Raised Garden Bed Liners – To Use or Not to Use

Image via Wikipedia

In response to a recent post on the advantages of raised garden beds, a reader posed an interesting question about using liners in raised beds that many folks might wonder about.

Interesting about raised beds -
Just setting up a few here in UK – going to be about 3’6″ wide x 10′, 2′ high. Going to make of timber but was thinking about what to put at ground level (they are going onto soil). How about thick plastic sheeting turned up to say 1′ around the sides. Will this stop any weed growth up and help retain water? Then was going to put 6″ brick/slate bits then top soil. What do you think? – Alan, Surrey Gourmet

I pointed out in my previous post that one of the advantages of using raised beds for gardening was that they use less water than traditional, in-ground gardens. Now, at first glance, using a plastic liner might seem like a great way to conserve the most water possible. However, it would probably end up destroying your garden – eventually.

Here’s why:

Any planting area, raised beds included, must have adequate drainage – if not, your plant roots will eventually rot and kill your precious veggies.
Most weeds will not find their way up through two feet of soil unless they are of the extremely invasive type like wild Morning Glory, which in this case would probably find their way through the plastic anyway. (They are persistent little buggers!)
Worms and other beneficial critters are great for your garden beds and a plastic liner would inhibit free movement of these creep crawlers.
The deeper root structures are allowed to go, the more moisture and nutrients they will find and benefit from.

The only time I would recommend placing a liner in the bottom of a raised garden bed is if you were going to place it directly on a hard surface such as a patio, rooftop, deck or balcony. You would want to keep your soil from seeping out of the bottom of the planter box, but remember, you still need adequate drainage. So be sure the liner material you use is a porous landscape fabric – not plastic.

Of course having raised garden beds on the ground is ideal, but not all of us have that option. If you do need to place your raised bed on a hard surface, you won’t benefit from the normal movement of worms and such from the ground, but you can add them, compost and other soil amendments to make the most of your situation and still have a grand harvest.

Happy Gardening!

Shop For Roof Top Raised Garden Beds with Liner