We operate a four-season, passive-solar greenhouse, which affords us a year-round harvest of the freshest and local-ist of produce. That is, until last winter. In February, when daytime low temperatures were sub-zero for a week, in a desperate attempt to save the tender-ish greens that grow year-round in the greenhouse, I dropped a 100 watt heater into the water barrel. And it worked! Its surprising how the smallest energy inputs are amplified by the greenhouse effect, and how that energy can actually be stored using the thermal mass in water barrels. It's exciting every time I re-discover the springtime smell of the greenhouse, even in the dead of winter. And even on the darkest, shortest days, we can have a few herbs and greens for our soup, from the greenhouse. But, given the 100-watt water-heater trick, I suppose I must relinquish my claim to a strictly passive-solar greenhouse.
Through the greenhouse, we are tuned into the rhythms of nature, intimately connected to the diurnal and seasonal fluctuations in temperature and daylight hours. Watching with awe, we notice how the gradual progression of the path of the sun across the sky, northward, southward and then northward again, is reflected in shadows in the garden and the yield and growth rates of the different crops we grow. In the greenhouse, we raise seedlings for the volunteer garden and other educational programs of the Neighborhood Farm Initiative.
It is true that the greenhouse is a useful tool to help extend the growing and harvest seasons, but we have learned the futility (and the opportunity cost) of trying to get a too much of jump on the warm season. Tomatoes, for example, want hot days and warm nights, so why waste valuable resources starting them in February and then coddling and coaxing them until summer? Especially since tomatoes that are sown in May, quickly catch up with those started indoors, months earlier. And here is the important part, if we don't plant tomatoes in February, then we have more room for all the the roots and greens that love the cooler springtime weather. There is a lesson there, not only for the garden, but for life: Everything in its own time.