Moon phases were used by the ancients to measure time, and today our months are roughly equal to a lunar cycle. Sir Johnny Scott explains how the moon phases not only mark the year, but also herald changing seasons and can even cause madness.

For more, discover the colourful celebrations of the Winter Solstice in bleak midwinter. Read winter solstice traditions: a bleak but beautiful midwinter.

MOON PHASES

The 29½-day cycle of moon phases was the earliest form of measuring time, and the present-day months are roughly equal to the lunar cycle. Each of the farming seasons – spring, summer, autumn and winter – lasts three months or three moon cycles, thus a year was made up of 12 full moons; the cycle of each following the same pattern. A new moon is completely black; over the next four nights, the moon ‘waxes’ or becomes more visible until a quarter, known as a ‘waxing crescent’, can be seen on the right side. Four nights later, half the moon, known as the ‘first quarter moon’, is visible. A couple of nights later, this has enlarged to become a ‘waxing gibbous moon’, then, two nights later, a full moon. After this it ‘wanes’ in similar time intervals on the left side, through ‘waning gibbous’, ‘last quarter’ and ‘waning crescent’ until it becomes a darkened or new moon.

A Hunter’s Moon in October provides light by which to shoot geese.

Each full moon had its own significance. The first full moon in March had various names: the Worm Moon, because the ground had warmed up sufficiently for earthworms to become active; the Crow Moon, from the vocal mating of crows; the Lenten Moon, since it was the last full moon of Lent; or Sap Moon, from the appearance of the first buds on trees. This full moon was of particular importance in the farming calendar as it was officially the last full moon of winter and heralded the start of the three-month Vernal Equinox. (The name ‘equinox’ is derived from the Latin aequus, meaning equal, and nox, night, because around the equinox the night and day are approximately equally long.) It was an important time for sowing seed; the ancients were aware of the moon’s influence on the tides and always endeavoured to plant with a waxing moon believing, as many do today, that just as the moon pulls the tides it causes moisture to rise in the earth, encouraging growth. The later stages of a waxing moon are also favoured for harvesting plants that need to be rich in moisture content, such as grapes, tomatoes, strawberries and wild mushrooms.

When the moon is at the full,
Mushrooms you may freely pull
But when the moon is on the wane,
Wait ‘ere you think to pluck again.

Root plants, such as potatoes, turnips and carrots, are best planted during the ‘dark of the moon’. The waning moon is the time for killing weeds, cutting back dead growth, harvesting root vegetables, drying herbs, flowers and fruit, and planting beans.

Sowe peason and beanes, in the wane of the moone,
Who soweth them sooner, he soweth too soone
That they with the planet may rest and arise,
And flourish, with bearing most plentiful wise. 

The next three moons all have names associated with growth and fertility: April has the Egg Moon or Hare Moon (both symbols of fertility), Grass Moon or Seed Moon; May has the Milk Moon from the first flush of grass providing milk; and June has the Flower or Honey Moon. The longest day of the year and start of the Summer Solstice is on or around 21 June. The days now become imperceptibly shorter and folklore insists the birds start singing later each morning.

RIPENING MONTHS

July, August and September are the ripening months of the farming year. July has the Hay Moon, when the hay is cut. August has the Grain Moon, when ‘grain ripens as much by day as by night’ under the full moon. September has the Fruit Moon – often also the Harvest Moon, the full moon nearest the Autumnal Equinox. This has a wonderful hazy, orange colour and appears bigger than other moons, caused by light from the moon passing through a greater amount of atmospheric particles than when the moon is overhead.

The Hunter’s Moon in October is so called because the moonlight enables sportsmen to shoot migratory geese arriving from their Arctic summer grazings. November has the Frost Moon and December the Long Night Moon; this occurs around 21 December, the shortest day and the longest night, and the start of the Winter Solstice when the position of the sun is lowest in the sky. The following two full moons are the Ice Moon or the Moon after Yule in January and the Wolf Moon in February, from the long-gone days when wolf packs roamed the countryside howling at the paucity of available food.

There are usually 12, but occasionally 13, full moons a year.

In addition to these 12 full lunar cycles, each solar calendar year contains an excess of roughly 11 days compared to the lunar year of 12 lunations. The extra days accumulate and every two or three years there is an extra full moon in one of the months. These phenomena are called Blue Moons, although no one quite knows how they became named ‘blue’, since they look no different to other moons. One credible hypothesis is put forward by the Oxford English Dictionary, which claims the first reference to a blue moon comes from a nonsensical proverb recorded in 1528:

If they say the moon is blue,
We must believe that it is true.

This is as meaningless as saying the moon is made of cheese, but a connection between the rarity of two full moons in one month and the absurdity of the proverb seems to have stuck. For early people, who recognised the effect of the moon on tides, the natural assumption at the appearance of two full moons in one month was to expect massive flooding and sea surges.

MOON MADNESS

There are an immense number of myths and folklore attached to the power of rays from a full moon, the most obvious of which is lunacy. Moon madness was taken seriously: “Lunacy grows worse at full and new moon,” proclaimed the 16th-century Swiss physician Paracelsus, referring to a disease that had been recognised since Classical times, and which became official under British Law in the mid-19th century. The 1842 Lunacy Act defined as a Lunatic: ‘A demented person enjoying lucid intervals during the first two phases of the moon and afflicted with a period of fatuity in the period following after the full moon.’

A waning gibbous, seen shortly after a full moon.

It was considered detrimental to sleep in a room with the curtains open during the full moon and a disaster to be born exposed to moonlight. Although the cottar’s pig was killed just after the November full moon, when it would be fat from gorging on acorns by moonlight, enormous care was taken to ensure that the carcass was not exposed to the malefic rays of a waning moon, less they corrupt the flesh. On the other hand, woodsmen avoided felling trees around the period of the full moon in the belief that the timber would contain too much water and quickly rot.

This is an edited extract from Johnny Scott’s A Book of Britain, published by Collins, and is reproduced by kind permission of the author.