Epsom salts

This is a pretty old one, but did you know Epsom salts are a great way to green up your plants? They are a natural source of magnesium sulphate, and a deficiency of minerals in the soil can cause your plants to have yellow leaves. (this is not the only cause of yellow leaves though!)

You can buy Epsom salts at a good price from supermarkets, and can be applied at a rate of 3-4 tablespoons to a watering can.

Keep it green