Topics in Subtropics

. A rule of thumb is that irrigation should be done when about 50% of the water has been depleted from the soil in the plant's root zone. This 50% value, however, allows a buffer of water in the soil in case the weather suddenly turns hot and windy.

Irrigation timing can be determined more precisely using a tensiometer. These water-filled tubes with a pressure gauge accurately reflect the amount of energy a plant needs to extract water from the soil. The pressure gauge measures tension values in centibar units (cbars).

Avocados and Water Avocados are the most salt and drought sensitive of our fruit tree crops. They are shallow rooted and are not able to exploit large volumes of soil and therefore are not capable of fully using stored rainfall.

This little mnemonic, or memory aid, in the title is helpful in remembering the critical levels of toxic constituents in irrigation water.

Deciduous plants need a certain period of dormancy during which they accumulate hours of cold. This is a very practical process on their part, since most dormant plants grow in cold climates. Differing areas have different patterns of cold.