OGStein

The yellowing may not be down to nutrition.How hot is it?Iv just been telling somebody else.When I swapped over to led,s from hid lamps I had pale leaves for weeks due to it not being warm enough.Lower than 27 and my leaves go pale.I try and get my leaf temps to 28 which is they say is the ideal leaf temp.

They need need a fulll dose of grow from day 20.You really could benefit from biobizz top max which is humic acid which a lot of top growers consider essential when growing with organics.Quality nutrients have it in already.If money isnt an issue then advanced nutrients are the best.Humic acid puts a possitive charge on the elements which make them more available which means more nutrition into the plant.Stand your water for at least 24hrs to disolve the chlorine as it kills the soil microbes and its them that convert the elements to make them plant available.The pale leaves could be general lack of nutrition or low temps or both along with lack of soil microbes if they be gettting hit with chlorine.I believe some survive but I stand mine for 2days.

And photoperiod plants are easier to grow.You have mnore control and they arent as sensitive.

I thought you were using soil but its coco.The microbes convert the food to a plang available form but coco is pretty sterile so theres not many microbes about.They will come in with the seed and they're airborn but you need more.I use great white microbes and Ecothrives biosys which is compost tea which is one of the best ways of getting microbes into your coco.Check out great white soil microbes or ecothrives biosys.