How much light is too much for seedlings?

[masshole61]

Just bought a sun leaves t5 8 bulb 4 foot flourescent to veg my outdoor plants. The seeds sprouted a week ago
(solo cups, light warrior) and are just coming out of the dirt. I put them under the light with four bulbs on and they seem ok, except two that look a little crinkled. Is this too much light,started too soon? They seem like a lighter shade of green, would that be bleaching? Thanks , masshole

 

[ttystikk]

I used to run my clones under a standard shop light. It was plenty. What you're doing is overkill- while the light pressure may not itself be excessive, all that heat definitely is going to hurt your babies. Twist most of those T5 bulbsso they aren't running, should solve your problem. Be sure your humidity is high, 70% @ 75 F.

 

[masshole61]

Thanks ttystikk, I kind of thought so. Temps are at77 but humidity is only 31%. Going to get a humidity dome. If I cut down the bulbs and lower the light, at what height can I amp it back up to four lights and when can I amp it up to eight? I don't want to eff up these plants while I experience a learning curve

 

[LexLuthor]

Wait for them to get 2-3 sets of leaves before you use 4 bulbs and they should be able to handle 8 bulbs when they have 5-7 sets of leaves. You can't keep them in a dome forever, get a humidifier and keep the RH around 60-65% during the entire veg phase, but like tty said around 70% the 1st week or so.

 

[masshole61]

Thanks lex, sounds like a good rule of thumb.

 

[LexLuthor]

Thanks lex, sounds like a good rule of thumb.

A 'rule of thumb' at best, IMO it really depends on the size of the canopy. Different strains will show different growth size, some have huge leaves and take up the same space with 2 sets of leaves as another plant would with 4 sets.

So it is a good rule of thumb to go by, but it mainly depends on the size of your canopy, good luck.

 

[reloader]

I run a 400 mh in my veg/clone/seedling room, it does it all, vegges big plants, grow clones, and I put seedlings in the corner, and they grow fine to.

 

[Seamaiden]

Just bought a sun leaves t5 8 bulb 4 foot flourescent to veg my outdoor plants. The seeds sprouted a week ago
(solo cups, light warrior) and are just coming out of the dirt. I put them under the light with four bulbs on and they seem ok, except two that look a little crinkled. Is this too much light,started too soon? They seem like a lighter shade of green, would that be bleaching? Thanks , masshole

Lighter shade of green usually indicates rapid growth. What you've got is nowhere nearly enough light to cause bleaching or burning. I can see it happening with HIDs or LEDs, but not fluoros.

I also never use a dome, too easy to cause mold/disease problems, plus IME they grow 'lazy roots,' i.e. roots that can't handle the change in VPD when moving out from the dome.

 

[baba G]

seedlings can grow in direct sunlight if started under it. If you take them from low lighting(flouro) to sunlight they might burn so you gotta introduce them to the intensity of the sun slowly. But there is no such thing as too much light for a seedling unless you've got 1kw 1foot from it...lol

 

[Texas Kid]

Once a clone shows roots out the cube, I go strait to the high bay 1k...Baba G knows whats up, mo light is mo better...seedlings I am under a t5 till they break the surface then I am strait to the 1k like day 4-5 from the start

 

[baba G]

This addresses the issue of momentum. If a seedling is thriving and getting the most light it can and all it's other needs are met, it will be in better health than a lowly lit seedling that is in a limbo state almost as it's not thriving like it could....