I can't tell but it looks like it's just the seed leaves that have brown tips. They worked hard to break the seed coat LOL! Really though, it's normal for the seed leaves to start to dry up and fall off :D

Vera

That may be an indication of a potash deficiency but since those leaves are the cotlydons and the first true leaves do not exhibit the smae I'd not be too concerned about it.

i presume these arent outdoors in z4 ...

so i then think of humidity regulation in a house with forced air furnace ...

this type of damage MIGHT be possible ... if the leaf dried out somehow ....

if you bought a commercial potting medium .. or seed medium .. i would NOT expect it to have deficiencies ... but hey .. you never know ...

have you started fertilizing them yet??? because it could be fertilizer burn also ....

ken

I've been fertilizing every time I water with a condensed seaweed fertilizer at a low dose. Could it be that? Last year and the year before my tomato plants jumped out of the dirt and grew like crazy. This year they are growing very slowly!!

It's not just the cotyledon leaves. On several of my tomatoe plants the leave tips are brown, and it goes onto the permanent leaves too. Any one know what this could be? Am I over or underwatering? Thanks.