once for every 20 days, can adjust the pH value of the basin. Conducive to the growth of flowers and trees which like acid.

Ferrous sulfate also known as copperas or black alum,common iron fertilizer for flowers and trees , it is easy to dissolve in water, can promote the chlorophyll formation, make color Nonglv and full of luster, effectively prevent the plant yellows due to iron deficiency , but also to regulate the soil acidity regulator, long-term use can change soil acidity and salinity, ensure that keep the soil acidity!