How much MSU is Weakly Weekly?

[Olivia]

On the MSU package it recommends a mix 1 tsp per gallon. I normally dilute other fertilizers further to follow the weakly weekly guidance but I wondered if this might be different since it was actually made with orchids in mind. Should this one also be diluted or is 1 tsp per gallon fine for weekly watering?

[ryrycochinco]

I always use half of what recommended on the label.

[zxyqu]

I use about 50ppm nitrogen or about 1/4 tsp per gallon with every watering. You could probably do more as suggested, but I wouldn't do a full tsp per gallon weekly.

[quiltergal]

1/2 tsp/gal should put you right around 125ppm nitrogen which is more than adequate for most orchids. That's what I'm using with the formula for tap water. For pure/RO water formula I use about 3/4 tsp/gal.

[Bud]

I suggest you dissolve a teaspoonful in 1 cup of water then heat it a bit and keep stirring so everything dissolves(do not reach boiling point) then half a cup to a gallon of the dissolved MSU is weakly weekly...

[Olivia]

Thanks everyone!

So I'll do about 1/2 tsp per gallon and we'll see if I'm ambitious enough to heat it

[quiltergal]

It disolves really fast. I don't think it needs to be cooked.

[Ray]

The people that formulated the so-called "MSU Fertilizers" tested and recommended 125 ppm N for continuous use - i.e., at every watering. If you divide 10 by the %N on the label of any fertilizer, the result is teaspoons per gallon to use for 125 pm N.

In discussions them, I learned that the 125 ppm level was not derived in any scientific manner - "we tried it, and it worked" was the method used.

I have been experimenting with about 75-85 ppm N for about 6 months, figuring that, like lab rats and people, a limited, complete diet is overall healthier than a heavy one, and I am pleased, so far. (6/%N gives teaspoons per gallon for 75 pm N)

[euplusia]

I check my fertilizer concentration by measuring the conductivity of electricity. When I put the recommended amout of MSU in rainwater, it gives about 1600 mikroSiemens. Thats pretty much for orchids.
For comparison: Pure rain in the city is 40 µS, well water 400 - 700 µS. For Masdevallias I gave rain enhanced with fertilizer up to 300 µS once a week. For cattleyas 600 µS once or twice a week, but not only into the pot, also over the leaves. Catasetums in summer in active growth 800 µS.
The recommended concentration may be fine if there is enough light and warmth and the plant is a strong grower and in active growth. Otherwise 30 - 50 percent of the recommended concentration diluted in rainwater is enough for my plants.

[Discus]

mS or μS?