Tarp underlay for my raised bed?

[LuckyDadGA]

Hi everybody!

Well, this is the year. I am finally getting a family garden started. I decided to keep it small and just build a raised bed or 2 here and there. Very first one is built.

I'm located in North Georgia (just outside of Athens) on 3.5 acres of what used to be a small horse farm. Most of my "yard" was paddocks and pastures. There's lots of wild pasture grass out there. And unfortunately, a whole boatload of fire ants.

I'm going to come clean. I am LAZY. I do not like busting sod any more than I like getting dental work. Being in red Georgia clay does not enhance the experience. So my hope is to just throw some good soil in my beds over the top of the existing grass. I'm debating if I should stretch an old tarp out underneath it. On the plus side, it will stop all the wild grass from coming up through the 12-15" of top soil I'm going to be filling my bed with. On the minus side, will it impact drainage?

Thanks for any thoughts and insights y'all can provide.

[DarrenP]

Hi, and welcome. Even from the other side of the world, I feel your pain with clay soil. When we lived in Adelaide, the soil was clay, rock hard in summer and soggy in winter. Luckily where we live now is a sandy soil, if somewhat compacted the deeper you go.
I wouldn't use a tarp, as you are correct in that it will impact your drainage. There is a product called geotextile that will help prevent the grasses and weeds coming up, but will allow drainage. It will also help with drainage into the clay soil underneath if you put a layer of gravel over the geotextile.
Being clay soil, you should also think about making your raised beds at least 500-600mm high (I think that's about 19-23 inches in your language). That way there will be plenty of drainage and also plenty of room for your plants to grow. A good blend of soil, mixed with some compost and aged manure will give you great results.
How will the fire ants affect your gardening? I believe we have them over here in Queensland, and they are a pest.

[rainbowgardener]

Agree, no tarp. Especially if you are only making your beds 12" high, you want your plants to be able to root down into the native soil. And has been mentioned, you need good drainage, which the tarp interferes with.

An easy solution is to lay down a layer or two of cardboard at the bottom and then add your soil. The cardboard suppresses the weeds, but then it breaks down and gets out of the way and feeds the soil. You want to wet the soil well first and then wet the cardboard well, to aid in the breaking down.

I am in No. East GA, near Chattanooga TN. I love my GA red clay. It is actually much less dense than the OH yellow clay I had before I moved down here and it is a rich, loamy, moisture holding soil.

[MoonShadows]

Welcome to the forum, LuckyDadGA.

Yes, collapsed corrugated cardboard boxes (so the cardboard is two layers thick) will kill of the grass and break down nicely.

[SQWIB]

Lazy way, and for a garden this year
Drop down cardboard
frame garden area with your desired framing (in your case just line the inside with cardboard if frame can't be lifted)
fill with compost, peat, manure, top soil etc..
Avoid anything that is not fully composted or broken down as this can tie up nitrogen.



I know you didn't ask but I'm gonna put this out there too because I think the benefits are worth it.

To me the next two methods suits lazy gardeners but the effort needs to be put up with only in the beginning and need to be started the prior fall.

These 2 are best started in the early fall but wont help you out this year.

I know you said your a lazy gardener but a great way to start a garden over clay is hugelkultur. Hugelkultur when done correctly may not need hardly any watering after 3 years or so unless of course you are in a drought.

Hugelkultur

Section off an area, remove sod, dig a trench about a foot
Build your frame around the trench
Fill trench with Logs, limbs, Sticks then other yard waste including the busted up sod.
Next, alternate the next few layers with straw and your clay, compost and a quality topsoil or other amendment.
Plant crimson clover and oats and chop and drop or if you are in zone 7 or cooler it should winter kill.
One caveat to this method is the nitrogen will be tied up a bit so your first year may need a nitrogen boost.


Lasagna Garden
Mark out garden area
lay down cardboard
Frame the area with your desired framing
start a compost pile on top of the cardboard

Some folks get scared away from hugelkultur because the general consensus is that it takes three years before it performs well, I have built quite a few and my first year in each were definitely acceptable.

Clay soil has not been a problem in my garden(s), I actually like it if amended correctly.

Heres a few pics









First year growth no problem








Another bed





PS. I'm a lazy gardener too but willing to bust my back "once", for the Lazy Payoff!

[LuckyDadGA]

Thank you for the replies everyone. I'm not so down on the clay from a soil quality standpoint so much as it makes it tough to break turf with a grub axe or shovel. Appreciate the suggestions everyone... wet cardboard it wound up being. By the way... I tacked chicken wire underneath, to keep any rodents from tunneling up underneath. Overkill?

[rainbowgardener]

Not overkill if you actually have gophers or woodchucks in your garden. Personally I have never seen either here. If you don't have a problem then it is kind of overkill and might hinder a bit the plants rooting into the native soil. But shouldn't be much of a problem.