Does anyone worry about their Root Zone Temp?!?

Meant to post this here.

My root zone temp is too high!

I switched to LED and from what I understand plants like much higher temps (85-87F, and as high as 96F with co2) because the leaf surface temperature is substantially lower with LED (lack of IR) when compared to HPS.

My room is currently
Phase: Week 1 Flower (Just flipped 12/12)
Medium: Rockwool - Top Feed - Drain to Waste
Nutrients: Full Heavy16 line
Lights: LED Spider Farmer SF-4000
Room Controller: Growtronix System
Light Intensity at Canopy: 600-700PPFD (I want 1000PPFD but lowering lights more will increase root zone temp)
Room Temp: 82F ( I want 90F but again, root zone temp )
Room Humidity: 62% (Following Early Flower VPD chart, see photos)
Co2: 1200 PPM
Leaf Surface Temp: 76F (I want 85F)
Root Zone Temp: 72-77F (I want 69F)

Watering Temp: 62F

All of the "I wants" I can actually make happen except for the root zone temp, it's already higher than I want. From my understanding I should not water lower than 60F. I was crop steering watering, only 1 minute every every 30 minutes but what I found was that water sitting in lines kept heating up from high room temp and lower water temp would never reach the plants because it was such short intervals. I now just water 2 hours after lights on for 11 minutes with two .5gal dripper's and this allows the Rockwool to get some of that cooled down water from res. These temps above are my current configuration but I would like to raise the temps way higher because I am running co2. Only problem is that my root zone is already high and above 75F most of the day and I want the root zone at 69F. Am I too concerned about the root zone temp? Anyone have high root zone temps with no issues? Roots coming out of the Rockwool are slightly brown and I can't tell if its nutrient stain or slight root rot due to higher root zone temps. Any good advice on how to keep a better handle on root zone temp when running high temp with co2? Or does the co2 allow the root zone temp to be higher as well? Thanks in advance for any advice!
 

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Transition to rdwc so the water always circulating through the chiller?
I have been thinking about switching to deep water, seems like a great way to have constant control of the root zone environment. My room with cooler temps have white roots and the room with hot temps + co2 looks like root rot. Hoping they can still produce some weight but not happy with the roots right now.
 

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yeah, before your canopy make shadow on your cubes you need to run cooler ambiant temps

try to keep your rockwool around 20 degree
Thanks for the tip! I just switched the room to flood tables and bunched the plants together to create a full canopy. Going to spread them out as needed and I am able to save 1300 watts with three lights off now until that spread needs to happen. Take a look at the brown roots above. You think they will still produce something worth while or this is a start over situation?
 

Offmymeds

Well-Known Member
Not that I have a lot of experience but I don't worry about it in a DTW. I keep the rez chilled to 68-69. Using the Mass Pro that came with my bucket system. Watering once a day. If I suspected trouble I might go with watering 3 times a day to periodically chill the roots.
 

Rdubz

Well-Known Member
Maybe a lot of work but get your roots closer to the ground as close to concrete as possible u would just have to make sure when lights off that it doesn’t get too cold but u can control temp with heat after lights off ... just a suggestion don’t know if u can actually implement or if it’s worth it but the concrete will be cooler
 

Southernontariogrower

Well-Known Member
I have been thinking about switching to deep water, seems like a great way to have constant control of the root zone environment. My room with cooler temps have white roots and the room with hot temps + co2 looks like root rot. Hoping they can still produce some weight but not happy with the roots right now.
I've tried hydro a few times, roots always end up stinking even with peroxide, lucky I guess. I've saved many by planting in promix hp, most didn't even slow up. Grow proceeded with no problems. Just a thought to ponder, is soil free, peat,perlite,lime and mycoryzae. I've used it for years
 
I've tried hydro a few times, roots always end up stinking even with peroxide, lucky I guess. I've saved many by planting in promix hp, most didn't even slow up. Grow proceeded with no problems. Just a thought to ponder, is soil free, peat,perlite,lime and mycoryzae. I've used it for years
You were in Rockwool and then went into promix hp? If it was, what size Rockwool cube did you put into the promix? I worry about mixing mediums but might be worth a try.
 
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