Try to stop me m8
Since I've started measuring the VPD and adjusting for that instead of the humidity I can see an improvement in growth. Not everything is nutrient related like many of us like to believe. Hope I'm not stepping on to many toes by saying this
Example: If your plants are unable to evaporate water, it is unable to uptake nutrients and so the roots die off and we see pH related issues in the leaves.
Why is this? Because we created a traffic jam in the circulation within the plant.
What to do? Lower the humidity in the tent so the leaves get the chance to evaporate water and the circulation is started once again. Or...
Example2: Other way around. The humidity in the tent is to low...You'll start noticing thick and leathery leaves, signs of overfeeding and clawing at worst.
Why is this? Because of the low humidity, the plants are evaporating more water and therefor more nutrients then they can handle.
What to do? Raise the humidity in the tent so the leaves don't evaporate as much water and less nutrients remain unused and pile up inside them leaves. Or...
And with the 'or'...comes VPD into play, because we can not only raise or lower the humidity, but also use temperature to keep VPD balanced.
In large professional grow spaces where the price of HVAC is more important, they tend to grow the plants at a higher temperature as then they can keep the humidity a tad higher and so save on the electric bill for the extraction fan as this can be run at lower speed...
Running things at higher temperature also has the advantage that you can add co², more light (DLI) and maybe even a bi-daily leaf feeding to speed things up to the max...This also means you need to water more often and so watch nutrient uptake, maybe even lowering the amount of nutrients you are giving with each feeding. This is of course more of interest for people growing with bottled nutrients, instead of the Organic way of growing we are doing, but even then we can adjust the amount of available nutrients by adding more or less bennies and feeding those (with Orgatrex) or deny them their carbs...
So since I've kinda became useless in these grows as I only needed to water, I started looking at other things to improve my skills on and this year it's...yep, you've guessed it...VPD
and I'm also watching my DLI as not to give to much light to the plants and prevent light burn, but VPD has got my main attention.
Anyway, I'm gonna stop talking now...
