How to Grow Cucumbers in a Greenhouse: A Step by Step Guide

Greenhouse Cucumbers

Planning on growing cucumbers in a greenhouse? Read this practical step-by-step guide to how to grow the best cucumbers. 

Wondering what to grow in your greenhouse? When it comes to gardening, few vegetables are as versatile (or delicious) as cucumbers. They can be grown in a garden, of course, but they can also be grown in a greenhouse – and generally with more success too. 

If you’re looking to add cucumbers to your greenhouse, this is the guide for you. 

We’re going to cover every step from planting through to harvesting cucumbers in a greenhouse, as well as tips on how to get the most out of your cucumber crop. 

Why Should You Grow Cucumbers in a Greenhouse?

Greenhouse cucumbers

There are several reasons why you should grow cucumbers in a greenhouse. Here are some of the benefits:

Allows You to Reliably Grow a Variety of Cucumbers in Cooler Climates

It is possible to grow some types of cucumber outside in cooler climates (like here in the UK) but if you want to be able to grow the widest range of cucumbers, you’ll need to grow them under cover.

Growing Cucumbers in Greenhouses Increases Yield

Another benefit of growing cucumbers in a greenhouse is that you can often get higher yields than you would if they were grown in the garden. This is because greenhouses provide a controlled environment, which allows cucumbers to thrive and produce more fruit. 

Extends the Growing Season 

Growing cucumbers in a greenhouse also allows you to extend your growing season, which can help you reduce your food costs. 

Enables You to Grow Fresh and Local Produce 

Growing cucumbers in a greenhouse also ensures that produce is fresh, so you can reduce your food waste. If you practice saving your seed, you can also cultivate a variety of cucumber that’s well-suited to the specific environment of your greenhouse. 

Select the Right Variety of Cucumbers to Grow in a Greenhouse

Bella Cucumber
F1 Bella

When it comes to growing cucumbers in a greenhouse, you have several options when it comes to varieties. Here are some of the most popular varieties:

  • F1 Bella – An all-female hybrid cucumber with good resistance to powdery mildew and no bitterness. Produces vigorously and thrives in an unheated greenhouse. 
  • Cucumber ‘Diva’ – A mini-cucumber that provides particularly high yields when grown in a greenhouse. No seeds and smooth skins containing crisp flesh. 
  • Cucumber Passandra F1. Organic mini-cucumber that is resistant to powdery mildew and crops heavily. Expect crisp and sweet flesh.

Starting the Cucumbers from Seed vs Buying Young Plants

When it comes to growing cucumbers in a greenhouse, you have two options: starting the cucumbers from seed or buying young plants. Here are some of the pros and cons of each option:

Benefits of Starting Cucumbers from Seed 

Cucumber Seedlings
Cucumber seedlings

Cost-effective: Starting cucumbers from seed is a cost-effective way to get started in greenhouse gardening. Seeds are relatively affordable, and they allow you to grow a large number of plants relatively cheaply.

Flexible: Another benefit of starting cucumbers from seed is that you have greater flexibility in terms of the type of cucumber you can grow. You can choose from a variety of heirloom and hybrid varieties that are not available as young plants.

Sustainable: Starting cucumbers from seed is also a more sustainable way to garden. You can save money on plastic pots and soil by using recycled materials to start your plants.

Benefits of buying young  cucumber plants to grow in your greenhouse

Young cucumber plants
Young cucumber plants

Convenience: One of the biggest benefits of buying young cucumber plants is that they are available when you need them. 

Less time-consuming than growing from seed: growing from seed is time-consuming. The seeds need to be started indoors, and the plants will only be ready for planting in your greenhouse when they are about 2 months old, whereas shop-bought plants are ready to plant immediately. 

How to Grow Cucumbers From Seed 

When it comes to starting cucumbers from seed, there are a few things you need to keep in mind. Here are some tips on how to get started:

  1. Start Seeds Indoors. Most cucumber seeds need to be started indoors about 6-8 weeks before you plan to transplant them into your greenhouse. Either use a heated propagator or germinate in a polythene bag. Germination normally takes 5-7 days.
  2. Pot the seedlings on when they’re about a month old into 12cm pots. Ensure plants are kept at a temperature above 15 ℃.  

Prepare the Soil to Grow Cucumbers in Your Greenhouse

When preparing the soil to grow cucumbers in a greenhouse, it is important to consider the needs of the plants. Here are some tips on how to get started:

Choose a Good Location 

When choosing a location for your greenhouse, make sure to pick a spot that gets plenty of sunlight. Cucumbers need at least 6 hours of direct sunlight per day to produce fruit.

Amend the Soil 

Before planting your cucumbers, it is important to amend the soil with compost or other organic matter. This will help to provide the plants with the nutrients they need to grow strong and produce fruit.

Use a Large Container 

If you’re growing cucumbers in a container, be sure to use one that is at least 18 inches deep. The container should also have plenty of drainage holes to prevent waterlogging or root rot.

Transplant the Cucumber Plants into the Greenhouse

When the cucumber plants are 2 months old, you can transplant them into your greenhouse. Be sure to space them out so they have enough room to grow.

Growing Tips for Your Greenhouse Cucumbers 

Cucumber greenhouse trellis
Ensure cucumbers are well-supported

Once you’ve transplanted the young plants, here are a few tips to help them thrive: 

  • Remove any male flowers to stop the fruit from becoming bitter (if the variety demands it). Male flowers do not have the swelling of the growing fruit underneath them. 
  • Train the plants on a trellis or up strings. Cucumber plants in full fruit can be surprisingly heavy so ensure the support can withstand the weight. 
  • Spray overhead in hot weather.
  • Pinch out the tops of plants when they reach the desired height – or train them to grow in another direction (but ensure they’re well supported). Also pinch out any side shoots. 
  • Pick fruit regularly to encourage more fruiting and harvest before they become too large. 
  • Regularly pile fresh compost around the base of the stem. Feed with a liquid feed every 10 days. 
  • Remove any yellowing or damaged leaves. 

Common Problems with Greenhouse Cucumbers 

Cucumber plant affected by powdery mildew
Cucumber plant affected by powdery mildew

Powdery Mildew – Appears on plants as white, powdery patches. It’s often caused by underwatering – water plants frequently to prevent, or buy a resistant variety of cucumber. 

Cucumber Mosaic Virus – Leaves marked by a yellow mosaic pattern. Remove and destroy affected plants immediately to prevent the disease spreading. 

Red Spider Mite – Causes leaves to look rusty. Remove and burn affected leaves. 

Whitefly – Can cause significant problems with mould. Use organic or inorganic (but vegetable safe) pesticides. 

Greenhouse Cucumbers vs Outdoor Cucumbers

When growing cucumbers in a greenhouse, you can expect to get a higher yield than if they were grown outdoors. This is because cucumbers grown in a greenhouse are protected from the elements, which can damage the plants and reduce yields. In addition, cucumbers grown in a greenhouse are less likely to be affected by pests and diseases.

Outdoor Growing Cucumbers 

Pros of Outdoor Growing 

  • Can be done almost anywhere
  • Cheap and easy to set up

Cons of Outdoor Growing 

  • Vulnerable to pests and diseases
  • Weather can be unpredictable and can affect yield

Greenhouse Growing Cucumbers 

Pros of Greenhouse Growing Cucumbers 

  • Some protection from pests and diseases
  • Controlled environment means plants can be grown for longer season 


  • More expensive than outdoor growing
  • Need to have access to electricity and water
  • Growing from seed takes time

How to Harvest Cucumbers from Your Greenhouse

Harvesting cucumbers

When it comes to harvesting cucumbers from your greenhouse, there are a few things you need to keep in mind. Here are some tips on how to get the most out of your crop. 

Harvest Cucumbers Regularly 

Harvest regularly: It is important to harvest your cucumbers regularly so they don’t get too big. If the cucumbers get too big, they will start to lose their flavor and sweetness and the plant will eventually stop producing new fruit. 

Harvest Cucumbers When They’re Young 

Cucumbers should be harvested when they are still young and tender. If you wait too long to harvest them, they will become tough and seedy.

Use a Sharp Knife to Harvest the Greenhouse Cucumbers 

When harvesting cucumbers, use a sharp knife or secateurs to cut them off the vine. This will help to prevent damage to the plant.

How to Store Cucumbers from Your Greenhouse

Cucumber pickle
Cucumbers make a great pickle

Once you have harvested your cucumbers from your greenhouse, it is important to store them properly so they stay fresh and crisp. Here are some tips on how to store your cucumbers:

Keep in a Cool and Dark Place 

Cucumbers should be stored in a cool, dark place where they will not be exposed to direct sunlight or heat. This will help them stay fresh for longer.

Don’t Wash The Cucumbers Until You’re Ready to Eat Them 

Washing the cucumbers before you store them will cause them to spoil faster. Wait until you are ready to eat them or use them in a recipe before you wash them.

Place The Cucumbers in an Airtight Container 

Cucumbers should be stored in an airtight container with plenty of room for air to circulate around them. Use a paper towel inside the container to absorb moisture and help keep the cucumbers dry.

Rinse Before Using 

If you use cucumbers from your greenhouse in a salad, be sure to rinse them under cold water first. This will help remove any dirt or debris that might have been left on them from the harvesting process.

Pickle Any Excess Cucumbers 

Cucumbers are one of the best vegetables for pickling. It’s likely that you will end up with more cucumbers than you can keep up with! Pickling excess cucumbers is a great way of saving them for the winter months. 

Growing cucumbers in a greenhouse can provide you with higher yields of more flavourful and crisp vegetables. Happy growing!

Now You Know How to Grow Cucumbers in Your Greenhouse, Read More Greenhouse Guides

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