Where in the world are you?

That looks like a nutrient deficiency, what is the soil these are growing in like?

Are these growing in containers or in the ground?

If in the ground what did a good reliable soil test say about soil pH and major nutrients?

kimmq is kimmsr

The lines are caused by leaf miners and the white spots appear to be caused by thrips. I see no sign of nutrient deficiency.

What is roca?

a scale would be nice.. i have never thought of leaf miners in seed leaves ...

why not cold damage ..???

if that is pure peat moss ... i would monder about out of kilter nutrients... or too acidic ...

when do you plant on thinning them.. or moving them out???

you might want to sacrifice one.. and look at the reverse side

i note the new leaves are nice and shiny .... and not affected ... did you apply liquid fert or spray water on them in sun??? ... seedlings this size should not be in sun ... in your backyard

as noted.. where are you .. always include such ...

ken

well it'smy first time planting. i started with mint and it was easy with no problems. so i tried to plant herbs. i plant in containers the soil i bought from a plantshop the guy said i can plant without mixing with other soil.as i'm still learning so i did.
Rocca, arugula,rocket green leaves used for salad

i'm in oman.
yes i plant outside but its shade.
i water my plants early morning.
no cold weather here.

thank you for your answers. I searched more on the web. i think its leaf miner. same description applies on my leaves,
i understand that i have to remove infected leaves and use some organic pesticide.

nisreem, I'd hate to see you remove leaves on such young seedlings, but yes....that is one of the recommended solutions. Leaf miners are very difficult to manage on leafy greens, and they love basil! I grow arugula and now that I think about it, leaf miners were a bit of a problem last year.

I use neem oil, which acts as an anti-feedant, and a kaolin clay product called Surround. The Surround really keeps them from laying eggs; it's great stuff.

i didnt doubt rhiz ... i just wanted to discuss other variables... of which you seem to have a handle on ...

ken

Surround, a product made of Kaolin clay, may not be available as Surround in Oman. Neem oil products should be.

kimmq is kimmsr