Plants should be selected according to the growth conditions and climate of the area. Place 3 containerized bean plants on a thermostatic heating pad set to 70 degrees, set 3 more plants next to these, just off of the heating pad. Make sure all of the plants get the water and light they need. After two weeks, compare the size of the plants in the two groups. Normal plant growth requires white light or sunlight.
Light intensity provides energy for photosynthesis.
The rate of photosynthesis is effected by the availability of water, CO2 and sunlight. In absence of light, plants will grow until their food reserves are exhausted. The growth will be elongated and abnormal. Plants vary in the intensity of light they need. Some plants such as Impatiens grow better in the shade with indirect light while others such as zinnias grow best in full sunlight.