That is something you have to do locally, so my own garden calendar probably applies to New Jersey, or just and this area of Essex County in some cases, and only specifically to my own square mile in other cases.
In fact, sometimes they seem to apply only to my own backyard microclimate! For example, the daffodils I have planted in the garden bloomed last year five days later than several houses around the block - probably due to the amount of sun they receive.
I also take note of things that are happening around the state with wildlife. There are people who focus just on bird migrations as a sign of spring, for example.
From my NJ nature calendar for spring:
around March 25 - piping plovers return to NJ - time to prune evergreens, turn compost, sow peas and spinach
April 26 - bluefish run usually begins.
April 29 - first piping plover nests on Jersey beaches.
You get the idea.
For centuries farmers, naturalists, and scientists have kept records of the patterns of plants and animals and used the information to predict the best time for planting and harvesting crops and when to start expecting problems with insect pests.
There are other "citizen scientists" out there. You can join thousands of others in gathering environmental and climate change information from across the country in a program called Project BudBurst.
It asks you to make careful observations of the phenophases in your area such as first leafing, first flower, and first fruit ripening of a diversity of trees, shrubs, flowers, and grasses. What is really important is to observe the first day of the appropriate phenophase (like the first flower).
Reporting what you observe contributes valuable environmental and climate change information - but it's also a great way to learn about the environment, connect to nature, and contribute to science, all at the same time.
Phenology (which I had never heard of, even though I was doing it) is the study of the timing of life cycle events like leafing, budding, and blooming in plants.
The phenological events of many species has changed recently as a result of changing temperatures and rainfall patterns. The average global temperature increased by 0.6°C ( 1.0°F) during the 20th century. The temperature is predicted to rise with another 1.8 to 4.0°C ( 3.2 to 7.2°F) in the 21st century. That probably seems like pretty small variations, but at the global scale it can have dramatic effects on the environment.
Climate change has the largest effect on plants because, unlike many animals, they cannot move easily from one area to another.
The results might be that the growing season could start earlier or continue over a longer period of time. In NJ, the "official" last frost date is anywhere from April 15 to May 15, but I have been keeping track myself and a May frost has been the rare exception for my little microclimate in the past 20 years.
So, watching for the phases of the plant life cycle (phenophases) causes you to be very mindful of things like temperature, rainfall and day length. Monitoring changes in events such as first bud, budburst, and flowering, can help scientists detect climate change.
Got a New Jersey plant or wildlife calendar observation? Click the comment link below and let us know.