The Ultimate Guide for Starting Cucumbers Indoors

Starting Cucumbers Indoors
The Ultimate Guide for Starting Cucumbers Indoors –

You might have heard that cucumber is a vegetable, but it is actually a fruit. Yes, a fruit enriched in health benefits. It is high in vitamins and minerals, low in calories, promotes hydration, and helps weight loss. And if you too love cucumbers and are wondering about starting cucumbers indoors, then this guide may help you.

Start cucumbers indoors about 4-5 weeks before they are ready to go out into warm temperatures and warm soil. I would also recommend you plant 2-3 seeds in larger containers, and the key is getting them into warm soil because they are thirsty and warm-weather crops.

Read on to find out everything you need to know for successful and easily starting cucumbers indoors.

See also: A Quick Guide On How to Germinate Tomato Seeds Faster

Important Things To Know Before Starting Cucumbers Indoors

Here are a few important things to know before starting cucumbers indoors:

Types of Cucumbers

The most important thing you should know before you start growing cucumbers indoors is the types of cucumbers.

  • Pickling cucumbers: These types of cucumbers are usually shorter than slicing cukes, 3-4 inches (7.5-10 cm.) long with thin skins and spines, and are typically ready for harvest sooner than their slicing cousins, but their harvest is shorter about 7-10 days. 
  • Slicing cucumbers are the type of cucumbers you see at your local groceries. Their thicker skin makes them easier to ship, and their absence of spines is more appealing to numerous consumers. They bear longer fruit, around 7-8 inches (17.5-20 cm.), and have thicker skins than pickling types. Some people refer to them as American slicing cucumber. 
  • Cocktail cucumbers, as you may have imagined, are small, thin-skinned fruits sometimes called “snack cucumbers,” as you can eat them in a few crunchy bites.

Varieties of Cucumber

There are many varieties of cucumber, often referred to as the part of the world they are most commonly cultivated:

  • English or European cucumber is one of the most common types of cucumber. They are almost seedless, thin-skinned without spines, and long (1-2 feet in length) (30-61 cm.). And they are grown in hothouses and also tend to be more expensive. 
  •  Kyuri, or Japanese cucumbers, are slim, dark green with minor bumps and thin skins. They are among the most delicious type of cucumbers.
  • As the name suggests, lemon cucumbers are the size of a lemon with pale lemon-hued skin. As this variety ripens, the skin becomes golden-yellow with fruit that is sweet and crisp. 
  • Persian (Sfran) cucumbers are comparable to American slicing cucumbers but a bit shorter and more compact. Persian cucumbers are juicy and crunchy, and sturdy enough to withstand heat. 

In addition, cucumbers are of mainly two types: vining and bush types. Choosing a type to grow depends upon how much space you have for growing them. The vining type usually takes up large space whereas the bush type occupies less space. Thus, for indoor plants, the bush type is usually recommended.

Some varieties of cucumbers are considered best to grow indoors while others grow outdoors.

See also: How To Naturally Remove Aphids From Kale: A Quick Guide

Stages of Growing Cucumbers

This is another important thing to know before you ask yourself “should you start cucumbers indoors?” The cucumbers usually grow through the following stages before they are fully grown.


This is the first stage. The first shoot and roots are produced by seeds in this stage. The warmer temperatures favor fast germination while the cooler ones result in slow germination.

The table below shows the temperature required for cucumbers to germinate.

Temperature Germination Time
Seeds inside 80°F to 90°F (26.6°C to 32.2°C)3 to 10 days to germinate.
Seeds inside 65°F to 80°F (18.3°C to 26.6°C) 10 days to germinate.
Seeds planted in soil below 50°F (10°C)Seeds will not germinate.
The Ultimate Guide for Starting Cucumbers Indoors –

And remember to plant your seeds no deeper than 1.5 inches (3.81 cm) and keep the soil moist and not saturated while your cucumber germinates.

Expert gardener’s tip: Use a soil thermometer to measure the morning and late-afternoon temperatures for a few days. It is safe to plant when the average daily readings are consistently above 65°F (26.6° C).


At this stage, the first set of immature leaves starts to appear. After that, true leaves develop. And soon after that, more leaves are produced and vines grow longer.

As soon as they put out vines, it is good to tie them loosely to a wooden trellis or other vertical plant support. They will be easier to water and harvest and less prone to diseases than sprawl on the ground.

Flowering and Fruiting

Both male and female flowers are produced by the majority of cucumbers. Female flowers bloom later than male flowers do. The center of male flowers is a sticky tube covered in pollen whereas the center of the female flower is the ovary.

Most cucumber variations produce male and female flowers, with the first males appearing in clusters around two weeks before the first females. You can identify males by the sticky, pollen-covered tubes in their centers, and at the base of each female is a tiny, underdeveloped cucumber.

At this stage:

  • Work a 2-inch (5.08 cm) layer of organic compost into the soil around the plants. Apply an organic, nitrogen-rich fertilizer like blood meal applied at the label’s suggested rate. 
  • Give your cucumber from 1 to 2 inches of water (6 to 12 gallons for every 10 square feet of soil) weekly and keep watering until your harvest.
  • Finally, protect the vines’ shallow roots with a 2-inch (5.08 cm) layer of organic mulch, including shredded leaves or straw.


It depends upon the type of cucumbers you are growing. But most of the types can be harvested in around 50 to 70 days.

See also: How To Quickly And Easily Get Rid of Clover Faster

Check out this video for valuable tips on how to harvest your cucumbers when they are at their most delicious.

The Ultimate Guide for Starting Cucumbers Indoors –

How to Grow Cucumbers Indoors?

The principles and methods for growing cucumbers indoors are very similar to growing any other plant indoors.

Choosing The Seeds

First, you need to choose the seeds depending on the space you have got to grow the plants. Choose the bush type of cucumbers for growing indoors.

And if in any case, you have to transplant them then you should know the answer to the question “How big should cucumber seedlings be before transplanting?” Generally, the seedling needs to have three to four true leaves before transplanting.

Planting the Seeds

A necessary thing to note here is the time cucumber seeds take or need to germinate indoors. So, how long does it take for cucumber seeds to germinate indoors? Well, if provided with suitable conditions, cucumber seeds take 10 days to germinate indoors. Moreover, they take around 60 days to fully mature. You need to space the plants 12 inches apart as well.


To ensure good growth, you need to provide the plants with the correct environment. Try to provide continuous light in the early stages of plants. Because it will provide stimulation. And if you can’t provide that, then make sure to provide them the light as long as you can.

And when the plants are at the fruiting stage, they need 8 hours of consistent light per day. If you can’t provide them the natural light, then must use grow light. And if you are wondering about “do cucumber seeds need light to germinate?” Then yes, they do.


It is recommended to provide high temperatures of around 25 to 30 degrees Celsius if you want to boost the growth of plants. Especially cucumbers need a specific temperature at which they can grow without any problem. 

See also: Treating Molybdenum Deficiency in Your Plants: Here’s How

Starting Cucumbers Indoors
The Ultimate Guide for Starting Cucumbers Indoors –


When you are starting cucumbers indoors, prepare yourself to water them often because cucumbers are very thirsty plants. They will need even more water when they are at the fruiting stage.

Because plants need to draw water for their fruits. So, you need to keep the soil mostly moist. If you are confused about which times are better for watering, then you can read many guides on it or watch videos of people online for their successful production of cucumber indoors. 

Food and Nutrition

Every plant needs proper and regular feeding and nutrition, to survive. Starting cucumbers indoors will bring a lot of responsibilities to you as well. You need to ensure their food and nutrition if you want juicy fruits at the end.

Moreover, the cucumber plants require feeding with a Nitrogen-based plant food dissolved in water. Apart from that, for keeping your plant healthy till it reaches maturity, two feedings are recommended. 


As you are starting cucumbers indoors, you need to make sure that your plants are productive. You already know that cucumber plants produce both male and female flowers. Male flowers are more than female ones. There are usually 10 male flowers for every female flower.

Look for the tiny cucumbers growing behind the flower, if you want to identify the female flowers. As pollination occurs by transferring pollen from male to female flowers and to do that you need to clip a male flower off the plant. Then peel the petals back to use the flowers as a brush.


Now, after learning “how do you germinate cucumber seeds indoors?” Learn to harvest them. Harvest the cucumbers when they have reached a desirable size. And to do this, pick the fruit by cutting the stem with hand shears roughly an inch or so from the end of the fruit.

Apart from that, be very vigilant i.e. if any fruit shows signs of yellowing, remove it. Because if not removed, it can destroy other fruits too, or maybe your entire plant. So, it is important to know how to harvest and ensure that you get the desired results from all of this hard work. 

Final Thoughts

Starting cucumbers indoors is not difficult. You just need to do your best, take great care, and be patient. Then your patience will surely be rewarded with juicy fruits.

Moreover, don’t forget to keep the plant safe from the common cucumber pest enemies. You can use some indoor-friendly pesticides to ensure that you and your family members are also safe from them. 


Hello friends, I am Altiné. I am SO excited you are here! I am the guy behind Plants Heaven is a blog that shares information about preparing, creating, and maintaining gardens in and out of your home, regardless of where you live. My goal is to help you learn to love gardening and reap the benefits that come with it. I am still learning; therefore, the information I share on this site may not always be “expert” advice or information. But, I do my VERY best to make sure the information shared on this blog is both accurate and helpful.

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