Building a Raised Planter Bed

kashimama · 11-05-2007, 06:00 PM

I have a narrow section of lawn on the side of the house that is surrounded by a wall/fence. I'd like to build a raised planter in that area along the wall. Do you think I should remove the grass in this area before building?

Mike Swearingen · 11-05-2007, 09:47 PM

I would remove the grass and loosen any compacted soil under the area to improve drainage. Do not use any CCA presure-treated lumber if you plant to plant anything to eat, as it contains arsenic and can possibly leach into vegetables. It would be O.K. for flowers and shrubs.
Mike

ciera · 11-07-2007, 01:12 PM

Removing the grass entirely isn't necessary. Just throw a tarp over it for a week, and it will dry up.

As long as you're doing this, you should turn over the soil. The soil is probably too compact for anything to grow well in it. I'd let the grass dry up and then immediately turn it under. That way, you get some organic matter in the soil.

kashimama · 11-07-2007, 01:16 PM

Those are great ideas. Our soil is pretty dense and full of clay around here (part of why I was thinking of doing a raised bed so I could put my own soil mix into there), do you think I should rent a machine of some sort to turn the grass under?

ciera · 11-07-2007, 01:25 PM

Quote:

Our soil is pretty dense and full of clay around here (part of why I was thinking of doing a raised bed so I could put my own soil mix into there)

We have the same problem; we're putting in a raised bed for vegetables right now. Our plan is to combine the few inches of grassy topsoil, some new soil, and some leaf mulch and let it sit over winter. The soil that the grass is in was fine for us, but it's mostly clay 6 inches down.

Quote:

do you think I should rent a machine of some sort to turn the grass under?

The vibrations from the machines cause something called "tiller bed". Basically, you get nicely tilled soil for a foot, but bellow that, it compacts it even more than before. It might not matter much if you've already got terrible soil and are raising a large amount.

We just did ours by hand, so I don't know how much easier it is to use.

BTW, someone told me that gypsum helps turn clay into good soil. He said that it works really slowly, but to sprinkle it on every fall. I haven't tried it yet, but the guy is a Master Gardner and said that you'd see results in a couple years.