like th Cammo said, mini flushes. depends on what style you go with. Soil...not really needed, organics, not really needed. Coco/synthetic. again, this depends. I run a really low EC, so I count on a bit of build-up to feed them when they demand more nutes. I go like 10% at best then if they start looking a bit off I do a good 30-40% (usually about every 2-3 weeks). If you push the EC higher and don't do a 20% runoff your begging for lockouts, nute burn, etc. commercial grower in Australia stick with 30%. I could do 20-30% runoff in coco 2-3 times a day and they'd thrive, but try that in soil and you'd drown them. learn to read your girls leaves. go for 20%, then rewater at 20% when they just start to droop. in coco you can use the lift test.(let em dry out till pot is about half the weigh between fully dry and fully wet.