Rehabilitating an old garden bed

Asked November 9, 2017, 9:34 AM EST

Hello. We removed the shrubs from the front beds and found various things. There was plastic, like from mulch bags, carpet, asphalt roofing shingles and lots of pea gravel. I'm sure it did a lot to keep the weeds down. I removed the carpet and plastic. Some of the carpet degraded so the backing has left kind of a colored film on the soil. I have picked out the largest pieces of shingle but there many small pieces. We have dug out some of the gravel but there is still plenty. I intend to put shrubs in these areas. Should I be concerned with bits of shingle and carpet film? Also should I keep trying to remove pea gravel? I've never seen anything like this. Linda

Gratiot County Michigan

1 Response

I could not find any literature about the shingles harming the plants. I did find a caution about using shingles for mulch in a vegetable garden but that isn't the plan here. Small pieces from shingles end up in soil around houses just from the removal of old roofs. If you have removed all the large pieces and maybe fish out the larger fragments from time to time you should be ok.
The film from the carpet is another story as it may inhibit water movement or root growth. Can you remove most of it? As far as the pea gravel is concerned, I am assuming that I can see it in the photo... all the small white pieces. You should remove sections of just pea gravel... Roots won't thrive in it. If it is mixed well with top soil and some compost, an amount of it shouldn't be a problem. You want to have more soil than gravel.
I would encourage you to test your soil with a MSU soil test. This will cost you $25. A kit and self mailer is available at "MSU Home and Garden soil test self mailer" Be sure you have the Home and Garden version. This will advise you on your soil ph, amount of organic material (versus pea gravel) and give fertilizer recommendations.