A Gardeners Forum
Posted By: TennesseeVolunteers New Bed - December 12th, 2006 at 02:26 AM
This past growing season was the first attempt I've made at gardening. I've been thinking about how I'm going to do it next year. I want to create raised beds with cement blocks. One problem I'm having is that the soil where I live is heavily clay.

Here's my question: Can I fill my raised beds completely with purchased topsoil or do I still need to mix it in with the native soil?

Thank you
Posted By: weezie13 Re: New Bed - December 12th, 2006 at 03:10 AM
I would map out your area...
and rototill some good compost into that bottom
layer *or would be the top layer of soil, but the end up being the bottom layer of your raised bed*...
Then you'll have a nice mix of Compost and your
soil that is heavily clay.
So, when you do plant, and you put your soil inthe top part.. you'll still have some nice, nutrious soil in the clay part.. and will also go down into that area to put their tap roots, and feeder roots if they have a tendancy to go deep..
Posted By: Longy Re: New Bed - December 23rd, 2006 at 05:46 AM
Depends how many blocks high you are going. Most vegies won't put down roots which are over say 10" deep. If it's only a single block then some prep' of the clay would be necessary but for two blocks high i'd just cover the clay with gypsum and chicken manure, then a layer of newspaper or cardboard to kill off any persistent weeds like couch grasses. Maybe a layer of sand above that, then your imported compost/soil. Worms and other critters will tranfer the layers and do your deep digging for you over time.
Bear in mind that you will need to ensure there is drainage out of the beds or your vegies may end up swimming during very heavy rain and the soil will become sour. So weep holes between every second block and/or perforated drainpipe below the beds would be a good idea..
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