Gardening science fair projects can be both fun and educational for children – especially for those who may have no experience with growing plants. There are endless possibilities in terms of gardening science fair projects, and most of them can be easily adapted to fit the needs of different ages.
- Make the soil the variable. Many common gardening science fair projects have to do with planting seeds in different substances. Young children can plant seeds in soil, charcoal, and sand to see what happens. Older students can get more sophisticated, changing the pH of the soil and determining what happens to the seeds, or including different types of fertilizers in the soil as their variable. Just make sure to always have a control plant in regular soil so that you can see what is supposed to happen.
- Use other variables. Another popular type of gardening science fair project is to plant seeds in the same type of soil, but change the amount of water or sunlight the plant receives. Again, this can be adapted to fit different age groups: young children can use the same type of seed, but keep one in the dark and one in the sunlight or give one plant more water than the other. Older students can try different types of plants and see which ones work best in the dark, which ones require more water, and which ones are actually damaged by watering them too much. Another interesting experiment is to vary the type of water being used on the plants – does distilled water create a different effect than tap water?
- Experiment with pesticides. Obviously, pesticides must be treated with caution, and young children should not be allowed to interact with any poisons. However, for students who are old enough to be careful and responsible, this can be an interesting gardening science fair project. In trying different forms of pesticides, students can not only see which pesticides are most effective, but also if the pesticides have any adverse effects on the plants themselves.
- Do plants get crowded? Many seed packets advise “thinning” the seedlings – why is this? Try gardening science fair projects with a control group of plants where you follow the directions and another group where you do not thin the plants at all. Does it really make a difference?
- Do plants need microorganisms in the soil? What exactly is it in the soil that helps plants grow? Try planting seeds in two different types of soil – one that has been baked in the oven to destroy all microorganisms. Keeping all other things the same, which plant grows better?
- Which temperatures are best for germination? For children who are younger (or more impatient!), you don't have to wait for plants to grow fully. Experiments can be performed to see how long it takes a seed to germinate. Place beans or tomato seeds wrapped in wet paper towels in plastic bags. Then put one set at room temperature not in the sun, one set in direct sunlight, and one set in the refrigerator. Which set germinates first? Are they all germinating successfully?
- Have the students get creative. Find out from your students what they want to learn about plants and base your gardening science experiments on their questions and hypotheses. There is no better way to interest students than to have them direct the learning! As a parent or teacher, you may have to refine their questions and direct their experiment, but let them control as much as possible.
- Make sure your students understand the scientific method. Again, this can vary according to the level and age of your students, but even very young students can follow the basic process of the scientific method. Help them understand why the scientific method is important to achieve scientific results.
Although gardening science fair projects must be carefully thought out, they are definitely worthwhile. It is extremely memorable for students to actually see how plants are affected by different variables. A garden in the classroom can be just the thing to get kids interested in science!