Indoor Best light for 8 sq feet

[late]

Saw an article that said 50 watts/sq foot was ideal. With 8 sq ft, that comes
out to exactly 400.

A local store has a very good 400 watt digital ballast that's on sale, it's been sitting
around for a couple years because small growers are usually on a tight budget.
That will give me the ideal amount of light, and allow me to veg at a reduced
wattage with the light close to the plants.

If I am not wrong, come monday I am going to talk to them. Am I wrong?

 

[Son of Hobbes]

Hey bro I don't know what your stance is on Ed Rosenthal's credibility, but there's a snippet from this article that's interesting and pertains to your question.

Here's the article.

And here's specifically what I'm looking at:

CO2 is one of the ingredients for photosynthesis. This is the process in which plants use light energy to create sugar from CO2 and water and release oxygen as a by-product. Under bright lights and indoor conditions lack of CO2 is often the limiting factor in photosynthesis and plant growth. When the parts per million (ppm) of CO2 is increased the growth rate climbs in a linear ratio until light becomes the limiting factor. Under 60 watts of light per square foot (psf), plants can use enrichment to 1500-2000ppm CO2 rather than the 400ppm found in the air.

I had always heard/seen at minimum of 50 watts per square foot but never really knew the answer why (I'm at 100W per sq/foot in my space.) I'd like to do a little more in-depth digging on on the "why" part of his answer, but according to Rosenthal, under 60W per square foot appears to limit the ability to uptake CO2 levels above around 400 ppm. 400 ppm is also around the average CO2 ppm that's in the atmosphere in most places. So at least from a carbon dioxide stand point, if you were planning on supplementing your plants with CO2, you may want to find out if your watts per square foot is a limiting factor.

Here's another Rosenthal Q and A: Enough light?

Is this a 400W HPS? Hood? Tube? Open air reflector? If it's HID, they produce a lot of heat, so keep that in mind! Depending on your ventilation, you may need to add or update some things. Burn and heat stress are more of a worry with HID's in my opinion.

Hope that helps a bit bro! Will try to find out a little more of the scientific part of the "why" for you!

 

[MoChillah]

From my experience, if you're in a limited space, a proper use of CFLs might do an amazing job for you. Also, much less heat than HPS aaaand you can use different spectrums of CFLS for veg and flowering!

Hope I helped!

Good luck!

 

[late]

Hey bro I don't know what your stance is on Ed Rosenthal's credibility, but there's a snippet from this article that's interesting and pertains to your question.

Here's the article.

And here's specifically what I'm looking at:



I had always heard/seen at minimum of 50 watts per square foot but never really knew the answer why (I'm at 100W per sq/foot in my space.) I'd like to do a little more in-depth digging on on the "why" part of his answer, but according to Rosenthal, under 60W per square foot appears to limit the ability to uptake CO2 levels above around 400 ppm. 400 ppm is also around the average CO2 ppm that's in the atmosphere in most places. So at least from a carbon dioxide stand point, if you were planning on supplementing your plants with CO2, you may want to find out if your watts per square foot is a limiting factor.

Here's another Rosenthal Q and A: Enough light?

Is this a 400W HPS? Hood? Tube? Open air reflector? If it's HID, they produce a lot of heat, so keep that in mind! Depending on your ventilation, you may need to add or update some things. Burn and heat stress are more of a worry with HID's in my opinion.

Hope that helps a bit bro! Will try to find out a little more of the scientific part of the "why" for you!

I have one of Rosenthal's books. CO2 is way beyond the simple grows I want to do,
but thanks for the info. The hood is enclosed and quite large for the tent, and I have a fan
pushing air through it.

 

[late]

From my experience, if you're in a limited space, a proper use of CFLs might do an amazing job for you. Also, much less heat than HPS aaaand you can use different spectrums of CFLS for veg and flowering!

Hope I helped!

Good luck!

Actually did my first 2 grows with cfl. Got some used HPS gear, think
I'll stick with it.

Come summer, I may change my mind. I have 2 Florowing lights, and with 2700K bulbs
they might be just the ticket for summer.

 

[Fish Juice]

I'm with S.O.H. on the heat in small spaces thing, but when I run my 4x4 on 400 rather than 600, it's WAAAAAAY cooler, the 400 really doesn't put out much heat at all. GO FOR IT, you can always figure out how to cool the grow area later. Just my two cents

 

[late]

I'm with S.O.H. on the heat in small spaces thing, but when I run my 4x4 on 400 rather than 600, it's WAAAAAAY cooler, the 400 really doesn't put out much heat at all. GO FOR IT, you can always figure out how to cool the grow area later. Just my two cents

S.O.H.?

I have a pretty good setup.
View attachment 309944

 

[Fish Juice]

Son of Hobbes, indeed, you do.