I love old time farm sayings like “plant potatoes when the first dandelions bloom” or “cut in June will come back too soon, cut in July will surely die.” Long before we had the internet and hundreds of gardening books to read, these sayings were handed down from parent to child and guided the yearly planting and harvesting. It turns out these sayings are accurate much of the time and the official name for them is Phenology. Many universities have devoted years to studying the validity of these sayings.
Events in the ‘natural calendar’ can be used to guide planting times in the vegetable garden or on the farm. The study and observation of seasonal events and their correlation to plant, insect, and animal life is called “phenology,” from the Greek for the “science of appearances.” Trees, shrubs, and flowers are sensitive to temperature and day length and develop on a regular schedule based on local conditions. It only makes sense to use these natural indicators to know when the weather is right for planting. Observations made over many years have led to some fairly reliable conclusions. According to the National Phenology Network“Phenology is nature’s calendar—when cherry trees bloom, when a robin builds its nest and when leaves turn color in the fall.”
The life cycle of the common lilac is an often used guide in Phenology studies and garden planning and planting. The leafing out and progression of lilac blooms (from bud to flower fade) can aid the vegetable gardener from year to year. For example, after years of observing the lilac, naturalists have concluded that it is safe to plant tender bean, cucumber, and squash seeds when the lilac is in full bloom.
Here are some of the most common sayings
Vegetable Garden Crop Planting Phenology
Beans: Plant beans when lilac is in full bloom, also cucumber seeds and squash seeds.
Beets: Blooming crocus are your cue to plant radishes, parsnips, and spinach.
Broccoli: Plant broccoli when lilacs first begin to leaf out and dandelions are in bloom.
Brussels sprouts: Plant Brussels sprouts when lilacs first begin to leaf out and dandelions are in bloom.
Cabbage: Plant cabbage and cabbage family crops (broccoli, Brussels sprouts, collards) when lilacs first begin to leaf out and dandelions are in bloom, also beets, carrots, lettuce, and spinach.
Cabbage for spring: Plant spring cabbage in fall when mock orange is in full bloom
Collards: Plant collards when lilacs first begin to leaf out and dandelions are in bloom.
Corn: Plant corn when apple blossoms begin to fall and when oak leaves are the size of a squirrel’s ear.
Cucumber: Plant cucumber seeds when lilac is in full bloom and when the blooms just start to fade, also bean seeds and squash seeds.
Eggplant: Transplant eggplant when irises bloom and daylilies start to bloom, also melons and peppers.
Hardy, cool-season spring crops: plant hardy crops when plum and peach trees are in full bloom.
Peas: Plant peas when daffodils and forsythia are in full bloom.
Potatoes: Plant potatoes when the first dandelions bloom.
Squash: Plant squash seeds when lilac is in full bloom and just as the blooms fade, also bean seeds and cucumber seeds.
Tomatoes: Plant tomatoes when day lilies start to bloom or lily-of-the-valley plants are in full bloom or flowering dogwood are in bloom.
Perennials: can be planted when the maple trees begin to leaf out
Vegetable Garden Pests Phenology
Apple maggot moths are at their peak when Canada thistle blooms; protect apple fruits.
Mexican bean beetle larvae appear when foxglove flowers open.
Cabbage root maggots are active when wild rocket blooms.
Japanese beetles arrive when morning glory vines begin to climb.
Squash vine borers are at their peak when chicory blooms; protect pumpkin plants.
Tent caterpillars are hatching when crabapple trees are in bud; begin caterpillar controls.
While not totally foolproof, following nature’s clock helps us tune in to the rhythm of life around us. Accumulating notes on insect indicator plants in your own garden over several seasons paves the way toward being a much more effective manager of pests that plague your garden year after year. This can help eliminate time wasted looking for pests that have yet to become active, and remind you to check plants closely when they are scheduled to be a certain insect’s next main course. As we wait on spring, we are wise to keep our eyes open and pencils handy to better understand the Phenology of our one-of-a-kind gardens. Consider the Chinese proverb, “Spring is sooner recognized by plants than by men.”
What are some signals where you live? I know that I am going to plant a lilac bush this spring so I can start being more cooperative with my natural world!
Beineke Rare Book and Manuscript Library