VPD climate around 70-73F
you need to run at around 26c to 28c 78f to 82f, for cannabis preferential growth, to control root temperature,..root temperature has a major effect on nute uptake....... the clawing is related to 'Low" respiration temperatures, stoma struggling to breath out due to high RH differential........... the plant is of ericaceous and tropical origin...... see VPd guide below, room temp controls RH = Vpd............... room temp controls soil temp needs to be 23-24c........ green band is sweet zone.... get your room temp at 26-28c........ it will all re-align itself.....
root temp controls nutrient assimilation, in other words root matrix Ph......... this needs to be within these ranges to assure correct nute uptake and avoid nute deffs..... see how the mg & phos drop out below "Ph5.8"............ asuming matrix temp is above 21c............. ALR
I'm gonna pick up a little oil radiant heater later today unless anyone has another suggestion?
these are the better choice to heat the cab lights out, and to assist cab temps lights "On" if, you use "LED's"....... if not it's a light out thermo fan with safty tilt switch 1kw thermo controlled, so you can have it go "O
" at 28c................come on at 24c.................. the other bennefit is. During flower, the hot metal AAA rated heater ellements, when the room stinks of fruits, in flower, it "Burns Of" some of the terps, delivering the stink !!............. helps take some of the VOc's = terps = aroma flavanoids, removal strain, off the carbon filter...... around 18 quid in Uk............ 1 & 2kw option, and thermo tune dial............
80w tube heaters run at to loew a temp to hit 26c lights out, 24c minimum....... so as to keep RH down during lights out, critically, if "RH" rises above 65-75%.................and the flow over the carbon from the fan is "Too Fast"............... aromas will "Bypass" the carbon filter, as it begins to fail due to dustt logging and high RjH, combined with high air flow ratio's........ oil rads, expensive, and take far to long to reach service temps, you need to set lights off heater fan 'Control Timer" to go "O
" 15mins after lights come on, so no temp drop during transition from lights off, to light on, when the thermo heater fan goes off....... hope that is of some help there Mr K....... all the best with the grow.................ALR
Addendum;
The plants are at 5 to 6th internode stage, so are ready for topping out "Prune" centre stem, above 5th internode............... energy re-direction will begin, end result is 20-25% more weight at drying time......... plus height control in fems.......... the Tooth looks the one to me........ a toothless alien hybrid i wouldn't wonder........... monster strain, tent dominater !! good luck K.........ALR
...Thank you again ALR, your help here has been a real treat for all! In fact, I'll be PM'ing you shortly about topping photo's for outside season,.. I'm over the "nice fat main cola " thing, the damn mold almost always hits there first and worst, so what's the point? 
... less girthy colas seem to fair much better.... this season, everybody gets topped!
