nuts

method matters... soilless is a bit different the soil grows but still the same concepts at play. buildup of salts can occure due to evaporation. what the plant doesn't drink, dries up and the mass of nutes previously in solution and not drunk become solids. plant cannot use the solid state of these nutrients, but as you re-water it goes back into solution -- this adds to what you had in the solution, this is EC levels can build up over time. in soilless grows you simply need to be religious about 10-15% runoff waste... cast it outside or down the drain.. don't let it sit in runoff. You feed every single time in this method. The runoff will maintain a safe EC level. As long as you feed in proper ratio of molecules, it'll turn out exceptionally well from seed to harvest. in soil grow you dont want so much runoff, but you do want to ensure entire volume gets watered. your soil is likely a higher EC than any soilless or hydro setup. you supplement what is in the soil with your fertilization. so this is a balancing act that requires familiarity with the soil you used and what it needs help providng.. what will be used up quickyl etc etc.. .so you can then add it to your fertilization regiment. soil you could fertilize with every 2nd or 3rd irrigation. What you should put in your fertilization in any given week is less certain. There is more reliance on observation of plant and past experience with the products you are using to preemptively avoid any past issues. eventually you have a well-mapped ramp up of your nutes or you adjust how you amend your soil... multiple ways to attack. With hot soil you may not need nutes for 8 weeks. With other packages of soil you may need to start ramping up from a low-dose fertilization within a couple weeks. perceive it as rates, not values. A plant metabolizes X/week of various nutes. you need to match that rate of useage... the plant will tell you when it is deficient or toxic. if you start in a good ballpark, the adjustments are small. So many variables that there is no 1 answer to this question... it's like learning to ride a bike. gotta just do it yourself beyond a few basic concepts. find a leaf symptom chart with google image search. learn difference between mobile and immobile nutes and how that helps decipher what you observe... don't be afriad of non-marijuana branded products... often times they are cheaper and the same exact re-packaged bs 5x more expensive for no reason other than ppl in this hobby like wasting their money on magic and popular brands :P