GrowTip:
Typically in weeks one and two, the plants are drinking less.
In this stage, the VPD should be around 8.0-11 which is a temperature of 77° – 79°F and 65 – 75 percent humidity.
Once the plants are in flowering and need to uptake more nutrients, the VPD should be around 10-13.5. This would be weeks three through four. To achieve this, temps would be a bit lower around 75° – 77°F with a humidity around 55 – 65 percent.
As you move through the flower stage, the VPD would then follow to between 13-15.5 in weeks five through nine. This would mean lower temps around 74° – 76°F and a relative humidity between 42 – 51 percent. This cooler and drier condition will allow the medium to dry out more evenly so that you could have more consistency with irrigation dry downs. The cooler temps will also better preserve the terpenes on the plant.
