If you're in zone 5, you should not topdress with sand. Golf courses top dress the GREENS with sand. But not the fairways. But that's because the greens have bentgrass. You don't. You probably have a KBG, Rye, Fescue lawn. In addition, adding sand to clay doesn't improve things.

So here you are. Not sand. In fact, you want to topdress with regular, garden variety, topsoil. That topsoil will, because it's spread loosely, fall into the valleys, and tend to make the valleys a little less deep. Very nice. Not enough to kill the grass there, just a tad less deep. Which is, of course, better than making those valleys a tad more deep. So topdressing, with topsoil, tends to even things out.

You can help that process along, by core-aerating. The plugs are pulled from the lawn, and the plugs lay around on the surface, and decompose. Sure enough, the now-loose soil tends to fill in the valleys. Sure enough, the core being pulled tends to round off, or make less tall, the mountains in that lawn. Everything, in some small, but relentless degree, is moved toward the middle, presumably, 'optimal' grade.

Now lets talk about topdressing with compost. That adds organic material to the lawn, which is good for lawns that are short of organic material. For lawns that are not actually short of organic material, it's generally a waste of time compared to the effort, but yes, "it's always good to add organic material"....for the most part, that's true.

But organic material will rot away. And be gone. So if you're doing some more or less permanent 'leveling' of the lawn, use topsoil for topdress. If you want to add 'good stuff' to the lawn, topdress with compost.

When the turf is not especially looked on as maybe in the best shape after all the snow-melt goes and the lawn has been allowed to dry somewhat, we often see where the grass might be needing fixing.

We don't want to walk on a lawn that is still wet from snow-melt or early spring rains, depressions can result which might be hard to get out.

So we let the lawn dry a spell before we walk on it.
At that time we can inspect it for early weeds or bare areas where overseeding might be done.
We use a fan rake and put a little elbow grease into removing debris or loose material that would otherwise just turn brown in any case. This we get rid of and look to areas that need fixing.

Depressions often will rebound on their own...once the wetness dries out. If not, and you feel the need, dig up around the perimeter and insinuate some soil to puff it up.
Or, put some soil on top and let the grass grow up through it.

opdressing is the application of organic material to the surface of the turf. The purpose of topdressing is to build an ideal soil layer over the years and to fill in low areas that have developed. Topdressing may need to be done annually for several years if the underlying soil is particularly poor.

The ingredients of the topdressing mixture should be fairly dry; thorough mixing is essential before use. Ideally, topdressing of compost/topsoil mix of sand and peat moss, should go through a spreader----set high enough to let it go through.
If not this way, then the wheelbarrow full with a spade in hand to throw it across the area building up a layer of about `1/2" - 1".
No need to water it.

Sometimes it is OK to don a pair of golf shoes and go trekking across your lawn. The spikes will open up the surface for laying down the compost.

Overseeding a lawn is a good idea to try to fill in those areas where the turf might be shallow rooting or in poor shape.
Overseeding a whole lawn is often felt to be the thing to do in early to mid spring when the rains can give it so much added benefit.

Layering 1/2" to 1" every early spring for at least 4 - 5 years is an excellent way to build strength in turf to barrier anything that might attack it through the summer and fall.

The goodness of the topsoil has to be thought that it is giving something to the soil, something that grass will grow in it without difficulty. The topsoil/compost...should have richness of bacteria to give nutrition to the soil. Worms will then wish to stick around.

I generally agree with the posts above, but I don't think you want to top dress with more than 1/2 inch because more than that can smother the grass. Also, for clay soils, spike aeration can be counter productive, so if you're going to aerate, do a core aeration. Using golf shoes (or those strap on spike aerator soles) for clay soil can actually be counter productive. It does create holes, which is kind of good, but it compresses the soil around those holes, which is not such a good thing.

Topdressing can be quite expensive. If I bought peat and sand at the local home depot I'd probably be around $100 a cubic yard. 5 yds delivered of compost soil mix runs $130 (+) in my neck of the woods. A rule of thumb I've learned is to plan about a cubic yard per 1000 of lawn. If you can find just plain cheap dirt then fix your bumpy area(s). If you want an easy organic amendment then broadcast rabbit pellets at about 20 pounds per thousand and mulch mow.

Just find a local source for soil that delivers by the yard. Most places have topsoil -OR- more preferably a "compost blend" which is 50/50 topsoil and organic matter such as cow manure, chicken manure, etc.

Prices vary wildly by location but I just top dressed my lawn and it was $24/yard delivered. 12 yards spread by shovel and wheelbarrel in one day. My back sure feels it :)

Ouch, dude!! You have GOT to be a whole lot younger than me. I've done the wheelbarrow-shoveltossin-composting-topsoil-thing myself a few times, but NO way anymore. With my back I'd be in the hospital for sure. I did buy a spreader that I hope I can whip up some kind of topdressing mixture to apply and do the trick in some bumpy areas.

BTW, I've been told by knowledgeable folks that the type of sand you use is critical for top dressing, but it's not a bad thing. Mixing contractor-grade course sand (the most course you can find) and topsoil to topdress is okay with clay soils and won't turn the soil into concrete and actually opens the soil up to penetration and draining.

I am located just outside of Boston, MA. I too have some bumpy areas that I plan to level out this spring, and I have a soil test on its way out the door. I'm guessing the soil test is going to tell me I need more organic matter in the soil, and if so, I'll topress with a similar mixture as those recommended above.

Assuming that is true, my questions is in regards to the timing of the topdressing vs the timing of the application of Halts. I'm probably still a week to a few weeks away from seeing the forsythia bloom, and thus my Halts application.

What I'm wondering about is if the order of Halts vs topdressing has any implications? Obviously the Halts timing is more important, and needs to be applied at a specific time. But should I try to get the topdressing and top soil leveling dropped and spread prior to dropping the Halts in a few weeks? Do I need to give the topdressing time to get down into the soil before applying the Halts?

Or, on the flip side, if I drop the Halts at the recommended time, but then a week or two later add a topdressing, would that topdressing on top of the Halts have any impact on the effectiveness of the Halts?

Anyone have any thoughts on the proper timing in trying to get both Halts and a topdressing applied? I want to do both, but want to make sure I don't negate the Halts barrier. Thanks in advance.

Topdress first, then Halts. I'm assuming you're putting a fair clip of soil down. If it's a sugar-coat of soil, the timing really doesn't matter.

As you approach the half-inch mark, the roots of the weeds have time to mature before hitting the pre-M layer. I can't state definitively that they'll be mature enough by then to tolerate it, but why take chances and waste the application?

Worst-case, you can pre-M all the other areas of the lawn and then just have to deal with the full compliment of weeds in the old bumpy areas.

Makes sense. Yes, it will be a decent amount of soil in spots. Thanks for the prompt response. I will try to brave the elements and get the topdressing and soil down as soon as possible.

I top dressed my lawn early this year using the directions on Vcompost.com and I can't believe the results. I have a heavy clay soil that had a lot of small depressions in it and the grass was barely covering the ground. By the end of the season, the grass had filled in and the ground was softer and more level. I would definately recommend.

Here is a link that might be useful: top dressing

If you don't need to even out your yard, a topdressing of good quality compost does wonders.

I can get it in bulk at around $45 a yard here. A yard of compost properly applied covers 800 to 1000 sq feet of lawn area.

Not cheap, and alot of work as Jim notes unless you have a fairly high dollar spreader that will work with compost (the small ones won't).

I can't believe someone would register here and just a day or two later find a year-old thread that has to do with topdressing and quickly post such glowing endorsement of a product that nobody has ever heard of! That's almost too incredible to believe!!