I've always used smaller plastic pots sitting in trays from the grow shop with decent results, but I just read an article on how much pot size can increase yield by means of root space and I want to start using 5 gallon buckets. Ultimately my question would be... Are drainage holes 100% neccessary? With my current setup I just don't have the space to use buckets that large and have drain holes in the bottom. I've read somewhere that people have grown without drain holes; you just have to water very accurately so that you're not overwatering at all and the plants are absorbing everything. And obviously this would make flushing the soil impossible at the end of flowering as well. I would appreciate anybodys input on this!