A greenhouse provides a great opportunity to extend the growing season for many crops. And when the temperatures drop outside, it remains a sheltered space to continue growing a range of vegetables.
The list of vegetable garden ideas that can be grown in a greenhouse in the fall or winter is long. The number of greenhouse ideas you can use may depend on whether your greenhouse is heated or unheated. A greenhouse heated during the winter can increase the range of foods you can grow during the fall and winter.
Whether you have a large backyard greenhouse, or a DIY greenhouse for your growing needs, we take a look at some of the best crops you can consider growing in a greenhouse in the fall for harvesting in late fall, winter, and beyond.
9 fall greenhouse crops to consider
A greenhouse is not only intended for growing heat-loving crops, such as growing tomatoes, eggplants, peppers or cucumbers. Many of the best greenhouse vegetables can be planted in the fall, ready to come to the fore when the summer crops end, with the benefit of being able to extend seasons through covert growth.
If you want to prepare a greenhouse for the winter, there are ways to help keep the temperature from dropping below zero – which will allow you to grow many more crops. In addition to the cold, when planning a greenhouse for fall and winter, it is important to consider lighting. Light levels are also important to plant growth, so artificial LED lighting, such as these grow lights available on Amazon, can be used to supplement natural light during the winter months.
Plants will take longer to grow in the fall than during the summer months, so it may take a little longer to grow food in the greenhouse in the fall and winter. It’s worth the wait because in the colder months, locally grown produce will outperform any store-bought vegetables or herbs.
Hardy winter lettuce varieties can be grown in a greenhouse in the fall to provide leafy crops throughout fall and winter. These winter varieties are better suited to cooler temperatures and lower light levels. When planting lettuce in the fall, varieties such as ‘Winter Gem’, ‘Winter Marvel’ or ‘Winter Density’ are the most ideal as well as alternatives to winter leafy greens, such as winter purslane or corn salad, also known as lamb’s lettuce. You can buy salad corn seeds at True Leaf Market that can be ready to harvest in 40 days.
The advantage of growing carrots in a greenhouse is the fact that you can extend the harvest season, sowing early in the spring or later in the fall to be able to harvest in late fall and early winter. Carrots grow well in cool temperatures and can be ready to harvest in as little as 80 days. Picking round varieties of carrots, such as the ‘Parisian’ carrot varieties available at True Leaf Market, can mean a faster harvest and you can have small, round orange roots that you can pick in as little as 60 days.
3. Asian leaves
The likes of bok choy, tatsoi, komatsuna, mizuna, or mustard are all suitable for greenhouse growing. There is a wide variety of asian greens to consider. It germinates quickly in warmer soils and prefers cooler temperatures in the fall. These leaves come in a range of flavors, from mild to spicier, and are versatile. Many can be picked as young leaves to add to salads, or left to grow to maturity for use in stir-fries. Explore the range of Asian garden seeds available at True Leaf Market.
Growing cabbage in a greenhouse for fall and winter may seem like a luxury because it’s a crop that can survive outside in a vegetable garden all winter long. However, while the plants can tolerate very low temperatures outside, growing cabbage indoors in the fall can continue to provide you with tender young cabbage leaves all winter and into spring, even in an unheated greenhouse. There are many different types of kale to choose from, which range in leaf size and color, while ‘Cavolo Nero’ can provide dark, belt-like leaves that are sweeter than other types of kale. See the range of rapeseed available at Burpee.
Most types of watercress, also known as rocket, are hardy enough to grow in unheated greenhouses throughout fall and winter. Sowing this cool season crop in early fall should give you plenty of yield throughout the cooler months. It can take up to 30-40 days to start getting your crop of young, spicy leaves of watercress.
Similar to watercress, this fast-growing vegetable is a leafy crop that loves cool temperatures and can grow quickly from a fall planting. It can take about eight weeks to go from sowing to harvesting spinach, a crop that can give you many crops from a single plant. Good air circulation is important when growing spinach in a greenhouse to reduce the chances of powdery mildew affecting plants.
7. Spring cabbage
The right time to plant spring cabbage for growing in a greenhouse is early fall in September. They can then be transplanted to their final growing site in October, ready for harvest in the spring. Plant each cabbage about 12 inches apart. In early spring, some can be picked as spring greens while others are left to fill in when they grow larger.
Radishes can be grown all fall in the greenhouse for a series of quick crops. They are a great vegetable to plant in the fall, either as fast-growing summer radishes or the larger, slower-growing winter radishes. The time to harvest the radishes can come in as little as 30 days from the crop being sown and the seeds can be sown in the ground or in raised beds, or you can grow the radishes in covered containers. You can see a bunch of radish seeds in Burpee.
If you can provide plenty of heat and light, it is possible to grow green plants throughout the fall and winter. The likes of pea shoots, watercress, beets or radish shoots can be planted and harvested when the first true leaves appear. They contain all the nutrients of a full-sized plant, but are harvested at the seedling stage to add to salads or use as a garnish. Heat and light are key to the success of young green plants in the fall, so heat mats and artificial grow lights will likely be required to ensure successful germination and growth. You can see a range of microplant kits and supplies at True Leaf Market, including seeds and trays that can help you grow microgreens in the greenhouse during the fall.
Can you grow vegetables all year round in a greenhouse?
With proper planning, you can grow vegetables in a greenhouse all year round. A heated greenhouse increases your choices of crops and means that you can certainly grow crops 52 weeks out of the year. However, even in many harsh regions, vegetables can still be grown all year round. Plants will benefit from a sheltered environment, especially if they can keep temperatures above freezing, but they will grow more slowly during the colder months.
When planning a kitchen garden, you want it to have the longest growing season possible. A greenhouse may be a luxury, although it opens up a world of additional possibilities. It is a real advantage to be able to consider planting your vegetables in the fall months, as well as getting started earlier in the spring.