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To Till or Not To Till My Compacted Soil

Springboro, OH(Zone 6a)

I was doing some interesting reading tonight and now I'm confused. Can ya'll help me out here?

Our house was finished late last winter and all the "good stuff" was stripped off our lot, leaving compacted clay behind. We have our sod established and have planted a few trees, but now are turning our thoughts toward mixed beds in the front of the house. The book I was reading tonight said to NOT turn over whole beds because of stirring up unwanted weed seeds and disturbing the microbial life. My original plans were to till the tar out of the beds and amend with organic matter like a mad woman before I planted anything else.

So, now I'm confused. Should I go with my original plan and till/amend before I plant??? Or should I lay out some newspaper, put 5-8 inches of amended topsoil over it and call it a day, forgetting that extremely heavy machinery was rolling all over these areas just 10 short months ago? Or, should I just amend the holes where I'm going to be planting??? I'm planting mostly perennials, about 80 of them, so that's a lot of holes. I'd really appreciate any help ya'll could offer. I learn so much on this forum :)

Thank you!!!
Hugs :)

Waxhaw (Charlotte), NC(Zone 7b)

Personally, I would amend the soil to a dept of 10-12" (one spades dept). By adding a layer of 3-4" of compost/maure over the beds and tilling it into the top 1 foot, you will get approximately 33% by volume organic matter which should provide for a very nice preparration.

I don't see the big deal about disturbing weed seeds. If anything young weed seeds can be hand weeded in spring/early summer if they come out. Not preparring the flower beds will put you and your plants at a cronic disadvantage from now onwards. Sure, the book is probably right when it comes to existing good loam soil, but what about less than ideal situations???. I can not see that the potential risks of tilling the soil should outweigh the benefits of amending a bed and relieving compaction.

Maybe they are referring to tilling a bed without amending ? I know that some gardeners will till a bed every spring for vegetable gardens, despite fact that it has been done many previous years. Maybe in this case, you could argue against it and just plant directly in the soil without tilling. In your case, however, you are amending the soil and preparring a bed which is going to be a permanent structure so I would not hesitate to go ahead and amend the bed.

Precipice Valley, BC(Zone 2a)

Heavens, the weed seeds would be the least of your problems!

I agree, till your soil to loosen it so that you can dig down and add your amendments. Once a garden is established and you've a good balance of nutrients, tilling is no longer a good idea.

Efland, NC(Zone 7a)

Clay? Clay you say?
Clay at night? And clay in the day?
Oh my goodness gracious me..
I'd amend that soil, and right away!

When you till,
and I hope you will...
Clay soil that is malcontent
Needs a treat, 'tis no big feat,
PEAT, the perfect amendment!

Whoops, sorry, huga! I slipped into my Dr. Suess mode...:>+

Till away, add some peat, till it in. This will do wonders to break up the clay into a very friable, workable, medium. You'll be amazed!. At this time you may also want to check your pH (meters are cheaply available at Lowe's/Home Depot) and if very acid throw in some dolomitic lime. It'll do ya justice!

Weeds? Bah! Humbug! Since this will be an established bed you may have to weed the first year for most of them (but also keep in mind that many weed seeds are airborne and "bird borne" and you will always have a few to deal with anyway). If you're not into weeding, you could try one of the many pre-emergent "weed-i-cides" available on the market, especially since you'll be transplanting your stuff and not starting them out from seed.

Seems to me your first thoughts will do ya good...i.e., "My original plans were to till the tar out of the beds and amend with organic matter like a mad woman before I planted anything else."

Happy Growing! τΏτ

Springboro, OH(Zone 6a)

Well, good!!! Guess I'm getting to the point where I can begin to trust my "Garden Gut" a bit more :) Tilling it is! :)

Shoe, I was planning on sphagnum peat in there with some already amended topsoil (soil, compost, manure). How's that sound? Yes, kd, I was thinking of about 3-4" as well. I'm not sure what this author's intention was... the rest of the book is terrific. It's just a book on annuals, but there was a section on site prep. Guess now I know :)

So, after the beds get established, should I topdress with a little compost every other year or so? Anything else I need to do regularly to the soil in a situation like this one?

Waxhaw (Charlotte), NC(Zone 7b)

Mulch after planting. If you want to add more compost, it is a good idea. draw back mulch, add compost, scratch in, and replace mulch.

8 miles from Athens, OH(Zone 6a)

I don't till, but double dig my beds. It's painful, but worth it. I work in peat, compost, plus composted manure along with any amendments a soil test suggests. My clay (can't use the term soil) is somewhat acidic so I've had to add lime. It also depends on what kind of plants you plan to grow. Learn what your plants require and amend accordingly.

Do a soil test (don't guess). Add the amendments needed, and then test again in a few months. I would also add a suggestion I got recently from an organic landscaper. He adds a fine gravel to clay along with the above mix to help provide the necessary air which clay soil prevents. He did a demonstration for us using ROCK hard fresh clay and turned it into great textured soil! It was awsome to watch. We aren't talkin' buckets here, but tons! As I write this I have 1.3 tons of #9 gravel --about the size of this....o....sitting in the bed of my truck to take home tonight. Cost me a little over $7. I dumped 38 cu feet of mushroom compost on the bed Saturday along with 1# of lime. Hopefully the weather will cooperate and I can turn this stuff under pretty soon. I want to plant potatoes, peas and onions in one bed, and am getting ready for some new roses and herbs in May in another. The rose bed ph has to be higher than the vege garden. The rose bed will require 5# of lime based on the acid level of the soil in that space.

Take the time to prepare your soil and you will not regret the effort.


This message was edited Mar 24, 2005 8:44 AM

Shenandoah Valley, VA(Zone 6b)

Would be fun to do a little test between digging/amending and going the no-till route, but who's got the time? As far as something other than peat to add tilth, the coconut coir fibre works very well too. And it's renewable.

Springboro, OH(Zone 6a)

Darlene, I read on a separate thread that you consider yourself a "lazy" gardener. HA! I've never met a lazy anything that DOUBLE DIGS!!! Did you mean "crazy" and just had a typo??? LOL :) Just kidding... Thanks so much for your input :)

Hugs :)

BTW, we're tilling for certain when the ground dries out a bit... very wet winter here

8 miles from Athens, OH(Zone 6a)

Crazy Lazy that's me! hee hee

8 miles from Athens, OH(Zone 6a)

I don't mind the double digging. 'Cause it means I don't have to do it again. Therein lies the lazy!

Springboro, OH(Zone 6a)

LOL :) Sure......

Marietta, GA(Zone 7b)

After you till I'd put down some great worm food and let them continue the process of breaking up the soil and keeping it fresh... Alphalpha pellets maybe??

Also, if this area is on a hill or slight incline, make sure that you do all this ammending right before you plant since the rain will wash it if there are no roots to hold it.

Susan McCoy

Conroe, TX(Zone 9a)

Cornmeal gluten is a good organic pre-emerge to prevent weed seeds from germinating, since you'll be planting young plants, not seeds. It has the added benefit of supplying additional nutrients to the soil.

8 miles from Athens, OH(Zone 6a)

Hey Huga, howzit going? Can you believe this weather? Gosh 3 whole days without rain. Might even get part of a 4th day without it. My vege garden site is still soggy tho. I'll never get my potatoes or onions in the ground...til August!

Springboro, OH(Zone 6a)

Going well :) Thanks for asking! BTW, the soil is tilled :) Quandry resolved!

Here's a link to my "Progress" thread, if anyone's interested...

Hugs :)

This message was edited Apr 5, 2005 11:18 PM

Mountain Home, AR(Zone 6b)

Similar situation. My land is established Bermuda pasture. I want to open up a section 20' x 100', long rows for corn, cornfield beans/peas, and Okra. The soil is Arkansas clay; I need to fluff and amend and do not want to fight the bermuda until I reach age 65 (59 in Dec). Other than a Kill it all, short acting herbicide, what are my options?



Charlotte, NC(Zone 7b)

Martin - I am plagued with Burmuda Grass, too! The only way I have found to truly get rid of it is to hand dig! Be sure to get all those little white pieces, otherwise it will grow back!

I AM 65 and too old to be fighting grass!

Raleigh, NC

if you are saying it's the really hard clay (unbaked brick) under where the topsoils used to be that's left....

ours doesn't break up easily (mostly red, and some yellow clay). we have to break it with a pickax and shovel by hand. no tiller I've tried [tried every tiller Home Depot rents] short of a large backhoe style Kabota can get in there to break it up. so I hired the Kabota guy last year, and although it saved my back, even he didn't get down 10", more like 5". then he spread our piles on top and did a last tilling. with all we put on there, we ended up with about 8"-10" friable dirt.

so I don't recommend you pile stuff on top until you've made many passes with the tiller if it's hardpan clay you have.

Deep South Coastal, TX(Zone 10a)

And I thought Texas soil was bad!

Raleigh, NC

Calalily, now you know why so very many homes in Carolina are made of brick! it's a no brainer, and brick here is very very cheap. just reach down a few inches and bake in a kiln.^_^

editted to add:

FYI, because it's so very very hard, I find the best way to break it is to put soaker hoses on the area to be tilled the night before, then take them off at dawn. by noon, that area is usually dried enough to work in, but the deep soaking water softens the clay enough to break far far more easily. This is how we can break clay by hand and shovel.

This message was edited Sep 30, 2009 1:16 PM

Albuquerque, NM(Zone 7b)

Back on the question of tilling bringing up weed seeds - I don't think that is really the reason not to till. Tilling breaks up the microbial life system in the soil. If your soil is compacted and dead, you can't harm it except perhaps structurally. Once you have a healthy, living system going, add ammendments at the surface. The microbes will come get it.

Hamilton, OH

We have the same newer home scenario.. they plow away all the topsoil... and then try to sell it back to you after the sod is down.

Depending on how large of a bed you are doing... double digging can be a difficult task. Unless the soil is damp, double digging can be near impossible. I purchased a set of discounted trees in 5 gallons pots that i had to plant near the end of spring... the ground was so hard, i used a 6 foot spud bar to break up the soil and then shovel it out.

For me, the only area i double dug was a veggie bed. For the rest of my perennial beds, i just dig as deep as the shovel will go and flip it and the sod over, then add 4-5 inches of compost/manure to the top. when i plant individual plants, i mix up the holes well with the same.

Raleigh, NC

one thing I forgot to mention - if you have hard clay soils, DO NOT DIG A HOLE AND AMEND AND PLANT IN IT. unless the plant likes to be wet. some trees don't mind this, but most of the shrubs and perennials I've done this to (before I learned better) either died immediately....or slowly.

in hard clay, a hole dug and then filled with amended soils acts like a bowl, holding in all the water. it does NOT drain well. the vast majority of plants like at least a bit of drainage. Clay doesn't drain worth crap. the roots drown. unless you are planting something that loves to be in a boggy situation, dig your hole but pile amended soil up above ground level at least 1 foot then plant in that. or dig a bed and pile up slightly above ground level.

Everett, WA(Zone 8a)

I agree!
" Till, ye tarriers, till!
Till right down to the bottom of the ground, yes
Till, ye tarriers, till!"

And I agree that pick, mattock and shovel must be used to lighten clay up enough for a roto-tiller to get its teeth in. I guess most towns don't like us using explosives.

Anyway, dig _deep_ once or twice a year for the first 2-3 years (two spade depths). Add organics: shredded pine bark, compost, shredded leaves, coir or peat. Also crushed rock though some would say "not until the soil already has plenty of OM mixed in".

Otherwise, those of us "blessed" with heavy clay might as well plant on top of concrete.

The good news is that each cubic foot of clay you "rescue" becomes a valuable soil component, buffering and exchanging mineral ions.

Depending on what you're planting, 8-12" may be almost enough, or 16" might be better. I've heard that annual flowers root shallowly, bushes and perennials need "deep", and vegetables are somewhere in the middle. I don't know.

Should you be industrious and lucky enoguh to improve that clay enough that weeds can grow in it, THEN worry about weeds! And bless their roots for adding organics deeply and improving the drainage further!

After a year or two of Garden Corps of Engineering, other considerations come in, and deep tilling should only be done "if needed". I found that after one year, the organics seemed all digested, and the clay had settled down to a gooey layyer a foot down, and I had to go after it again with more manure compost, sand and pine bark mulch.

They tell me that "worms will do it for you", once you get the soil good enough for worms. Unrtil then, I think that double digging or deep tilling while adding amendments is valuable.

For the first few years, till in all the organic matter you can afford, then some crushed rock or grit (around 1/8" grains).

At first, I didn't know that very fine gravel (grit) was more helpful than sand! Now I like shredded pine bark (fine mulch) and coconut "coir", and they are cheaper than peat moss. If I had a cubic mile of aged manure, and an anti-gravity wheelbarrow, I would be one happy gardener.

When I buy cheap bark mulch, I screen it. Anything I can force through a 1/4" screen is better of turned under. Anything over 1/2" is probably better used as a top-dress mulch. You can always turn it under next year or the year after. If you have lots of heavy clay, you prbably want to turn under the bark between 1/4" and and 1/2" - the coarse stuff will add structure and aid aeration until it breaks down over several years.

To get a LOT of benefit from adding coarse stuff to gooey clay, you have to add a lot - like 40% or more. But I think it helps some even before you have the clay fully amended and mellow.

I agree with bonjon that any excavation _below grade_ fills with water and becomes a dead zone. An alternative to the very raised bed is a drainage trench from the lowest point of your bed to a low point in your yard, or to a point that already runs off to a place other than your basement.

(One friend had a neghbor lead a lot of runoff right into HIS yard! Of course, that was in New Jersey ... and he drilled it one night and used some acid to breach this neghbor's concrete barrier. )

My clay is so hard and permanent that I did not even need to fill the trench with drainage gravel. It looks like a mini-culvert lined with concrete.

First I dug out one huge trench, 6+ inches wide and as deep as needed to maintain the always-lower slope, plus contain a 4" corrugated slitted drainage pipe, wrapped in filter cloth, surrounded by drainage gravel and rock, wrapped in more filter cloth, then covered with river pebbles. (This is VAST overkill unless you're draining the Amazon River Basin in monsoon season.)

Then I tried just scraping out a little trench as wide as my mattock blade, leaving it open at the top. Always downhill. Done deal!

P.S. You could also dig out _some_ beds and completely replace the soil - if they are sited so as to be easy to create the needed drainage with some short trenches. Call that a depressed bed, below grade and below the PREVIOUS water table, but above the NEW wtaer table created by your trench.

You could move the excavated clay to another spot, where you need to RAISE a bed ABOVE grade, and make a kind of raised platform of solid clay. THAT will lift your raised bed up high enough to drain well, even if you live in a swamp!

I suspect that my clay is hard enough that I didn't really need the paving blocks I use as bed walls. I could have made the walls (narrow berms) out of clay, and just cut one opening for drainage. I bet those would last for years!

Personally, I would add at least some organics and wood shavings to the top 2-3" of the clay layer, and expect that, after some years, roots, frost and worms will loosen that up also, giving you another 4-6" of usable soil.

Advocates of the lasagna system say all this is unecessary: that you can garden in what I would have called a layer of "sheet composting", and expect the leachings from that process to soften the clay for you over a period of years.


This message was edited Aug 25, 2011 3:44 PM

Helena, MT

I don't think you could find much worse 'soil' than we had here in the valley. Nine years ago I started my garden using a rock picker which removed bolders and small rocks from the top six inches of soil and left mostly gravel and rock dust or clay. For three years I hand dug and removed rock fromt he top 12-inches of this glacial deposit using a 1/4th-inch screen/box over a wheel barrel. Today my feet are worthless for digging, but I now have a 100ft x 70ft garden plus three rows of 4ft x 60ft which are vertially rock free. I amended the soil with horse manure each fall tilling it in and continue to do so each fall after all the garden refuse is removed. The tilling process actually starts with an initial till, added manure (now cow manure and straw well aged), a second till, and then I wait for a rain to finish the fall tilling process. In the spring I do a serious till before planting. This sounds like over kill to most people, but I content that aeration of the soil is as important as watering. I agree with soil testing, however my results usually come back high in all components (PKN) in the fall, but with the tilling procedure I use it is perferct in the spring. Never experienced a burn and I add copious amounts of well aged manure in the spring to hills and holes for squash, cukes, tomatoes, and peppers. Corn gets a really good application of manure in the fall, probably double of what is added to the rest of the garden, and I am talking pickup loads.

The 'rock wall' formed by the removal of rock from my garden areas is now an extension of the yard into a road culvert. The wall is six feet deep, fifteen feet wide, and nearly 200 feet long. I have covered the wall with weeds removed from the garden and lawn, garden fruse, and layers of well composted horse manure. The 'Lasagna Gardening' project is now ready for asparagus plantings. One end has been producing dill, and the inner side closest to the garden is a row of Yuccas.

Although Lasagna Gardening is akin to no-till farming I don't fully agree with this principal. I regularly hand cultivate with a long handle three prong fork to provide the essential aeration, which I believe is essential to all gardening. I use soaker and drip feed hoses to water my garden areas and looseness of soil helps to maximize the water uptake along with the other benefits or aerating the soil. So it is my firm belief that overtilling or cultivating the soil is not disadvantageous.


Everett, WA(Zone 8a)

It's good to get an opinion that goes against popular thought! I think a lot of deep digging is needed UNTIL you get the whole profile the way you wnat it. Then I'm not sure how much is "enoguh", and whether there is a "too much". I guess the great Dust Bowl came from super-excessive surface tilling (like every time it rained!)

Morgan, do I understand that you still till _deeply_ three times per year, after several years of improvement? How deep do you go, just the top few inches or 12-18"? I can't argue with turning it enough every year to mix the manure in, and later shallowly to prepare the seed bed..

I think that adding lots of manure is always very beneficial, but I don't understand why it's necessary to keep deep tilling AFTER the deep soil is well-amended. I would have guessed that one _deep_ turning every 3-5 or even 7 years would be enough to counter things like compaction, oxidation, elluviation and illuviation.

But I also can't argue with good results!

Does it get packed down each year, for example by walking on it or running a tractor? Maybe adding more sand down deep would keep it aerated with less-frequent turning.

Just from reading, I hear that "too much tilling" of soil that is already porous may even speed up decomposition and oxidation of organic matter. That's not experience talking, just what I've heard.


Helena, MT

OKay Corey, I've read pretty much the same information as you on tilling and have had some reservations about my program, however my soil is still less than loamy and it make take years to accomplish that. The rock dust or clay which was my original starting point after removing the rock is primariy inorganic and in some respects good from the stand point of trace metals. However, the continued addition of organic material has not been detrimental in any fashion as far as I can tell. Multiple tillings in the fall will reduce the amount of ammonical nitrogen content sure, but what's left is basically organic nitrogen which is slowly release over a period of time up to four years. Aerating or cultivating the soil tends to assist the plants in the uptake of organic nitrogen in my openion.

I till my garden with a Sears tractor mower (26hp) and a pull behind tiller. Depth of tilling is probalby not much more than six to eight inches. In the fall the initial tilling after crop residue has been removed loosens the soil. After that I add the manure and till once more; wait for a good rain; let it dry sufficiently to till again; and complete the process with a thorough tilling which means several passes. A thorough mix of the manure and soil is left untouched until spring when I till once more thoroughly before planting. I totally agree that is over kill by most people's standards.

I have a layer of bed rock about two feet deep under my garden which is vertually inpentrable with out a pick. I have dug some deeper holes for trees however I don't go below 18-inches for holes in the garden which I dig for potted plants such as tomates and peppers. The bottom twelve inches of these holes are clay and rock which is removed for other purposes and the holes filled with the top six inches of soil and composted manure. I do the same for hills of squash, pumpkin, and cucumbers. Potatoes, peas, beans, and corn are shallow row planted. Potatoes and corn are mounded, getting the benefit of the adjacent surface soil and manure mix. So Corey, to answer you question, I can see no ill effects so far from this procedure.

Each year my soil gets darker in color. The original gray color is slowly changing to a black color, which to me is the idea condition I hope to achieve, But I may be years away from that. At that point I can begin to back off on the addition of manure and tilling I suppose, but untill I see any evidence that this program is not working properly I will continue as described. And by the way I have a new neighbor who also has a large adjoining garden and it's interesting to compare results. He has decided to take my lead based on his crop production vs mine over the past two years.


Everett, WA(Zone 8a)

I'm no expert, but the fact that you are only going 6-8" deep answers my doubts.

The biggest argument against frequent shallow tilling that I know (the Dust Bowl) would not apply to you unless you were semi-arid.

And I don't know if "a couple of times in the fall plus once in the spring" even counts as "frequent". The only thing that sounds in any way more excessive, considering the stage of "soil rescue" you are in, might be that you do a through job of tilling under and tilling in the manure. And it sounds good to me, if you can afford the gas!

>> Aerating or cultivating the soil tends to assist the plants in the uptake of organic nitrogen in my opinion.

I agree. It has many benefits if the soil tends to be heavy, poorly-draining, or not porous enough. I only meant that excessive loosening of already-open or sandy soil might accelerate the loss of organics. It doesn't sound as if your soil is excessily open yet!

Your plan sounds wise. If it were me, and 5-10 years from now I thought the top 8" was as good as it was going to get, I would even start being tempted to go deeper. If gas were free!

Helena, MT

Good points Rick. Gas is not a really big deal here since the combination of the lawnmower and tiller takes very little time compared to the walk behind tillers. Unfortunately my tiller does not go much below the 8-inch level, which is why I hand dig deeper holes for various crops. And, I would consider the valley somewhat arid in a sense. That is the reason I use soaker hoses and drip feeders. Fortunately I am on a well or that too could get expensive. Organic nitrogen is not volatile like the ammonical nitrogen which as I understand it is responsible for the 'burning' of plants if the manure applications are not well digested. The horse manure was much more difficult to break down than the well aged cow manure/hay mix which I started last year. The horse 'biscuits' would somethimes still be evident in the spring tilling, but there is little residual evidence in the cow manure applications, and that is the presence of some hay. I do plan to do a soils analysis next spring prior to planting. This will be an annual practice from now on and should keep me out of trouble. Thanks Rick...good feed back...will keep me thinking on the matter.


Everett, WA(Zone 8a)

>> Organic nitrogen is not volatile like the ammonical nitrogen

I was thinking more of the carbon. Too much turning of light, well-aerated sandy soil encourages the carbon to be digested more rapdily and oxidize, removing it from the soil. Especially in warm climates.

But I think few of us have light, airy soil!


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