Can you grow cucumbers in the winter in a greenhouse?
Noah Mitchell
Published Jan 16, 2026
Cucumbers. Start cucumber seeds in your greenhouse in late winter/early spring. The timing should be planned so they are ready to be transplanted once the outside temperature is consistently above 70F.
When can cucumbers be planted in unheated greenhouse?
Cucumbers are raised from seed. The seed for plants to be grown in a heated greenhouse is sown during February to March and for growing in the unheated greenhouse during April. For quick germination maintain a minimum temperature of 70F/21C.
How do you grow cucumbers in an unheated greenhouse?
Sow in February or March if your greenhouse is heated, or in April if you have an unheated greenhouse. Fill small 5cm pots with peat-free, multi-purpose compost and sow the seeds vertically or on their sides (not flat), 1cm-2cm deep. Sow two cucumber seeds per pot, then water.
How do you grow cucumbers in the winter?
Put the cucumber plant in a warm place where it gets direct sunlight for six to eight hours per day or provide the plants with a grow light for the same length of time. Keep newly planted cucumbers warm at all times.
What can you grow in a cold greenhouse in winter?
Plants for winter are; Winter Lettuce, Potatoes, Spinach, kale, cabbage, Bok choy, Chinese cabbage, Onions, Shallots, Peas, Broad beans, Garlic and Spinach. These plants can all be grown in an unheated greenhouse through winter, providing you follow a few guidelines; Guidelines.
20 related questions foundWhen can I put plants in an unheated greenhouse?
The major secret, at the same time a tip to success, using an unheated greenhouse is to preferably sow seed indoors around the middle of March and then towards the end of April. The seedlings should be transplanted to your unheated greenhouse.
What temperature is too cold for a greenhouse?
So with this in mind, it's safe to say that any temperatures below 55 degrees Fahrenheit for a hothouse and below 45 degrees Fahrenheit for a cold house can be termed as “too cold for a greenhouse.” To maintain these temperatures, there must be a way to heat your greenhouse when it gets too cold.
Can cucumbers grow in cold weather?
A temperature of 32 degrees Fahrenheit (0 degrees Celsius) or below will result in frost, which will kill cucumber plants. Any temperature below 50 degrees Fahrenheit (10 degrees Celsius) will result in slower growth of cucumber plants, and will eventually damage them.
Can cucumber plant survive winter?
The optimum temperature for cucumber plants is 77 – 95°F (25°C and 35°C). Seeds typically won't germinate below 50°F (10°C). Frost may harm, or even destroy, cucumber crops. Cucumber plants can be protected using row covers, cloches, and planting in sheltered areas.
Will cucumbers grow in winter season?
Cucumbers grow very well in well-drained, warm, protected spot with rich, fertile soil that is extremely rich in organic matter. Plant them in full sun during cold climate and provide shade during scorching summer heat or dry climate. Space the seeds about 3 feet apart. The plant will start fruiting within 2-3 months.
Do cucumbers do well in a greenhouse?
Benefits of growing cucumbers in a greenhouse
For one, cucumbers hate the cold and frost, so they really thrive in a greenhouse environment. Another advantage is that you don't need much room at all, and you can really take advantage of vertical space by using a trellis.
Do cucumbers grow well in a greenhouse?
You can grow cucumbers in a greenhouse or outdoors. Indoor cucumbers crop earlier, need to be trained and produce long and succulent fruits. Greenhouse cultivars such as “Futura F1” or “Telegraph Improved” can also be grown in frames.
Can I grow outdoor cucumbers in a greenhouse?
Actually, they're quite straightforward, but it all comes down to variety choice. There are different types of cucumber that need different growing conditions. Indoor or greenhouse cucumbers do best in a greenhouse, although may fare well outside in a very sheltered and warm spot.
What temperatures do cucumbers like?
Cucumber (Cucumis sativus) is a warm-season vegetable that grows best at temperatures between 75 and 85 °F. Cucumbers are very tender and can be killed by light frosts.
What temperature can cucumber tolerate?
Cucumbers (Cucumis sativus) are tender annuals that thrive in warm temperatures of between 65-75 degrees F. (18-23 C.). Even prolonged exposure to temperatures below 55 degrees F.
What temperature can cucumber seedlings tolerate?
Cucumber plants only tolerate temperatures down to 55℉ (13℃) before their growth starts to falter. On top of that, cucumber seeds will only germinate when soil temperatures are above 65℉ (18℃). Because cucumbers are not cold-tolerant, it's important to protect them from cold weather and frost.
Can I grow cucumber all year round?
If you really love cucumbers, the extra challenges involved with growing them indoors can be worth it. You'll have home grown cucumbers all year round, even if you live in an area with cold winters or don't have much outdoor space.
Can cucumbers survive frost?
Cucumbers cannot tolerate freezing temperatures. Protect young plants from late spring frosts with cloches, row covers or frost blankets.
Can you start seeds in a greenhouse in winter?
When to Plant Greenhouse Seeds
Greenhouses allow you to control the temperature and humidity required for seed propagation and young seedlings to grow. Because of this controlled environment, you can actually start seeds in greenhouses anytime.
Will plants freeze in a greenhouse?
During the day, a typical greenhouse will trap heat from the sun, which allows the plants inside to stay warm at night. However, when winter nights get really cold, frost damage in the greenhouse can occur without added protection.
Will plants survive winter in a greenhouse?
Because a greenhouse offers growers a controlled and consistent environment regardless of the season, many can keep their crops coming up throughout the year - and that means you can keep growing all through the winter.
How do you winterize a greenhouse?
How to Winterize a Greenhouse
- Repair any panels. ...
- Shore up your caulking and sealing. ...
- Check your heating system. ...
- Drain any pipes that may freeze. ...
- Clean the entire greenhouse. ...
- Insulate with bubble wrap. ...
- Set up circulating fans for airflow. ...
- Place plastic sheeting around frost-susceptible plants.
How do I keep my greenhouse warm at night?
How to heat a greenhouse: 6 ways to keep your glasshouse warm
- Invest in an electric fan heater. ...
- Heat larger structures with a boiler. ...
- Create a hot bed. ...
- Try an air or ground source heat pump. ...
- Keep it insulated. ...
- Try passive solar heating.
Do plastic greenhouses protect from frost?
Yes, plastic greenhouses protect plants from frost. A plastic greenhouse will offer enough insulation to ensure that the temperature inside the greenhouse stays at least 5 degrees higher than outside. Therefore, a plastic greenhouse will offer enough protection to your plants during cold winter weather.
How do you support a cucumber in a greenhouse?
As the cucumber grows wind it gently around the canes and tie in with soft string. Stretch a wire from one side of the greenhouse to the other, making sure it is taut. Push in a cane beside the cucumber and tie the top to the wire. Tie in the cucumbers as they grow.