my guess is that it depends on the type of lights you are using and its known that HPS have higher Lumens than any other bulb so maybe thats a factor too. I find HPS bulbs are generally more yellow which i find makes them grow tall as well.
sirruler Reviewed by sirruler on . This makes no sense ........... I have had 5 plants under a 400w MH bulb for almost 2 weeks now and they are green as hell and have nice big, fat leaves but they dont seem to be getting taller. A few grows ago when all I had was an HPS bulb I didnt seem to notice this type of behavior so I guess my question would be does an MH bulb slow down vertical growth??? At the rate they are going I'll be retired before I can clone them lol (but really crying :( ) Rating: 5