What is the correct ratios for Epsom Salt and Gypsum solutions?

Question

I want to use solutions of Gypsum and Epsom Salts to augment the nutrients in my pot plants. They seem to be having some mineral deficiencies. I'm wondering what is the correct amount of Calcium Sulphate and Magnesium Sulphate for a two-liter solution.

I would also like to ask whether it be better to spray my plants bi-weekly or once a week.

EDIT:

Although these are not my plants the problem is white veins on my squash plants, which is because of a Calcium deficiency in the soil (As I was told.) (This may be bad advice, I'm still new at this.)

which plants? and what symptoms, precisely, are they showing, please. Or photographs would be really good... — Bamboo, Sep 20 '16 at 11:28

score 3 · Accepted Answer · answered Sep 20 '16 at 12:52

Magnesium makes up about 10% of the mass of Epsom salt (magnesium sulfate heptahydrate). so 1 gram per liter is about 100 ppm magnesium. Plants will take that with no problem. Most commercial fertilizers lack magnesium because it forms an insoluble complex with phosphate. I find that an occasional watering with 100ppm Epsom salt will green up plants that have been in the same soil too long. The metal ion is an essential cofactor for chlorophyll. I've never met dirt with a calcium deficiency, but around here, there's close to 100 ppm in the water supply. However, CaSO4-2H2O, MW 140, is about 23% by mass in Calcium ion, so 0.43 g/L will give you about 100ppm in Ca ion; a reasonable amount to add. Be aware that the sacks of Gypsum available at most greenhouse supply store are actually an indeterminate mix of calcium and magnesium sulfates.

My gypsum was bought at a drug store, the label says only magnesium sulphate. — Neil Meyer, Sep 20 '16 at 12:56
Epsom salt is usually pretty pure. It's the Calcium stuff people buy to raise their soil pH that contains a variety of Calcium and Magnesium salts. — Wayfaring Stranger, Sep 20 '16 at 13:01

score 2 · Answer 2 · answered Sep 20 '16 at 17:16

If its just white veins, but the plant is otherwise completely healthy and growing well, it might not be a disorder at all - squash leaves vary enormously and some do have this silver venation, see discussion in the link below

http://forums2.gardenweb.com/discussions/3797449/white-veins-on-squash-leaves

What is the correct ratios for Epsom Salt and Gypsum solutions?

2 Answers2