Edible Gardens
10 Great Crops for a Winter Greenhouse
Treat yourself to fresh produce during the winter months by growing these edible favorites in your greenhouse
Want to keep your greenhouse productive during the cold winter months? These nine cool-season edibles, plus one summer crop, are good options to get you started. Growing edibles in winter can be more challenging than in the warmer months, but the combination of the shelter of the greenhouse and the cold tolerance of these edibles means you can enjoy a harvest year-round.
1. Lettuce and Salad Greens
When to plant. Start seeds or set out seedlings at any time. Soil temperatures should be at least 35 degrees Fahrenheit (1.7 degrees Celsius), ideally between 45 and 75 degrees Fahrenheit (7.2 and 23.9 degrees Celsius) for lettuce seeds to germinate. Arugula seeds will germinate in soil temperatures between 40 and 55 degrees Fahrenheit (4.4 and 12.8 degrees Celsius). Seeds for mustard greens will germinate at 40 degrees Fahrenheit (4.4 degrees Celsius). For radicchio, germination will do best in soil temperatures between 50 and 72 degrees Fahrenheit (10 and 22 degrees Celsius).
When to harvest. Start harvesting when leaves are big enough to use. You can start harvesting in as little as a month or as long as three months, depending on what you’re growing.
Keep some lettuce and other leafy greens growing in your greenhouse to ensure you have fresh salad makings year-round. Lettuces love cooler weather, so try to keep things between 45 and 65 degrees Fahrenheit (7.2 and 18.3 degrees Celsius). They can handle colder temperatures, even down to freezing for a short while. Just don’t let it get too warm. Anything above 80 degrees Fahrenheit (26.7 degrees Celsius) will cause them to bolt or turn bitter.
Your best choices for lettuce are leaf lettuce, butterhead lettuces and Romaine or cos lettuces. Favorite leafy greens include arugula, mustard greens and radicchio.
Look for wide but shallow containers that are at least 6 inches deep, though they don’t need to be much deeper. If you have a relatively wide or long pot, mix up different types of these greens for a colorful look. Adding new seedlings as the winter progresses will ensure you’ll have a continuous crop.
Learn more about growing lettuce and salad greens
When to plant. Start seeds or set out seedlings at any time. Soil temperatures should be at least 35 degrees Fahrenheit (1.7 degrees Celsius), ideally between 45 and 75 degrees Fahrenheit (7.2 and 23.9 degrees Celsius) for lettuce seeds to germinate. Arugula seeds will germinate in soil temperatures between 40 and 55 degrees Fahrenheit (4.4 and 12.8 degrees Celsius). Seeds for mustard greens will germinate at 40 degrees Fahrenheit (4.4 degrees Celsius). For radicchio, germination will do best in soil temperatures between 50 and 72 degrees Fahrenheit (10 and 22 degrees Celsius).
When to harvest. Start harvesting when leaves are big enough to use. You can start harvesting in as little as a month or as long as three months, depending on what you’re growing.
Keep some lettuce and other leafy greens growing in your greenhouse to ensure you have fresh salad makings year-round. Lettuces love cooler weather, so try to keep things between 45 and 65 degrees Fahrenheit (7.2 and 18.3 degrees Celsius). They can handle colder temperatures, even down to freezing for a short while. Just don’t let it get too warm. Anything above 80 degrees Fahrenheit (26.7 degrees Celsius) will cause them to bolt or turn bitter.
Your best choices for lettuce are leaf lettuce, butterhead lettuces and Romaine or cos lettuces. Favorite leafy greens include arugula, mustard greens and radicchio.
Look for wide but shallow containers that are at least 6 inches deep, though they don’t need to be much deeper. If you have a relatively wide or long pot, mix up different types of these greens for a colorful look. Adding new seedlings as the winter progresses will ensure you’ll have a continuous crop.
Learn more about growing lettuce and salad greens
2. Spinach
When to plant. Start seeds or set out seedlings at any time. Soil temperatures should be at least 35 degrees Fahrenheit (1.7 degrees Celsius) and ideally between 45 and 75 degrees Fahrenheit (7.2 and 23.9 degrees Celsius) for seeds to germinate.
When to harvest. The earliest varieties are ready to harvest in 45 days; others may take up to 150 days.
Lettuce isn’t the only familiar salad crop that does well in a greenhouse. Supplement your traditional lettuces and salad greens with a container or two of spinach. They are happy in similar conditions, usually preferring temperatures between 50 and 75 degrees Fahrenheit (10 to 23.9 degrees Celsius) though they will still do well even if the temperatures dip to around 35 degrees Fahrenheit (1.7 degrees Celsius).
Spinach is another great option for smaller and wider containers; they will do well in containers that are only 4 to 6 inches deep.
Learn more about growing spinach
When to plant. Start seeds or set out seedlings at any time. Soil temperatures should be at least 35 degrees Fahrenheit (1.7 degrees Celsius) and ideally between 45 and 75 degrees Fahrenheit (7.2 and 23.9 degrees Celsius) for seeds to germinate.
When to harvest. The earliest varieties are ready to harvest in 45 days; others may take up to 150 days.
Lettuce isn’t the only familiar salad crop that does well in a greenhouse. Supplement your traditional lettuces and salad greens with a container or two of spinach. They are happy in similar conditions, usually preferring temperatures between 50 and 75 degrees Fahrenheit (10 to 23.9 degrees Celsius) though they will still do well even if the temperatures dip to around 35 degrees Fahrenheit (1.7 degrees Celsius).
Spinach is another great option for smaller and wider containers; they will do well in containers that are only 4 to 6 inches deep.
Learn more about growing spinach
3. Kale
When to plant. Start seeds or set out seedlings at any time. Soil temperatures should be at least 40 degrees Fahrenheit (4.4 degrees Celsius) and ideally between 50 and 85 degrees Fahrenheit (10 and 29.4 degrees Celsius) for seeds to germinate.
When to harvest. Kale is ready to harvest in 55 to 75 days.
Kale loves the cold. It even tastes better after the first frost and does fine under a blanket of snow as long as its roots don’t get too wet. But if you don’t relish the idea of digging through the snow when it’s time to fix dinner, move it inside a cool greenhouse so you’ll both be happy. It can handle temperatures between 60 and 70 degrees Fahrenheit (15.6 and 21.1 degrees Celsius). This is one crop you needn’t worry about if temperatures drop below freezing, especially if it’s a gradual temperature drop.
Kale needs a container at least 6 inches deep, though up to 12 or even 16 inches deep is fine. You’ll want at least a one-gallon pot, as kale is a bit larger than lettuce, greens and spinach. You can go even larger and put several plants in a single container. You should also avoid having kale near strawberries.
Learn more about growing kale
When to plant. Start seeds or set out seedlings at any time. Soil temperatures should be at least 40 degrees Fahrenheit (4.4 degrees Celsius) and ideally between 50 and 85 degrees Fahrenheit (10 and 29.4 degrees Celsius) for seeds to germinate.
When to harvest. Kale is ready to harvest in 55 to 75 days.
Kale loves the cold. It even tastes better after the first frost and does fine under a blanket of snow as long as its roots don’t get too wet. But if you don’t relish the idea of digging through the snow when it’s time to fix dinner, move it inside a cool greenhouse so you’ll both be happy. It can handle temperatures between 60 and 70 degrees Fahrenheit (15.6 and 21.1 degrees Celsius). This is one crop you needn’t worry about if temperatures drop below freezing, especially if it’s a gradual temperature drop.
Kale needs a container at least 6 inches deep, though up to 12 or even 16 inches deep is fine. You’ll want at least a one-gallon pot, as kale is a bit larger than lettuce, greens and spinach. You can go even larger and put several plants in a single container. You should also avoid having kale near strawberries.
Learn more about growing kale
4. Chard
When to plant. Start seeds or set out seedlings at any time. Soil temperatures should be at least 40 degrees Fahrenheit (4.4 degrees Celsius) and ideally between 45 and 75 degrees Fahrenheit (7.2 and 23.9 degrees Celsius) for seeds to germinate.
When to harvest. You can start harvesting chard leaves after about two months.
If you have a bit more room, add in some chard. To make things more colorful during the winter months, choose either the Bright Lights or Rainbow varieties. One advantage of chard is that it can handle far warmer temperatures than other greens, so it should be fine in your winter greenhouse unless it gets heat levels equal to and as intense as those in summer.
You’ll need slightly larger containers for chard. Look for one that is a minimum of 16 inches deep or a maximum of 24 inches deep for the best result. Once it starts producing, usually in about two months, just keep harvesting the outer leaves to keep it growing.
Learn more about growing chard
When to plant. Start seeds or set out seedlings at any time. Soil temperatures should be at least 40 degrees Fahrenheit (4.4 degrees Celsius) and ideally between 45 and 75 degrees Fahrenheit (7.2 and 23.9 degrees Celsius) for seeds to germinate.
When to harvest. You can start harvesting chard leaves after about two months.
If you have a bit more room, add in some chard. To make things more colorful during the winter months, choose either the Bright Lights or Rainbow varieties. One advantage of chard is that it can handle far warmer temperatures than other greens, so it should be fine in your winter greenhouse unless it gets heat levels equal to and as intense as those in summer.
You’ll need slightly larger containers for chard. Look for one that is a minimum of 16 inches deep or a maximum of 24 inches deep for the best result. Once it starts producing, usually in about two months, just keep harvesting the outer leaves to keep it growing.
Learn more about growing chard
5. Beets
When to plant. Start seeds at any time. Soil temperatures should be at least 40 degrees Fahrenheit (4.4 degrees Celsius) and ideally between 50 and 85 degrees Fahrenheit (10 and 29.4 degrees Celsius) for seeds to germinate.
When to harvest. Beets are ready to harvest in 45 to 65 days.
Bright beets add vibrancy to any meal, but their traditional red color seems particularly ideal for a winter meal. Plus, growing them in a container in an easy-access greenhouse location means you can control both the soil texture and drainage. For best container results, look for varieties that are short and round rather than long.
You’ll want to sow beet seeds directly into the container they’ll be growing in. Choose one that is at least 8 inches deep, preferably 12 to 16 inches deep. Beets like plenty of room, so choosing a wide container is ideal. Because beets are root crops, you needn’t worry as much about the ambient temperature, though you won’t want it much above 80 degrees Fahrenheit (26.7 degrees Celsius). The soil temperature should be around 50 degrees Fahrenheit (10 degrees Celsius).
Learn about growing beets
When to plant. Start seeds at any time. Soil temperatures should be at least 40 degrees Fahrenheit (4.4 degrees Celsius) and ideally between 50 and 85 degrees Fahrenheit (10 and 29.4 degrees Celsius) for seeds to germinate.
When to harvest. Beets are ready to harvest in 45 to 65 days.
Bright beets add vibrancy to any meal, but their traditional red color seems particularly ideal for a winter meal. Plus, growing them in a container in an easy-access greenhouse location means you can control both the soil texture and drainage. For best container results, look for varieties that are short and round rather than long.
You’ll want to sow beet seeds directly into the container they’ll be growing in. Choose one that is at least 8 inches deep, preferably 12 to 16 inches deep. Beets like plenty of room, so choosing a wide container is ideal. Because beets are root crops, you needn’t worry as much about the ambient temperature, though you won’t want it much above 80 degrees Fahrenheit (26.7 degrees Celsius). The soil temperature should be around 50 degrees Fahrenheit (10 degrees Celsius).
Learn about growing beets
6. Carrots
When to plant. Start seeds at any time. Soil temperatures should be at least 35 degrees Fahrenheit (1.7 degrees Celsius) and ideally between 45 and 75 degrees Fahrenheit (7.2 and 23.9 degrees Celsius) for seeds to germinate.
When to harvest. Smaller carrot varieties will be ready in about 30 days; others will take up to 80 days.
Carrots are another root crop that will thrive in a winter greenhouse. In fact, you won’t want the greenhouse temperatures to get above 64 degrees Fahrenheit (17.8 degrees Celsius). Carrots will need a container that is about 16 to 24 inches deep if you don’t want to end up with misshapen results. Carrots don’t transplant well, so you’ll be sowing seeds directly into the pot. The seeds are also tiny, so you will need to thin them.
Learn more about growing carrots
When to plant. Start seeds at any time. Soil temperatures should be at least 35 degrees Fahrenheit (1.7 degrees Celsius) and ideally between 45 and 75 degrees Fahrenheit (7.2 and 23.9 degrees Celsius) for seeds to germinate.
When to harvest. Smaller carrot varieties will be ready in about 30 days; others will take up to 80 days.
Carrots are another root crop that will thrive in a winter greenhouse. In fact, you won’t want the greenhouse temperatures to get above 64 degrees Fahrenheit (17.8 degrees Celsius). Carrots will need a container that is about 16 to 24 inches deep if you don’t want to end up with misshapen results. Carrots don’t transplant well, so you’ll be sowing seeds directly into the pot. The seeds are also tiny, so you will need to thin them.
Learn more about growing carrots
7. Radishes
When to plant. Start seeds or set out seedlings any time. Soil temperatures should be at least 35 degrees Fahrenheit (1.7 degrees Celsius) and ideally between 45 and 85 degrees Fahrenheit (7.2 and 29.4 degrees Celsius) for seeds to germinate.
When to harvest. Radishes are ready to harvest in 21 to 150 days.
Radishes have the reputation of being one of the quickest crops to grow, a bonus for impatient gardeners in the spring. With a greenhouse, you don’t even have to wait that long. Look for the “winter radishes,” the best choice for fall planting, to keep your radish crop growing throughout the winter. To prevent overcrowding, choose smaller varieties. Also, plan to do successive plantings to keep the crop producing.
Sow radishes directly into a pot that is at least 6 inches deep and 16 inches in diameter. They’re happiest in temperatures between 45 and 85 degrees Fahrenheit (7.2 and 29.4 degrees Celsius) but can handle winter chill down to 26 degrees Fahrenheit (minus 3.3 degrees Celsius).
Learn more about growing radishes
When to plant. Start seeds or set out seedlings any time. Soil temperatures should be at least 35 degrees Fahrenheit (1.7 degrees Celsius) and ideally between 45 and 85 degrees Fahrenheit (7.2 and 29.4 degrees Celsius) for seeds to germinate.
When to harvest. Radishes are ready to harvest in 21 to 150 days.
Radishes have the reputation of being one of the quickest crops to grow, a bonus for impatient gardeners in the spring. With a greenhouse, you don’t even have to wait that long. Look for the “winter radishes,” the best choice for fall planting, to keep your radish crop growing throughout the winter. To prevent overcrowding, choose smaller varieties. Also, plan to do successive plantings to keep the crop producing.
Sow radishes directly into a pot that is at least 6 inches deep and 16 inches in diameter. They’re happiest in temperatures between 45 and 85 degrees Fahrenheit (7.2 and 29.4 degrees Celsius) but can handle winter chill down to 26 degrees Fahrenheit (minus 3.3 degrees Celsius).
Learn more about growing radishes
Photo by Quinn Dombrowski
8. Green Onions
When to plant. Start seeds or plant bulbs at any time. Soil temperatures should be at least 40 degrees Fahrenheit (1.6 degrees Celsius) and ideally between 45 and 75 degrees Fahrenheit (7 and 24 degrees Celsius) for seeds to germinate.
When to harvest. Start cutting off tops or pulling the entire plant as soon as they are big enough to use.
You can grow any onion in a greenhouse, but space may be an issue. That’s when green onions, also known as scallions, can come to the rescue. They need less room to spread out and can be harvested earlier than bulbing onions. Place them in a pot that’s 6 to 10 inches deep and as wide as you want. Keep the greenhouse temperatures around 55 to 75 degrees Fahrenheit (12.8 to 23.9 degrees Celsius) for the best results.
Learn more about growing green onions
8. Green Onions
When to plant. Start seeds or plant bulbs at any time. Soil temperatures should be at least 40 degrees Fahrenheit (1.6 degrees Celsius) and ideally between 45 and 75 degrees Fahrenheit (7 and 24 degrees Celsius) for seeds to germinate.
When to harvest. Start cutting off tops or pulling the entire plant as soon as they are big enough to use.
You can grow any onion in a greenhouse, but space may be an issue. That’s when green onions, also known as scallions, can come to the rescue. They need less room to spread out and can be harvested earlier than bulbing onions. Place them in a pot that’s 6 to 10 inches deep and as wide as you want. Keep the greenhouse temperatures around 55 to 75 degrees Fahrenheit (12.8 to 23.9 degrees Celsius) for the best results.
Learn more about growing green onions
9. Cilantro
When to plant. Start seeds or set out seedlings at any time. Soil temperatures should be between 55 and 70 degrees Fahrenheit (12.8 and 21.1 degrees Celsius) for seeds to germinate.
When to harvest. Start cutting when the plants are 3 to 4 inches tall, harvesting every week or every two weeks.
Unlike most herbs, cilantro prefers it to be cooler, making it a good addition to a winter greenhouse garden. This is another crop that does well with successive plantings, so you can enjoy the fresh taste of this herb throughout the winter.
For cilantro, choose a container that is about 16 to 18 inches wide and 8 to 10 inches deep. It can handle cool temperatures but not temperatures that are too hot or too cold, so aim for between 60 to 80 degrees Fahrenheit (15.6 to 26.7 degrees Celsius).
Learn more about growing cilantro
When to plant. Start seeds or set out seedlings at any time. Soil temperatures should be between 55 and 70 degrees Fahrenheit (12.8 and 21.1 degrees Celsius) for seeds to germinate.
When to harvest. Start cutting when the plants are 3 to 4 inches tall, harvesting every week or every two weeks.
Unlike most herbs, cilantro prefers it to be cooler, making it a good addition to a winter greenhouse garden. This is another crop that does well with successive plantings, so you can enjoy the fresh taste of this herb throughout the winter.
For cilantro, choose a container that is about 16 to 18 inches wide and 8 to 10 inches deep. It can handle cool temperatures but not temperatures that are too hot or too cold, so aim for between 60 to 80 degrees Fahrenheit (15.6 to 26.7 degrees Celsius).
Learn more about growing cilantro
10. Strawberries
When to plant. Set out plants any time.
When to harvest. Strawberries are ready to harvest as soon as they turn bright red. Do a taste test to be sure they’re ripe.
Strawberries are technically a summer crop, but if you can’t wait until late spring for your fresh strawberry fix, try growing them in a greenhouse. You can create a raised bed, but they also do well in containers, strawberry jars and hanging baskets. Just don’t place them near your kale.
If you’re planting in a container or raised bed, look for one that is at least 8 inches deep. Hanging planters should be at least 12 inches deep. For ideal growing conditions, keep the greenhouse temperatures between 60 and 80 degrees Fahrenheit (15.6 and 26.7 degrees Celsius), but the plants will do well as low as 19 degrees Fahrenheit or minus 7 degrees Celsius.
Find out the secrets for growing strawberries
More
10 Easy Edibles to Grow in Containers
How to Plan Your Edible Garden
10 Things to Include in Your Greenhouse
When to plant. Set out plants any time.
When to harvest. Strawberries are ready to harvest as soon as they turn bright red. Do a taste test to be sure they’re ripe.
Strawberries are technically a summer crop, but if you can’t wait until late spring for your fresh strawberry fix, try growing them in a greenhouse. You can create a raised bed, but they also do well in containers, strawberry jars and hanging baskets. Just don’t place them near your kale.
If you’re planting in a container or raised bed, look for one that is at least 8 inches deep. Hanging planters should be at least 12 inches deep. For ideal growing conditions, keep the greenhouse temperatures between 60 and 80 degrees Fahrenheit (15.6 and 26.7 degrees Celsius), but the plants will do well as low as 19 degrees Fahrenheit or minus 7 degrees Celsius.
Find out the secrets for growing strawberries
More
10 Easy Edibles to Grow in Containers
How to Plan Your Edible Garden
10 Things to Include in Your Greenhouse
Your one concern will be keeping the soil temperature warm enough that the seeds will germinate. You may need to use a germination mat to warm things up. Be sure to keep an eye on daytime temperatures for the best results. Temperatures can go lower at night, but some of these will not do well if nighttime temperatures dip below freezing.
All of these grow well in containers — anything from shallow flats to deeper containers, depending on their growing needs. If you’re feeling more ambitious, you can also build garden beds inside your greenhouse.