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Optimum intensity for preflower and early flower phase ?

Hi all . i m looking to find out what is the optimum light intensity for the early stages of flowering period for both kinds of cannabis. outside i dont worry about it but indoors i dont know where i should be . should i be full intensity by this time of the growth? i dont have a par meter so from your experience where do you think i should be regarding intensity ?

thanks

4 answers1 reply

Comments (5)

E_heroi

Apr 05, 2021

ok so the lights shouldn't be on max around that time right ? if we suppose that my light on 100% dim give 1000ppfd would it be correct to say that for the first 1-2 weeks of flower they should be at 75%? does the intensity in this period affect yield ? is it related to the stretch of the plant in the first weeks or is it purely genetics that define the stretch ? sorry for the many questions . this is a grey area for me as im coming from purely outdoors to indoor growing . now i respect the sun so much more.......lol

Mr. Grow It

Apr 05, 2021

Replying to

I would run it at 75% for the first few weeks then increase to 100%. Someone else might argue otherwise. If you give too might light it could actually hurt yield. That's called "light burn". Here's more info: https://www.mrgrowit.com/post/light-burn-light-stress-in-cannabis-plants

So IMO it's better to be a little under when it comes to the amount of PAR rather than over. Lots of people give their plants too much light and their plants end up suffering - especially with these newer LED grow lights.

Stretch is mostly genetics and of course the health of the plant. If the plant is over-watered and/or suffering from deficiencies then it won't stretch as much. Also, blue spectrum of light inhibits cell division so that can also impact the stretch. That's why some growers like a lot of blue light in Veg so the plant will have tighter node spacing.

Mr. Grow It

Apr 05, 2021

Around 600 PPFD but without a PAR meter you can't truly measure it so you may want to reference the grow light's PAR charts to dial in light distance.

gregthe357

Apr 05, 2021

In my experience its kinda hard to give them TOO much light, you know what I mean? I do know that they are one of the most light hungry plants in the world.

mwhite9829

Apr 04, 2021

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I wish I could answer this for you, definitely a @Mr. Grow It question. I still use heat on the back of my hand as base start and plant reaction for adjustments.