Lowest light intensity with good results?

[Red Fang]

I was inspired by another similar poll, but I am not talking total light like they were there, but light intensity. what is the lowest intensity you have gotten with good results, you know something that would have bag appeal?

 

[FreezerBoy]

50 wsf is considered minimum. 100 watts, the point of diminishing returns.

 

[lost in a sea]

you need a powerful enough light, to penetrate far enough through your canopy to give all your bud sites enough light...

the ability to get enough light to all your bud sites would also depend on the height you wanted your plants to acheive, what structure (ie topped and bushy, or single cola'd and columnar) and how densely your plants were packed in to the area...

like FB said, 50-100 watts per foot is best to aim for because in most cases it is intense enough to go all the way through to the bottom bud sites......but with a light rail you can cheat and have double the number of pants on half the wattage !!

 

[Red Fang]

really? I almost started growing almost 20 years ago, and opted for outdoor instead. But the thinking back then was 20 minimum, 40 diminishing returns right? how things have changed!

ps. I still think I heard someone suggest you could even run a single 1000 in an 8 x 8 area!
I guess that is "old skool" but what do I know? That's what I want to find out! So are we talking 50 minimum even without CO2 or only if you use CO2?

pps. I meant 60-65 in the poll, not "over 60-65". that should be obvious but wanted to clear it up just in case.

 

[Red Fang]

yeah that's what I would prefer to do, as low a light intensity as would produce good results so I can have a larger space with more plants. Let's assume the use of 1 or 2 lamps of 1000 W each for example, what size room would you build if you had a basement where you could construct any size room?

 

[Castelvetro]

for vegging im blown away what low light to ''some'' will really do, im not a big believer of sprouts under a 1k simply becuase the sun is so powerful and nature is nature.. for budding from what ive seen on this site id say even in budding its far below what about 85 percent of people believe wil produce nice nugs, we all know more is better for budding, 50 watts psf doesnt sound bad-

 

[FreezerBoy]

really? I almost started growing almost 20 years ago, and opted for outdoor instead. But the thinking back then was 20 minimum, 40 diminishing returns right? how things have changed!

I started with a 150 or 34 wsf. Now I've a 250 or 56 wsf. The difference is staggering.

 

[Red Fang]

I imagine it would be. But is that partly due to them being 150's or 250's, therefore less penetration due to less total lumens? With 400's or 1000's could the intensity be a bit lower with good results? Well let's just use a single 400 and a single 1000 as examples then, if you could construct any size room to house those lamps, you would construct an 8 square foot and a 20 square foot room respectively? Would the yield be better or the same in a larger room with more plants?

 

[stink.whistler]

A 1k @40 wsf (5x5 footprint) is the sweet spot IMO.

 

[FreezerBoy]

The difference was wattage. Lumens measures the human eye's ability to see the green light the plant rejects as useless. Supposedly 600s are the most efficient.

In your scenario the larger room will yield more because it's a larger room and holds more plants. It would also yield more per plant due to increased penetration.

Lamps throw darkness ahead and little behind, light goes perpendicular to the lamp. Because of this, square gardens should be avoided in preference to one that is slightly more rectangular with the lamp parallel to the short side of the grow.

 

[Helis]

https://www.icmag.com/ic/showthread.php?t=144438

I've been monitoring my own grows closely and have been growing between 3400 and 8000 Lumens per sqft with CFL's and 150 HPS. I have yet to get over 8000 Lumens/sqft.

My grows are running 7-9 g/1000 Lumens or 1.2-1.3 g/w if I had a 600 HPS. The g/kL is linear and I haven't shown diminishing returns by increasing lighting intensity.

With the CFL lighting, the point of diminishing returns in g/w is about 85 w/sqft.

I'd like to throw my 2 cents into the pot. I'm a hobbyist and a medical grower and there's a difference between Hobbyist and Commercial growing.

When you look at g/Lumens it is a fair appraisal of the grow interms of the light intensity and can be used as a general comparison between growers and technique.

From a commercial point of view, g/watts makes sense as it is a measure of efficiency in terms of power consumption. If this is the yardstick to be used, then this measurement is strongly biased in favour of the 600 HPS which produces 150 Lumens/Watt.

With my cab at 5400 Lumens/sqft of CFL's, I'm running 0.6 g/sqft/day with a 9 week LUI, 10 week Shiskaberry and a 11 week Thai-Lights. All the results are close over 2 back to back grows.

The best I've grown is Shiskaberry 0.9 g/sqft/day with a 150 HPS @ 75w/sqft, 8000 Lumens/sqft.

Here's a table of common bulb wattage sizes and their Lumens output.

If we accept that a 600 HPS @ 55 to 65 w/sqft is the optimum, then 8,000 to 10,000 Lumens/sqft is the optimum light intensity.

The Lumens per Watt falls off terribly with the smaller lights. If you have a large grow room it makes sense to add more growspace than to add another light. With the small cabs it makes sense to setup for 8000 to 10,000 L/sqft even though the g/w falls off between 75 and 85 w/sqft.

Incidentally, to make g/w a fair assessment between lights, multiply your g/w by the W/L multiplier which is normalizing it to the output of a 600 HPS light.

Hope some of this helps... Was just reading up a few minutes before you posted.

 

[habeeb]

go with what you have, plants can "flourish" on what some people call impossible

bag appeal means nothing to me..

 

[stink.whistler]

Other points to consider -

• LEDs dialed to specific PAR values will most likely give you lowest light intensity w/good results in the future, but the kinks are still being worked out...
• With a single light, you can lower the w/ft2 needed w/ a light mover
• With multiple lights w/ no mover you can lower the w/ft2 needed by configuring either 3 in a triangle, or 4 in a square (as opposed to rows)
• Highly reflective wall surfaces fully enclosing the room will help you get the most bang for your buck (flat white paint, cleaned fairly regularly & repainted when needed is the most practical)

And, Habeeb makes a good point

 

[Castelvetro]

i find the hopes of l.e.d lights to be to high, for small gardens they might have there day but im not holding my breath or saving my dough for overpriced kits like they are now. plus warm radiant heat seems to make plants very happy.

as crazy as it sounds, with l.e.d's being so cool they should design them to be actually hung right on your plants like christmas lights.

 

[Red Fang]

ok I saw a thread on sealed vs unsealed rooms, and if you are running 2k or less would it pay to still have a sealed room? For smaller personal grows in other words? Using an AC is something I'd rather avoid and for personal growers on a budget I would think sealed would be not needed, right or wrong?

 

[Aerokush101]

This is more like it, let me put my vote in...

 

[Hydrosun]

50 wsf is considered minimum. 100 watts, the point of diminishing returns.

And that conventional wisdom is crap. Here is a pix of 56day Purple Kush run at less than 80% of that minimum. I got a little over 12oz per plant. 49.5oz in 50 square feet with 2Kw or 40w per square foot, however if I had a light mover instead of two lights I could have gotten the same 3lbs with 20w per square foot. The proof is in they pudding as the say.





There is no way that I could have doubled to 99oz by going from 40w to 80w per square foot. The point of diminishing return for each additional watt of light begins WELL before 100w.

Peace,

 

[Castelvetro]

your overestimateing light movers, for the most part there shit and yeild nothing, if you have a 1k and an area of 4by4 or 5by5 lets say, u might get up to 7x7 but u sure aint going to get another 4 more feet out of a bulb, u can try and yeild your popcorn even with the mighty 1k light. trust me ive seen them in action and talked with others who have used them, they dont double your space-

 

[chronisseur]

i got 2 600s in a 6x7 room plants in 5x7 of it. This is under 40 and Im still getting about 1g/w. Adding a 400w MH next time around and switching it to HPS halfway through. This should brighten up any dark spots and help w penetration and keeping plants low. Also using a screen can really help efficiency wise. Building a modular 1ftx1ft with 1inch squares ScrOG mounted over 5gal buckets. Anything thats not at canopy level a week or so into flower will be hacked up into clones etc. My hope is to have each hol in the screen filled with a nice bud growing to a few inches above the screen. This way the light intensity can be made best use of and only the canopy will need light and have any buds! Im using stakes, chicken wire, twine now and some of the results are AMAZING though its messy and unorganized so I cant wait until I get these metal racks in!!

BTW this poll is MINIMUM youve seen nice buds from... How can minimum be over 65?? minimum has to be like 30 or less even because Im getting VERY respectable yields and nice nuggs with my 35-40wpf...

 

[Cranberry]

I'm with Hydrosun: "conventional wisdom is crap."

After years of blasting 50 wsf I wanted to grow more with less.
{AKA oldschool}

I can consistently pull super nice smoke at 11.11 WSF using a thousand MH. I am running a light rail, get buds to the trunk on three foot shrubs.

A reason some outdoor varieties dont do well inside is because we blast them with to much light. Heck go stand in the desert for a day and see how you like the sun on your head for 16 hours..

Guys running spinners run super low wsf numbers with staggering results. More is only better if your selling them more!