Magnesium deficiency

[BradGC]

Hey,

Over the last couple of weeks I have realised that my garden is really low in magnesium.
How should I apply the Epsom salts? Spray on leaves or pour thru medium or both?
Will the colour come back to the older leaves when I'm adding sufficient Epsom salts?

Thanks

[tucker85]

What makes you think it's a magnesium deficiency? Yellowing leaves can be caused by other problems also. In any case, it won't hurt to apply magnesium. I use one tablespoon of epson salts to a gallon of water. Don't add it to your fertilizer or any other supplement. Apply it by itself because other nutrients, like phosphorus can prevent the uptake of magnesium. I spray the leaves, any visible roots and the growing medium. Last year I applied magnesium once a month.

[Cym Ladye]

Originally Posted by tucker85

........ Don't add it to your fertilizer or any other supplement. Apply it by itself because other nutrients, like phosphorus can prevent the uptake of magnesium. ........

Where did you get your information? If there were a problem as you say, why do most commercial fertilizers, including the MSU formula, contain trace elements of Mag in their blends?

One of the top commercial growers in Holland uses Epsom Salts mixed on a ratio of 6 parts fertilizer and 1 part Epsom Salts with every watering. Another top grower in Australia uses it at a ratio of 4 to 1 every third watering. I use it on a 2 to 1 ratio once a month, but I am considering going to an every watering at the 6-1 ratio.

I agree with the questioning of the yellowing of leaves in Brad's garden actually being caused by a lack of magnesium. Yellowing of garden leaves is often just a sign of winter coming. And is "garden" all plants of all genera or just orchids?

CL

[DavidCampen]

Sure you can mix magnesium sulfate in with your other nutrients - if you know what you are doing or are lucky, but, as Tucker says, it is also possible to form insoluble magnesium phosphates so the simplest advice is to apply the magnesium sulfate separately.

[DavidCampen]

I use Dynagro Orchid Pro, NPK 7-8-6 plus 2% Ca, 0.5% Mg.

I use an entire 8 oz. bottle each time to make 1/2 gallon of concentrate that I use with my chemical metering pump. Every bottle of Orchid-Pro has solid in the bottom and despite transfering the solid to a bottle with 1 liter of RO water and allowing it to stand for a week with occasional stirring, a significant amount remains undissolved.

I plan to start preparing my own nutirent mixtures from chemicals, principally - calcium ammonium nitrate, magnesium nitrate and potassium dihydrogen phosphate. I will check that no precipitate drops out of the concentrate that I prepare for the chemical metering pump and if it does then I will have to consider using a 2 component concentrate with 2 metering pumps.

[BradGC]

Yellowing of garden leaves is often just a sign of winter coming. And is "garden" all plants of all genera or just orchids?

I'm in the southern hemisphere so we're just coming into summer.

It's actually on my lemon tree that I noticed the leaves going mottled yellow as well as a chilli tree and a dendrobium had a slight yellow mottling on one of it's older leaves.

I used to fertilize my garden(not Inc orchids) with blood n bone and no Epsom salts and I've heard that it can create a deficiency

[Cym Ladye]

Originally Posted by DavidCampen

Sure you can mix magnesium sulfate in with your other nutrients - if you know what you are doing or are lucky, but, as Tucker says, it is also possible to form insoluble magnesium phosphates so the simplest advice is to apply the magnesium sulfate separately.

David,

You appear to be a do it yourself grower with wanting to create your own formulas, which is fine, and where you have to be doubly conscious of the forms of the chemicals used. But no one has answered my two questions:
1) What is the source of the information on counter active absorption?
2) If there is a problem, why do most commercial fertilizers, including the MSU formula, contain trace elements of Mag in their blends?

I am not being critical here, just curious to know the scientific sources.

Cym Ladye

[Ray]

Adding Epsom Salts to an already-diluted fertilizer solution is not going to lead to any appreciable reaction or "complexing" of minerals.

I will also add that a foliar spray of a dilute solution having urea as its nitrogen source will "green up" plants in an amazing hurry.

[DavidCampen]

Originally Posted by Cym Ladye

David,

1) What is the source of the information on counter active absorption?

I don't understand what you mean by counter active absorption. Are you asking where is information that calcium, magnesium iron and other elements form insoluble phosphates? There are many solubility tables that will give this information or you could ask a first year chemistry student.

2) If there is a problem, why do most commercial fertilizers, including the MSU formula, contain trace elements of Mag in their blends?

You mean the formation of insoluble compounds? That is why many formulations have only traces of calcium and magnesium, if larger amounts were used then insolubles would form. This is why many people have observed that they should supplement the trace amounts of calcium and magnesium that are in most fertilizers with applications of magnesium and calcium salts.

If you read some of the JR Peters literature here:

Jack's LX - J. R. Peters Inc. Fertilizer Products And Services

You will see that they talk frequently about whether or not various formulations can be tank mixed and think it is noteworthy that many of theirs can, even the ones with high calcium and magnesium.

"The Jack's LX blends are designed to keep N, P, K, Ca, and Mg available when mixed in concentrated form like in a stock tank.
All formulations in this enhanced line of fertilizers are fully mixable to tailor customized blends for individual growers and water supplies ... The LX flexibility lets you mix different formulas in one tank; therefore, you can vary your potential acidity and basicity very easily."

Also read here on the Peters website:
Hydroponics - J. R. Peters Inc. Fertilizer Products And Services

"SPECIAL MIXING DIRECTIONS FOR TRADITIONAL NUTRIENTS
Jack’s Hydroponic formulation and Jack’s Calcium Nitrate are packaged separately, and require a little special attention when mixing - in order to avoid forming a precipitant in the tank. These products must be dissolved either in a two-tank system or in dilute (or Ready-to-Use) quantities. Following these specific stepwise directions is vital, along with the knowledge that these items should NEVER be mixed in a concentrate tank together.
...
Note: An alternative to mixing the products together is to apply them separately, using one at a time and alternating them every other feeding. This will assure that your plants are receiving the ideal levels of nutrients."


And here they are quite proud of their:
"NEW – COMPLETE, ONE BAG FORMULAS
The research and development team at JR PETERS has developed several new products that deliver all the essential elements for hydroponically grown crops with the ease and innovation of a one bag blend. "

[DavidCampen]

Originally Posted by Ray

Adding Epsom Salts to an already-diluted fertilizer solution is not going to lead to any appreciable reaction or "complexing" of minerals.

By "diluted fertilizer" I am guessing that you mean diluted to application strength. But some people make concentrates to be used at 1:16 with a Hozon or 1:200 with an injection pump.