125ppm N frequency OF feeding

[Masdyman]

I have been using a MSU type feed at the recommended dosage 125 ppm N ,but for my Masdys went for 100 ppm N .
All getting 3 feeds then RO only .As the MSU orchid collection article said they feed Slipper/Pleuros less .

I have since found out this meaning less frequency not strength , so what frequency do you shoot for ?

I was thinking sticking to 3 feeds then Ro for others then 2 feeds ro for Masdys .

I am wanting someone here to respond who has specific experience with this feed /strength and has used it with slipper /Massies.
Thanks In advance .

[Ray]

What you're really playing with is the mass of nutrients provided to the plants, and that should be determined by the type of plant and your growing conditions, as that affects growth rate, hence nutritional need. (You can read more about that concept here: Feeding by Mass).

Look at it this way: feeding at 100 pm N twice a week is the identical loading to 200 ppm N once a week. Obviously a sensitive plant will tolerate the more dilute solution better.

I don't grow masdevallias, but do grow a lot of paphs, and at almost 13° farther south than you, I feed at 125 ppm at every watering. In winter that will be once or twice a week, and in summer more like 3x per week, occasionally more.

[Masdyman]

Hi Ray , My predicament is i want to simplify my watering/feeding schedule by only using one storage container /feeding strength instead on one @100 ppm & another @125 ppm .
But don't know whether to go for 125 or 100 , i know at 125 ppm @ 3 times then RO only i shouldn't encounter any problems but i am unsure what effect this might have on Masdevallias.
I suppose what i am hoping for is that there is someone out there that is doing this or has done this so knows the effects -good or bad .

[boytjie]

Ray, with a typical MSU solution, what does that 125 ppm work out to per gallon of water? (Ballpark figure, even?)

[Ray]

The simplest way to estimate is to divide 10 by the %N on the label, which gives the teaspoons per gallon to use. For the original Greencare formula for well (tap) water, that's 19%N, we're talking about 1/2 tsp/gal. For the RO formula at 13%N, it's more like 3/4 tsp/gal.

For folks using metric measures, divide 13 by the %N to get the ml/L.

Masdyman, I seriously doubt that the difference between 100 ppm N and 125 ppm N will mean much, but if I wanted to be super conservative, I'd choose to deliver at 100 ppm and feed the other plants more often.

FWIW, I feed salt-sensitive phrags at 125 ppm on the same schedule as my other plants, and I have never had an issue - and I don't EVER flush with plain water.

[Masdyman]

Originally Posted by Ray

The simplest way to estimate is to divide 10 by the %N on the label, which gives the teaspoons per gallon to use. For the original Greencare formula for well (tap) water, that's 19%N, we're talking about 1/2 tsp/gal. For the RO formula at 13%N, it's more like 3/4 tsp/gal.

For folks using metric measures, divide 13 by the %N to get the ml/L.

Masdyman, I seriously doubt that the difference between 100 ppm N and 125 ppm N will mean much, but if I wanted to be super conservative, I'd choose to deliver at 100 ppm and feed the other plants more often.

FWIW, I feed salt-sensitive phrags at 125 ppm on the same schedule as my other plants, and I have never had an issue - and I don't EVER flush with plain water.

Going on the calculations you say , 13 by the 13 % N is obviously 1 ml/L , As i use a 80 lt drum thats 80 ml of feed- Right ? .
I have worked out 80lt/ 17.59 Gal X 0.76 =13.51 tsp x 5ml(tsp)=67.57ml feed to 80 lt .

So why the difference between the two ?
Is this the difference between USA & UK measures but both actually work out at 125 ppm N ?.Or have i been under feeding at not actually 125 ppm ?

[Ray]

The teaspoon/gallon ratio is the same for imperial and US ("English" - how ironic) measures - 768 tsp/gal. The trouble is in your ml/tsp factor.

A US gallon is 3.785 liters, so a US teaspoon is 3785/768=4.928 ml - so 5 is a good estimate.

An Imperial gallon however, is 4.546 liters, so an imperial teaspoon is 4546/768=5.92ml - closer to 6. You, therefore, have been feeding at a lower concentration than you thought.

[mojomick]

Ray, I just checked my container of MSU for well water. I got it from you. The label says 1/2 tsp is 100 ppm N and 3/4 tsp is 150. I have been giving the 150 on a regular basis to the majority of my plants. Too much? Betty

[Ray]

What do your plants say?

Any evidence of fertilizer burn?

[mojomick]

Most of them seem happy. I did back off on the Phrags and water with plain water more often as they showed some signs of burn on the edge of the leaves. I have been feeding with 3/4 tsp. but may back off to 1/2 tsp for a while to see if the 100ppm might encourage more bloom than leaf production.