your bullshit LUDA learn your plant problems and stop giving bad advice. yes its mag def. 100% that early in plant life IF it was mites, would have NO brown spots. that plants what 3-4 weeks old? mites need to infest for a solid six weeks to BROWN spot damage. the mites need time to eat plant, plant needs time to brown the damaged spot.bullshit.
LUDA.
i get this as well in every grow i do. at first sign i spray with epsom salt foliar feed @ 1 tsp per 32oz of water. make sure to use 2 oz of warm water to desolve the salt. fill rest of the way with cool water. spray 2x week till problem stops. should take no time at all, your plants will respond very well and fast to a foliar feeding.
peace \m/ SOTW