Credit Kathryn Simmons
For ten years I have been keeping phenology records, as a guide to when to plant certain crops, and as a way of tracking how fast the season is progressing.
Phenology involves tracking when certain wild and cultivated flowers bloom, seedlings emerge, or various insects are first seen. These natural events can substitute for Growing Degree Day calculations. Certain natural phenomena are related to the accumulated warmth of the season (rather than, say, the day-length), and by paying attention to nature’s calendar you will be in sync with actual conditions, which can vary from year to year, and are changing over a longer time-scale..
Many people know to sow sweet corn when oak leaves are the size of a squirrel’s ear. By this point, regardless of date, the season has warmed enough to get oak leaves to that size, which happens to be warm enough for sweet corn seed to germinate and grow well. Some people transplant eggplant, melons and peppers when irises bloom; sow fall brassicas when catalpas and mockoranges bloom; and know to look for squash vine borers laying eggs for the two weeks after chicory flowers. Some transplant tomatoes when the lily of the valley is in full bloom, or the daylilies start to bloom.
Lilac is often used to indicate when conditions are suitable for various plantings:
- When lilac leaves first form, plant potatoes
- When lilac is in first leaf (expanded), plant carrots, beets, brassicas, spinach, lettuce
- When lilac is in early bloom, watch out for crabgrass germinating
- When lilac is in full bloom, plant beans, squash, corn. Grasshopper eggs hatch.
- When lilac flowers fade, plant cucumbers.
Also, recording the dates of the same biological events each year can show longer term climate changes. In Europe, 500 years of recorded dates of grape harvests provide information about summer temperatures during that time. Project Budburst is a citizen science field campaign to log leafing and flowering of native species of trees and flowers across the US each year. Each participant observes one or more species of plant for the whole season.
| Here’s our Twin Oaks Phenology Record so far:
(c) Pam Dawling, 2013 |
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| Event | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | Notes |
| Crocus blooming | 26-Jan | 25-Jan | 6-Feb | 10-Feb | 28-Feb | 17-Feb | 30-Jan | |||||
| Chickweed blooming | 8-Feb | 1-Jan | 5-Mar | 10-Feb | 13-Mar | 19-Feb | 13-Feb | 15-Feb | ||||
| Robins arrive | 27-Feb | 31-Jan | 20-Jan | 26-Feb | 2-Mar | 14-Feb | ||||||
| Henbit blooming | 14-Mar | 7-Mar | 12-Jan | 6-Jan | 7-Feb | 20-Feb | 22-Mar | 2-Mar | 15-Feb | 15-Feb | ||
| Daffodils blooming | 17-Mar | 9-Mar | 7-Mar | 1-Mar | 22-Feb | 3-Mar | 5-Mar | 15-Mar | 3-Mar | 17-Feb | Plant potatoes | |
| Dead-nettle blooming | 18-Mar | 6-Mar | 7-Mar | 8-Mar | 14-Mar | 9-Feb | 24-Feb | 13-Mar | 21-Jan | 22-Feb | 10-Feb | |
| Spring Peepers first heard | 4-Mar | 11-Mar | 10-Mar | 3-Mar | 3-Mar | 6-Mar | 11-Mar | 28-Feb | 23-Feb | 5-Mar | Plant peas | |
| Overwinter Grasshoppers seen | 26-Feb | 4-Apr | 25-Feb | |||||||||
| Maples Blooming | 10-Mar | 6-Mar | 15-Mar | 12-Mar | 28-Feb | |||||||
| Dandelion blooming | 16-Mar | 16-Mar | 24-Jan | 1-Jan | 3-Mar | 17-Mar | 9-Mar | 8-Mar | 19-Mar | Sow beets, carrots | ||
| Forsythia blooming | 13-Mar | 12-Mar | 28-Mar | 10-Mar | 23-Mar | 13-Mar | 17-Mar | 21-Mar | 15-Mar | 12-Mar | 15-Mar | Plant peas. Crabgrass germinates. |
| Peach blooming | 15-Mar | 25-Mar | 26-Mar | 25-Mar | 13-Mar | |||||||
| Cabbage White Butterfly | 25-Mar | 20-Mar | 7-Mar | 8-Mar | 11-Mar | 6-Apr | 24-Mar | 12-Mar | 14-Mar | Dutch white clover blooms | ||
| Harlequin bugs | 10-Apr | 13-Mar | 26-Mar | 12-May | 16-Apr | 29-Apr | 14-Mar | |||||
| Johnny Jump-up blooming | 16-Mar | 30-Mar | 14-Mar | 20-Mar | 3-Apr | 17-Mar | ||||||
| Flowering Cherry blooming | 27-Mar | 4-Apr | 3-Apr | 1-Apr | 6-Apr | 25-Mar | 17-Mar | 18-Mar | 20-Mar | |||
| Asparagus spears | 6-Apr | 4-Apr | 4-Apr | 5-Apr | 6-Apr | 6-Apr | 21-Mar | 19-Mar | ||||
| Redbud blooming | 5-Apr | 13-Apr | 9-Apr | 3-Apr | 2-Apr | 7-Apr | 9-Apr | 7-Apr | 4-Apr | 19-Mar | Expect flea beetles | |
| Smartweed germinating | 15-Apr | 10-Apr | 15-Apr | 6-Apr | 11-Apr | 1-Apr | 23-Mar | 20-Mar | <149 GDD base 48F | |||
| Lambsquarters germinating | 20-Mar | 20-Mar | <150 GDD base 48F | |||||||||
| Violets blooming | 29-Mar | 26-Mar | 28-Mar | 6-Apr | 22-Mar | 20-Mar | ||||||
| Morning Glory germinating | 27-Apr | 10-Apr | 3-Apr | 26-Apr | 24-Apr | 25-Apr | 22-Mar | >349 GDD base 48F | ||||
| Tiger Swallowtail | 19-Apr | 29-Mar | 15-Apr | 16-Apr | 18-Apr | 10-Apr | 28-Mar | |||||
| Apples blooming | 18-Apr | 20-Apr | 14-Apr | 7-Apr | 12-Apr | 28-Mar | ||||||
| Dogwood (Amer.) full bloom | 5-Apr | 21-Apr | 13-Apr | 28-Mar | Plant peppers; soil 65 F | |||||||
| Strawberries bloom | 13-Apr | 11-Apr | 14-Apr | 12-Apr | 4-Apr | 2-Apr | 15-Apr | 6-Apr | 8-Apr | 30-Mar | ||
| Lilac full bloom | 16-Apr | 20-Apr | 21-Apr | 22-Apr | 19-Apr | 21-Apr | 14-Apr | 18-Apr | 1-Apr | Plant beans, squash | ||
| Crimson Clover blooming | 29-Apr | 2-May | 16-Apr | 22-Apr | 23-Apr | 27-Apr | 18-Apr | 25-Apr | 4-Apr | |||
| Whippoorwill first heard | 1-May | 22-Apr | 15-Apr | 24-Apr | 17-Apr | 25-Apr | 8-Apr | 14-Apr | 5-Apr | |||
| Galinsoga germinating | 1-May | 22-Apr | 16-Apr | 20-Apr | 6-Apr | |||||||
| White Oak “squirrel’s ear” | 20-Apr | 26-Apr | 23-Apr | 26-Apr | 25-Apr | 14-Apr | 23-Apr | 12-Apr | Plant sweet corn | |||
| Tulip Poplar blooming | 2-May | 10-May | 3-May | 26-Apr | 3-May | 6-May | 26-Apr | 28-Apr | 17-Apr | Plant sw corn 200 GDD base 50F | ||
| Ragweed germinating | 20-Apr | 16-Apr | 25-Apr | 26-Apr | 21-Apr | Plant sw corn 200 GDD base 50F | ||||||
| Last Frost | 24-Apr | 4-May | 3-May | 1-May | 8-May | 17-Apr | 19-May | 10-May | 14-Apr | 25-Apr | Average 4/30 (10 yrs) | |
| Fireflies | 7-May | 2-May | 1-May | |||||||||
| Colorado Potato Beetle adult | 22-May | 3-May | 7-May | 29-Apr | 27-Apr | 3-May | 25-Apr | 2-May | ||||
| Strawberries ripe | 10-May | 17-May | 12-May | 10-May | 7-May | 15-May | 3-May | 10-May | 7-May | |||
| Purslane germinating | 26-May | 8-May | 22-May | 5-May | 20-May | 15-May | 8-May | |||||
| Baby Grasshoppers | 12-Jul | 30-Jun | 26-Jun | 17-Jun | 16-May | |||||||
| Cicada first heard/seen | 14-May | 5-Jul | 3-Jul | 29-Jun | 17-May | |||||||
| Hardneck garlic mature | 14-Jun | 19-Jun | 13-Jun | 5-Jun | 4-Jun | 30-May | 9-Jun | 11-Jun | 6-Jun | 31-May | ||
| Foxgloves bloom | 6-Jun | 11-Jun | 8-Jun | Bean beetle eggs hatch | ||||||||
| Bean Beetle eggs | 4-Jun | 16-Jun | 10-Jun | 6-Jun | 20-Jun | Hatch when foxgloves bloom | ||||||
| Japanese Beetle first seen | 16-Jun | 21-Apr | 15-Jun | 20-Jun | 29-Jun | 21-Jun | 850 GDD (base 50F) | |||||
| “June” Bugs first seen | 5-Jul | 11-Jul | 2-Jul | 12-Aug | 10-Jul | 30-Jun | 29-Jun | 30-Jun | 23-Jun | |||
| Corn Earworm first seen | 28-Jul | 8-Jul | 12-Jul | 10-Jul | 14-Jul | 150-490 (base 54F) | ||||||
| Fall Dead-nettle germinating | 1-Sep | 20-Aug | 30-Aug | 20-Aug | 16-Aug | 20-Aug | 15-Aug | 29-Aug | 18-Aug | Plant spinach | ||
| Fall Henbit germinating | 28-Aug | 20-Aug | 29-Aug | 18-Aug | ||||||||
| Fall Chickweed germinating | 7-Sep | 7-Sep | 5-Sep | 6-Sep | Plant spinach | |||||||
| First Fall Frost | 3-Oct | 6-Nov | 27-Oct | 13-Oct | 29-Oct | 20-Oct | 19-Oct | 23-Oct | 30-Oct | 22-Oct | Average 10/22 (9 yrs) | |
| Harmonia Ladybugs migrate east | 18-Oct | 12-Nov | 21-Oct | 27-Oct | ||||||||
| Garlic planted (hardneck) | 25-Oct | 20-Oct | 9-Nov | 3-Nov | 11-Nov | 1-Nov | 5-Nov | 11-Nov | 15-Nov | 6-Nov | Soil temp 50 F | |
| Event | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | Notes |