Greenhouses can often take a back seat during the summer months, when gardens are flourishing outside. But that doesn’t mean they’re un-used. In fact, year-round greenhouses take on new roles to continue growing. Here are 4 strategies for getting the most out of a greenhouse in the summer.
1. Warm Crop Sanctuary
One great strategy is to use the greenhouse primarily for heat-tolerant crops like tomatoes, cucumbers, peppers, and basil. While shade cloth and heat-storage systems like a Ground to Air Heat Transfer (GAHT™) system can help control greenhouse temperatures, it is still a warm spot in the garden. Indeed, the greenhouse may occupy the sunniest spot in your yard. We recommend taking advantage of it by shifting what you grow in there to things that like heat and full-sun.
2. Sitting Area
Many gardeners take their garden almost completely outdoors in the summer, opening up the greenhouse as a sitting area or extra living space in the summer. The large greenhouse at The Green Center in Cape Cod Massachusetts, for example, houses mature lemon trees and a range of vegetables for most of the year. During summer, the trees, flowers, and vegetables are moved outside, adorning the exterior of the greenhouse and creating huge outdoor gardens for the owners. That leaves generous room for morning coffee and a meeting area in the greenhouse. For greenhouses in climates with more intense sunshine, a shade cloth should be added to keep the greenhouse a comfortable temperature for people.
3. Year-Round Growing
Other growers use measures to prevent overheating in the greenhouse and stick to business as usual during the summer. They grow a wide array of crops, hot and cool. Sharon, in Boulder CO, noted of her solar greenhouse: “everything is so much healthier in there compared to my outside garden. Believe it or not, I still have spring greens, kale and chard, growing. The tomatoes, peppers, and basil are great too.” Adding shade cloth and controlling the heat gain is critical in the greenhouse. A Ground to Air Heat Transfer (GAHT™) system is one way – it allows the greenhouse to store extra heat in the soil for heating in the winter.
In hot climates, a year-round greenhouse is the only garden that’s able to grow during the summer. At the Judith and John’s greenhouse in Grand Junction, Colorado, the outdoor temps regularly soar above 100. Combined with the intense Colorado sun, many plants struggle outside.
An energy-efficient greenhouse provides a controlled environment to grow a wide variety of crops during the summer, including kale and chard, as well as heat-lovers like tomatoes, peppers, and cucumbers. A combination of shade cloth, a Ground to Air Heat Transfer (GAHT™), and evaporative cooler prevent Judith and John’s greenhouse (picture below) from overheating. It allows them to grow year-round.
4. New Beginnings
While most gardeners focus on their outdoor beds during the summer, greenhouse growers should also be preparing for their second growing season that occurs in the greenhouse. Growing year-round often requires getting plants started early, in the late summer / early fall while the days are still long enough. This allows seedlings to get sufficient light and mature before light levels wane. The healthy, mature plants continue to grow in the greenhouse through the colder months, providing a year-round harvest. If started too late, seedlings will suffer from reduced light levels and come out spindly or “leggy.”
Thus, the greenhouse is a spot for new beginnings in the summer… You can start crops in trays or directly in the soil, depending on your planting plan. Which crops you plant for the second growing season greatly depends on your climate and greenhouse design. Just remember to plan for them well in advance.
Summer growing tip:
We advise our clients to take off and store window screens during the summer, leaving the greenhouse open as an extension of the outdoor garden. Screens are not effective at keeping out harmful insects like aphids and white flies which too small to be thwarted by a screen. Screens do block larger insects that can help the greenhouse – pollinators like bees, and beneficial insects like ladybugs. They also reduce airflow through the windows. Thus, leaving the greenhouse completely open to both the good and bad insects usually yields to the healthiest indoor garden. We also recommend planting flowers just outside the greenhouse windows and doors to help attract beneficial insects into the greenhouse. You may be inclined to wander in there more as well.