Light power for different stages of growth

[dwmi]

I was just needing to get a general idea about how strong the light is on different stages of veg and flower. In the beginning of veg, middle of veg and the end of veg approximately how bright in percentage and or distance do they need to be. What's a little confusing is I see when you flip from veg to flower I've seen to where you turn the brightness down quite a bit and as the flower matures around mid cycle the lights are real bright. And towards the end of the buds it looks like you turn down your light strength. I've always started out low and keep increasing it as the plant grows. I always assumed that you keep turning the light up all the way through the growth of your plant more and more without reducing the light at all through the flowering stage and or two to three to four weeks towards the end. What I'm basically seen of the lights start out low at early beds you turn them up a lot more around mid beds and confusing me is you turn it down low when you switch to flower and at mid flower you've got the lights pretty much maxed out and towards the end of flower it shows the light gets turned down for two or three weeks is what I'm trying to say. And I have a true 1000 watt light that is 43 in by 43 in a 4x4 tent. What little reading I read on it seems that my light needs to stay up pretty high around the 30 inch mark

 

[JIMKSI64]

There are guidelines for high and low for both light energy and DLI available online with a simple search but it sounds like that's not what you want.
No one can say how high YOUR light should be on YOUR plant, the plant will tell you.
Recommend you do some research on lights and reactions to lights such as cupping and curling leaves and drooping. Learn to read the lights you are growing a living thing and every single one of em can be different.
Most growers measure lights in Lux or PPDF with electronic tools. Even so there are only guidelines, you must learn to read the plants.

 

[dwmi]

There are guidelines for high and low for both light energy and DLI available online with a simple search but it sounds like that's not what you want.
No one can say how high YOUR light should be on YOUR plant, the plant will tell you.
Recommend you do some research on lights and reactions to lights such as cupping and curling leaves and drooping. Learn to read the lights you are growing a living thing and every single one of em can be different.
Most growers measure lights in Lux or PPDF with electronic tools. Even so there are only guidelines, you must learn to read the plants.

I use that phone app for the ppfds. I was just wondering if you turn down your lights when you go from veg to flower and also towards the end of flowering or should I say harvest Time it looks like people turn their lights down a lot lower for the last couple of weeks. I use that phone app well but I'm just wanting to know if I need to adjust the light strength throughout different phases of the veg and flower. Like I said I start out low when I transplant and I keep increasing the power the further I go through my grow. So I have basically never turn my lights down or up and back down again.

 

[ArtfulCodger]

People do all sorts of things with lights. Different varieties and even different phenotypes will react differently to light levels. Here's a general guideline that's worked for me over the years, with the caveat, like @JIMKSI64 said, that reading the plants and adjusting appropriately is more important than any recipe or meter.

I run seedlings 6" below a 25W 2-foot fluorescent T5 for about a month after they pop. Then I move to my veg tent, where I start my LED at 25% of the intensity I think they'll finish at. My finishing intensity is generally around 35-38W/ft² of canopy, if I'm hand watering media in ambient CO2. In hydro and supplemented CO2, I'd finish with more. After three weeks at that level, I turn up the light to 50% of my estimated finishing intensity. I maintain that until the end of the second week of flower. Then I bump up to 75% of finishing intensity. Three weeks before my projected finish, I bump up to my finishing intensity.

That's a rough guideline. If the top fan leaves are flat, level, and vibrant green, I assume they're happy with the light. If they're contorted in any way (twist, edge curl, taco-ing, etc.), or if there are colors other than green, I turn the light down. 1000 true watts of LED in a 4x4 is a lot more light than I have in my tents. I hang my lights at the top of my tents, and never move them lower.

Hope that helps.

 

[dwmi]

Thanks a lot for that, I have a lot better understanding now

 

[Ninjadogma]

An easy way to remember it is 2/4/6/8. This just a rough estimate of the ppfd values... 200 for seedlings, 400 for young plants and 600 - 800 for mature plants.

Check the support documents of your light. There should be a diagram that shows the approximate ppfd levels you should expect from your light at different distances and is a good guide for setting the distance based on what you need on the plants for their stage of life. Then use a light meter and check the reading at that distance to confirm. Most folks dont have a light meter, there's a free app called Photone you can download to your smart phone and take some rough ballpark readings.

 

[dwmi]

People do all sorts of things with lights. Different varieties and even different phenotypes will react differently to light levels. Here's a general guideline that's worked for me over the years, with the caveat, like @JIMKSI64 said, that reading the plants and adjusting appropriately is more important than any recipe or meter.

I run seedlings 6" below a 25W 2-foot fluorescent T5 for about a month after they pop. Then I move to my veg tent, where I start my LED at 25% of the intensity I think they'll finish at. My finishing intensity is generally around 35-38W/ft² of canopy, if I'm hand watering media in ambient CO2. In hydro and supplemented CO2, I'd finish with more. After three weeks at that level, I turn up the light to 50% of my estimated finishing intensity. I maintain that until the end of the second week of flower. Then I bump up to 75% of finishing intensity. Three weeks before my projected finish, I bump up to my finishing intensity.

That's a rough guideline. If the top fan leaves are flat, level, and vibrant green, I assume they're happy with the light. If they're contorted in any way (twist, edge curl, taco-ing, etc.), or if there are colors other than green, I turn the light down. 1000 true watts of LED in a 4x4 is a lot more light than I have in my tents. I hang my lights at the top of my tents, and never move them lower.

Hope that helps.

I went back in my tent and measured the distance from my light to the top of my plants and it was at 30 in but I had it at 70% brightness. Sounds like that's Overkill, correct. I don't feel like making a diffuser for that photon app right now because I have a good Indica buzz going ha. But thank God I know how to run the app. I thought it was pretty cool and informative to use the phone app to get my readings.