Well if they are black on the inside it shouldn't be bad as long as it is light proof, i thought that they were all white bags. If you want to gro in bags ask your retailer about Supernatural Gro Pot bags. The muti layered bags have a high air exchange in the root zone. Super size tip for you is never feed your plants though the top, it is natural for the roots to search out water by going down to the bottom of the bag. Feed from the bottom, top feeding causes roots to be lazy, creates a weaker plant. The more your roots go down the bigger plants you can have. Try ti out you will notice a difference but if the plant does not take up all the water from the bottom, then dump out the excess in the tray