth answers here and mixing them up is the single most common mistake in bare spot repair.
Over seed in a shallow patch, go about a quarter inch. That is it. Just enough soil to hold moisture around the seed and press it into contact with the ground underneath. Grass seed is small and it does not have much stored energy. Bury it deeper than a quarter inch and germination falls off, because the seedling runs out of fuel before it reaches light.
For low spots and regrading, topsoil goes in at a typical install depth of 3 to 6 inches. Before you fill, loosen the existing soil in the bottom of the depression with a fork or a rake. That step lets the new soil knit into the old rather than sitting on top of it as a slab with a hard boundary underneath.
Then there is the step almost everyone skips. Feather the edges. Where your new soil meets the existing lawn, taper it rather than leaving a hard shoulder. A square edged patch settles into a visible ring by spring, and that ring is what makes a repair look like a repair for the next two years. Rake each patch level with the surrounding lawn and firm it lightly. Loose, smooth, level soil is what lets new seedlings push roots down.
If a low spot needs more than about 4 inches of fill, split it into two passes a couple of weeks apart. Fill most of the way, water it or let it take a rain, let the lower layer settle, then top it off and seed. Filling deep in one shot and seeding the same afternoon usually means the whole patch drops an inch by November and you are back where you started.
Running the numbers for a few hundred square feet
Working from our coverage figures
Our topsoil runs 1.2 tons per cubic yard, and one cubic yard covers about 108 square feet at 3 inches deep. Those two figures do most of the work.
To scale for thinner layers, just divide. At 1 inch deep, one cubic yard covers roughly three times 108, so about 324 square feet. At a quarter inch, it goes about four times further than that again, which is why shallow patch work uses a surprisingly small amount of soil. A single yard of material dusted a quarter inch deep covers a large area, far more than most people have in scattered bare spots.
A worked example
Say you walked the yard and came back with two numbers. Roughly 300 square feet of scattered shallow bare patches that just need a quarter inch dusting, plus two low spots that together add up to 40 square feet and need 4 inches of fill.
The dusting first. One cubic yard covers 108 square feet at 3 inches. At a quarter inch, that yard stretches twelve times as far, so about 1,296 square feet. You need 300 of that, so 300 divided by 1,296 is under a quarter of a cubic yard.
Now the low spots. One cubic yard covers 108 square feet at 3 inches, so at 4 inches it covers three quarters of that, about 81 square feet. You need 40 square feet at that depth, so 40 divided by 81 is right around half a cubic yard.
Add them and you are at roughly three quarters of a cubic yard total. Notice what happened. The low spots are 40 square feet and the shallow patches are 300 square feet, but the 40 square feet ate about twice as much soil. Depth drives volume, not area.
That is the real takeaway. Patch area is a bad predictor of order size. Measure your depressions separately from your flat dead spots and estimate them as two different numbers, then add. If you want to check your own figures, our soil calculator runs the same math.
Two practical notes on ordering. Bulk soil is noticeably cheaper per unit than bagged once you are past a handful of bags, and bags get heavy fast when the material runs 1.2 tons per cubic yard. And round up rather than down. Leftover topsoil has an obvious home in garden beds, along a fence line, or behind a wall, and a second trip out for one more bag on the day you are trying to get seed down is worse than a small pile left over.
Seeding and the first two weeks
Order of operations, in the order you actually do it. Clear the dead material out of the patch. Loosen the soil underneath. Fill and grade if it is a low spot. Seed. Add the light soil cover. Then water.
Seed to soil contact is the whole game and everything else is detail. After you broadcast seed, rake it in lightly so it settles into the surface rather than sitting on top of it, then firm the area. The back of a rake works. So does laying a board down and walking on it. Seed lying loose on top of soil either blows off, washes off, or gets eaten.
Watering is where most patches are won or lost. Light and often beats deep and rare during germination. The standard pattern is early morning and again in the evening until the seed comes up. What you are protecting is the top quarter inch. It has to stay damp. Once it dries out hard, germinating seed dies and does not restart. After the grass is up and has some height, you can start backing off to less frequent, deeper watering.
Keep foot traffic off the new patches, and keep the mower off them until the new grass has been through a couple of mowings of the surrounding lawn. When you do mow, make sure the blade is sharp. A dull blade pulls young grass out of soft soil by the roots.
Last one. No weed control in the patch through the rest of the fall. New seedlings will not tolerate it, and the weeds coming up alongside your new grass are far less of a problem than losing the seeding. Deal with weeds next season once the grass has a real root system.
How We Started
We started Mulch Mound because we got tired of the hassle that came with buying landscaping materials. The options were either loading bags into your car at a garden center or calling around to local suppliers, trying to figure out pricing, minimums, and delivery schedules. Neither option felt convenient or transparent.
Three of us – Alec, Mo, and Tyler – decided there had to be a better way. Alec and Tyler got their start back in 2013 running a landscaping business during college, moving mulch and mowing lawns to pay tuition. That experience taught them how frustrating it was to source materials, and years later, that frustration turned into Mulch Mound.
We focus on making it simple to get mulch, stone, and soil delivered directly to your home. Order online, pick your delivery date, and we handle the rest. No loading bags. No calling multiple suppliers. No wondering if you bought enough or paid a fair price.
We work with quality local suppliers in the areas we serve and aim to be straightforward about what we offer and what it costs. Landscaping is hard work. Buying the materials for it shouldn't be.
Frequently asked questions
Can I put topsoil directly on top of existing lawn soil, or do I need to loosen it first?
Loosen it first. When fresh soil goes down on hard untouched ground, the interface between the two acts like a boundary. Roots reach it and stall rather than pushing through, so you end up with grass rooted only in the thin new layer. That layer then dries out fast, because water that soaks into it cannot move down into the compacted soil below and instead sits and evaporates.
Scratching or forking the base only takes a few minutes per patch, and on a compacted walking path it is arguably the most valuable thing you do all day. If the ground is so hard the fork will not go in, water it the day before and try again.
Is late August too early to seed bare spots, or should I wait until September?
It depends on where you are more than on the calendar. A yard in the upper Midwest or northern New England is usually already in the window by the last week of August. A cool season lawn in the upper South or the lower Midwest often is not, because the soil is still running hot and the nights have not broken yet.
The honest test is your nights, not the date. If evenings have started cooling off and the lawn is no longer visibly stressed by late afternoon, go. If you are still getting warm nights and the turf is struggling every day, give it another week or two. Seeding into a heat wave wastes seed no matter what the calendar says.
What if my bare spots are under a maple or along a fence line in heavy shade?
No soil blend fixes a light problem. You can put down perfect soil, perfect seed, and perfect watering, and grass that does not get enough light will germinate, look promising for a month, and thin out anyway. Dense shallow rooted trees also compete hard for water right at the surface, which is exactly where your new seedlings are living.
You have three real options. Use a shade tolerant seed type and accept thinner turf. Thin some lower branches to get more light to the ground, if that is possible without hurting the tree. Or stop fighting it and convert that area to a mulched bed or a shade planting. That last option is often the one that finally ends the annual repair cycle under a big maple.
How much topsoil for a few hundred square feet?
Less than people expect if the patches are flat, and more than people expect if any of them are sunken. For a quick check, one cubic yard covers about 108 square feet at 3 inches, so 200 square feet of true flat patches at a quarter inch dusting works out to well under a quarter of a cubic yard. But a single sunken area only 10 feet by 6 feet that needs 6 inches of fill is more than a full cubic yard on its own.
Measure the depressions first. They decide your order. The flat patches are close to a rounding error by comparison.