Disease? Light burn? What happened to my melon seedlings?

[GVGardens]

Help! I started some melons under grow lights because I won't have room to direct seed in that bed til later. The leaves are looking terrible. I started these in sterile seed starting mix. I've never done melons under grow lights before.
-Seedborne disease that spread in the tray? Odds of it spreading to the tomatoes on the same grow shelf?
-Light burn?
-Nutrient problem?

It started with a charentais melon seedling so I pulled it because I had extra. The photos are of the two watermelon seedlings that it's now on.

melon 2.jpg

Melon1.jpg

[patihum]

I'm far from an expert on watermelon diseases but my first guess is downy mildew but I wouldn't expect it on plants kept inside.

If it were me I'd dispose of them just to be safe.

[GVGardens]

I'm far from an expert on watermelon diseases but my first guess is downy mildew but I wouldn't expect it on plants kept inside.

If it were me I'd dispose of them just to be safe.

Thanks! I was hoping someone would say it was light burn but it seems diseasey to me so I'm going to trash them. I am worried about everything else on that shelf and how the melons got diseased in the first place.

I guess I need to treat the seeds before re-planting.

[bower]

I do get light burn on plants in the winter setup from time to time - that first pic is a bit beyond light burn though, and the second one is a damp thing afaict.
It can be tough for plants in indoor setups if humidity is not just right and air circulation missing. Sometimes just too dry, other times spores found a happy place.
At the least, you have to remove disease as soon as you see it.
IDK watermelons, but some things will recover if you just clip off the troubles.

[GVGardens]

Thanks @bower. They get good ventilation but the indoor humidity is as wacky as our Texas winter temperatures because I really try not to run the AC or heater.

I don't want to deal with even more diseases than usual this year so I'll probably chuck them and start fresh.

[Cole_Robbie]

In my experience with powdery mildew, keeping night time or dark period temperature from dropping too low helps a lot. As air temp drops, it loses ability to hold moisture, and that moisture condenses on leaves, which in turn feeds the mildew.

[bower]

I'm currently doing a huge purge on my seed starting area: plaster, paint, the works. It's not enough (yeah it's still full of under cupboards full of wood stuff so many spore sources) but I'm telling myself it's better than nothing!

[Cole_Robbie]

I'm currently doing a huge purge on my seed starting area: plaster, paint, the works. It's not enough (yeah it's still full of under cupboards full of wood stuff so many spore sources) but I'm telling myself it's better than nothing!

If you ever come across a deal on an ozone generator, they are great for sterilizing a room.