None. :-)

Plug aeration is occasionally useful and might benefit you once, but it doesn't reduce soil compaction over time. Whereas it does inject oxygen into layers where it shouldn't be, and it does it all at once, which is a biological mistake.

You might find the shampoo remedy more useful, although it certainly isn't an instant solution. Similarly, organic feedings will transform your soil over time.

However, plug aeration can be useful to lower a high spot, or to reduce severe thatch (by throwing soil over the top, which keeps it damp and helps it decay). In the thatch case, organic feeding does the same thing and keeps it from building up in the future.

Was there a specific reason you wanted to plug aerate? There may be a better solution for your issue.

I agree and disagree with morpheuspa. Aeration can pay benefits in short-term turf recovery and for initial soil amendment, but in the long run you want low maintenance.
Aeration can be very helpful for quickly amending and loosening the soil. Aeration followed by fertilizing, adding gypsum or OM, etc. can help bring turf/soil up to speed quickly. It is hard work and makes a mess. Both undesirable features. Initial aeration in conjunction with following the more "organic" and "best practices" advice that you will find here will result in healthy turf and soil and should eliminate the need for future mechanical intervention. As you will eventually no longer need (or want) to aerate, buying a new powered aerator will involve a high initial cost followed by depreciation. Renting an aerator 2-3 times a year for 2-3 years is cheaper. If you have a tractor, a Brinley plugger should do. Anything else is going to eventually be an expensive waste of storage space.

OK now I am very sure I am totally out of my league. Here is the deal I am the estate gardener on a big farm in Northern Virginia. I hired a lawn company to fix a much neglected lawn, they were terrible (long story) I fired them and told the owners I would try to fix the lawn GULP!! There is tons of crabgrass, weeds and the soil is very compact good ol' Virginia clay. I thought an aerator would help. Now I am not sure... Maybe I will rent an aerator. Can you guys point me in the direction of a good book or article to read. The owners are not lawn purest they are not looking for that golf course look they just want green and healthy. 80% of the lawn is irrigated. What is the shampoo remedy? What is OM? Thanks everyone

Crabgrass will die later this fall. To prevent it next year (you will have plenty of crabgrass seeds waiting to germinate in the spring), use a pre-emergent when the forsythia blooms (and a second treatment about six weeks later or when the instructions tell you). OM is organic matter. You should mulch mow the grass instead of bagging it. Mulch mow as many leaves as you can find in the fall. If you have an inexpensive source of compost, you could spread compost. All of that is organic matter. Do a search on here to find the details on shampoo. It acts as a surfactant to allow better penetration of water, which encourages fungi and soil bacteria, which will help your soil. You should get a soil test. Your calcium and magnesium balance may be off and that could be contributing to the "hardness" of the soil. Aeration is useful on certain occasions but it has downsides. It brings up weed seeds which otherwise would never have seen the light of day.

Unfortunately I've never seen a lawn care book that I was happy with. The problem with them is some guy in Iowa will go on and on about how to grow grass and never even consider that grass grows outside his neighborhood. What is good in Iowa is not good in Florida. Between the writing and the editing, the author comes across as being ignorant about lawns - at least in my opinion.

You're in Northern VA, so that is important to know for proper help. The good news is lawn care is just a little bit tricky, but the tricks are easy to learn. Then it's really easy. Water, mow, and fertilize! How many tricks can there be, right?

Let's just forget about core aeration for now and look at what you have and where you want to go.

How big is the area? and what equipment do you have at your disposal?

The soil is hard, so try treating with shampoo before aerating. Aerating punches a few hundred to a few thousand holes in the ground. Shampoo ultimately creates billions of holes, but it does it biologically. There are beneficial fungi which live in healthy soil which cause it to become soft when it is moist and return to hard again when the soil is dry. Many neglected soils become soft when moist, so check that first. The shampoo treatment is to apply 3 ounces of shampoo per 1,000 square feet. Follow that with an inch of irrigation or rainfall and repeat in 2 weeks. If the soil is not soft after 2 apps, then repeat a few more times. It will get there and you won't need an aerator.

Is there any shade in this area? Shade will be a factor in reseeding the crabgrass areas.

Crabgrass will completely die at the first frost. Good news! But that's too late to renovate the crabgrass areas. If you can rake the crabgrass out with a power rake (rented) you can start seeding in September. Write back about the shade and we can suggest some grass types to give you a dense turf by spring. Dense turf and proper watering will prevent crabgrass from returning in the spring.

Are you interested in an organic approach to fertilizing? The cost for organics is only slightly more than for chemical fertilizer. However, I believe there are benefits to organic which cannot be easily measured by cost.

How will the lawn be watered? Is there an in-ground system or will someone be moving hoses and sprinklers? This doesn't make much difference unless there is no labor around to move the hoses when they need it.

Write back with a little more information or maybe a picture and we can help you more. Don't buy anything or commit to anything before getting a little more help. Just a few hints: Never rototill. You likely do not need topsoil unless drainage is an issue. You don't need to "work in" any amendments, at least not that we know of and most go on top of the soil, anyway.

Do you know what type of grass is there?
http://turfid.ncsu.edu/ItemID.aspx?orderID=GR&orderDesc=Grass

How many square feet of lawn? How much is irrigated?

Consider a soil test. Logan Labs in Ohio does a good test quickly for $25 and for another 25 will give recommendations or post the test here and possibly someone will give you advice. :) morpheus?

What equipment is available? Spreaders, tractors, mowers? etc.

Pictures of the turf/grass can be useful.

>>possibly someone will give you advice. :) morpheus?

Well, since you twisted my arm and all. :-)

Lawn problems are frequently related to resource levels in the soil. There's a hole there...why? In a good soil, and with a spreading grass, that won't ever happen. With clump grasses like fescues and rye, reseeding might be necessary...but it's going to go worse if soil resources aren't correct.

I'd roughly say that nearly 100% of soil tests I see (including my own every year) require some adjustment. Occasionally that's minor. Usually it's moderate. For a neglected soil, it's frequently a major problem or two or six.

Don't randomly throw lime or anything else at a soil without a soil test. Doing so is an invitation to disaster.

Hint: I'm pretty sure you actually have a silt mix instead of clay. Why? Most people who "have clay" just have compacted, magnesium-imbalanced soils of other types.

Clays are fairly rare; I'm extremely unusual in actually having 40% clay! And my clay is so soft you can dig it with your finger tips if you want to. No soil type is a barrier to a beautiful soil that will grow anything you want (within reason for your climate).

You can look up the jar test if you want (ask if you can't find it) if you want to see what kind of soil is actually there.

>>Maybe I will rent an aerator.

Doing this once might be a good idea, and if it makes you feel better I say go for it. It's going to bury some of that nice seed the crabgrass has been pumping out all summer, however, and that's going to sprout--if not now in the dropping temperatures, next summer when soil temps rise above seventy again. Just be warned about that.

It'll work well if you spread compost immediately afterward. It is a good way of getting OM deeper into the lawn faster, although just adding organic matter (OM) any old way will eventually get it into the soil. The increasing worm population will move it in for you, as will the natural and healthy insect population. Fungi. Bacteria. Healthy roots. And so on.

What David said about lawn care books. Thanks for giving me a great New Hampshire lawn, but I'm in extreme eastern Pennsylvania.

Northern VA is deeper (somewhat) into the transition zone than I am, so your care will differ from mine a little bit. Mostly in terms of dates things should go.

You can kill out the crabgrass right now with any good crabgrass killer (I have a tendency to lean toward Weed B Gone with Crabgrass Control, but really, they all work and they're all much the same). If you have a vast crabgrass issue, this one time I'd probably blanket spray with a hose end sprayer.

If you want to overseed this year, do so after the crabgrass is dead...but you're going to have to hurry. Optimal seeding dates for you are around August 20th through September 10th, about a week off from me.

Too much later than that and the bluegrass (if any in the mix) can't sprout before the soil's getting too cool. Bluegrass can take a month for full sprout. None of the grasses are able to grow full roots before winter--which is surprisingly survivable--and it shorts them on time to grow roots before summer 2015, at which point you'll really pay for being late when the grass fades out.

Like BeckyBeck said, next year make sure the crabgrass shield is down when the forsythia bloom (crabgrass is actually much later, but this will help protect the lawn from many spring sprouting weeds). We use the forsythia as a biological indicator as they don't particularly care where they're located--they bloom when soil temperatures rise over 50 and start heading to 55. That's the correct time for pre-emergents.

Reapply throughout the season as per bag instructions and the stated duration of the shield. For one full growing season, keep the shield up at all times. After that, just hit it at the forsythia bloom time and again when the shield drops to slow down the crabgrass at least. By that time, hopefully the lawn will be far enough along to disallow weeds (mine very rarely gets any at all).

Proper feeding is important. For most lawns, feed around Memorial Day, Labor Day, and October 1st. If the lawn has a lot of bluegrass, add in a November first feeding.

Proper mowing is important. Mow as long as the owners of the property can stand having it, and mow again before it increases height by 1/3 (so 3" mowed grass should be mowed again at or before 4"). Always mulch mow.

Longer grass is less thirsty, shadows out weeds better, and grows stronger roots that can access deeper and wider resources from the soil.

If they demand 1" cut grass, there's not much you can do. But remind them that it'll cost a fortune to water it and keep it green in summer.

In all cases, feed when top growth stops for the year, which should generally be in early December for you. This is winterization and is probably the most important feeding of the year as it gets stored for winter survival and for growth and development early next spring.

Never feed in early spring as this will set off tons of juicy, weak growth that lawn diseases and pests just love. It also taps the root systems of energy, leaving them less able to survive the summer.

That's done synthetically (like Scott's fertilizer off the shelf). Organically? Hurl the stuff around at will--although I'd still avoid early spring, use a light hand in summer, and emphasize fall. Organically, I drop 15 pounds per thousand square feet of soybean meal in May, August, September, October, and then winterize with a synthetic in late November when growth stops here (most years).

Feel like you're drowning in information yet? I'll stop here for now.

Morph can you expand on the idea of "juicy, weak growth" in the spring? Most people would be surprised by this because everybody is told to fertilize in the spring.

>>Morph can you expand on the idea of "juicy, weak growth" in the spring? Most people would be surprised by this because everybody is told to fertilize in the spring.

Tell me about it. This is probably the one concept we get the most resistance on. And I cringe every year when the Scott's "Feed your lawn! Feed it!" ads are on in March.

This is for northern grasses like we have. Southern grasses like Bermuda have very different feeding patterns.

Your lawn stores carbohydrates in its root system for winter survival. By spring, amounts of these are down, but there are still plenty to fuel growth through May.

Grass growth in April and early May is always very, very strong as the grass is attempting to grow to its genetic height (usually anywhere from 18" to 36" depending on the cultivar). It's using the remaining carbohydrate storage to fuel that.

Adding nitrogen at this stage just accelerates the growth, and speeds up how fast the stored carbohydrates tap (nitrogen is not common in nature and plants are geared to absorb everything they can get and use it).

As the roots tap, they die off and slough. For feeder roots, that's not a major issue as this will happen anyway. For larger roots, it's a problem as it reduces their ability to tap water from the soil.

Genetically speaking, grasses don't care about summer performance. By then, they've seeded out and the seeds just need to develop and age a bit, then fall to the ground and get ready to sprout when the weather shifts in fall. So in nature, tapping the root systems and looking terrible in July isn't a problem (and why some grasses have dormancy mechanisms to survive the [dry] summer).

We don't like that tendency, so avoiding excess N in spring will help with this.

Faster growth on anything tends to be weaker, more watery, and less well-defended. Overfeed any plant with nitrogen and you'll see that as the internode lengths increase drastically, and the stems become easy to bend and a bit weak.

You've now created a weakened grass with a ton of available mass. Herbivorous insects now move in to eat it (it's there, there's a lot of it, it's an invitation). Breaks in the structure also allow disease to move in and set up light housekeeping--disease fungi love that.

Holding off feeding until May when growth slows puts the nitrogen to a different use. Instead of fueling growth, the grass is shifting to summer mode where it stores energy to survive the dry and hot periods. Rather than decrease summer performance, you're increasing it a little.

Summer is a "hang on and survive" period for grasses, so sparking growth by feeding isn't a good idea here either.

Similarly, fall doesn't light off nearly the growth surge that spring does, so feeding tends to go to carbohydrate storage, root growth, and general health.

That last fall feeding when the grass is no longer growing is actually the most important--the very vast majority of it will go directly to carbohydrate storage (the rest goes to root growth, which continues right up to ground freeze). That's providing energy to survive the winter, and to support normal growth rates in spring.

These rules are for synthetics...nature provides very few fast nitrogen sources to plants (urea and blood being the only two I can think of offhand). Most natural sources are slow to very slow, and don't cause these issues. Organic feeding simulates a more natural feeding regimen, while still holding feeding levels high (as they have to be for our not very natural lawns). We stress the heck out of these things by mowing them constantly, planting densely, and demanding a weed-free environment.

Interesting. Thanks for the exposition. It makes more sense when you know the "why's."

Yikes you guys are great! So much information so little brain cells no really thanks it is a lot to take in but I will with a bit of time. So the lawn area I would like to fix is approximately 1.5 acres and about 75% of that is irrigated the rest I would have to do by hand. My owners will get me whatever I need to make this work and they do not care if we do it organically but I do. I am the one dealing with the chemicals and on my hands and knees on their lawn, plus I bring my dog to work with me and they have cats and kids. Money is not an issue with them so I want to go organic if I can get good results. The grass appears to be mostly fescues but some perennial rye is mixed in here and there. There a few areas under trees, they have the most magnificent copper beech you have ever seen and it is very shady under it. I will have a soil test done but I know it is time to seed so can I seed and then fix issues in the soil? I will have one of my workers hand pull the crabgrass areas this week. I will do the shampoo application does dish detergent work too? I cannot thank you guys enough for all this helpful information. I posted somewhere else about a little battery operated lawn mower to use in tight spaces which there are many do you have any suggestions? Thanks again. Lynn

>> I will have a soil test done but I know it is time to seed so can I seed and then fix issues in the soil?

Absolutely. Due to the young, tender grass, some adjustments will have to wait until spring. That's not a problem.

>>I will do the shampoo application does dish detergent work too?

I don't recommend it as I've never tested it. In theory, it's harsher (and absolutely avoid it if it contains boron or boric acid).

I've tested sodium lauryl sulfate, sodium laurel sulfate, baby shampoo, and Suave shampoo (most other cheap shampoos are very similar to Suave so I call those close enough--White Rain is a known-good formula as well).

I've gone as far as soil inspection under a loupe to view the peds. A microscope would be better, but I don't own one.

I have learned so much from you all thank you thank you. I feel a bit more confident about having some success with this lawn. Guess I am off to the dollar store to buy a lot of shampoo. Hmmmm should I get green apple or tropical delight! Morph your information has been very interesting and useful

I prefer the green apple as I like the scent when I'm applying it.

Fortunately, scent is a neutral chemical in the soap and which scent you get doesn't matter at all.

And yes, I know that was humor, but it does bear mentioning. :)

With 1.75 acres, in the future you may want to make your own concentrated soap--it's cheaper, you can do it a gallon or more at a time, it stores forever, and the components are non-toxic (but are irritants at high concentrations).

Bramble Berry, among plenty of other places, sells sodium laryl sulfate: http://www.brambleberry.com/Sodium-Lauryl-Sulfate-P3562.aspx

Wear a mask (irritant, and by that I mean hideously irritating in the powder form when airborne), do this outside on a still day. Mix 4 oz of powder with 1 gallon of water. Shake very well and let settle for a day or so.

Use this just like you'd use the shampoo--3 oz or so per thousand square feet, diluted well by your hose-end sprayer.

A slurry of the powder and a little water will also remove grease from workroom and garage floors, although several applications scrubbed well may be necessary as oil stains tend to rise back out of concrete.

Thanks again morph for the useful information. So green apple it is in your honor. Lynn

So I told the farm manager on the estate where I work that I was going to put down shampoo on the lawn. He looked at me like I had horns growing out of my head. I will never hear the end of it!

Get used to that look if you go full-on organic and home-brewed for your lawn care chemicals.

Yesterday evening, I cleaned the fridge and removed (among other things, some of which went into the compost) the remains of a quart of milk that was a little sour. I dripped a little on the potted plants, and the rest on the rose. Why does it work? Clueless, but it helps.

Once a year, I spray milk on the lawn (usually about 10 ounces per thousand square feet as that's what a gallon works out to). It does enhance performance, but I wouldn't recommend it unless your soil's already tuned.

I make about three quarters of my own lawn applications. The joke around here is I look like an alchemist when I do it...