I received an email yesterday from Bill, a new subscriber living in Pennsylvania. He writes,
“I have wet and heavy clay which means I need to raise my beds in order to promote proper drainage.
I was thinking of bringing in topsoil, manure and compost and just mixing it together right on top of the existing soil. The existing soil has grass right now.
Should I rototill the existing turf or just pile the new materials right on top?”
Since I’ve received quite a few emails along these lines, I decided to answer my reader’s email via this post for the benefit of all readers who may have similar questions. Also, there’s an important comment I’d like to make regarding purchased soils.
Following Nature’s Principles
Although I can’t tell other folks what to do in detail because only they know all the facts of their situation, I can advise people on principles of nature. Nature’s a pretty dependable source and her principles are foundational truths that apply to everyone, everywhere.
What makes things even better is that although her laws/principles are fixed, the methods to accomplish what those laws and principles require are endless. Each person can tailor the methods to their own needs and situation. After you have all the facts, then you can choose your preferred method of carrying out the plan.
(You will recall I discussed this at greater length in a recent post Organic Organic Gardening the Laws /Principles are Fixed/ the Methods are Endless.
Below are my comments to the statement: I have wet and heavy clay which means I need to raise my beds in order to promote proper drainage.
Although I’m not 100% sure, I would probably have a 99% chance of being correct if I said that by “raised beds” my reader means framed beds that purchased material will be poured into.
In my book, I explained at great length about naturally “raised beds” and why they are preferable to framed raised beds in the majority of cases. I also listed times that framed raised beds may be helpful or necessary.
All the advantages of raised beds like ease of working, improved soil conditions, and higher yields can be reaped without having the beds contained; thereby totally eliminating the disadvantages which I discussed in the book. (I’ve also mentioned some of that here on TMG.)
Promoting Proper Drainage
Adding organic matter to the soil improves drainage. The quickest way to improve hard clay soil is to properly prepare the soil which involves loosening the soil. If you have the time to wait, you can pile things on top and eventually the soil will become friable and drain well. It’ll take some time.
The “added” ingredients (hopefully) may drain at least to the hard clay soil. Drainage has really not been improved.
My first garden was one foot above sea level and heavy clay soil. Much of the area looked like a pond in the rainy season. It was brick-hard in the dry season. I told in detail exactly how I dealt with that in my post 3 Things of Primary Importance When Starting a Garden.
When clay soil is improved it’s just about the best soil there is. I saw a difference immediately after I improved my clay-soil beds, but it took about 3 years to really get to where I wanted to be with the soil.
Below are my comments to the statement: “I was thinking of bringing in topsoil, manure and compost and just mixing it together right on top of the existing soil. The existing soil has grass right now.”
Years ago, “topsoil” meant the first few inches of good soil that was high in organic matter. I think most of us think in those terms when we speak of topsoil.
Unfortunately, when you buy something called “topsoil” today, it may not be what you think it is. It’s very common for some sellers of these “soils” to take heavy clay soil and put it through a machine that cuts it up and makes it look and feel friable. The buyer doesn’t realize he’s been “had” until he gets the soil where he wants it and it rains. Then he knows he has unimproved clay soil, not topsoil.
Even if that’s not the case, it can still be very poor soil that is “unimproved.”
The bottom line here is: be careful what you buy. Know the seller well if possible. Ask a lot questions. Do your homework.
Manure and Compost
Good if you can get stuff without residual herbicides. Always a good idea to do your homework before you spend your money.
These posts will give you the information you need to decide wisely:
Placing Manure, Topsoil and Compost on Top of Existing Soil
I touched on this previously. Bill, after you read all my information on how to properly prepare soil and the advantages of that, you can better make your decision.
Below are my comments to the question: “Should I rototill the existing turf or just pile the new materials right on top?”
The only time I would recommend a tiller is when ground is first being prepared. (Like now, Bill, if you decided that is what you are going to do.) After that, if you follow nature, there is no need to till ever again.
Preparing Your Soil
Here are the posts that will give you a lot of detail on preparing your soil:
Proper soil preparation is one of the best things you can do to help yourself be more successful in organic gardening.
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