Once the germination part of the experiment is over, students may wish to continue to experiment with the growth of their plants to maturity and to the development of fruit.
The growth of the plant can be explored under a variety of conditions, by varying:
Follow the scientific method when you continue your experiment. Plan carefully; control all variables except the one you are investigating.
If you are going to investigate the effect of light on plant growth and fruit development, every plant should be exposed to identical conditions for all other variables such as, temperature, soil type, fertilizer, frequency and amount of watering.
Additional equipment may be required depending upon the nature of the experiment undertaken.
If your school is equipped with the facilities to extend the experiment or if some of the students plan to continue to grow the tomato plants until they bear fruit, these suggestions may help with the process.
Transplanting: After approximately six weeks of growth, you may transfer the plants, including the peat pellets, to the final indoor containers - the 10 to 20 litre pots. Leave the plants in the pellets so as not to disturb the roots.
Culturing: Bury half of the stem after removing any leaves that might be covered by the potting soil. After the plants have achieved a height of 35 cm, they will need extra support. Using strips of soft cloth (about 2 cm by 25 cm), tie the plant stem in 2-3 places to a support stake that extends at least 1 metre above the ground. Wire tomato cages or other commercial support devices may also be used.
Flowering: Tomato flowers will begin to appear in about 30 days and will be ready for pollination. You can stimulate the self-pollination by shaking the plant gently every few days, holding the stem at the middle of the plant with the thumb and forefinger.
Transplanting: Set the plants outdoors for a short time each day to adapt to the cold and wind. The first exposure should last approximately 15 minutes. Gradually lengthen the exposure time to several hours per day during a two-week period. Do not set the plants in direct sunlight or wind for several days. Water the plants sparingly but do not apply fertilizer. After two weeks of "cold hardening" the plants may be transplanted outdoors as long as the daytime temperature generally exceeds 15 degrees Celsius and there is no danger of frost at night.
Culturing: After approximately eight weeks of indoor growth, pick a cloudy day so the plants will not become water-stressed. When transplanting, hold the plants gently. Place the stem of the plant halfway down in the soil, carefully removing any leaves that would be buried. More roots will form where the stem is buried and anchor the plant in the soil. Water the newly transferred plant until the soil is quite moist but avoid leaving standing water. Continue to water daily but do not soak the soil. Measure and record the new height of the plant as well as the greatest width. After the plants have achieved a height of 35 cm, they will need extra support. Using strips of soft cloth (about 2 cm by 25 cm), tie the plant stem in 2-3 places to a support stake that extends at least 1 metre above the ground. Wire tomato cages or other commercial support devices may also be used.
Flowering: Tomato flowers will begin to appear in about 30 days and will be ready for pollination. These flowers will self-pollinate when shaken. They may also cross-pollinate from wind, insects, or other contact.
Data should be recorded on a regular basis. To make the observations consistent, students should record their results on the same day.
Some suggested variables which may be observed, measured, and recorded are: