Dirt covered the table. Dirt covered my son’s hair. Dirt covered everything. While I wanted to be annoyed, I really wasn’t. It was all in the name of learning – and growing food in our new garden.
While trowels and compost may not seem like obvious tools for teaching science, vegetable gardens can be incredible classrooms. That day, my son was learning about the life cycle of plants while we started tomato seeds.
The best part is that gardening provides the potential for kids of all ages to learn. While my three-year-old is just beginning to learn the basics, even I’ve learned quite a bit in my years of gardening. If you don’t garden yet, consider planting a few flowerpots so you can share the benefits with your kids.
Here are a few of the STEM topics you can discuss:
The most obvious lesson is the life cycle of a plant. Starting with planting seeds, you can talk to kids about how they sprout, turn into seedlings, produce flowers, get pollinated, fruit, and then die off. You can also talk about what resources plants need to grow: nutrients, water and sunlight.
Gardening is also a great opportunity to talk about various insect species. You can observe the different parts of an insect, as well as how they differ from each other. For example, through observation and a little bit of research, you can look at how butterflies and bees have different methods of pollinating plants. You can even turn bad luck into a lesson. If harmful insects invade your garden, you can identify their species, look up their life cycles, find out their place of origin, and learn more about their harmful effects. Many garden nuisances eat plants in the larval stage, such as caterpillars and grubs (Japanese beetles).
My scientific background is in ecology, so I personally see the strongest connections there. In addition, I practice a form of gardening called permaculture that structures gardening around ecological principles instead of trying to fight against them.
Even when it’s not raining, the water cycle is essential to plants. Hot days provide a great chance to discuss transpiration, when plants release water vapor into the air. You can discuss why different plants may do better or worse in your climate, depending on the amount of precipitation you get. (For the best results, you can actually buy seeds adapted specifically to your area.)
Understanding the nitrogen cycle is also key to yielding a good crop. Nitrogen is essential to a plant’s growth. If plants don’t get enough, they’ll turn yellow and become weak. In the forest, tiny organisms break down leaf litter and other organic matter over time to return nitrogen to the soil. In addition, bacteria that have a relationship with tree roots “fix” the nitrogen to the soil and make it available for other plants to use.
But for our gardens to produce as much as we want them to, we have to add nitrogen. Many gardeners do that by adding conventional fertilizer, but that’s made using fossil fuels and washes out into watersheds. A more sustainable option is composting, which mimics how organic matter breaks down in nature.
Layer composting, also called lasagna gardening, takes the “forest floor” concept a step further. With lasagna gardening, gardeners lay down layers of leaves and other matter and then plant into it (not the dirt), just like the forest floor. You can also mimic the role of nitrogen-fixing bacteria by planting plants that carry out the same duties, like beans.
Another ecological concept that’s very helpful to gardening is evolutionary niches. Niches are specific roles that plants or animals have gradually taken over time through the process of adaptation. (For cultivated plants, this is also guided by human cultivation.) Some plants do well in very sunny places, some need acidic soil, and some do poorly with too much water. If you try to plant two plants that have the same niche near each other, they’ll compete and neither will do well.
In contrast, if you plant plants with complementary niches, they’ll actually do better than planting them separately. The classic example of crops with complementary niches are the Native Americans’ “Three Sisters”: corn, beans, and squash. The corn requires a lot of nitrogen, which the beans fix in the soil. The corn provides stalks for the beans to grow up as well as shade for the squash. The squash creates ground cover that prevents weeds from invading.
For more background on using ecological principles in gardening, I recommend the book Gaia’s Garden by Toby Hemenway.
While your kids won’t learn calculus from gardening, it does involve geometry, measuring, and a lot of counting. When you first design your garden, you’ll need to measure how exactly how large you want it to be. Based on how much space you have for each type of plant (like tomatoes), you can then figure out how many plants you can plant. Just divide the length of the section you’ve assigned to that plant, by the distances needed between seeds as you’re planting. (These are usually indicated on the seed packet.) Then, just use a ruler or measuring tape to measure them out!
If you decide to go DIY, you can develop all sorts of engineering projects.
Cold frames allow gardeners to raise seedlings outside before it’s too cold to plant them in the garden. Building a cold frame and raising plants in it illustrates the greenhouse effect as the window concentrates and traps heat. Because having the box closed too much can raise the temperature too high, you may need to experiment while collecting and analyzing data to determine the ideal angle for ventilation.
You can also build your own spinning composter, from recycled materials, like a bin from a local soda manufacturing plant (there are a surprising number of these around). You can find other potential sources for food-grade barrels here.
If your soil is compacted or may be contaminated, you’ll probably want to build a raised bed. There are a number of different forms of raised beds, but they all require assessing your needs and selecting the appropriate materials.
Of course, because food is such an essential part of our lives, learning about STEM is just the start. You can also explore history, nutrition, culture, and more! I learned an incredible amount about my own neighborhood when my neighbor saw me gardening and told me about the history of growing food in our community.
Whatever you and your curious Nerds choose to learn about in your garden classroom, I hope you’ll get dirty soon, have a great time discovering, and a enjoy a bountiful harvest.
Shannon Brescher Shea is a senior science writer/editor for the federal government. The mom of two very young sons, she also writes about parenting on her blog We’ll Eat You Up, We Love You So.