hey guys. this is my 2nd outdoor growing session. on the internet i read sometimes that mostly yhe basic soils have too less cal/mag and that the plants will like it to get some extra. my plants are like 3 weeks old right now. what do you think about this?
If your plant is not cal/mag deficient, why add extra? For the most part your soil and water will provide enough cal/mag.
Mix up a tablespoon of unsulphured blackstrap molasses in a gallon of water and feed it that. Great source of energy and calcium/magnesium for your plant.
Of course a shop will highly recommend it to you. That's what they do. Unless you're using distilled water, you don't need extra cal/mag.