It happens every year. The holiday ribbons are hardly packed away when the urges to plant start coming. When I go into the cool pantry to fetch oranges, I can almost hear little voices coming from my seed storage box, calling "Plant me! Plant me!" The itch to plant has no respect for the fact that winter has three months to go. At the same time, planting too early is fraught with pitfalls.
Waiting for Light
Because of the Earth’s position in the solar system, winter days in the northern hemisphere become too short for growing most edible plants. Even if you have an insulated greenhouse, you can’t get much growth from the most cold-tolerant leafy greens when days are shorter than 10 hours long. Winter sun is also less intense than summer sun, so pushing plants to grow in winter can be an exercise in frustration.