Light Green/Yellowing Spots on Seedlings


I am a new grower, and I am noticing light green/yellowing spots are starting to form on my cannabis seedlings. Leaves are a bit wrinkly.

I germinated 3 Bruce Banner Autoflower seeds 12 days ago, and the last one sprouted 8 days ago. I planted the seeds in jiffy pellets, and then planted them directly into the medium. The idea was to keep the seeds moist in the Jiffy Pellets.

The Promix is amended with 70% Gaia Green 444, and 30% 284.

I have them under 3 full spectrum QGLED grow lights, which are 3 1/2’ above the seedlings.

Humidity has been between 40-60 RH, which has been hard to dial in because I live in a dry climate.

Temps have been between 24-27°C in the day, and between 21-23°C at night.

Was worried about over watering, and so I waited for the medium/jiffy pellets to dry out before watering them yesterday. I made sure to only water a small radius around the seedlings. The water I used was pH to 6.6.

I noticed the light coloured spots on the seedlings throughout their grow, but seems more pronounced in newer growth.

Can anyone tell me what these spots could mean? Is it something to worry about? Can I fix it somehow?

Any help would be appreciated.

Welcome to ILGM and the forum.

They look pretty healthy to me. Could the spotting be from misting the plants while the lights are on? It really doesn’t look like you have much to worry about to me.

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Thank you for your response.

I have been doing my best not to get the leaves wet while the lights are on.

I think it might be a bit of light stress, and so I lowered the intensity of my grow lights.

I got worried after seeing pristine green cannabis leaves on Google.

It looks like you are doing fine. Watch your new growth. In general, so long as your girls are putting up healthy new growth you don’t have much to worry about. It’s not time to worry until you see wider discoloration, chronic spotting, or leaf edge browning.

It looks like you are are over watering by a ton. Secondly don’t water where the plant is. Put the water in a spiral pattern a few inches from the plant. When they are are this small we are talking no more than 10 ml of water per feeding.


I’m going to suggest you put a clear dome over the plant and spray the inside of the dome twice per day. At this size the plants derive all of their moisture from the air.

Your ‘soil’ mix is anyone’s guess. The problem is having a soil or media that retains the correct PH. Most I’ve seen develop problems in flower at the worst possible time to deal with.

Lights are likely too high: something like 24" should do fine for seedlings.


Also welcome to the community. :+1:

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Thank you for the advice.

I will wait awhile before adding anymore water, and then water sparingly.

I have been using a spray bottle to water them, but will start using the little syringes I use to measure my cannabis oil until they are bigger.

I will crank up the humidity in my tent.

About the lights: I have high powered LEDs, and the seedlings are getting 7k lux of light.

I will move them closer, but I have been worried about stressing them out with light.

Also, the soil is Promix HP. I chose this soil because I read that Promix can be acidic, but HP comes with Dolomite to control pH.

The Gaia Green should also help to balance the pH, because it has bone meal, glacial rock dust, basalt rock dust, fish bone meal, fossilized carbon complex, oyster shell flour, mineralized phosphate, potassium sulfute, and rock phosphate.

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Well good luck; hopefully that mix won’t cause any trouble. I have no experience with it. Promix is great stuff and my preferred substrate. But I run it straight and feed.

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Thank you.

Everyone told me to get promix.

I moved my lights down to 24".

I have 4 LED lights, but have only been using 2, because I was worried about light stress.

Should I turn them all on?

Can you provide more info on your lights? Spectrum? Power draw? Size?

I’m running high-efficacy custom LED’s and seedlings typically 18 to 24" for me.

Spoke to someone at the grow store where I bought the light, and they told me the lights will be okay at 24" from the seedlings.