What should be under my raised beds?

15 years ago

I have an area of my backyard that has landscape plastic on top of the soil and then about 4 inches of gravel/small rock on top of the plastic material. I want to build raised beds for a vegetable garden on this area, but I need to know if I need to remove the landscape plastic and gravel/small rock, or if I can build my raised bed right on top of the gravel. I was thinking the gravel/small rock wouldnÃ¢ÂÂt be a problem as it would create great drainage for my garden, but I am worried about the plastic Ã¢ÂÂsuffocatingÃ¢ÂÂ my plants because of standing water. Since the raised beds will be approximately 10-12 inches above the landscape plastic I thought it might not cause me any problems, but am unsure. Any advice will help! Thanks!

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Comments (2)

mayberrygardener
15 years ago
Sara

I'm not sure what kind of drainage you have off of the rocks/landscaping plastic--if it were raining, would the water puddle there, or would it run elsewhere? I think that's going to be your big question. If the water doens't have anywhere to go, then you'll definitely need to pull the plastic out.

I don't know how many beds your planning on, but if I may make a suggestion: Regardless of drainage, how difficult would it be to "trace around" where your final beds are going to go, and pull up the plastic? That way, you have drainage under the raised beds themselves, and still relatively clean walkways between. Should you do this, I can't recommend heartily enough the lasagna-style bed preparation--putting down newspapers, and layering brown and green (aka "dry" & "wet") compostables, for improving not only the beds themselves, but also drainage. All those friendly underground tunnelers, aka worms, not only feed the plants, but also loosen the soil underneath, making life much easier for both you and your plants.

If you do that, you could even leave the landscape rock in place under the beds--and wouldn't that be a labor- and time-saver!?!

Since your full-on lasagna bed would still be cooking down as you're getting ready for planting, you could build the beds, rip out the plastic under just the beds, layer in the newspaper/corrugated cardboard (many places don't tell you to avoid the glossy or colored pages if the bed will be for edibles, since there is bad stuff in the dyes; same thing for avoiding things like cereal boxes, etc. Doesn't matter if it's for flowers-only beds, unless you might change the plantings in the future) and the first several layers to the top of the raised-bed frame. Then, assuming any of the landscaping plastic is still in any semblance of usable, cover the beds with the plastic to help it cook down in size--this will happen pretty quickly, especially if you dampen it down (do not soak, though) with the hose before covering, even better if you can sprinkle a little compost-starter on it. Then, when you're getting ready to plant, you can bring in whatever you were originally going use to fill the raised beds, and you'll need a lot less of it; also, it won't fully "cook down" and leave your beds looking like they need to be filled, which is how it might be if you only used the lasagna method. Really, for 18-24" bed of stuff, it just doesn't fit into a 10-12" tall raised bed without going everywhere!!

Good luck, and let us know what you end up doing with the beds!
digdirt2
15 years ago
I believe you will be much happier with the beds and have less problems in the long run if you remove both the gravel and the landscape fabric - especially the landscape fabric.

Many find they have to dig up their beds later because it creates what is called "ponding" with the water in the beds.

If the fabric is still intact you should be able to just use it as a tarp and lift the gravel right off the desired area.

But I also agree that mayberrygardener has a great ides to leave it as paths between/around the beds.

Dave
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What should be under my raised beds?

Comments (2)

mayberrygardener

digdirt2

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