93.9 BayFM Geelong

Most of us know that without water plants die, but why do plants need water?

1. Transport
Plants use water to transport dissolved nutrients from one part of the plant to another. This is how food in the soil is taken up roots to be used by all the other parts of the plant.

2. Structure
Plants use water to keep themselves upright. This is especially true of vegetables, which can’t form woody tissue. The water is pulled up the stem of the plant by capillary action, which maintains a water tension.This chain of water molecules acts like a spine keeping the plant upright. When the stem of a plant is cut, the chain is broken and the plant wilts. This is what you observe when you cut a bunch of flowers.

3. Cooling
Plants need to modify the environment around them to function properly. Just as animals sweat by releasing water out of the pores of their skin, so plants release water vapor out of stomata (plant pores) that cool the air around the plant.

4. Photosynthesis
This is the term given to the way plants use the energy of light to convert water and carbon dioxide into sugar. Water is an essential ingredient of this process, without water, plants can’t photosynthesise. If you under-water your plants you will slow their growth. If the water stress continues, the plants begin to starve. This is especially important when growing vegetables. To grow a good crop, vegetables need lots of water.

Vegetables lose most water through their leaves, which is a necessary process. Mulching will not change this. Mulching is of dubious benefit in winter because slugs and slaters breed under the mulch and feed on the vegetables at night. If the mulch is a light colour eg straw, sunlight is reflected rather than absorbed into the soil. Cold soil equals slow growth. A thin layer of dark mulch will keep weeds at bay.