Check out 26min. 40 sec. On video that’s where he explains high light on seedlings
Cleaned some of the recent discourse. Temporarily closing this thread for a chill session.
6 Likes
Please keep the discourse cordial.
4 Likes
I have a few LED lights. One says to only run ceilings six hours a day. The light is a little too bright it does take up too much energy out of the plants. I use a mars Hydro 48 I think it is. HLG 4k is a little bright. I definitely have to hang it at a very high distance because I cannot turn them down. I do believe if your light is too bright it will burn your plants up at a young age. Just my comments and my thoughts. I do have to keep my light at a distance until they get big enough. But that could be because of cheap lights. You should have a chart that comes with your light that lets you know how far to keep them from your plants. A few years ago I use the regular household lightbulb put over my plants. It had a blue shield. It worked very nicely. It kept them very small and they got a nice feel to them the leaves filled out very nicely.
2 Likes
Seedlings can withstand even 2,000 if all other inputs are optimal. It just takes extra study time and experience to figure all the inputs indoors. They handle 2,000 outdoors and seedlings love it.
3 Likes
Right… I stated in the very beginning distance matters not intensity as much… I am currently at 42 inches away… that 6 inches further than gavitas recommended distance…
1 Like
Sometimes I may not always understand. My eyes are getting bad. Lol. I’m not worried. I hope you have happy growing. I try and show and share. One Love
1 Like
Don’t get me wrong… I mean if your plant is too small to intake enough nutrients then obviously your light can’t be too high… but as far as intensity it’s much higher than people expect… so if it has big enough roots you can move over 400 ppfd … if not… then it can struggle… but if it’s all in line then you can go up from 300 to 450 in 1 day no slow moving up etc… you can go up quick… also once leaves are receiving high light the next set that comes out are for higher light… thicker type leaves that are made for it
4 Likes
I didn’t take it that way. We are good. Good topic.
2 Likes
OK just wanted to be sure lol… thanks man!
3 Likes
Hey bro… just to revisit this… I’d like to add… that what increases most when you move the light closer is leaf penetration… you’re right about too high on seedlings… it has proven difficult at higher ppfd. Better to get them ready a tad 1st… then go up… but nevertheless… I still think if proper uptake … which I had issue with until raising Temps even more under led lighting… more like 88 degrees fans kick on and at 64 percent humidity as well… keeping things between 58 % humidity and 64 % and between 85 and 87.9 degrees… seems to do very well… and light intensity lower… around 300 ppfd at seedling… and can go up much more once established a little better… again though… with my light… gavita pro 1700e and 4x4 space I’ve seen others put the light at 100 percent at 42 inches for 1st week and 36 for the rest of veg do a perfect job… so again . I think you are referring to penetration rather than ppfd… with these huge leds we don’t need to put light very close to plants… at any stage
1 Like
460 ppfd is pretty low, I use 350ppfd for clones. Sure, when I don’t want my plants to grow too fast I drop the ppfd’s lower, closer to 400, but seedlings do fine under 1200 ppfd’s too
1 Like
your referenced expert claimed that his studies concluded that light penetration is less than 5%… you can’t increase penetration enough to have any worthwhile effect, instead we need distributed light sources to provide ancillary side lighting.
1 Like
I dont understand this statement: How is this? Intensity is inversely proportional to the square of the distance 
A light manufacturers suggested distances are to maximize reflected light while minimizing losses due to dispersal.
1 Like
Could use a couple 1000 hps and not have any of the issues I see here?
2 Likes
The company I worked for popped all seeds under 1000W HPS bulbs with no issues. The key is having the environment dialed in and the correct nutrient concentration relative to the plants nutrient uptake.
3 Likes
I’m confused at what you are asking me @herojuana.tom ?
The uniformity of a gavita pro 1700e is very well laid out… the outsides are very very uniform compared to the center… now… I’m just trying to refer to what was being said earlier… as far as led lighting… vs hps… hps has very known parameters for proper growth… under led… it’s all still being perfected I think… uptake is lower due to lack of infrared radiant heat… so Temps need to be higher … and with uptake minimized in that way… sometimes ppfd can appear too high… honestly that isn’t the deal… it’s more Temps vs ppfd along with humidity settings… I’m no know it all… I’m trying to line this out still because under this led it has proven very difficult to find proper parameters for vigorous fast growth… doing a plethora of tests with the previously stated gavita pro user I referred to starting today…
When referring to led growing… an hps suggestion is preposterous they do not or hardly ever will relate to each other in any way… I’m open to opinions and or facts on the matter… but I am doing this to help new high end led users to realize alot of the math on growing … has been done with hps… not led… like vpd charts… watering schedules and frequency… literally everything changes when you go to a big ass led like the gavita 1700e. Unless you add radiant heat… or ir light… or something to help uptake with those leaf surfaces… I got confused and made last statement hastily… so referring back to that… I’d think what increases more when moving lights closer besides the ppfd is the temps… but that would not work for me… To gain proper temps… I plan on just upping temps… but that is still up in air as well due to being a co2 user also… so alot is different from grow to grow… I’d like led users to chime in
2 Likes
Yeah that’s true… but also an extremely higher electric bill 
… also I plan on using uvb in flower… don’t need the extra heat from hps at that point… just veg is an issue… hps won’t compare to this led anyway… it’s already been proven… it yields more… costs less to run… and lasts longer. Enough said there yeah? Just the learning curve is terrible my friend !!! 
1 Like