Lumens and temp for autoflower

A question from a fellow grower:

Real quickly, how much light (roughly in Lumens) do autoflower plants require if I were to get them started now? Can I use the new LED ‘daylight’ lightbulbs? I anticipate about 16 or more hours of light per day. Whats the minimum temp that they’ll grow?

Temperature depends on strain. Every strain will react differently too different temps, and i wanna say roughly around 8-10,000 lumens minimal, and well the more the marrier lol

less light equals airy buds

So does to much temperature fluctuations

really just treat as any other -keep it simple - to add what other said.

formula for lumen amounts in grow space - LxW = ? then ? x’s 2,000 = ? needed for your space

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Do we use Inches in the LxW formula ?

Usually it’s in inches yes

Or you can go with the watts per sqft math 40-50 watts sqft for flower

lets say you have a 4 ft by 4 ft grow space - 4x4=16 then 16 x’x 2,000=32,000 lumens needed for proper lighting (takes’ 2,000 lumen to cover 1 square foot . Or you can figure by watts (40 watts to cover 1 square ft) 4x4=16 the 16 x’s 40 = 560 watts needed as what “Donaldj” said

It’s easier to do what you and @steve2 are talking about shortcuts the math and also saves half the work great job, @steve2 great job to you as well

I have 2 hlg 260’s turned all the way down in a 16 sf room. I got 15,000 lumens on my autos at a distance of 32” away. They are in an NFT setup and I’m trying to get them as tall as possible before they switch.
Does lamp to distance or too many lumens cause them to stay shorter? My current record for height out of the 7 i’ve Grown is 26”.