So I was having a problem with stretch. A couple of plants grew from 6" to 24" in 2 weeks with very large spacing in between nodes. Part of the problem which i have resolved (I think) was the light (a 4 bulb T5) was too far away. I pruned the tall plants and moved the light closer to the canopy. Right now the bulb itself is 2-3" away from top of the canopy. Second part of the problem (I think) was overcrowding. I had 24 plants in 4x4x4" rockwool cubes in half of a 3x3' tray tray under the 4' T5 lamp. The rockwool cubes were all next to each other with no space in between. There were a lot of leaves touching between the plants. I read in a couple of places that overcrowding will cause the plants to stretch, competing for the light. So I took the 6 weakest plants out and spread the rest apart evenly. Does overcrowding cause stretch? Do the plants now have enough space to avoid more stretching? The strain is sour diesel. I will be vegging these plants to 2' before I flower them. The internode lengths at the top three nodes average about 2 - 3 cm. Is that about right? The other nodes down to the roots average about 4 - 5 cm. Is that about right?