Due to a recent move my grow setup has been relocated to the attic. Im usually in a 1.2m tent but due to the size of the attic this isnt possible so i have a D.I.Y (w.i.p) going on at the min . I have approx 1.5m2 to work with which has been sheeted off with reflective plastic sheeting. I have a 5" intake (to be replaced with an 8" asap) which is taken from a breezy hallway and an 8" outake which is pushed down the other end of the attic and placed between the tiles and the felt (there are no vents atm). 4 X GHS Exodus Cheese (was 5 but 1 turned out to have balls) 2x15l & 2x 25l pots Medium is Sohum Living Soil in Autopots (hand watering when pot feels light til i see runoff in the tray) 1000w HPS in cooltube extracted via the 8" rvk 4 1/5 - 5 week veg (i dont remember the exact dates but do know they were flipped on the 19th may) My issue is with the temps at the minute . I run my lights at night. 8:15am lights off 8:15pm lights on My daytime temps (ie night time in realtime are not to bad) My night temps however drift over 33c at times for around 4-5 hours due to the heat outside DT temps are around 23c - 26c at lights on and by lights out they have either stayed the same or maybe increased to 27c max. The Rh is around 35% to 45% this whole time unless its dropping down from NT Rh of 55% for an hour or so. NT temps start at around 22% (as the temp drops when the hps is off) and on overcast days increase to 27c-28c after around 4 hours and stay like that sometimes for around 4-5 hours until they start coming back down again and reach a low of around 21c-22c for an hour or two , then the hps comes back on . On hot days however during the hot test period the temps could rise to 33c-35c !. Rh ranges in NT from 40% to 55%. I realised about the negative dif after the weather started to warm and i noticed a difference in structure to the plants than in previous grows of the same strain hydro. At the minute there is around 4-5 days of warm weather before a few overcast days set in. I have read up a bit on negative dif and different reports and had a read through this post here https://www.rollitup.org/t/any-advice-apreciated.964561/#post-14261811 1.But i cannot find any where that says how much it will effect yield by? ie will the buds be light and fluffy with no weight ? 2. Do the buds in the pics appear to be small at around 3 weeks since flip? I have also read of other grows where they say they have had great results with negative dif within a controlled environment normally of only a few degrees creating pretty much a zero diff mine can be running a neg dif of -10 at times if i am reading into this correctly . 3. Is it the lowest temp of the night at its lowest point read until the hottest point of the day temp ? Or is it worked on an average overall temp ? Or maybe a temp at a particular time before lights on and the max day time temp? (ive read of the cold air dump) A lot of the grows ive read as i said have been under controlled conditions and so i 4. Wondered if anyone has had to grow under similar conditions before and if so how they turned out as i have looked up what i can but there seems to be very little info on it, as im pretty sure some people i know are completely even unaware of it ...... The plants are around or just over 1m tall and seem to have plenty of light throughout the whole of the plants almost to the bottom as i have plenty of spacing between them as it does get hot directly underneath the cooltube even with the 8" extracting. (i also turn the plants every 2-3 days 1/4 of a turn) 5 Im a little concerned the bud sites although there seem to be quite a lot are quite small and that the stems are quite flimsy and stretched to hold any buds with any kind of weight although they do feel quite firm ? 6 Sohum Soil just plain water all way through or anything added? Till now they have had just plain water ph 6.8 to 7. The temps and rh posted are what they seem to have stabled out to at the minute and have been like that throughout the first few weeks of flower showing sex after about 8-12 days The temps in veg were a bit different as i was obviously trying to get more rh in a dry attic which had an rh of 20% at times before i got the air circulating a bit up there and the plants got bigger. Thanks for any advise , ive attached some pics and added as much info as i can, weren`t sure which section to post in so posted where i thought relevant pics in no particular order although i will edit later.