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A Calendar’s Leap for Gardening

Agriculture and the Modern Calendar

It is leap year-2020. Our current Gregorian calendar, which was adopted from the Julian calendar, corrected for the 365.25 days it takes the Earth to orbit the sun. Every four years our calendar adds an additional day to help ensure our calendar says relatively aligned with our Earth’s position with the sun and stars. We refer to these calendars as solar calendars.

Regarding agricultural production, we rely on our calendar to adhere to the best planting dates for specific crops. Planting dates are based on prime growing seasons for specific crops, which includes climate shifts associated with the seasonal change. In agriculture, we rely on an accurate calendar for planting. Therefore, without a leap year our calendar year would slowly, but surely, misalign with our relative position with the sun and stars. This would inevitably make agricultural production difficult.

Historic Solar Calendars

Prior to the adoption of our modern calendar, many different cultures planned their agricultural planting dates slightly differently. Nonetheless, many relied upon the sun and stars.

SunWatch Archaeological Park

I remember visiting SunWatch Archaeological Park in Dayton, Ohio, as a kid.  The village’s layout was arranged in a circular pattern around a central plaza. A grouping of posts was situated within the center of the plaza. Throughout the solar year, the positions of the posts’ shadows would communicate certain ritual and key agricultural periods. As a kid and discovering the role of the sun in ancient cultures, I found this absolutely fascinating.

SunWatch Archaeological Park in Dayton, Ohio. The Native American tribe utilized a series of poles and the sun’s position to determine agricultural planting dates.

Puebloan Calendar

Ancient Puebloan ruins built large kivas aligning with the summer solstice. This is evident at the Aztec Ruins National Monument in Aztec, New Mexico. The central kiva’s main doors align with the summer solstice. Additionally, the outer edge of the ruins’ aligns with the sun’s path during the summer solstice. There is lots of speculation relating to the reasons the Puebloan culture aligned their architecture with the summer solstice, but a major theory includes agriculture.

The Summer Solstice sunrise alignment with Aztec West great house in Aztec, New Mexico.

Mayan Calendar

Ancient Mayan’s had a 365-day calendar reflecting the annual solar cycle. Based on the zenith passage of the sun, the Mayan’s also developed a 260-day Mayan ceremonial calendar. The initial zenith passage in the year, which occurs around late April to mid-May (depending on your location within the Mayan Empire), earmarks the beginning of the corn planting season. The second zenith passage of the year earmarks the period to harvest corn. This 105-day corn growing season led to the 260-day Mayan ceremonial calendar. Therefore, the ancient Mayan calendar is based on the sun and corn. For more information click here.

Keeping Us on Track

These are a few examples, but ancient cultures utilizing our solar alignment to determine agricultural production was instrumental in their success and our success as a civilization. To this day, there are many agricultural producers and backyard gardeners utilizing solar positioning and lunar cycles to inform agriculture. But as we celebrate leap year, let us celebrate by preparing our spring gardens and thinking about the role our calendar plays in agricultural production.

If you have any questions about planting, selecting, and maintaining your garden and are unsure how to read the stars and sun to determine planting dates, reach out to the Master Gardener Volunteer Help Desk at Alachua County’s extension office more tips. We have Gregorian-based planting calendars available for you. You can call at (352)955-2402 or email your questions to mag@alachuacounty.us.

For more information, follow us on our Facebook Page: UF IFAS Alachua County Extension Master Gardeners.

For more blog posts from Dr. Taylor Clem, visit his Blog Homepage.

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