# Advice on best way to amend clay soil in a future bed



## GA_Bermuda (Jun 22, 2019)

I am making plans to completely change the flower bed on a new home purchase. I have already ripped out all of the old shrubs and discovered the soil is nothing but clay. The clay is so bad that shrubs(boxwoods) that were 10 years old had a root ball that was under 6" deep and no more than 18" wide. This week we had almost 5" of rain. A couple hours later I started digging again and the soil as best was wet less than 2". Everything after 3" was bone dry.

What do recommend as the best amendment to completely break up the clay and prevent it from hardening in the future?

Could I accomplish this by adding a soil conditioner, compost, and then tilling it down 8-10 inches? Would adding sand, peat moss, or ground charcoal give me any additional benefits? Would you follow the Back to Eden method of adding cardboard and then covering with mulch?

Cheers


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## corneliani (Apr 2, 2019)

I'm in Buford and definitely feel your pain! Here's my opinion on this - if you're replanting smaller/denser plants then tilling makes sense as you'll be planting at 12" o/c. But if you're planting larger shrubs then just deal with their individual planting holes. No need to amend an entire bed when they only need 5 sqft to live in. Very importantly, imo, is to make sure you have drainage at the bottom of the hole. Dig down deep until you hit permeable soil.. otherwise water will never drain well enough. Ask me how I found that out. :x

As to how amend the soil.. all of your stated options are viable. Soil conditioner adds larger pieces of organic matter and helps aerate the soil. Compost does that on a smaller particle scale along with adding nutritional value - great for alkaline loving plants. Peat moss helps with water retention too - great with native acid-loving plants. Ground charcoal (biochar?) can help with drainage but is especially helpful binding soil nutrients and keeping them from leeching. You technically cannot go wrong doing all of the above, but that would be a bit over the top even for us obsessive types 

What would I do in your shoes? I'd buy landscape mix by the CY (similar to the Soil Conditioner sold at the big box stores), dig holes 3x width of ball & twice as deep, mix 50/50 with native clay soil and plant. Top it all off with 4" of compost (or cottonseed meal, etc) to help with slow-release fertilization, and mulch the remaining bed (Back to Eden style?) which will help with any future soil amendment.

Hope this helps. :thumbup:


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## gm560 (Feb 22, 2018)

If you are tilling it, how about some perlite? Nothing fancy but cheap, effective and lasts forever.


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## GA_Bermuda (Jun 22, 2019)

@corneliani @gm560

I found broken bags of perlite at my local HD so going to add that in.

I am a little concerned after digging the holes. I went down about 12-16" and hit solid stone. I need to do more reading. I would hate to dig a clay hole that will just flood my plants.


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## gm560 (Feb 22, 2018)

GA_Bermuda said:


> @corneliani @gm560
> 
> I found broken bags of perlite at my local HD so going to add that in.
> 
> I am a little concerned after digging the holes. I went down about 12-16" and hit solid stone. I need to do more reading. I would hate to dig a clay hole that will just flood my plants.


That should help.

It might be a good idea to work some gypsum into the soil around the planting holes, too. Something like this:

https://www.espoma.com/product/garden-gypsum/


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## Todd1970 (May 7, 2019)

Add expanded shale and till in.


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