From a different angle: tawraste do you top your plants? Here's four options that I've used to control height.
If you do a double top for 4 colas you will get shorter plants than if you left it for a single cola. The extra time it takes to veg gives you more time for the plant to mature while staying short in Veg. I find double topping easiest but you could tripple top for 8 colas 12" long each in veg and get less stretch in flower, maybe 18" - 36" depending on strain. I put a Big Laughing clone and a shitty genetics AK 47 clone in aero flower at 5" and 4.75" at the same time, now the BL is 14" and the AK 28". You'll have to get to know your strains.
Another trick for keeping a plant short is to keep your plants in a small pot for the first week or two of flower, the roots can't grow properly so they can't feed/water the plant to make it grow taller. In flower you transplant to your bigger pot to let the roots grow. Robs you of yield but it keeps the plant short. If you notice root lock when you transplant rub your hand on the sides of the root ball to break some roots to grow out into the new medium.
Train the plant to grow around the pot, then to the center of the pot and straight up. Very simple to do with a young plant, a 12" bucket gives you 37" of plant around the out side, another 8"-12" of lower stem bending towards the edge, another 6"-8" going back to the middle, and up as much as you want. I've done with 12 x 6'-8' sativas and got my best yield ever - the buds grow straight up and get the most light. Extra work. One plant, one pot and no screen, SOG basically.
Finally, and I'll leave you alone - Flower with a 3000 K to 4000 K HID. I use a 3000 K MH Sun Pluse, less stretch than a 2100 K HPS and the buds are tighter. There are some great MH bulbs out there for flowering, like the Sun Master Warm Deluxe. Make sure you get a full spectrum light if you're going to use MH for flower. I've noticed a decrease in yield - volume - because of tighter buds, but very very little decrease in weight. I grew with HPS for 5 years, MH for 1 and I'm sold on MH for flower for personal bud (not commercial unless premium priced).
SunPulse PS Lamps
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