Night time temp differential with LED

[ruwtz]

Running x8 3590's @ 1.4a in veg only (5000k) on a 3x7ft e&f table.

I have 12k BTU mini split AC keeping the room at 75F, and a dehu at 65-70%.

Plants are fine but in my ongoing attempts to refine everything I would like to establish a night time temperature drop if possible.

These cobs kick out hardly any heat that would otherwise contribute to a natural temp decrease at lights off, as with HID etc.

I cannot program a separate temp for the AC but it does have an on/off timer program, which I trialed to sync with the lights off. However since this room is 90% sealed this didn't really do much: temps just held in the mid to high 70's. I'd rather condition the air and keep that number stable, so AC continues to run 24/7.

There is no intake or exhaust nor do I want it, so outside night conditions won't be brought in. Tank CO2 is added in small amounts throughout the day.

Any cool ideas, cob users?

 

[weed-whacker]

other than the obvious i got nothing

 

[ruwtz]

other than the obvious i got nothing

Ok cool

 

[optzulu]

A split airco for 400W of Cree CXB ? Thats a overkill , best temps when light on is +- 80F and off 73F its importent that the temprature drop goes slow just like in nature.

 

[ruwtz]

A split airco for 400W of Cree CXB ? Thats a overkill , best temps when light on is +- 80F and off 73F its importent that the temprature drop goes slow just like in nature.

8x8 room with 10ft ceiling also sharing with nursery, so no its not overkill, the AC just doesn't have to work very hard / is more efficient.

I'm gonna disagree with your temps there too, although its all relative to the room, available CO2 and of course humidity.

And nature? Dude we're growing in space labs, this isn't nature anymore. But I get what you're saying.

 

[sixstring2112]

I like to run 78f lights on and 75f lights off.i have good control for that but with my ac cycling it does range from about 75 to 80f during lights on.i ran 78f on and 68 to 70f off for a long time and i think my plants are happier keeping the temps closer now.

 

[optzulu]

Nevermind...

Not worth it

 

[ruwtz]

Haha al those American growers with there indoor grow labs. A lab ... a wooden box you can call it yes.

It was a joke, friend. Do you have those over there?

 

[optzulu]

Nah my english is bad Going to get hard to explain why nature always wins.And even harder to explain why a spike in the temprature drop is effecting your hole grow and you cant see it until your harvest is on the scale. And its to late

 

[matriculated bean]

8x8 room with 10ft ceiling also sharing with nursery

Running x8 3590's @ 1.4a in veg only (5000k) on a 3x7ft e&f table

You could get a water chiller, position it outside the conditioned space and try going radiant (thinking radiator and fan). I would think canopy temp swing of 10-20+ degrees? and root zone swing between 5-10 degrees. 1 chiller, 1 rez, 2pumps, a timer, possibly a thermostat, a fan, plumbing and a radiator. Pump 1 runs all the time from the chiller to the rez, pump 2 and fan are on the timer or timer > thermostat.

This might be a little beyond the pale so to speak, but since you're already doing E&F I would suggest looking into DWC for the flower room. E&F provides slower growth than DWC and transitions nicely to DWC using expanded clay type medium. Veg in E&F, flower in DWC, or better yet if you can keep from overgrowing your veg space go DWC for both. Since IME, the main benefit of DWC is aggressive plant growth in veg.

Also with DWC you can get more consistent and better control day/night root zone temps separate from canopy. E&F or F&D? is the way to go normally I'd say, since you are wanting more control you might consider DWC though.

.

 

[ruwtz]

Nah my english is bad Going to get hard to explain why nature always wins.And even harder to explain why a spike in the temprature drop is effecting your hole grow and you cant see it until your harvest is on the scale. And its to late

Actually at this stage in veg the lack of a temp differential is keeping them short and stocky, which is ideal ahead of the stretch. I have Gavitas waiting in flower so the diff is inevitable due to hot lights.

I'm not disputing nature, i'm just saying its not always a useful word to throw around since we are continuously manipulating this plant for our own interests in very unnatural ways. We take a 9 month cycle and squeeze it into 12 weeks... if this is just nature then she is just on steroids.

You could get a water chiller, position it outside the conditioned space and try going radiant (thinking radiator and fan). I would think canopy temp swing of 10-20+ degrees? and root zone swing between 5-10 degrees. 1 chiller, 1 rez, 2pumps, a timer, possibly a thermostat, a fan, plumbing and a radiator. Pump 1 runs all the time from the chiller to the rez, pump 2 and fan are on the timer or timer > thermostat.

This might be a little beyond the pale so to speak, but since you're already doing E&F I would suggest looking into DWC for the flower room. E&F provides slower growth than DWC and transitions nicely to DWC using expanded clay type medium. Veg in E&F, flower in DWC, or better yet if you can keep from overgrowing your veg space go DWC for both. Since IME, the main benefit of DWC is aggressive plant growth in veg.

Also with DWC you can get more consistent and better control day/night root zone temps separate from canopy. E&F or F&D? is the way to go normally I'd say, since you are wanting more control you might consider DWC though.

.

Thanks for some clever thinking there, its food for thought. I definitely have an unorthodox approach in using E&F with hydroton layer and these 4x4 rockwool blocks, and refining is a challenge. Its working ok so far.

Currently the flower room plan is blocks into fabric pots of coco as this is an easier transition for me from a few years of soil outdoors. Once I am up to speed with strain traits, DWC can be a future option for sure.

 

[matriculated bean]

I always thought hydroton worked great for both E&F and DWC. Straight from the aero cloner into hydroton. Never used the rockwool though. Rapid rooters on occasion. DWC veg growth rates really can be a problem if you run longer than expected in flower lol.

 

[ruwtz]

I always thought hydroton worked great for both E&F and DWC. Straight from the aero cloner into hydroton. Never used the rockwool though. Rapid rooters on occasion.

Seeds exploded out of Root Riots (same as Rapid Rooters), but I had challenges stepping them up into these 6x6" Pargro blocks for the first time - so easy to overwater saplings and overfeed due to salt buildup. I flushed, dried them back and then hand watered until roots emerged from the base. Now roots have fully colonized the blocks and we are back to flooding. This took a couple of weeks to get right so its a minor setback and a good learning curve.

Flood level can be set very low and the blocks will wick up before draining fast and pulling in oxygen to the root zone. They are designed well, just takes some tweaking.