Grow plants into lights or raise lights with plants? (LED)

calvin.m16

calvin.m16

Well-Known Member
Hoping the title makes sense, basically, for a while I have been letting plants grow into my lights which are mounted in a fixed position vs growing plants with the lights and raising them as they grow. I think this has been a self admitted fatal error..

I see many guys saying they are getting 2-2.5 pounds per/600-700w LED fixture where I'm in the ballpark of 1-1.5 max per light. One thing I have totally overlooked is that my plants aren't getting full PPFD until they've finished stretching up into the lights, which is like 3 weeks of lacking PPFD.

Not only do I believe this is limiting the plants by causing additional stretch but possibly limiting biomass overall. Am I mistaken there?

Looking to hear any advice and feel free to cast shame. I haven't been able to search and find any specific threads on this exact topic.

Summary
Let plants grow up into lights or raise lights as plants grow keeping PPFD high start to finish, primarily in flower.
 
Southernontariogrower

Southernontariogrower

Well-Known Member
calvin.m16 said:
Hoping the title makes sense, basically, for a while I have been letting plants grow into my lights which are mounted in a fixed position vs growing plants with the lights and raising them as they grow. I think this has been a self admitted fatal error..

I see many guys saying they are getting 2-2.5 pounds per/600-700w LED fixture where I'm in the ballpark of 1-1.5 max per light. One thing I have totally overlooked is that my plants aren't getting full PPFD until they've finished stretching up into the lights, which is like 3 weeks of lacking PPFD.

Not only do I believe this is limiting the plants by causing additional stretch but possibly limiting biomass overall. Am I mistaken there?

Looking to hear any advice and feel free to cast shame. I haven't been able to search and find any specific threads on this exact topic.

Summary
Let plants grow up into lights or raise lights as plants grow keeping PPFD high start to finish, primarily in flower.
Click to expand...
I keep my light as close as I can, not much heat so don't mind the odd bud touching the light here and there. Don't get much stretch with leds. At least I dont. I'm a fan of raising the light!
 
W

whelk

Well-Known Member
I find that my plants start to yellow a bit if they are any less that 24 inches away, and its only a 250w led. Sometimes I let them go a bit nearer and as they fade a bit but it doesn't actually seem to have any negative impact on the yield or weed quality
 
B

Budget Buds

Well-Known Member
Really you should figure out what distance the lights are most efficient for that specific light, For example my light produces 1000 umol/m2 in the center at 14.5 inches high and gives me 630 umol/m2 at the corners of the tent.

In reality you can run it closer to the canopy and get higher numbers in the center but it hurts numbers on the edge and possibly burns or bleaches plants in the center, or you can run it higher and get slightly better numbers at the edges and worse in the center but your just wasting light .
 
Star Dog

Star Dog

Well-Known Member
I raise my lights as the plants grow trying to keep them ideal, during veg ec is all pretty stable.
After flipping i gradually increase light intensity over about a month using the plants as a guide,
The gradual light increase is reflected with a gradual ec increase,
idk about other tents but i need more nutrients with more light intensity.

Iirc you use soil, i use coco so i can't really offer much help.
 
Rurumo

Rurumo

Well-Known Member
Once you've got your grow more or less dialed in, more yield really comes from genetics and maximizing your light footprint. I've tested all sorts of #'s of primary bud sites per plant, and the highest yields come from filling up your footprint with colas (there will be more larf, but also more quality bud since more top bud material will be exposed to more light). This doesn't work for all plants though, yield varies, as does how well a plant responds to aggressive topping. The kind of plant you want is one that will grow big colas even if you top it for 20-25 primary bud sites. Once you find that plant, grow clones with it and be amazed at your yields! I average 2.5 lb per 4x4 with 4 mixed strain plants. In one of those grows, a single Sour D cross produced 1 lb, while a runty White Widow produced 3 oz...so I'm certain I would have produced 3-4 lb with clones of that plant. Unfortunately, it wasn't Sour enough for me to keep around. Finding a plant that responds to aggressive topping with "overcompensation" is something to watch for when pheno hunting.

As for lighting, there seems to be a linear increase in yield as light intensity goes up, even past the point of leaf damage (light burn.) So once you find your high yielding plant, then you can dial in the perfect amount of light for it by figuring out how far you can push it without cooking the tops. Packing a tent like this is mainly for production-I only do it when I want to compete with myself just for entertainment. Besides yield, the other big benefit is there is less botrytis with more/smaller buds, and less loss if you do get botrytis on a bud.
 
B

Bud man 43

Well-Known Member
I started by lowering the lights and raising them as the plants grew. The problem I ran into was different strains growing at different rates, hitting my head on low hanging lights and dealing with all the cords.
Now I have my lights fixed at the maximum height and I put the plants on milk crates to bring the plants up to around 24-30 inches from the fixtures- then remove the milk crates as the plants grow.
I use a rolling adjustable shelf for the first 8 weeks or so- then onto the crate’s which are placed in plastic tubs to catch the run off.
 
calvin.m16

calvin.m16

Well-Known Member
Bud man 43 said:
I started by lowering the lights and raising them as the plants grew. The problem I ran into was different strains growing at different rates, hitting my head on low hanging lights and dealing with all the cords.
Now I have my lights fixed at the maximum height and I put the plants on milk crates to bring the plants up to around 24-30 inches from the fixtures- then remove the milk crates as the plants grow.
I use a rolling adjustable shelf for the first 8 weeks or so- then onto the crate’s which are placed in plastic tubs to catch the run off.
Click to expand...
Thanks for sharing. Have you noticed a decrease in overall stretch of the plants by giving them more intense light? I am really curious if these same genetics will stay lower with the more intense PPFD throughout all of flower.
 
PadawanWarrior

PadawanWarrior

Well-Known Member
I use boards, and they're all at 90 watts a piece except 2 are 100 watt HLG's. It's like 650 watts total in a ~3x8 closet. I'm lazy. I don't adjust them anymore. I just let them grow into it. If they get really tall I'll supercrop. I probably get about about 1/2# a plant and just have been putting 3 in there. Last run that I just chopped got closer than ever to the lights. I measured the LUX for fun and it was a little over 100,000 LUX, lol. Of course the top buds are bigger but I don't think that's avoidable.
 
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