Seedlings: Not enough light or too much?

[SleepIsWrong]

Okay! Problem solved. Little ones already respondend and oriented towards the light.

I figure the reason for bending was due to light reflection. As light reflects in the tent, it creates 4 bright spots on the sides of the tent where more light rays come together and create a more intense spot than the light itself. This happens because light was not pushing enough. It's more complicated than that of course but I hope it makes sense. That's my assumption at least, did not test that yet. That's why the little ones were bending and stretching ... and only towards those spots.

(Excuse my drawing skills. Never liked it.)

Anyways, thanks guys! You really helped, as usual!

Physically, I don't think that is possible. Light intensity falls off with 1/d^2 - double the distance and light is down by a factor of 4, etc. The light path for light that reflects off of the reflective (and not 100% reflective, more like 70% reflective) surfaces is longer and so the light is much diminished for anything reflected versus directly from the light.

 

[safeman]

Phone light meters apps are highly inaccurate. I've done 2 different comparisons about 2 years apart. They are located HERE and HERE. It's well worth the $30 spent on a real meter if you're wanting to get the most out of your light.

HERE is a link on how to use a lux meter for cannabis. I tend to give my seedlings a bit more light than the article. They may be a bit shy for a couple days but they get accustomed quick and it keeps them from stretching. Above 60-65k I've seen some light damage so i usually cut it off there.

I agree -- one needs to spend at lwast $100,00 or more quality stuff

 

[Delps8]

Physically, I don't think that is possible. Light intensity falls off with 1/d^2 - double the distance and light is down by a factor of 4, etc. The light path for light that reflects off of the reflective (and not 100% reflective, more like 70% reflective) surfaces is longer and so the light is much diminished for anything reflected versus directly from the light.

At that low intensity level (5%), I'm inclined to agree. Shane from Migro did a review and best case on the edges is 760 * 0.05 = 38 µmols when measured at 19" vs 1.2 meters (47") so we're in DAWA territory ("dark as a whale's ass").

That's not a knock on the OP. A year ago, when I unarchived my grow tent that I put away in 2017, I went through two sets of seeds, one reason being that I wasn't giving them enough light. After the second set, I took a pause. I got rid of the light (it was a Kind blurple from 2017) and put my shekels into things like a SuperSprouter, Rapid Routers, and an Apogee. Things have turned out better since then.