What temperature to plant cucumbers outside?

Author: Dr. Mariah Huel III  |  Last update: Sunday, December 7, 2025

Cucumber (Cucumis sativus) is a warm-season vegetable that grows best at temperatures between 75 and 85 °F. Plant seed or transplants after the fear of frost has passed, and the soil temperature has reached 70 °F. Seeds will not germinate at soil temperatures below 50 °F.

When can I put my cucumber plants outside?

Outdoor cucumbers – harden off carefully, before being planting outside from early June, once you're sure temperatures won't drop below 12–15°C (53–59°F) at night. Choose a warm, sunny, sheltered spot.

What is the lowest temperature cucumber plants can tolerate?

Like all crops, cucumbers too have a preferred temperature range. As a warm season crop, the ideal temperature range for cucumbers is generally 21-26°C (70-80°F). However, the plants can withstand a wider range, if necessary, ranging from 15-29°C (60-85°F).

Will cucumbers survive 40 degrees?

Cucumbers are heat-sensitive and do best in temperatures between 60-90°F (16-32°C). They can tolerate some heat but will become stressed if temperatures exceed 95°F (35°C). Cucumbers can also be damaged by frost and temperatures below 50°F (10°C).

What happens if you plant cucumbers too early?

Cucumbers are on of the best garden vegetables. If you start them too early in the garden, the frost will kill them. Timing is critical to your cucumber success.

Your Cucumber Plants Will DIE Every Time You Make This Mistake!

What is the best month to plant cucumber?

Cucumbers grow best in warm weather. Start seeds indoors in late April for transplants. Sow seed directly in the garden after soil has warmed, usually in May. Plastic mulch and row covers allow earlier planting.

What not to plant near cucumbers?

Here are a few plants that do not grow well with cucumbers:
  • Pumpkin (Cucurbita)
  • Squash (Cucurbita)
  • Courgette (Cucurbita pepo)
  • Potato (Solanum tuberosum)
  • Broccoli (Brassica oleracea var. italica)
  • Cabbage (Brassica oleracea var. capitata)
  • Kale (Brassica oleracea)
  • Sage (Salvia officinalis)

Is 40 degrees at night too cold for plants?

Each plant has a different threshold when it comes to dealing with the cold. Some plants can survive outside even when temperatures hit freezing. Others need to be brought indoors when temperatures reach the mid-40s.

What temperature should cucumbers be at night?

Grow above 70 F during the day and above 60 F at night. Be careful when hardening-off plants not to expose them to cold temperatures. Plants with one or two true leaves transplant best. Transplant into black plastic mulch or warm garden soil after danger of frost has passed and weather has settled.

Do I need to cover plants at 40 degrees?

Many tropical plants cannot survive temperatures below 40 degrees. If you cannot move your pots (with annual or perennial plants), or you have tender plants in the ground, cover your plants. The idea behind covering plants is to trap the heat from the soil and keep the cold air out.

Should I cover tomatoes at 40 degrees?

So when temperatures start dipping below 50º F, leave the tomatoes on the vine if warmer days and nights are forecast. But if temperatures have started on a steady downward slide, go ahead and pick the mature green tomatoes and bring them indoors.

How cold can cucumber plants stand?

Cucumbers have zero frost tolerance. They thrive when the temps are between 65°F and 84°F.

What is the best fertilizer for cucumbers?

A high potassium fertiliser, such as tomato feed or a balanced fertiliser mix including potassium can be used as per the instructions.

What is the trick to growing cucumbers?

Water often enough to keep the soil slightly moist all the time. Cucumbers will be small and can taste bitter if they get stressed for water. Mulch the soil around the plants to keep in moisture.

What temperature is bad for cucumber plants?

Even prolonged exposure to temperatures below 55 degrees F. (13 C.) can cause decay, pitting, and water-soaked areas on fruit. Sudden cold snaps can cause cucumber plant damage on leaves, stems, and fruit or even kill the plants.

Is 39 degrees too cold for seedlings?

Seedlings, with their tender new leaves, often give up the ghost when temperatures dip to 32-33°F. Tropical plants have differing low-temperature thresholds. Some keel over when temps fall to 40°F; others crumble at 35°F. Other plants are just hardy by nature and can withstand temperatures as low as 18-20°F.

Is 50 degrees too cold for cucumber plants?

Below 63°F, cucumbers do not grow. In such conditions, plants sit in the soil and become susceptible to damages caused by pests in the soil. With that said, check soil temperatures and be sure they are above 63°F before planting cucumbers.

Is it better to water cucumbers in the morning or evening?

Timing is everything. Watering in the early morning sets your cucumbers up for a day of hydrated success, reducing evaporation and giving them time to drink up before the midday sun turns your garden into a sauna.

How to keep bugs off of cucumber plants?

Planting borage, scarlet runner beans, and other flowers near your cucumbers attracts bumblebees, whose presence helps deter cucumber beetles. Grow repellent plants. Flowers like nasturtium and marigolds, an herb such as catnip, and veggies like radishes and corn help keep cucumber beetles away. Keep the garden clean.

Can peppers survive 40 degrees?

So will peppers survive 40 degrees? To sum it up, most peppers won't necessarily DIE from 40˚ F temperatures, but their growth can be stunted, and they may be slow to recover so it's best to keep them warm if possible.

What is the lowest temperature to leave plants outside?

There is no universal temperature for all plants that is too cold, so that is why it is important to do your research. However, it is safe to say if living in an environment with harsh winters and temperatures below 20°F, it is always wise to bring plants indoors during this time, if possible.

Will my plants be OK in 50 degree weather?

For many plants, temperatures below 50°F can cause problems. Adjust thermostats to cater to your comfort, but remember your plants need some consideration. Avoid placing plants near cold drafts or heat sources. Keep plants several inches away from exterior windows.

Why should you not plant cucumbers near tomatoes?

Planting cucumbers and tomatoes together? Planting cucumbers and tomatoes right next to each other is often not recommended. These two plants often have similar requirements for nutrients, water and light, which can lead to competition. Both plants are heavy feeders and require a lot of nitrogen for healthy growth.

Do cucumbers like pots or ground?

They're ideal for growing in containers or small raised beds. Vining cucumbers produce more fruit, but they require more space than bush varieties. Though some gardeners let vining cucumbers sprawl on the ground, that practice promotes disease.

What should not be mixed with cucumber?

Cucumber is a kind of cold-natured food, while peanut contains a lot of oil and fat. If cucumber and peanut interact with each other, it is easy to cause diarrhea.

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