I've just planted cosmos bight lights seed 3 weeks ago, and it just sprouted first true leaves, but after a week or so, the leaf started to curl for unclear reason.
I've put it on morning dan late afternoon sunlight approx 4 hour/day (live on jakarta, indonesia). the growing medium contains coco peat, burnt rice husk, and compost 1:1:1 (sifted before use)
only after I see the leaf curled up, then I give them their first diluted fertilizer (1/3 strength)
the strange thing is... the cotyledon looks fine, while true leaves died...
anyone got ideas where I did wrong?