Gardens have Circadian Rhythms, Too!

Our bodies are controlled by circadian rhythms that tell us when we should be sleeping and when we should be awake. The same is true of every animal. Diurnal creatures are awake during the day and nocturnal animals wake for the night. Sure, we can get out of sync but our natural rhythms dictate when we should be active and when we should be resting. And it’s not just animals that follow this natural cycle. Gardens have circadian rhythms too!



This year I missed the boat on planting my early spring crops like broccoli and cabbage. I do have some coming up but, for the full crop I want I’ll have to do a mid-summer planting to get a fall harvest. That’s good news in a way as cabbage is always sweeter after having gone through a frost. Yet it’s not so much the temperature that these crops are reacting to but the longer days. Just as our bodies set our internal clocks by sunlight, many crops do the same.

Plants keep track of the seasons to ensure the survival of their species. They are sensitive to day length which is called photoperiodism. Potatoes use this to determine when to produce storage tubers and other plants use it to time when they fruit or bolt. We would know spring from summer and summer from winter without clocks or calendars by daylight and plants are the same.

“The {circadian} clock has a light-sensitive window at the end of the day that acts as a gating mechanism” according to Takato Imaizumi, a University of Washington biologist. Sunlight is still crucial to our biological sense of time but that gating mechanism communicates to plants and animals the changing of seasons. Latitude also plays a role in the success of your garden.

Long-day plants like tomatoes and peppers want to flower and fruit as we move toward the longest days each year. Plants such as cabbage and turnips want to flower in early spring or in the fall. Some plants require a prolonged period of cold, known as Vernalization. Carrots, parsnips, and beets won’t go to seed in their first summer with this cold.

When trying to create a garden be sure to purchase plants or seeds that are suited to your locale. If you’re in Florida, it’s not use trying to grow crops intended for cold weather areas. You can also adjust when you plant various crops so that you can mimic the circadian rhythm of your garden.


Author: Elizabeth

I'm a wife, mom, and grandma (known as Bam) who loves cooking, baking, gardening, and all things that go into making a cozy coop for my brood. I have a disability so you may pick up tips on how to do things when some things just don't work right!

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