? Leaf burn

ontopofthehill

As an impatient sort I decided to try get some seeds started inside early (don't have a greenhouse) in a grow tent with a grow light. I had about 400 seedlings at one point all over the kitchen floor last year and with two small kids my husband put the foot down on a repeat of that this year! It's a whopper of a light so usually have it turned down to 10%-20% and hung high up. My chinese lanterns have flown along but one of the plants (probably closest to the light) has started getting this weird discolouration and holes in the leaves. There's a small amount of fungus gnats hanging about but I sterilised all the pots before using them so don't think it's obviously any particular bug. I know most of you don't use indoor lights for this purpose but just wondering if anyone had any idea what's causing it? Might try harden them off and lob them outside into my cold frame but worried the slugs will have a party if I do. Everything else in the tent (mostly houseplant & penstemon cuttings and a few seeds) seem fine so not sure if it is just too much light.  Any theories most welcome, thanks! 

Pete.8

It may be oedema which is caused by too much water.
If that plant is closest to the light it will be working hard and sucking up plenty (too much) water which can cause blisters on the leaves.

It's not a plant I grow, so could also be something else

ontopofthehill

Thanks for the reply Pete! Interesting, sounds like it could be that alright. A few of the others are starting to get it too so not sure what's going on but might try them away from the light for a few days and see if that improves it. Cheers!

Pete.8

If it is oedema then it's likely to be the leaves that get the most light that are worst.
Just raise the light a few inches (if you can) - that may solve it, and only water them when needed.
🤞