How large a pot is needed for the taproot when growing on a patio/DECk? What is the best kind of soil mixture? I'm a senior and never tried this before, though a longtime gardener.
Growing Milkweeds in Pots How Deep for Taproot?H
Certified GKH Gardening Expert
It would be hard to say, as some cultivars have a longer taproot than others. I would say the tallest container you can find. At least a foot tall, but I would recommend more.
You can use a regular potting mix, or mix compost in with it. This will be fine.
Here is an article for more information on growing milkweed: https://www.gardeningknowhow.com/ornamental/flowers/milkweed/growing-milkweed.htm