If you currently have a deficiency surfacing on your plant I recently mixed a solution of 3ml
Calmag+ and 1 gallon of distilled water, PH'd at 5.80 for a struggling 2 week old seedling that was showing stress very early in its life. 4 weeks or later in growth 5ml of
CalMag+ per 1 gallon of distilled water is perfect. After nearly a week of lightly spraying her foliage 2 different days and a couple heavy sprays into the coco coir at same time for good measure, I now am seeing her start to rebound which really helped me feel better because I had realized I forgot to pretreat my coco coir perlite mix with a low
calmag and
fox farm snack for early seedling development. I will say be extremely careful if you are doing a hydro coco coir grow with bottled nutes. Use a 1/2 or even a 1/3 of the normal dose for that week because it's super easy to burn your young crop if your not checking your vitals like ph, ec, tds, ppm, ppt, temp and runoff etc. Seeds also have all the nutes they should need for first 2 to 3 weeks of growth. We are only going for a pre optimised soil and **2 herbseamless transition of food for your seedling. My recommendation is too rinse and strain your coir before doing 2 - 8 hour covered soaks in a ph'd baby nute mix before planting your seeds or seedlings. Never reuse your soak solution! It also filters some of the very fine coir and stuff you dont want because water logging sucks. Just do a run off test on each pot etc before planting so that you have perfect environment for your babies to thrive and your first set of notes for that cycle!!!