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Additional reading: https://www.rollitup.org/2834596-post17.html

This is wrong. And really, it's a glaringly obvious contradiction. How will a reflector improve anything but more light emitting sources themselves won't? Ugh! He was doing so well.... Sigh. But apparently he thinks(according to the analogy about water temperature) that adding more bulbs...

Cover soil with sand. If it's really bad get fly strips.

Color rendering/rendition index doesn't mean much for plants. You could 'knock out' the sun's entire spectrum from 500-600nm and grow plants just as well(making CRI drop significantly). Case in point: HPS, very low CRI(around 22), flowers plants very nicely. Gro Lux(one of the best, based on the...

Plants can use more than 10k lm/sq ft. Not really the issue. Yield does not increase at a constant rate with more and more lumens, it's a game of diminishing returns. After 6-8k lm/sq ft(HPS, less for fluoros, but it'll still be more watts), you're actually providing more total radiant energy...

T8's are also highly affordable and quite effective. Though T5's are as much as 25% more efficient, but cost 10 times as much.

Cover soil with sand, about an inch should do it.

Sure: https://www.rollitup.org/indoor-growing/221347-why-lumen-output-matters-less.html He's measuring the bulb, apparently. Instead he should try measuring 1 foot away, or something more substantial, and then measuring the flux more so than the bulb, Lux does have an cumulative effect, but...

Tube fluoros are good to 2 feet in height. Then again they can get a lot closer to the tops. Green Cross's numbers are about right, sans reflector, but who uses a light without a reflector? With a decent reflector those measurements are easily doubled.

I'm surprised you're not an LED grower, as they have, by far, the best lumen maintenance of any bulb. This guy must own stock in some bulb manufacturer or something.

Yea more CFLs will help! Spread them out, though. Try to achieve even coverage.

Reflectance is not the same as reflectivity. White paint has very high reflectance, while a mirror has very high reflectivity(technically defined by how close it is to mirror image), and very high reflectance(the sum of all reflected radiance, diffuse or specular, it sometimes even includes the...

So you've probably heard it a thousand times, or more. Lumens per square foot and how it matters so much. Well, it doesn't, really. There's this awful comparison chart going around. It compares HPS(400w) with T5, CFL, T12, and incandescent. How does it do this? With lumen output alone. Why is...

Light decays the same for all light types, according to the inverse square decay law. Which means a brighter source will decay more rapidly than a less-bright source. Or, the volume gained as the source intensity increases is a diminishing return. The volume of a sphere as it gets larger...

That seems like a good way to keep the lights extra cool. I want one!

Yes, the noon sun is about 10k lm/sq ft. But not even half of the sun's spectrum is plant-usable. 5,000 lm/sq ft is plenty when using a highly plant-friendly light source, like plant-specific fluorescents.

It depends on the model. NLite's PURple is excellent, and the best choice for plants. The spectrum is ideal for flowering and/or veg. And the watts in to PUR-out is vastly superior to anything Envirolite offers. Envirolite doesn't seem to offer a plant-specialty bulb, they pretty much...

Every gardener I know has a dehydrator. :lol:

Aluminized Mylar only reflects up to 92% of visible light, and it's blue(400-500 nm) light. It does reflect up to 98% of IR, though, completely worthless for plants, but nearly perfect reflectivity!

It's also going to be less effective immediately upon igniting it for the first time, and every time thereafter. Where's the air-wank emoticon?