← Encyclopedia of Astrology · lesson 156/235
Planting by the Moon
What it is
Planting by the Moon — also called lunar gardening or gardening by the signs — is the custom of choosing the day for garden and farm work from the Moon's place in the sky. It is one of the oldest and most widespread pieces of astrological practice: Roman writers such as Pliny gave lunar rules for sowing and felling timber, the seventeenth-century electional books gave whole chapters to tillage, planting and sowing, and country almanacs have printed "best days" tables ever since.
It is easiest to understand as three separate systems that are often printed side by side. They come from different periods, answer to different parts of the sky, and do not always agree.
By the Moon's phase
The simplest and most widely known rule follows the waxing and waning Moon: what grows above ground is sown while the Moon is growing in light, and what grows below ground is planted while she is waning. Many almanacs refine this into the four quarters:
- First quarter (New Moon to first quarter) — leafy crops that bear their seed outside a fruit: lettuce, spinach, cabbage; annual flowers.
- Second quarter (first quarter to Full Moon) — crops with seed inside a fruit: beans, peas, tomatoes, squash, melons.
- Third quarter (Full Moon to last quarter) — roots, bulbs, perennials, trees and shrubs.
- Fourth quarter (last quarter to New Moon) — sow nothing; weed, cultivate, mulch and deal with pests.
The same logic gives pruning to the waning Moon when regrowth should be slow, and harvesting for storage to the waning Moon, when crops are said to hold less water.
By the Moon's sign
The older astrological system looks instead at the sign the Moon is passing through. Signs were classed as fruitful or barren — the water signs Cancer, Scorpio and Pisces the most fruitful, Taurus, Capricorn and Libra moderately so, and Gemini, Leo and Virgo barren, with Aries, Sagittarius and Aquarius leaning barren (see fruitful and barren signs). Sow and plant in a fruitful sign; weed, mow, clear and harvest in a barren one.
William Ramesey's rules of 1653 are a good example of the electional version. For trees he wanted the Moon in a fixed sign, "but especially in Taurus", then Aquarius; for seeds that should come up quickly, the Moon in a moveable earth or water sign, Cancer or Capricorn, and "increasing in light and motion" — except for peas, which he would sow with the Moon decreasing "for otherwise they will never leave blooming". Throughout he keeps the Moon clear of Mars, "for he is destructive".
By the constellation: biodynamics
The third system is modern. In the twentieth century Maria Thun, working in the biodynamic movement founded on Rudolf Steiner's lectures, divided the month into root, leaf, flower and fruit days by the element of the constellation the Moon stands in — the actual star groups, which are unequal in size, rather than the twelve equal signs of the tropical zodiac. Because the two are now about a sign apart, a biodynamic "root day" in the constellation Taurus may fall while the Moon is in tropical Gemini. See biodynamic calendar.
How the systems combine — and disagree
Most almanacs layer the phase and the sign: sow leafy crops in the first quarter and a fruitful sign; plant potatoes in the third quarter and Taurus or Capricorn. When they conflict, writers usually say the phase sets the broad window and the sign picks the day within it. The biodynamic calendar is a different reckoning of the same Moon, and it can name a different day for the same job; gardeners generally follow one system or the other rather than trying to satisfy both. Even within one system the authorities vary — whether Libra counts as fruitful, whether pruning belongs to the waxing or waning Moon, whether the change of phase is reckoned at the quarter or the Full.
What the evidence says
The practice is old and sincerely held, and some gardeners find that working with the Moon gives their year a rhythm. Controlled trials have not settled whether it changes a harvest. Maria Thun reported effects in her own trials; a German study by Hartmut Spiess in 1990 did not find the sidereal "Thun effect"; a 2001 review by Nick Kollerstrom and Gerhard Staudenmaier argued that a re-analysis supported it. Weather, soil, water and the season matter far more than any of these rhythms, and the Moon's light and tides are real, but whether they reach a seed in a garden bed is still an open question.
In the almanac
The Almanac's Moon panel can show what each system says about today: tick gardening by phase, gardening by sign or biodynamic days separately, so the three are never blended into one verdict.