Athosanswered grow question 6 years ago Anything at or below 0.6 EC is ok, most of what you are seeing is whatever soil gets dissolved in the water passing through. Personally I always strive to feed on the low side, and thus I don't flush soil (I don't even get runoff when feeding or watering), I just give water only for the last week or two, leting the plant consume whatever is left on the soil and tis own reserves