The Autumn Equinox is one of the four key points in the year for gardeners and farmers in particular. Harvest festivals are traditionally celebrated around the time of the Harvest Moon, which is the full moon that occurs closest to the Autumn Equinox.
These three closely-knit events may seem less important in the modern day world, but just because most people live in urban areas doesn’t mean they don’t need to eat. And, as we’re seeing as a result of global weather changes and the Covid pandemic, the more food we can grow within the UK, the more reliable the supply will be.
Growing fruit and vegetables in our allotments, gardens and balconies may seem small scale, but its part of the larger picture. Making autumn an important time in the garden as well as on the farms.
What are Harvest Festivals?
Harvest festivals are thanksgiving festivals. A way of showing gratitude to one’s God or gods for a good store of food to keep people fed through the lean winter months. Historically, harvest festivals were also an opportunity for the Landowner to give a feast for his workers in recognition of their hard work over the growing season. The first new ale would be drunk and loaves of bread made with the freshly gathered and milled wheat. Corn dollies, a fertility symbol, were made from the last stalks of the wheat harvest and placed in a prominent position.
Harvest Moon
Sometimes called the Corn Moon, in two years out of three, the Harvest Moon comes in September. But due to the varying length of our calendar year, it will also occur in October. Which means it may happen just before, on, or just after the Autumn Equinox.
At the peak of harvest, farmers can work late into the night by the light of this Moon. Historically, when horse power meant horses not tractors, this could be crucial.
What is the Autumn Equinox?
The word “equinox” means “equal night” in Latin, “aequus” meaning equal and “nox” meaning night. So at the time of both the autumn and the spring equinox one would expect the number of daylight hours to match the number of night-time hours. And it nearly does.
The solstice and equinox are one of the two main methods used to determine the seasons in the United Kingdom. This is known as the Astronomical method. Autumn is generally considered to run from September 21 or 22 to December 20 or 21. However, there is some dispute as whether the equinox and solstice fall at the start of a season or in the middle of it.
For Meteorological purposes, autumn covers the months of September, October and November. This allows for exact comparison between years and ignores, for example, fluctuations caused by leap years in the Solstice dates.
A third way to define the seasons is by using phenological indicators. These indicators are various ecological and biological signs suggesting change. For example, autumn signs would include leaves falling from trees. Because of the influences of the weather and climate, it is difficult to take precise measurements to compare one year with another.
How the Autumn Equinox affects your Garden
It’s fairly easy to see why holding harvest festivals in some form around the autumn equinox is a tradition that has continued. Using a celebratory meal to eat the crops that won’t store well over winter is a good idea. All those windfall apples will make a tasty crumble now but be hopeless in a month’s time.
But why is the autumn equinox important to your plants as well as to you? Well, you know that this is one of two points in the year that the day length and night length are equal. But the point is that the plants in your garden and allotment will notice the difference as they respond to the length of daylight.
Well actually, it’s not quite that simple. Not all plants decide to hibernate once the nights become longer than the days. Whether we’re having an Indian Summer or an early hoar frost makes a difference too. So, without dumbing down as you’re an intelligent bunch of readers, let’s have a brief botanical explanation as to why the plants in your garden start behaving differently once we’ve reached the autumnal equinox.
Seed Germination
It’s important for a plant’s existence that it knows not to let its seed germinate during winter. Hard frosts and low temperatures would likely kill the emerging seedling. Obviously there are some plants where this doesn’t apply, as they need cold, but we’re ignoring those for now.
Nor would it be productive to flower when the correct pollinating insects needed by that plant are not around. For example, there are some plant species which can only be pollinated by butterflies.
Neither is a good plan for survival of the species!
Plant Growth
There are both internal plant factors and external factors that affect plant growth. Internal factors include the production of particular proteins and hormones. However, it is the two major external factors that we’re looking at, and the effect that they have on the internal. They are, as you’ve probably guessed, light and temperature.
Generally speaking, most plants require a certain temperature in order for the seed to germinate and for the plant to grow. Which is why many plants lie dormant or semi-dormant over the winter months. Some plant species require a period of cold to encourage germination of the seed; Tulips are one of these species. When tulips are grown where the winter is not cold enough, Florida for example, they can be artificially chilled so as to stimulate flowering in the spring.
How Plants in Your Garden Respond to Day Length
Photoperiodism, or plants’ response to day length, has been constant over millennia. It is only over the past couple of hundred years or so that humans have been successfully able to interfere with the process artificially. But it wasn’t until the 1920s that the onset of flowering was linked with day length, during experiments by Garden and Allard with soybeans and tobacco.
Flowering plants are especially sensitive to photoperiodic stimulus. For example, have you ever forced Hyacinth bulbs for Christmas by putting them in a cool dark cellar, then bringing them in to the warmth and light to flower?
Assuming that the plant is sufficiently mature and ready to flower, the day length becomes crucial for many of our favourite garden flowers. Plants respond to the comparative length of daylight and darkness with a photoreceptor protein which senses the change in light levels, and the autumn equinox is a key marker.
There are three main grouping of flowering plants in relation to photoperiodism: –
Short day plants
Chrysanthemum, for example, react to the day length being shorter than a specified time. Or put another way, when the hours of darkness are longer than the hours of daylight. So these plants tend to flower later in the season, during late summer and autumn.
Long day plants
Such as Gypsophilla, tend to be spring and summer flowering plant. They respond to the day length being longer than a specified amount of time.
Day neutral plants
For example, Viburnum, are unaffected by the length of daylight hours and will simply flower when they are mature enough to do so.
Autumn Equinox and the Gardening Year
For gardeners the autumn equinox is a crucial turning point in the year. Many of the food crops we grow ourselves are maturing like crazy and we are hard pressed to find time to pick and store.
Then there are semi-ripe cuttings to take from tender perennials, in case they don’t survive the winter’s frosts. And seeds to collect both from annual flowers and vegetables we cultivate as annuals. Oh yes, and herbaceous perennials to lift and divide to share with friends.
After all that hard work, I think we deserve a celebratory harvest festival, don’t you?
There are links below if you’d like to learn how to take cuttings, find out what lasagna gardening is and more
If you would like help with learning more about your garden and gardening, why not ask about our bespoke Gardening Lessons, where your classroom is actually your own garden. We can help you learn gardening basics, and also show you how to plan an ornamental border or kitchen garden.
And for further gardening advice and inspiration, check out Plews Potting Shed blogs, including the selection below and our monthly Tipsheet – You could come and find us on Instagram Pinterest and Facebook too.
Related Gardening Blogs from the award winning Plews Potting Shed
Is Yours a Shady or a Sunny Garden?
Why do leaves fall? And other Autumn Gardening Questions
Why are there Changes to Your Garden Growing Season?
Collecting Seeds from Your Garden
Grow Your Own Garden – Semi-ripe Cuttings
Dividing Herbaceous Perennials
What is an Ornamental Edible Garden?
What is Organic Gardening?
Grow Your Own Vegetables in Rows
Lasagna Gardening – Growing Methods for Gardeners
The cover illustration for our eBook “In Your Autumn Garden” shows Demeter, who was the Greek goddess of the harvest and fertility and one of the aspects of the Triple Goddess, or Earth Mother, Gaia. An appropriate subject for a book about the autumn equinox, harvest and crops in your garden and allotment, we thought.
