is it neccesary to have drainage holes at the bottom of a container... i have 2 plants growin in approx 1 gallon plastic folgers coffee cans neither has holes and one plant growing in a cut off gatorade bottle. (until trasnplanted) should i put holes in these? if i dont will it affect my plant? it seems no holes would mean water lasts longer and im leaving for five days next week so i was hesitant to put holes in my pots.. also will my plants need to be trasnplanted from the 1 gal containers?