A guide to growth fertilizer?

[RNCollins]

Originally Posted by Ray

Back to the original query, for a moment...

I think the best thing to do is to choose a target nitrogen concentration - chosen based upon application frequency - and stick to that, no matter the formula.

I water 3-4 times a week in summer, always with fertilizer, so I shoot for 25 ppm N. To achieve that, I divide 2 by the %N on the label of any formula, with the result being the teaspoons per gallon (2.6/%N gives ml/L).

If I fed only once a week, I'd probably go with about 100 ppm N, so I'd use 8/%N for teaspoons/gallon (10.4/%N for ml/L).

If you go to Ray's website and enter your fertilizer numbers into the worksheet it will give you the ppm (parts per million) of Nitrogen, Phosphorus, and Potassium. I'm too lazy to do the math so I just use Ray's formula.

Fertilizer TDS Calculator - First Rays LLC