Humidity Greenhouse Gardening Watering W atering is an ongoing challenge for school greenhouse growers.
Water is the solvent that carries minerals from the soil to plants via the roots.
A raw material used in photosynthesis, water enters the roots as a liquid and exits the leaves as a vapor as it's transpired. Not all plants have the same watering requirements. The amount of water plants require is affected by the drainage capacity of the growing medium used, the temperature and light plants receive, the amount of air circulation, the stage of plant growth, and the type of plant. Young, actively growing seedlings, for instance, require constant moisture, while a mature cactus needs very little. If the soil feels dry an inch down, it's time to water.