MSU & Supplementing Magnesium

[Masdyman]

I have read & heard that some are getting great results by supplementing Mg sulphate .

Is there any need when using a feed like Greencare/MSU formulas ?
I know some do with greencare/MSU .
A mate of mine is going to do this but i am wondering is there really any need ,is it just extra work/cost and something else to go wrong .

Regards

[BikerDoc5968]

As you know, the MSU fertilizer comes in two flavors: one for tap water and the other for RO (Reverse Osmosis). The RO differs because it has added Ca++ and Mg++ so there would be no need to add anything else.

[Masdyman]

Originally Posted by BikerDoc5968

As you know, the MSU fertilizer comes in two flavors: one for tap water and the other for RO (Reverse Osmosis). The RO differs because it has added Ca++ and Mg++ so there would be no need to add anything else.

We are using RO /MSU .
He grows mainly Paphs/Phrags.
Thanks

[jeffg]

At our OS show this past weekend, Hadley Cash from Mariott Orchids had this guidance for the Paphs water/fert: (These are my notes, not his exact words)

Water: Establish a watering routine: his example: 3 applications fert, then 2 waterings with just water. Then 3 fert etc. Rotate in cal-mag 15-5-15 as a fert application.

Epson Salt: He recommends Epson salt 2 T/gal. (Yes tablespoons) from April-End Aug. Use this in the water cycle between applications of just water i.e. water – Epson – water, and then resume regular fert schedule. Do not use Epson just after or just before fert as they will cancel each other out and cause toxicity. The Epson adds Mg and sulfur – which helps colors show, especially reds.

Fertilizer: Maint fert for Paphs: Peter’s 20-20-20 or another balanced or high N food

Blooming:

To re-bloom: Early Fall – Mid Sept. switch to a “bloom booster” 1-2x/mo. (higher P) until the plant spikes. Once spikes, go back to 20-20-20 1x/mo. While in bloom (Jan-March).
Temp: First Sept – Oct, the plant needs a swing of 15-20 degrees and a low of low-mid 50’s to bloom.

[Ray]

While the Greencare RO formula does have added calcium (8%) and magnesium (2%), some paph growers feel it is beneficial to add more of each.

I cannot see how adding Epsom Salts to a fertilizer solution will "cancel out" anything or cause toxicity. Magnesium sulfate in solution reacts little - if at all - with the other nutrient ions. More likely, Hadley just ends up with an entirely too concentrated irrigation solution by adding two tablespoons of Epsom Salts to each gallon of his fertilizer.

Phosphorus is not a "bloom booster." Read this: Plant Boosters

[orchidsamore]

I agree with Ray that there is no such thing as Bloom Booster, especially with the use of high phosphorus.

Phosphorus also takes up to 5 years to decompose and it kills all the beneficial microbes in the medium. It is the major cause of plant death in the Florida everglades and has now been banned for use in Florida. ( with a special exemption for sugar cane and golf courses the worst offenders - money buys everything in politics)

In Ray's article he mentions the short term effect of changing fertile solutions. I use 'Worm Tea' extensively. The first time anyone uses it they will see a noticeable effect. Usually a jump in size. After the first month the effects are more normal. I compare it to taking a starving man to a buffet table. He will pig out and eat everything then slow down when he realizes the food will not be going away.

Plants will absorb huge amounts of whatever they needed but have been denied, then take everything at a normal pace.

[iceicebaby]

Important information, is it possible to bookmark this information on orchidboard?

[Masdyman]

Interesting , 2 tablespoons mg does seem alot my friend was thinking 1 teaspoon per GAL but in with the msu RO feed.
So i agree with Ray that he is using Mg in water only as it would bump his TDS levels to toxic levels if mixed with his feed .
Will have to test this ?
Why might this be beneficial to Paphs and not other orchids ?

[Masdyman]

I tried the TDS of 1.25 ml Mg sulphate in 1 lt/1000ml in RO @ 5 ppm .
Came out at 440 ppm ,even at my lower ratio if this was in a UK Gal(4.54 l) the TDS would be touching 2000 ppm .
So why isn't he burning roots ?
Doesn`t Mg TDS work in the same way as feed ?

[Ray]

Originally Posted by Masdyman

I tried the TDS of 1.25 ml Mg sulphate in 1 lt/1000ml in RO @ 5 ppm .
Came out at 440 ppm ,even at my lower ratio if this was in a UK Gal(4.54 l) the TDS would be touching 2000 ppm .
So why isn't he burning roots ?
Doesn`t Mg TDS work in the same way as feed ?

First of all, a TDS meter is just an inexpensive electrical conductivity meter with a built-in conversion factor to ppm solids. Unfortunately as solutions differ in their ionic content, that "conversion factor" needs to be different for every solution. Read TDS and EC.

Epsom salts, as we can get it, is actually MgSO4-7 H2O (that is, only 48.8% MgSO4 by mass) , and has a density of 1.68g/cc. (The bulk density of the powder is probably lower than that, but as I don't know what that really is, we'll assume the 1.68 number.) Therefore, 1.25 ml x 1.68g/ml x 48.8% = 1.025g of MgSO4 was added to 1kg of water, meaning the solution is actually 1025 mg/1.001025kg = 1025 ppm MgSO4