Graytail;3871971 said:
Graytail;3872053 said:Ah, no, that's even better. You're better off keeping the lights high.Rich Farmer;3872029 said:
It's counter-intutive, but you get a deeper effective canopy if you increase headroom. Turn up wattage before you decrease headroom. Then your half-strength point is deeper. Make sense?
[Edit] I originally posted this from a phone and didn't want to go into detail, but I will now. This is something I've brought up a couple times on other threads and I can see that it's hard to grasp. We know that light intensity falls the farther away we get, and it falls faster the farther we get. The Law is that at twice the distance, you get 1/4 of the intensity. We've found, by measuring real life setups, that with widely dispersed sources the loss is more like 1/3 to 1/2. So, if the light is twice as far away, you'll get 30-40% roughly?
At the top of the canopy in bloom, we want 1200 umols of light, and 500 umols is what a plant needs for good metabolism. 500 is, whaddya know, about 40% of 1200. So if the bottom of the canopy is getting its 500 minimum and the top is getting 1200, you have a well lit canopy - very efficient.
That means that if you want a canopy 2 feet deep, you want 2 feet of headroom. Right? Because at twice the distance, the bottom will get 40% of the light the top gets. If you increase headroom, it deepens the canopy. If the tops are 3 feet from the source, then the bottoms can be 3 feet farther away - twice.
My latest setup has been working exactly like that. My lower nugs are now no different than the upper ones, and they're all denser. I'm running 700 watts for bloom in a 4x4, for 43.75 watts/sqft, and I have the lights mounted at 6 1/2 feet off the floor and I can run full canopies 2-3 feet deep. They started with over 3 feet of headroom and grew up to the panels. I have hard nugs that grew the entire time 3 feet from the lights.
Whatever your headroom is, is what your effective canopy depth will be.
