Greenhouse riding out winter in bloom

Looking through my greenhouse windows, I see snow, snow and more snow.

While I'm grateful for the snow, it makes it tough to grow plants. Although there are plenty of tasks I could do outside during the winter, being a fair-weather horticulturist, I prefer to stay inside where it is warm and dry.

So what is happening in the greenhouse? Am I picking tomatoes and cucumbers? Do I have thousands of seeds germinating to beautify my summer garden? The short answer is ... no.

Greenhouses are not all the same, so greenhouse growers or potential growers need to ask themselves some questions. Will you operate a cool- or warm-season greenhouse? What do you want to grow in the greenhouse?

Mine is a solar-heated, cool-season greenhouse, meaning it has no heat source other than the sun. I could raise the temperature and make it into a warm-season house, but that would require adding heaters and paying for fuel. Since I am unwilling to do that, it stays a cool-season greenhouse.

While I am not growing any vegetables at the moment, the greenhouse is full. Two large jade plants are in bloom; several over-wintering planters are biding their time until they can be moved outside; and a number of other summer holdovers are filling space on the shelves.

A large split leaf Monstera deliciosa and a Philodendron are sitting against a brick wall, and a collection of cacti and succulents occupy another shelf. My daughter has a couple of flats of pelargonium (geranium) cuttings she took last fall. By the time spring rolls around, they'll be nice-size plants.

If you want to know where the tomatoes are, there aren't any. They only grow in warm-season houses. Cool-season vegetables need daytime temperatures of 50 to 70 degrees F and nighttime temperatures of 45 to 55 degrees F.

They will take short-term temperature extremes of 35 to 90 degrees F, but these temperature extremes are not conducive to quality vegetables. The high temperature ranges make the crops tough and bitter. Dips in temperature to near freezing are not critical, but plants don't grow much in those ranges.

Another advantage of cool-season crops is that high light intensity is not as critical. Keep in mind that seed germination temperatures for these crops can vary between 40 to 75 degrees F, so you may need to use a heat mat or germinate them elsewhere before moving them into your cool-season house.