watts per sq. ft. and lumens

zvuv

zvuv

Active Member
Your yield depends on a number of things, of course, strain and cultivation as well as light. Growing with an HID lamp one expects to get about 0.5g per watt. Good growers can get 1g per watt. You are not able to make full use of your lamp with a flat canopy because of the narrowness but you can make up for some of that by putting reflective material on the two 4' long walls. HIDs are just great

You want your light as close to the plants as you can without heat stressing them. The hand test is too subjective. I start a bit high and lower the light a couple of inches a time over several days. When the top leaves begin to show the first signs of heat stress - edges start to curl up and the leaf may canoe - back off a bit. If you run cool air across the tops of the plants you can get closer and because of the inv sq effect, just one inch can make a significant difference.

One issue you haven't discussed is cooling. A 400W in a closet is going to need some kind of cooling

PS

Your plants look very good. Not a big yield but it looks like everything went right.
 
Clint Torres

Clint Torres

New Member
zvuv said:
Your yield depends on a number of things, of course, strain and cultivation as well as light. Growing with an HID lamp one expects to get about 0.5g per watt. Good growers can get 1g per watt. You are not able to make full use of your lamp with a flat canopy because of the narrowness but you can make up for some of that by putting reflective material on the two 4' long walls. HIDs are just great

You want your light as close to the plants as you can without heat stressing them. The hand test is too subjective. I start a bit high and lower the light a couple of inches a time over several days. When the top leaves begin to show the first signs of heat stress - edges start to curl up and the leaf may canoe - back off a bit. If you run cool air across the tops of the plants you can get closer and because of the inv sq effect, just one inch can make a significant difference.

One issue you haven't discussed is cooling. A 400W in a closet is going to need some kind of cooling

PS

Your plants look very good. Not a big yield but it looks like everything went right.
Click to expand...
Oh no, those plants in the pics still have 4-5 weeks. i have it well ventilated with the addition of ducting from the light going up and out of the bathroom exhaust fan.

I have been keeping the light about 12' above. i need to go get some panda or ORCA film tomorrow.
 
nicougrik

nicougrik

Well-Known Member
Ok so after reading this.. Watts is a shit measurement for measuring light, since its a measure of consumption and so depends on the efficiency of the light bulb, and not actual output..
And lumens is shit because its in relation to human perspective and makes no sense for plants..

So what is an actual good measure of how much light you need >?
Einsteins ? https://en.wikipedia.org/wiki/Einstein_(unit)
"An einstein is a unit defined as the energy in one mole (6.022×1023) of photons.' ?
 
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