Looking for advice for renovating garden beds that had plastic weed barrier

Asked July 9, 2018, 4:21 PM EDT

Hi folks, I'm a new homeowner in zone 7a looking for some help with the best way to proceed with renovating my garden beds. The previous owner put down 6mil plastic weed barrier and mulch. Under the plastic looks like mostly clay. I plan to scoop up the dead mulch and put it in my compost pile, then pull up the plastic and till the top 4-6" of soil before putting down 3" of new mulch. Is this the best way to proceed? Should I also mix in any compost or fertilizer? Thanks!

Cecil County Maryland

1 Response

Yes, by all means remove the mulch and plastic. The old mulch has not broken down yet, so if you want to use it elsewhere, you certainly can do that.

Before you till the bed, you'll want to add organic amendments to the clay soil. Good topsoil has at least 5% (by weight) of organics.

Also, do a soil test. It won't take long (search 'soil testing' on our website). Then you can also add any nutrients that are low when you are tilling it all in. It is especially important to add lime to get the best pH if you are planting vegetables. And tilling is the best way to get lime into the soil. Spreading it on the soil surface is not as effective (it will only penetrate about an 1" because it does not dissolve like fertilizer.)

After you have tilled everything in, then apply the new mulch. We recommend 2-3".

If you want to raise vegetables, here is more about veggies in raised beds:

Soil- general

Soil supplies plants with water, nutrients, and mechanical support. Ideal vegetable garden soil should be loose, deep and crumbly. It should drain well (water should not stand on top after rain) and contain plenty of organic matter. Good garden soil will deliver the right mixture of air, water, and nutrients to grow a large root system and strong, productive plants.

Test the soilTest the existing soil where the raised bed will be located even if you plan to add purchased topsoil. Pay for a basic soil test from a certified soil lab (more accurate and complete and usually less costly than diy testers. The pH level should be in the 6.2-6.8 range.) Test your soil for lead. Soil test page with link to list of certified soil testing labs.

Use existing soil If the soil is in good shape (not compacted, drains well) add 4 inches of compost and mix it with the top 4-inches of existing soil using a tiller, spade, or garden fork. You can also help loosen soils with high clay content by pushing in your garden fork and rocking it back and forth. Move the fork 6-8 inches and repeat across the entire bed.

To have permanent pathways around veggie raised beds, cover 2-ft. wide pathways around the raised beds with newspaper or weed barrier to kill vegetation. Dig up the top 2-3 inches of soil and dead vegetation and add it to the raised beds. Your permanent paths can be covered with wood chips, shredded bark, brick, or heavyweight landscape fabric (>3 oz. per square yard). If you don’t have time to kill the vegetation in the paths you can slice through it horizontally with a spade. Compost the weeds and grass and dig out 1-2 inches of soil that you will add to the raised bed.