[phillyguy]

First off, I hope you dont get in trouble for posting to much.
Just checked the ppfd with Photone app and it shows 162ppfd. Should it be higher than that? This is how big she is. I would say she has been out of the ground 2 weeks. Should I stay where I'm at or increase the light. It's running at 50% right now at 16 inches. Thoughts?

 

[Siz]

First off, I hope you dont get in trouble for posting to much.
Just checked the ppfd with Photone app and it shows 162ppfd. Should it be higher than that? This is how big she is. I would say she has been out of the ground 2 weeks. Should I stay where I'm at or increase the light. It's running at 50% right now at 16 inches. Thoughts?

Ppfd # is good if accurate, 18/6 light schedule? Your light might be a little too close for seedlings though.

 

[Captspaulding]

Less is more set light to 15-25%
Height at 30 inches. If you plant starts stretching, drop the light 5 inches.


Don’t worry about ppfd……

 

[LoveGrowingIt]

I have seedlings growing now and I have the light at 30 inches and 20% power of a 240-watt light for 48 watts of actual power.

 

[phillyguy]

Ppfd # is good if accurate, 18/6 light schedule? Your light might be a little too close for seedlings though.

I've been doing 16/8. It is an auto flower.

 

[Captspaulding]

I've been doing 16/8. It is an auto flower.

You can do 20/4 for autos, drives more vegetative growth, your on a clock when they sprout, so try to cram more hours in the day. You can add the hours when ever you like. It’ll get you a larger plant in the end homine

 

[phillyguy]

I have seedlings growing now and I have the light at 30 inches and 20% power of a 240-watt light for 48 watts of actual power.

I'm running 100 watt light at 50%. It's a viparspectra.

 

[phillyguy]

Raised light to 30". Was said it doesn't matter the par drops to 63. Really appreciate all your help.

 

[LoveGrowingIt]

I'm running 100 watt light at 50%. It's a viparspectra.

I use ViparSpectra lights. They tend to have plenty of power.

Raised light to 30". Was said it doesn't matter the par drops to 63. Really appreciate all your help.

Young plants are sensitive, so I like to have ample light distance for them. Some folks use CFL bulbs. If they stretch a lot, they're reaching for the light. If not and the color looks good, they should be fine.

 

[Captspaulding]

Raised light to 30". Was said it doesn't matter the par drops to 63. Really appreciate all your help.

It’ll be fine, don’t sweat the ppfd, I hang mine at 30in at 40% output in my veg room. I run all vipar In there.

 

[Grower1974]

I aim for 200-250ppfd for the first 2 weeks after sprout. Then 400-500 until flower.

 

[Choppr]

For Seedlings it smart to have a hygrometer/thermometer sitting in the soil - (77-81 Fahrenheit is safe )

 

[Grower1974]

For Seedlings it smart to have a hygrometer/thermometer sitting in the soil - (77-81 Fahrenheit is safe )

You know what’s nuts? I’ve experimented with soil temps on seedlings. From sprout to around 2 weeks, my seedlings always grew fastest with the soil and air temps between 64-70F. Honestly, as long as the room/tent is 64-78F, and 50-70% RH, I never even worry. They all sprout and go into veg perfectly for the last 10 years. :).

I believe early in a natural setting, seedlings expect soil and air temps to be on the cooler side.

 

[Mikedin]

If you wanna go by PPFD on photone that’s fine I like to see around 150-200 not too much but enough to not let them stretch like crazy, go by stretch if they start extending too much drop the light a inch

At the end of the day it’s strain dependent some like more, some can’t handle what others can watch the leaves and node spacing it’ll tell you more than any meter can ever tell you

 

[Choppr]

You know what’s nuts? I’ve experimented with soil temps on seedlings. From sprout to around 2 weeks, my seedlings always grew fastest with the soil and air temps between 64-70F. Honestly, as long as the room/tent is 64-78F, and 50-70% RH, I never even worry. They all sprout and go into veg perfectly for the last 10 years. :).

I believe early in a natural setting, seedlings expect soil and air temps to be on the cooler side.

Whenever "new growers" are asking these kind of questions(how much ppfd for seedlings), I try to steer them away from ppfd/par etc. and to give them safe temps at the soil level so they dont burn their seedlings, to me the easiest way to set lighting is just to make sure temps are nominal at seedling height. Meaning you could put your light 5 feet away at full power, or 30 inches away at 50% power, but what matters are the temps on the seedling, ultimately it will be heat/temps that shrivel a seedling. Most of Us who have grown for years forget what its like to be a new grower with seedlings... For experienced growers its simple...

 

[labomba]

I've been experimenting seedling in a heated propagator with 150w led (close to seedling). Vs growing in my tent with a 350w at 50% (far from seedlings).

I've noticed that when I move a seedling to the tent, it tends to back away from the light, turning the cotyledons down and the first fan leaves up. The one seedling I left in the heated propagator still standing and looking more firm.

Does that mean the 350w are too strong for them and they are trying to back away from it? Or is it temperature related?

 

[Grower1974]

I've been experimenting seedling in a heated propagator with 150w led (close to seedling). Vs growing in my tent with a 350w at 50% (far from seedlings).

I've noticed that when I move a seedling to the tent, it tends to back away from the light, turning the cotyledons down and the first fan leaves up. The one seedling I left in the heated propagator still standing and looking more firm.

Does that mean the 350w are too strong for them and they are trying to back away from it? Or is it temperature related?

Probably still getting over 300 PPFD………

 

[logic]

For anyone searching the same question: several answers from this thread are in our PPFD and DLI guide. It puts seedlings at about 150 to 300 PPFD, starting low, and covers measuring with Photone and when to change height versus the dimmer.