Negative Dif & High Temps...

Discussion in 'General Marijuana Growing' started by fatc2k3, Jun 10, 2018.


    fatc2k3 Well-Known Member

    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

    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.

    Attached Files:


    fatc2k3 Well-Known Member

    pic of male before being tossed.

    Attached Files:

    Lucky Luke

    Lucky Luke Well-Known Member

    Mid 30c is very doable. Lots of air movement.

    Attics are meant to be really difficult to grow in. GL

    ANC Well-Known Member

    There is only one real exodus and she doesn't grow balls. It is cut only... unless you want to buy those femed shit Franco made.
    Kingrow1 likes this.

    fatc2k3 Well-Known Member

    I have a 12" oscilating fan blowing a gentle breeze between the tops of the plants and the cooltube. Im more concerned that the temp is so high of a night time as im sure i read in one of the reports in late flower this can cause issues?
    Ye i suddenly realised after i thought i had everything planned out that growing in the attic maybe wasnt the best location lol.

    I know the the only true ex cheese is from a cut only but ill have to settle for second best as i dont know anyone with a cut :)
    Dr. Who

    Dr. Who Well-Known Member

    So I gotta ask. Whats your beef with S1's?

    Kaliman does a good S1, So does Greenthumb.

    I would consider those to be true female Ex......
    Then, there is the fact that males do happen from "fem"ing female plants.....Say 1:3000 beans are male. Get the idea from that? Kinda left field but,,,,,,

    Kingrow1 Well-Known Member

    There not pure like the cut, no beef if its as good as the cut, most arent :-)
    Dr. Who and ANC like this.

    ANC Well-Known Member

    many people have tried to copy/modify exodus....
    None of them, in my opinion, is like the original great bear.
    Dr. Who and Kingrow1 like this.
    Dr. Who

    Dr. Who Well-Known Member

    Kali's is taken from the original cut, same for Greenthumb.

    Agreed on the everything but...If it ain't the cut..

    Kali did "F" with the cut in his other offerings. Yet one of them is quite nice and still very popular near my parts.....Rasta version or something like it....

    Kingrow1 Well-Known Member

    When weed gets that strong and good you cannot modify it as its already at its max imo, why cheese is never as good as the original cut.

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