Here she is.. day 32 today..
Indoor Hope's perpetual Skyline grow
- Thread starter hope2grow
- Start date
you'll have to enlighten me Bro. I dunno what VPD even stands for, let alone wtf it's all about.
And it will probably scare the shit out of me.
And it will probably scare the shit out of me.
Can you separate the driver from the light? I have mine outside the tent to keep the temps down. Also does the 3000 have a dimmer? I have the 4800 and I can only go up to 75% before the plants start to revolt.So having had my trusty Skyline 400 for about 10 years and figuring that her best hours were probably behind her.. I bought a Mars FC-3000.. the one with the Samsung diodes.. 300W.. 4 bars of light.
As soon as I stuck it in the temp in the tent went up to 30c.. and higher.. high 20s at best. It ran around 23/24c with the Skyline in.. usually 50/60% RH. With the temp increase of course came a drop in RH.. the 2 figures getting further away from each other.
I noticed when I moved my grape crinkle from under the 50W spotlight to the 300w mars light that within a few days I had brown spotting on the leaves.. calcium issues.. the plant was about 25 days old and lovely lush green with not a mark on a leaf when I put it under the 300W light.
That was when I started to look for answers. What did I find. VPD!!
Id read about VPD before but never paid much attention as my plants looked healthy and grew fine so the importance of it hadnt really landed with me until I witnessed what happens to a plant when VPD gets way out of range.. the Grape Crinkle was wilting.. felt papery.. leaves curling.. generally unhappy. Of course one of the things that VPD can affect is nutrient uptake as i have now learned.. leading to issues with your plants!!
I put my Skyline back in last night.. the climate changed almost immediately.. temp down RH up.. and the plant looked so much happier.
Then I remembered.. I grew that big Mazar under the Mars light.. in the conditions it generated with VPD a mile off range for most of its life.. so its no wonder she struggled especially after the introduction of the Silic Rock!!
Just wanted to share that experience and the importance of VPD.. im sure all you sensible growers out there already know.. but it may help someone someday! VPD.. it seems to matter lol
Anyway.. while i have you.. anyone interested in a Mars 300w light.. barely used.. mates rates
Yea the driver comes off m8 so thats an idea.. I juat wanted it out of there asap last night.. didn't want to watch the plant suffer any more.. I had it turned down to 75%! Temps still high 20s.. full power temps are 30c +
I'll leave rhe Skyline in for a few days while I mull it over.
Awwww m8.. your know what growers and rabbit holes are like lol Anyway.. its basically the relationship between your temperature and RH and what effect that has on your plants.. long and short is if your VPD isn't in range or close your plant will stop performing the tasks that it needs to to grow.. nutrient uptake being one thing affected.. and in my case.. all my own investigation and conclusions of course.. that translated as an almost immediate inability to take up calcium in the Grape Crinkle when I put it under that light in that environment.
VPD seems simple enough to understand.. a quick Google will get you a VPD chart and a million articles on it.. and chances are unless you deal with unusually high or low temps or RH then its never been a problem and never will.. but if you do find yourself faced with either then as far as I can see you should be concerned about your VPD.
Have a read over a few articles and say wow.. im only discovering this now lol
Seems more prominent in the growing world than it was before with new tech advances etc for reading it.. im looking at a hydrometer that gives a VPD readout as well as temp and RH to keep it handy.. examples below..
Its almost like in the old days.. when we'd say what's your temps and humidity and how many watts are you runnin.. today's equivalent seems to be what's your VPD and DLI lol
Imagine sayin that to a guy 30 years ago as he busts out a big 1000w HPS banger for his 6x6 tent lol just about to add 30c to his room temps lol hed be like waaaaa??
Time marches on.
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