coco is soilless medium. Treat it as such. Coco itself is not special nor any different than any fibrous, solid substrate that absorbs water. All the magical things people associate with it are nonsense.
So, fertilizing soilless is easy.
1) fertilize every time with 10% runoff or more -- this waste water is fine for plants in the earth but not potted plants if you don't want to throw it down the drain.
2) Wait for top layer to start to change color and repeat.
A more developed plant you can increase frequency a bit. Make sure you have at least 1/3rd weight loss and you can fertigate more often and get a boost to growth. I'd follow this more pronounced wet-dry cycle early to promote thick roots to take advantage of any increased frequency later on.
Coco has no nutes in it, so this is the way. A well balacned diet given each time and the runoff ensures it cannot build up. The resulting equilibrium may not be exactly the same as what you feed, but that is expected. The key is that it remains consistent - at which point any adjustment to formula also changes the resulting equilibrium. This is the super power of soiless growing and why you get better, faster growth compared to soils.
use a free app to take your gauranteed analysis labels off each product you mix into solution and it can give you dosage to hit target ppms. this excludes anything your tap water adds and you may need small tweaks relative to local variables -- ratios will be the same, but overal concentration may deviate.
Vege formual, fine for seedlings, too
N 120-130
P 40-60
K 180-200
Ca 100+
Mg 75ish
S 100+
your tap water and differing local variables may require a few adjustments, but it's a good start. Small adjustments needed based on observing the plant and how it grows. Within 1-2 grows you should have it dialed in where you barely think of it ever again.
In flower, drop to ~100ppm N. If canopy continues to darken over first few weeks of flower, drop it further. easy-peasy. Should be fine otherwise.
I regularly grow 6-7 different strains that pull off the same reservoir and in the last 4 years i've never had to hand water any "odd" plant that didn't like it and showed virtually no deficiency/toxicity symptoms at any point that matters. Most plants will show some 'ugly' the last few weeks due to senescence. The idea that these plants are uniquely picky is a product of poorly fed plants using esoteric formuals.
This formula is not "mine." it's the product of research that several professional ag companies mimic for a soiless/hydro line of nutrients. Not some formula a random person growing a handful of plants and riddled with small sample size error created. it's trustworthy and results are easily repeatable for that reason.
