As summer’s temperatures climb, it can seem hopeless to grow anything inside the greenhouse. But with adequate ventilation, there are actually some excellent candidates for these conditions. If you think in terms of plants that like the heat—there really are quite a few.
You’ll need to decide whether to plant them in containers—these should be sizeable if you choose this option (at least 2’ across for tomato plants)—or whether to create beds on the floor of the greenhouse. Either way, provide a soil depth of at least 12-18” and plan to water at least once a day. Both fans and vents are absolutely necessary if you plan to grow summer crops; make certain that your systems are in good repair.
Tomatoes and peppers, in fact, most members of the Solanaceae family, originate in the warmer regions of South America, where temperatures seasonally climb well above 85 degrees. They’ll definitely enjoy your greenhouse interior, and depending on how warm the summers usually are where you live, these vegetables might be much more productive than they would have been outside.
Eggplants come from the warm and humid climates of Southeast Asia. Consider “Ichiban” or “Machiaw”—in my experience, these Asian varieties are much more productive than larger-fruited Italian types. And if you have space, include a few hot pepper plants. You’ll be glad you did when those frozen or dried spicy peppers are on hand to use all winter in your cooking projects. ( of course, sweet peppers freeze nicely too)
Summer squash and zucchini are also heat-lovers, and thrive in warm greenhouse conditions. Try the climbing zucchini variety “Trombetta” trained up one of your greenhouse walls. It bears delicious small zucchinis which take on amusing gourd-like shapes when grown to maturity. Mediterranean herbs, such as oregano, marjoram and thyme will soak up the heat, and require less water than vegetable plants.
Although it is relatively uncommon in American gardens, the Asian veggie, the “Yard-Long” bean loves hot weather. Despite the name, “Yard-Long” beans should really be harvested at a length closer to twenty inches. And unlike the standard bush or climbing green beans we usually grow, they produce prolifically in the heat. Their delicious, sweet flavor is most at home in stir-fries; “Yard-Long” beans are vigorous growers–trellis them for maximum productivity and best bean quality.
So don’t leave your greenhouse empty just because it’s getting hot in there. Take advantage of the heat and grow some delicious vegetables!