I think you can grow Basal from a Window Box, inside or out. While it might be best to grow it out in the Garden, a Window box may be the better option when too much rainfall is ruining your attemps. Too much rain or watering can also lead to Shallow Root systems.
Constructing a small HotHouse from 1x2's or 2x4's and Plastic Sheeting would definitly work too. But them you may find yourself watering the plants inside.
Alot of Plant Nurseries around my area have the whole outside area covered with some kind of Screening, that allows Sunlight and Heavy Rain to difuse in. Using this system over a small area of Basal may be cost effective.