After finding a video on YouTube about using reusable grocery bags as a grow bag, I decided to try it. (I was short on planters and had plenty of unused bags.) My roots are growing through the bottom of the bag! I think I planted too close to the bottom. (I planted potatoes, so I thought most of the growing would be up, and I would continue to add soil to the bag to "mound.") I also set the bags out on my patio. I know I need to elevate them now. Is there anything else I should do? I'm planning on putting them in a container with about a half inch of water to water from the bottom up. Good idea? Mistake? Any tips would be very much appreciated. Thanks in advance!

Gardening newbie,
Anna