Most substances in cooking salt is NaCl. Cooking salt can be a good fertilizer. You can use it to stimulate your plant's growth.

Based on research from the Research Team from the Coffee and Cocoa Research Center, salt with a chemical content of NaCl can replace KCl fertilizer with a certain dose. Then, one of the lecturers at the Bogor Agricultural University (IPB) conducted research on the effect of salt fertilization on melon plants in the 1980s and the results showed a positive correlation with the sweetness level of melons.
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Firstly, I do not believe that cooking salt can be a fertilizer. Then I read some articles about how to use the cooking salt to fertilize my banana tree.
My banana trees grow well after I pour salt liquid around the roots. I have tried cooking salt on my chilli trees, but I put too much salt so that the leaves turn yellow.

How to use cooking salt in your garden?

1 spoon of cooking salt
1 litre of water.

Put 1 spoon of cooking salt in a litre of water. stir until the salt is mixed with the water. Make some holes with a stick around the root of the banana trees randomly until you reach a 0.5 metre radius. Pour 1 litre of the salt liquid into the holes evenly. You can do it once a week. After, one or two weeks, you will see the banana tree growing faster with larger leaves. After that, you need to fertilize your banana tree once a month.

This is my banana tree. The tree grows well, and there is a bunch of fruit that I will harvest next week. The banana fruits look bigger.

The banana fruits look healthy. There are no black scratches on them.
Note - Giving too much salt will make the leaves turn yellow, so you should be careful to fertilize your plants with cooking salt.