Gardening

Two-week garden calendar#

Moon phases and available overnight temperatures.

Fourteen days, starting today (or at the chosen date when it is further ahead). Each day shows its weekday letter and date, the Moon as it looks that day, a short bar for the Moon's half of the month, and the forecast low. Tap a day to choose it: the advice under the calendar and the sections below follow it.

The low is the coldest temperature forecast for that day, which usually comes around dawn. Forecasts reach about a week to ten days ahead; further days show a dash.

Frost#

Forecast frost and near-frost conditions.

Today's lowest forecast temperature and the frost risk: high when the low is 0 °C (32 °F) or colder. When the forecast service has no daily minimum, the lowest of the next 12 hours, or of today's hourly values, is used instead, and the label says so.

Coming days lists the days in the forecast with frost or near frost, from the same forecast as the calendar. Cover tender plants, bring pots in and hold back on watering in the evening before a frosty night. Frost settles first in hollows and on clear, still nights; a forecast low of a few degrees can still mean frost on the ground.

Weather recap#

A summary of conditions for the garden.

The recap summarizes the Open-Meteo forecast for this location with advice on sowing seeds, watering and protecting seedlings. Soil conditions and plant varieties are unknown, so check them before planting. The displayed period belongs to that forecast; choosing another calendar day does not turn it into a forecast for that day. The recap is cached with the weather data, so showing it needs no extra API request. When the recap is unavailable, the detailed weather cards remain usable.

Sunlight#

Day length, sunrise, sunset and noon altitude.

For the chosen day: the hours of daylight, sunrise, solar noon (when the Sun is highest, due south in the northern hemisphere and due north in the southern) and sunset, and how high the Sun climbs at noon. The higher it climbs, the more energy reaches your beds.

Day length tells whether days are growing or shrinking and by how much since the day before. Many plants time flowering by day length: spinach and onions bolt as days lengthen, chrysanthemums flower as they shorten.

Solar energy#

Available solar-energy estimates.

How much sunlight energy reaches a square metre of flat ground today, in kilowatt-hours. It drives photosynthesis and how fast soil warms and dries. The level and the tip below it follow from the total.

All sunlight (global) is the total; direct is the part arriving straight from the Sun's disc, diffuse the part scattered by the sky and clouds. On overcast days nearly all of it is diffuse, which is gentler on seedlings.

UV is the forecast highest ultraviolet index today, and in brackets what it would be under a clear sky. Protect your skin when working outside from 3 up.

The Moon#

Moon phase and the traditional planting calendar.

Planting by the Moon is an old farming tradition rather than proven science: trials have found little effect. Many gardeners still enjoy it as a rhythm for the month. iCaelum follows the common four-part version:

The chosen day's phase, how much of the Moon is lit and whether it is waxing or waning, the moon-gardening advice for it, and the dates of the next full and new Moon.