CBD 1:1 Silver Lime Haze Auto

35 days after planting seed. Plants have bushed out quite a lot more this week and gained some height. I don't think it is flowering yet, but I expect them to begin soon. Temps problem has come back the last couple of days I have struggled to get it over 15c. Plants appear to be healthy apart from what looks like nute burn on a few leaves. Decided to cut back on the rhizotonic this week, will probably cut it out altogether next week. A few changes to the set up this week, changed light from Meizhi "450w" to a Meizhi "900w" and put turned my autopot system on. I have noticed there are lots of lower branches developing underneath but are not able to get much light as are under a dense upper canopy of large leaves. would I benefit from any sort of cropping?