Mix for raised beds

[Matthew Langholtz]

I'm working off the book "Cinder Block Gardening" and I'm about to fill my beds. The book suggests filling with equal parts by volume sand, humus, and compost. I have piles of unused native clay lying around from my landscaping work. Should I use that clay instead of hauling in some or all of the recommended sand? My bed is 25x4ft and 2 ft deep. I might make 2 more, so it's lots. Thanks in advance for any (good) advice!

[David Trout]

Matthew,

Most people think clay is a poor soil for gardening.  Actually, when it is amended with organic matter, it is a very good soil to have because of its water holding capabilities.  In Bill Mollison's "Introduction to Permaculture" he says of clay:  

"If the area where you want to start

your garden has heavy wet clay, you

are in a happy situation. You are in for

real trouble where there is siliceous

sand. Clay is fantastic for water re-

tention. Because you are mulching,

your roots are well up in surface

area, and don't have to encounter the

clay. The clay holds enormous quanti-

ties of water. Sturdy clay gardens

make the best mulch gardens.

If you wish to start a garden on

lawn, just go straight on to it. At

home, we have people who keep

mulching across their lawn. This

year, you decide that a bit of lawn is

going to be a garden, so you mulch

straight across it, and in a small

handful of soil you plant all your little

plants through the mulch.  Put your

potatoes at the base, and go straight

into garden."

He advocates mulching heavily over bare dirt or even a lawn using cardboard, newspaper, carpet or even mattress ticking!  Then you just plant straight into the ground through the mulch and continue to mulch heavily through the seasons.  If you have standing water, consider swales in combination with raised beds created with soil from paths dug around them plus any amendments, followed by cardboard, newspaper and then straw.  If you are wary of using manufactured paper products, as many folks are, just use lots of mulch.  

So I used to think I had a bad situation here in Tennessee because the soil is so heavily laden with red clay. Now, I realize we have a good situation.  Especially if we don't till and destroy the subterranean soil structure which is developed and sustained by worms and microorganisms.  Just mulch and mulch and mulch more and more every year.  I use straw, but lots of mulches are available.  If you plant clover in the paths around your beds, you can whack it down occasionally and throw the greens on top of your bed.  Toss your weeds on top too.  This adds nutrients that decompose slowly and feed the soil and the worms.  Plant some comfrey in the yard and you will have a great "chop and drop" soil amendment that you can toss on the beds.  You can cut comfrey back several times a year.  It has VERY deep roots and pulls up lots of nutrients from way down deep, storing them in the leaves.  I got seed from Horizion Herb Company.  Comfrey is a must have plant in the permaculture garden.  Send me your email and I will try to send you a pdf with some great info.  Check out the videos I posted titled "Natural Farming".

David

[Jeremy Spiers]

If you have the compost and humus to make the mixture loose and fertile, I don't see a problem. I am using a mixture this year of yard dirt/clay, rabbit manure, a little compost from this winter, and a LOT of compost from Sevier County's composting facility. Let me know how your's turns our, and I'll let you know about mine! The goal would be, for your beds, an organically balanced, highly nutritious, and fairly loose mixture that the plants can root in. For the beds, it might not be a bad idea to include some worms... I like the method detailed HERE, and I hope to try in in conjunction with container gardening this year.

[Jeremy Spiers]

I didn't see David's reply before I posted, but he is right. I planted last year straight into the lawn in several locations last year, and mulched with straw and then grass clippings (being careful to keep the fresh ones out of direct contact to avoid burning) I produced romas and squash like never before and the beans and peas loved it! (I live on the Knox fault line, with limestone erupting in the yard, and cedar laced clay as most of the soil.) However, things such as corn and wheat seem not to like it quite so much. I am creating more beds this year, by tilling and then adding compost and nutrients. Also, an interesting thing I have seen recently is windrow gardening on contour. After the storms last year, Frank Callo and family collected small limbs and piled them in long rows along contour. Then, they put compost, lawn clippings, and kitchen scraps on top. The resulting bed seems quite rich, and grows onions and greens quite well. Eventually, it will subside to a very rich swell. That said, even things like straw and decomposing wood can be quite good in a bed.

[Matthew Langholtz]

Thanks for the info!  Anyone think I add gypsum and iron sulphate like is recommended here?  http://www.dailymotion.com/video/xjm681_how-to-amend-clay-soil_school 

[Jeremy Spiers]

The only additives I have used are compost, rabbit manure, cow manure tea, and epsom salts (to help with mineral uptake.) It would be interesting to see what happens. Let us know how it goes!