All vegetables do well in a greenhouse environment. The trick is usually to get greenhouse vegetables to retain a robust, rich flavor. A lack of sunlight or the wrong temperatures can result in bland flavors. Even though any vegetable will grow in a greenhouse, only certain vegetables with specific temperature or light requirements do best in them.
Lettuce is a plant that desires cool temperatures and indirect lighting. Both light and temperature are easy to control in a greenhouse environment. All types of lettuce do exceptionally well in a greenhouse.
The vast majority of tomato varieties all do well in a greenhouse. They love humidity and heat so the elevated temperatures are usually wonderful for tomatoes. However, even tomatoes will not fruit in extreme temperatures, and greenhouses need ventilation to cool them in the hottest days of summer where the temperature may spike to over 90 degrees.
Another heat-loving vegetable that thrives in a greenhouse, and is better suited to a small environment because it is one of the smaller vegetable plants, is the pepper. From the hottest Jalapeño to the sweetest bell, peppers are easy to grow in a greenhouse.
The many varieties of squash do well when started in a greenhouse to get a jump on the growing season. They can be grown completely in the greenhouse, but tend to be very large, spread-out plants that take a lot of room as full-grown plants.
Cucumbers generally do great in a greenhouse. The growth cycle is fast and they are very prolific. Because they are a vine, the cucumber can grow up on a trellis to minimize floor space requirements.
One of the biggest drawbacks to growing plants in a greenhouse versus outdoors is that nature will not take care of the pollination for you. All indoor pollination requires a manual shaking or painting of leaves to get the job done.
Plants kept in a greenhouse in the summer need adequate ventilation. Temperatures in an glass- or plastic-enclosed environment rise quick and will smother even the most dedicated hothouse plant.
Vegetables can grow year-round in the controlled climate of a greenhouse. However, adult vegetable plants tend to be very large and space requirements increase with every week of growth. Most home greenhouses contain infant plants in the seed to seedling stages. Using a greenhouse like this extends the growing season by letting gardeners start their plants in the late winter months prior to planting them outside in the spring and summer months.