New Grower, a little nervous about seedling progress

Hello All, Your wisdom is very much appreciated. So if i can provide an update, i would like to better understand your thoughts on light intensity and height.

I’m at Day 12 since my seedlings broke the soil surface.
3x3 grow tent
using FF soil
18 hours on and 6 hours off
Have 2 Gold Leaf and 2 Super Skunk, each in 4 gal bags
I spray water on the soil 2x per day
I run a humidifier to keep humidity around 45 to 50%. Southern CA dry
Temperature is about 8o to 82 degrees
I have an oscillating fan for circulation, and an exhaust fan
I installed a SF4000 2 days ago (i had a SF1000 but it was not powerful enough)
Using the photone app, with my light set about 14" above seedlings, and intensity about 45%, i get around 50 DLI, and about 600 ppfd
Because my seedlings were spindly, i added/mounded soil around the bases as needed
As you can see, still a little spindly (back seedling more spindly than front) and i think a little behind in the growth curve (only 2 or 3 lobes after 12 days)…but if i lower the light, temps go up. If i lower intensity, i assumed the plants would stretch more

Do i find a way to lower the tent temperature so i can lower the light?
Do I increase intensity and still find a way to lower temperature?
Do i keep as is?

Please provide some thoughts so i can rest better and grow better… THANKS


Kick your rh up to about 60% and water in a ring a few inches from the stem. Maybe ½ cup at a time, either distilled, RO or pH’ed tap is fine. Overwatering is the most common reason for stunted growth in the beginning.

This is way too much for seedlings, even for flowering photos. I suggest pulling your light up to about 20-24", keeping intensity as is. They only need a DLI of around 20 the first couple/few weeks, while gradually increasing to 42-45 DLI until you’re ready to flower. If they begin stretching, you can turn the intensity up.


This :point_up:

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@GrowLargeOrGoHome i agree with @Borderryan22 you have too much light intensity. Additionally, in the seedling stage you want more humidity.

Chart below to dial in your DLI

You can raise humidity by putting a transparent dome over your seedlings.

Some folks cut the bottom off a plastic water bottle. I personally use sandwich size ziplock bags and fold over the zipper to hold the bags open.

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Your numbers don’t make sense to me. A ppfd of 600 at 18/6 light schedule is only a DLI of about 39. Still too much light for seedlings but something is not right if your app is telling you a ppfd of 600 and DLI of 50.

Edit: It looks like you have your app setting for 24 hours of light. That would account for the incorrect DLI value. Change that setting to 18 hours to get correct DLI.


I get 38.88 DLI @600ppfd Like merlin said way to much.


Thank you all for your thoughts. I rechecked the Photone app reading. I mispoke: it is about 38 DLI, not 50. So my bad. But the humidity is an issue.

I put a plastic bottle dome over the plants, and I also raised the light up to about 24". I dropped the intensity down to about 40%. I am about 480 PPFD and 30 DLI now.

I do notice when i open the tent to spray water or check the plants, the humidity jumps dramatically from 45 or so to 55 or more. And the temp can drop from 82 or so down to upper 70s or 80. I know i cant leave the tent open, but do i have a temperature problem at 80 to 84 degrees, and is that a significant reason why the humidity is also low (too high temperature)? If so, and the humidifier itself cant get me up to 60%, what do you all suggest? Thanks again/


I leave my tent open almost all the time. Temps get too high if I close it during lights on. Unless the smell becomes an issue, it has not been a problem for me.
4x8 tent, growing in less than 1/2 the space. Autos and photos here.


Thanks HMGRWN. I may try that now, and see how that works. I did deploy the plastic dome on my seedlings to help keep humidity a little high as well. I think the tips provided above have helped. Plants are filling in and not getting more spindly. So i am very happy about that and all the input u are all providing.

Are temps between 80 and 85 problematic for the seedlings? That appears to be where i will be, especially as summer kicks in here in SoCal.

So much to learn and do, but i must admit, it is fun, challenging, and science based…and i like science… so thanks again.


High temp and high humidity are ok/good for seedlings and veg stage. Temp and humidity need to go down during flower.


Great. Thanks much. Is there a bug killer that is not harmful to plants or subsequently consuming them? I just saw a few gnat-like bugs on the soil of one of my 3 bags.

And to show all your advice and support is helping, here we are at 14 days since breaking through the soil surface. So much better than Day 12…

Thanks again…enjoying this a lot.


This is what I use.
This one is very popular among growers on this forum.
Safe to use right up to harvest as long as you do a bud wash when you cut it.
(Bud wash is a good idea in any case. :+1:)

They are looking good. Get ready for the wild ride they will take you on. Explosive growth is imminent. :rocket:


I’m getting excited now. The p

lants are taking off like you said. I think my babies are doing well and definitely look better and more robust than last time I posted. Thank you all for your guidance.

I am at Day 20 since seedling broke surface. My humidifier is really helping and humidity with me running it all day is about 60% right now. I have temperatures around 70 to 84.

Am i now past seedling stage and into vegetation stage? If so, do i evaluate DLI gain and bump it up: i am around 30 DLI and close to 500 PPFD. Do i bump up to 35 to 40 DLI, or do i still keep it around 30?

And do i start thinking about nutrients, or is my FF soil still good without any nutrients yet?


I think the dli is in a good range for being three weeks in. To get a better idea light charts can be helpful. Reading the plant and how it responds! ( photo’s)


Thanks for that. I think I am not quite to veg stage yet. Will keep as is this week and then evaluate. This next set of leaves will provide more info and get me into Week 4. I can then consider topping and increasing light intensity. Appreciate your input…