It’s a good idea to plant a variety of colorful vegetables that are relatively easy to grow, prolific, and easy to store. Beans, broccoli, carrots, beets, cucumbers, squash, cabbage, spinach, kale and sweet potatoes are all good candidates for greenhouses or cold frames. Corn is a great summer crop that can be grown outdoors in profusion and stored.
Grow What You’ll Eat
It doesn’t matter if habanero peppers are high in vitamins, if no-one in your household likes spicy food, they won’t be eaten. (Actually, hot peppers are very nutrient dense and contain more vitamin C than oranges. They’re full of vitamins A, B, and E, potassium, iron and calcium.)
Here are some nutrient-dense vegetables and a few notes about how they’ll do in a greenhouse.
Cool Season Vegetables
- Spinach is one of the most nutrient-dense vegetables and full of antioxidants. It’s fast and easy to grow, will produce year-round in your greenhouse, and is well suited to cold frames even through winter. If you plant spinach close together in a cold frame, you can harvest a steady crop of baby spinach. In summer, when daytime temperatures rise above 75°F, consider giving spinach a break and focus on warm season loose-leaf lettuces like romaine and green and red lettuces, then switching back to spinach in the fall.
- Carrots are easy to grow, but really take up an inconvenient amount of space in a greenhouse. They’re well suited to grow in well-tilled soil and can be started early in cold frames. Even better, you can grow an abundance of carrots in the spring and store your crop in a root cellar to use until the next crop is ready.
- Broccoli is easy to grow and yields quickly. It’s well suited for greenhouse production all year round, although it also does well in a cold frame.
- Garlic is a great bulb that can make a boring meal extraordinary. It’s nutritious, easy to grow, and doesn’t need supplemental heat in a greenhouse. Cold frames are excellent options as well. Garlic will stop growing when the soil reaches 90°F, so you can either move potted garlic plants into a cooled greenhouse or go ahead and harvest, using your supply until the soil cools off in the fall.
- Brussels sprouts, like broccoli, are very nutrient dense and can thrive in summer or over the winter even in a cold greenhouse or a simple cold frame. They’re relatively easy to grow so long as they have plenty of sun and consistent moisture.
- Kale is known as a superfood for its nutrient density and antioxidant content. It’s also easy to grow year-round in your greenhouse and does quite well in a cold frame, since its flavor is known to improve with cool temperatures.
- Green Peas prefer cooler temperatures (60-75°F), so they do well in an unheated greenhouse or planted early in the season under a cold frame so they mature before the weather gets too hot. Once temperatures are warm enough, keep your cold frame window open or remove it altogether and provide an upside-down tomato cage for the peas to grow up.
- Swiss chard is easy to grow and rich in vitamins. Although it’s technically a member of the beet family, it’s counted nutritionally as a dark leafy vegetable. Chard has relatively shallow roots, so it’s a good candidate for container or raised bed gardening, and it can tolerate weather as low as 32°F. If you have very cold winters, chard will happily thrive in an unheated greenhouse or a tall cold frame.
- Beets are a nutrient packed food that are one of the easiest vegetables to grow straight from seed. They’re ideal for greenhouses and cold frames since they require very little attention until they’re ready to harvest. You can sow seeds periodically throughout the year and enjoy the fruits of your labor in as little as 6 weeks.
- Asparagus is valued for its nutrients, including especially high folate levels. It’s an easy to grow perennial plant that produces repeatedly for 10-15 years or more. It prefers cooler weather and is ideal to start out in a cold frame until soil temperatures reach 75°F. Since asparagus is such a long-lived plant, it’s best to move it out of the greenhouse into an area that won’t be disturbed in the long term. Once outside, asparagus is pretty maintenance free, although in cold regions, dormant asparagus crowns should be winterized and covered with several inches of mulch.
Warm Season Vegetables
- Sweet potatoes are a heat loving crop and do very well in greenhouses where there’s no danger of frost. In fact, sweet potatoes improve in flavor with higher temperatures.
- Tomatoes are well suited to year-round greenhouse production if the greenhouse is warm during winter. Nutritionally, tomatoes do better in cooked, concentrated forms like sauces, but their flavor can’t be beat even when fresh. In a greenhouse, your tomatoes will always be vine-ripened for the peak of flavor and the controlled condition of a greenhouse helps improve the health of the plants and appearance of the fruit. Word to the wise: greenhouse tomatoes may need some help getting pollinated in order to produce fruit. This can be done by hand with a Q-tip, but since they can self-pollinate, simply shaking the entire plant for a few seconds whenever flowers are blooming is usually sufficient.
- Zucchini are one of the simplest vegetables to grow and produce a large crop in as little as 3-4 weeks. Have you been the recipient of mysterious bags of zucchini on your doorstep in high summer? That’s the surreptitious gift of a gardener who is overwhelmed by their crop and want -- nay insist -- on passing it on! Zucchini do well in the ground as well as in the greenhouse, but they will likely produce longer in a warm greenhouse as compared to cooler outdoor temperatures as the season advances.
