Tried finding out some data on asphalt roof shingles as to whether they are good for plants or bad. The Internet is mixed on this question. A University says that tar is toxic to plants. But that does not make sense relative to the known fact that each year now I receive baby trees grown in tar-paper pots.
What brings me to this issue is the fact that I have about 50 bundles of unused asphalt shingles. I have several options-- 1) sell them cheap to get rid of 2) haul them to the dump 3) use them as a mulch or ground cover in the tree windbreak and perhaps elsewhere in the gardens.
So, what is the straight truth about asphalt shingles relative to plants? Are they toxic. Or do they help plants in providing acidity and micronutrients to the soil as well as acting as a mulch.
If I recall, raspberries seemed to love the soil where trash and tires and shingles were dumped.
So who is correct, the college professor who says tar and asphalt is toxic to plants or the commonsense inference that since tar-paper pots are normally used with plants says it is beneficial to plants.
I suspect the tar in asphalt shingles provides much needed sulfur to the soil and makes a base-pH more acid pH.
The science literature on tar in soil is contradictory.
Archimedes Plutonium