For mother plants I would use larger container than 1 gallon, esp if you want to keep them for awhile.
One gallon works very well for flowering plants in, if you don't let them veg too long or get too big.
Flower when they are 1 foot or less and you should be fine.
You can fit a lot more of these 1 gallons under lights than larger containers, so if you keep them sorta short you don't sacrifice too much in yield using smaller containers...(depending on strain).
I like to start seeds once they pop open, in 16 oz Styrofoam cups, I transplant to larger container after a couple of weeks.
I have grown plants to mature, potent buds in containers as small as 16 oz.
....you get a much smaller yield, and the little buds have to be watered more often, but it can be done. They turn into little popsicles, even without pruning them.
I have done this with lots of the plants I am too lazy to transplant, after they don't make the cut for transplanting, and they also turn out to be female! I only kill the males!
I grow using soil-less mix.