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I was just wondering what is the best temperature for c02 enrichment, to achieve optimal growth rate. I have heard and read many different things. Like above 85 up to 95 degrees is best and that below 80 it is pointless to use c02. I have also heard that between 75 and 80 is best and that when temps get above 90 growth rate is stopped completely, even when using co2. Someone must be wrong here.
I would really appreciate if someone could shed light on this subject.
if i'm getting 1500ppm, i like to keep my temps between 82-85. any higher and some strains will being to show heat stress, especially ones directly under the HID.
from Marijuana Horticulture - The Indoor Outdoor Medical Grower's Bible (just so i also post an official source):
Quote:
Carbon dioxide-enriched cannabis demands a
higher level of maintenance than normal plants.
Carbon dioxide-enriched plants use nutrients,
water, and space faster than non-enriched
plants. A higher temperature, from 75 to 80°F
(24 to 26°C) will help stimulate more rapid
metabolism within the super-enriched plants.
When temperatures climb beyond 85°F (29°C),
C O 2, enrichment becomes ineffective, and at
90°F (32°C) growth stops.
yea man, I have read that one, but I also have seen this in ed rosenthal's book
Standard growing conditions typically include concentrations of CO2 at 300-500 ppm, temperatures between 65-80°F, and relatively low humidity (20-40% rH). Studies have shown optimal growth and yields at 90-95°F, 1,500 ppm CO2, 45-50% relative humidity, 7,500-10,000 lumens/square foot of light, and vigorous air movement both above and below the canopy. CO2 enrichment under 80°F, under 7500 lumens/sf, or above 50% humidity is not recommended because plants will not be conducting photosynthesis quickly enough to benefit from the enrichment.
ya see what I am saying, there are many different points of view here.
Anyone else got a opinion on this subject ?
I think you want it as warm as possible w/o stressing the plants. The temperature that begins to stress the plants will be strain specific. I've found 85 degrees to be a temp where some strains begin to show heat stress with clawed leaves.
My last batch was finally weighed and jarred earlier this week. With temps not exceeding 85 during the day and dropping to the low-mid 70s at night and supplementing CO2 to 1500ppm and keeping humidity under 60%, my last harvest of 5x 600watts was 1.24 grams per watt; some sativa dominant, some indica dominant.