I'm trying to grow mint, and lettuce in the window sill, and was wondering if just epsom salt with water is enough to keep the "clippings" alive for giving a crop.


If you have good soil, possibly it is enough for a year. According wikipedia epsom salt (Magnesium sulfate) is MgSO4·7H2O so it will give only few substances to the plants. On the wikipedia article is also described that epsom salt could be used as fertiliser in case of deficit in magnesium or sulfur.

But the epsom salt lacks a lot of other important nutrients: see Plant nutrition (Wikipedia). The most important components are N, P and K, but also other minerals are essential (but on very small doses).

I expect lettuce to have high requirements on fertilisers. Mints growths on poor soils, so it has less requirements, but for the flavours, it still needs minerals.

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  • My goodness, Epsom salts are helpful for very specific problems that have to do with magnesium and pH. But I have NEVER used them yet. My horses and their hoof problems yes. In my bath, yes...but to add stuff to plants without knowing why is worse than doing nothing. Giacomo is correct. Careful adding ANYTHING to soil for a plant. – stormy Aug 10 '16 at 23:39
  • Many of the common indoor fertilizers do not contain Mg ions, because magnesium phosphate is basically insoluble: en.wikipedia.org/wiki/Magnesium_phosphate_tribasic. Watering with a couple hundred ppm of Epsom salts a couple times a year can ensure there's enough magnesium in the pot to saturate a plant's chlorophyll, but doing it constantly will end up immobilizing phosphorous. For happy plants, you want to use a mostly balanced fertilizer, as Giacomo Catenazzi says, and spare the Epsom salts for special occasions. – Wayfaring Stranger Dec 5 '16 at 15:07

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