Why Can't Salty Water Be Used to Water Plants?

Fresh water must be used to water plants instead of the water for washing dishes because the latter will contain some salt. If it is often used to water plants, the pro- portion of salt in the earth will increase, preventing the roots from absorbing mois-ture, or even making the moisture within the tree run out from the roots. Finally the tree would die from lack of water. In order to clear away snow from streets in big cities, salt solution is usually sprinkled on the snow. Some people heap the melting snow around trees, thinking they are watering them. In fact the salty snow will kill them.