SH update

  • Thread starter Eric Muehlbauer
  • Start date
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How you water probably has a big influence on the total salts in the pots. if your plants run on the dry side you will need to watch for salt problems more than if they are kept wet. Plants absorb nutrients through their foliage so I like to get them wet with nutrient rich water as often as possible.

Keep in mind also when using MSU fertilizer at a target rate of 125 ppm nitrogen a slight mis-measurement may put the total salts level higher than some phrags may tolerate well.

The label of the MSU brand I'm using says to use 1 teaspoon (4.3 grams) per gallon to achieve 150 ppm nitrogen. But when dealing with ppm a "teaspoon" is not an accurate measurement. My average teaspoon scoop actually weighs 5.2 grams which is a 20% overdose! The coarseness of the dry fertilizer will greatly influence the weight even a carefully measured scoop.

4.3 grams of MSU fertilizer per gallon of water yields 605 ppm total salts in RO water whereas 5.2 grams of MSU fertilizer per gallon of water yields 721 ppm total salts.

605 ppm is probably OK for phrags and 721 ppm is probably to high for sensitive species. I don't know if anyone knows the real tolerance level?

So be careful to measure fertilizer amounts and water amount correctly, especially for S/H culture where the roots are constantly in the solution.

I mix 2 tablespoons MSU fertilizer in 8 gallons of water and the plants are growing well. (3/4 tsp per gallon)