I have 9 dahlias which I started off in April in my conservatory. They're getting quite big now and I'd like to plant them out, but we are buying a house and will probably move early July. I have a couple of big 50 cm Milano planters. Do you think I could put 3 in each or would that be too small? Ideally I'd like to put them in the ground but won't be able to do that until we've moved.