Seedling blunder?

So it’s our third grow, and we popped a Gorilla Glue, a Girl Scout Cookies Extreme (both photos), and three autos: FastBuds’ Strawberry Pie (2) and Grapefruit. The idea is to keep the photos in our custom 3x2 tent and put the autos outside in bags after a hardening-off period.

After a disappointing yield from our previous effort, we got great advice from @dbrn32, @KeystoneCops, @Not2SureYet and others who suggested upgrading our dinky light to a new HLG 260 XL. After assembling and hanging the kit, we couldn’t believe its brightness.

The problem: although it comes with a dimmer, I mistakenly left the light on full power for the first couple of days of our young seedlings’ lives. Light is hung 23" inches above them, and the edges of the cotyledons’ leaves on the GSC Extreme appear to have gotten burned, possibly when a little water got on them, which I know can magnify the heat in bad ways. (We also had fungus gnats, so I followed @Hellraiser’s advice of diatomaceous earth and mosquito bits - visible in photo - and haven’t had a problem since.)

Question: Will our little Girl Scout with her toasted cotyledons be okay? I’m hoping a long veg period will help her muscle through this early blunder. Thoughts?

I looked up ideal PPFD ranges for seedlings and found 200-300 being optimal. At full blast and at the same height, the new light was giving them around 700, so I turned it down less than halfway (the dimmer actually has 11 settings, and it’s currently on 4 - but I LOVE the fact that, like Nigel Tufnel’s amp, this one goes to 11!).

Another question: At the current output setting, most of the plants are receiving about 250, but Gorilla Glue is getting about 350. Is this still too high? If I turn the light down to 3, some of the readings go below 200, and I thought it would be best to be a little over than a lot under. Thoughts?

Also, we planted the taproots directly in their Happy Frog “forever” homes: 7-gallon bags for the photos, 5-gallon bags for the autos. Will this affect yield, or should we go for seedlings in Solo cups and then transplant for next time?

Thanks to all the usual (and unusual) suspects who have helped us along so nicely in the past with encouragement, advice, and kind words.


I think she’ll be fine as the first true leaves seem OK but yeah you really blasted them with some serious light.

350 ppfd is fine for seedlings, close enough.

I would start photos in solo cups and transplant up when they are ready, I believe they grow faster with transplants and it makes watering easier when they are in appropriate size pots in relation to plant size. I like solo cup to 1 gal to 5 gal in coco, in potting soil I normally went solo cup to 3 gal to 7 gals. I won’t comment on autos as I don’t grow them.

Happy Growing!


Your plant will be fine, the slight burn won’t hurt anything.

The fact that you have the ability to measure the PPFD output and knowing that 200-300 is optimum for seedlings puts you much further ahead then everyone else that is just guessing. 350 PPFD won’t hurt. If it did most would kill their plants.

Many people plant into final pots.

Personally I find it more difficult to control conditions. I prefer starting in small pots, using a single humidity dome and heating mat to control the environment. I’ve never had difficulties transplanting and don’t think there is any stress doing so if done properly.


Thanks so much, @Hellraiser and @CMichGrower! Good to know we haven’t set her back.

By the way, to measure PPFD, I downloaded the Photone app and that makes it pretty easy. We newbies need all the help we can get!


I agree. Your little ones should be fine. You could dome her for a day or so to add a little moisture back into her. Normally for my plants. I go a solo cup size to the final pots. Every thing I have done that way take off a little faster. Or so it seems. An up side to that is it is harder to over water. Over time. You will find what works best for you. Photos are a better choice to learn on as you have all the time you need to figure things out. Good to see you chose to spend a little extra for the bigger light. You will find it will pay you back quick. :grin:

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The others have you set, you should be fine moving forward.

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Thanks, @dbrn32 and @Not2SureYet! Appreciate your responses.


i would plant your autos in their final pot. and transplants for your photo

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If u do this long enough u’ll make every mistake u can possibly make. s**t happens. The important thing here is u knew what mistake u made, u done ur homework. Kudos :v::v::alien:


wise words :wink:

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Another thing is after buying something like a high $ shiny new grow light is, read them instructions first thing :grimacing::thinking::v: :alien:

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