Phenology: Using Nature’s Signs & Signals

Are You Paying Attention?

If you like to spend time in the garden (or outdoors in general) you probably already notice various signs and signals that indicate natural seasonal changes are underway.

What triggers the budding of leaves, the blooming of tulips, or the mating calls of peepers? Why do they start on one day and not another? And which circumstances lead up to these natural events?

What is Phenology?

This is all a part of phenology—pheno (appearance) + logos (study)—the study of plants and animals through seasonal changes. We see it in everything from budding, flowering, and fruiting, to breeding, nesting, and migration. By paying attention and recording your observations (see checklist below) you can not only become a more proficient gardener but assist with national volunteer projects that collect this information to give us a better understanding of nature and climate change.

To get started, this short video shows how climate change causes natural cycles to get out of sync:

It’s All Connected

One of the coolest things about being a gardener (or avid nature lover) is how, over time, you start to notice the profound relationships between living things and the timing of their events. It’s like the ultimate symphony made up of domino effects.

If you live in a cold climate like I do, we hold it all together until late winter. And then we go bonkers waiting for spring. Parades are held when one lone robin makes an appearance. Never mind he was here all along!

The quest to find signs of spring actually begins back in December with the increase in daylight following winter solstice. It’s still freezing outside but the days start to get longer and we know winter cannot outsmart the sun and the tilt of the earth forever.

Several months later, snow gradually melts, we start tapping the trees for sap to make syrup, tree buds start to open, insects appear, and spring fever (the people’s euphoria) sets in.

With insects come the birds and bats that feast upon them.

Tree leaves fill out and baby birds hatch in their nests, nicely hidden from predators.

Fledglings leave the nest when food sources are abundant, giving them their best chance to succeed on their own.

These are just a few examples, of course. And on and on it goes: everything works in harmony.

Nina Leopold Bradley describes it beautifully:

It’s not just the natural events themselves, but the correlation between them that we see: there’s perfection in the timing that we cannot afford to tamper with without risking incredible, irreversible losses.

Phenology is What We All Do

Phenology is not magic or woo-woo, but, quite simply how nature works: adapting to climate and weather; acting on favourable conditions.

• Birds aren’t going to migrate until there’s food sources available at their next resting places.
• Bats aren’t awakening from their winter’s rest until there’s lots of insects to gobble up in the air.
• Peepers don’t peep until their intended mates are also out of hibernation and ready to rumba.
• Apple trees produce fruit when the conditions are favourable.
• Bees are most active when nectar and pollen is abundant.

How Gardeners Use Phenology

As gardeners we can use phenology to make the best choices for our planting schedules, relying on natural signs and signals rather than specific dates on the calendar to ensure planting and harvest times are right. These observations used to be called ‘garden wisdoms’ and sometimes ‘wives’ tales’.

Some of the old-fashioned ones fall short because they name dates instead of natural events to go by.

For example, Plant peas on St. Patrick’s Day may work in regions much farther south than I am, but here, the only thing I’d have if I planted pea seeds outdoors in mid-March is frozen peas.

These are examples that works quite reliably for me:

Plant potatoes when the first dandelions bloom and

Plant potatoes when the apple trees blooms (see more examples here).

Either way, here in Ontario, both events mark the spring days when we’re (hopefully) past the risk of frost and the ground is warm enough for digging and planting some slow-growing, cold-loving crops.

Another reliable one is, the birds will tell you when it’s time to save seeds.

This happens in the fall. I know it’s time to start collecting seeds for seed saving when the birds start dining on old flower heads on sunny afternoons. I can tell by their enthusiasm that the seeds are getting nice and toasty which is my cue to bring some indoors for final drying and storage.

Need a garden journal? See how mine has made me a better gardener.

More Examples of Phenology

Here’s some more examples from the University of Wisconsin-Extension office.
Do any of them match your experience?

• Plant peas when forsythia blooms.
• Plant potatoes when the first dandelion blooms.
• Plant beets, carrots, cole crops, lettuce and spinach when lilac is in first leaf.
• Plant corn when oak leaves are the size of a squirrel’s ear.
• Plant bean, cucumber, and squash seeds when lilac is in full bloom.
• Plant tomatoes when lily-of-the-valley plants are in full bloom.
• Transplant eggplant, melons, and peppers when irises bloom.

As you can see, the phenological garden wisdoms tend be quite regional-centric, and sometimes amusing (squirrels ears and all).

Related: Natural Signs it’s Time to Plant Fall Bulbs

Ideas For Keeping Your Own Phenological Records

By noting our observations, we become more aware. Sign up with an organization or simply start jotting down your own notes. I’ve listed some suggestions below. You can adapt it to suit your growing region. It’s much the same as a garden journal with some notes about seasonal natural events added in. It’s very interesting to compare notes year after year to see how things change and to better understand what timing works best in your garden.

Spring to fall: record the dates, any unusual weather, and take photos 

• Last frost date
• Final melting of ice and snow
• Trees start budding out (pick a particular tree type to observe)
• Trees leafing out
• Trees leaves fully open
• First trilliums in the woods
• Tulips 2″ out of ground
• Tulips blooming
• Apple and plum tree blossoms fully open
• Lilacs budding and blooming
• Poppies in bloom
• Irises in bloom
• Delphiniums in bloom
• Asters in bloom
• First worms out of soil
• First male cardinal mating calls
• First robins (several) in garden
• First peeper mating calls (this can vary by many weeks: it’s very interesting!)
• First bats swooping for mosquitoes in the evenings
• First baby toads
• First bees
• First hummingbirds, Baltimore orioles, and Rose-breasted grosbeaks at feeders
• First butterflies and moths
• First tomatoes ripe
• First frost (at end of season)
• Also note any unusual weather / temperatures
• Record the planting dates of all annual veggies and how successful the crops were

Resources for National Phenology Groups in the U.S.

These are just a few of many. Try Googling to see what’s available in your area.

• Nature’s Notebook | there’s also an app for Android and iPhone
• Chicago Botanical Phenology

Are You Ready?

This topic is so huge (as huge as nature itself) but I hope this has given ideas for your own phenological studies. Have fun with it and perhaps you’ll come up with new garden widsoms to pass along to your grandkiddles.

~Melissa the Empress of Dirt ♛