An explanation of the conditions needed for plant growth, with particular emphasis on water requirements. A greenhouse manager, Julian, tells us they have thousands of plants growing, including wheat, barley and maize. They help the plants to grow by providing light, water, soil and warm temperatures. Julian explains how some plants, such as water hyacinths and rice, need a lot of water and even have their roots standing in water. Cereals, potatoes and maize might need water once a day, whereas cacti only need water every two to three days.

First broadcast:
8 October 2007

Students could design an experiment to find out what plants need in order to grow and develop. Students could plant three tubs or plastic cups with the same type of plant, but place these under different conditions in order to assess which factors are required for growth. One could be given water but kept in the dark, the second could be kept in sunlight but never watered, and the third could be given both water and sunlight. Predictions could be made on which plant will grow most effectively. Students could then observe the progress of the plant growth and record their findings. From their results students could conclude some of the factors that plants need to grow effectively. They could also explore the effect of temperature on plant growth by adding more plant pots to the experiment.