Growing Cucumbers Indoors

Wouldn’t it be fantastic to pick and eat fresh cucumbers all year long without going outside to the garden? But wait! Don’t cucumbers demand a specific outside growing environment? Perhaps, you can recreate the right setting to produce a hearty crop of cucumbers inside your home. 

You can grow cucumbers indoors year-round with some know-how and the right gardening supplies. Provide your indoor cucumbers with the right growing environment, warmth, water, and a hefty amount of attention, and you can expect to harvest a decent yield.

Growing cucumbers inside requires some planning, a few items like a trellis and space, and a bit of patience. Indoor cucumbers tend to increase rapidly, but you must harvest them at the right time since they also expire quickly.

Growing Cucumbers Indoors

Cucumbers often get overlooked as an inside plant-growing option since they are a summer crop. 

They thrive in warm temperatures and love full sunshine. 

But don’t let that scare you into thinking they won’t thrive indoors year-round. 

Many gardeners are delighted to learn that growing cucumbers indoors works well. 

Growing cucumbers indoors requires enough space t0 allows the cucumbers to spread upward on a trellis, allowing them to grow in either soil or hydroponics growing medium, a temperature between 75 and 85 degrees Fahrenheit, and about 12 hours of daily light.

First, to get started growing indoor cucumbers, select a variety of cucumbers that thrive in an indoor setting. 

Self-pollinating cucumbers work best inside. 

Next, gather the right gardening supplies starting with the right soil mix. 

Or, choose a hydroponics method such as Ebb & Flow or Wick.

Check out our complete guide to growing vegetables with hydroponics.

Also, a trellis helps the plant spread to grow upward, saving needed indoor space.

Finally, find the best location inside where your cucumber plants can thrive. 

Place the plants in a well-lit window. 

Or, use artificial lighting to give the cucumbers at least 12 hours of daily light. 

Also, plant them in an area with a constant temperature of between 75 and 85 degrees Fahrenheit.

Growing cucumbers indoors in winter

Cucumbers are considered a summer plant. Ideally, they thrive in temperatures between 75 to 85 degrees Fahrenheit

However, the desire to harvest cucumbers throughout the cold winter is why many gardeners choose to grow the plants indoors. 

Cucumbers will need supplemental indoor lighting in winter since the sun changes positions and won’t provide enough light during winter. The plants will also require a daytime temperature between 70 and 75 degrees Fahrenheit and no less than 65 degrees Fahrenheit at night.

In the winter, place the cucumber plants in a south-facing window to get the most light. 

Elevate the containers at least four inches above the ground.

Use a heat mat. 

Or, put the plants on top of the refrigerator where it is warm.

The humidity inside also needs to be monitored, especially in the winter when the air inside tends to dry. 

When the cucumber plant gets too dry, it prevents proper leaf growth and produces small and puckered leaves. 

If the humidity goes below 50 percent, place an open pan of water in the greenhouse. 

However, fungus spores may grow if the humidity levels are too high.

See the top reasons your little cucumbers are dying.

Growing cucumbers indoors in a greenhouse

Get ready for a massive harvest of cucumbers grown indoors in a greenhouse.

Growing cucumbers indoors in a greenhouse requires a few changes from growing them outdoors. 

To grow cucumbers in a greenhouse, get suitable soil and containers as well as a trellis. Also, maintain the proper lighting for about 12 hours daily, a temperature of about 75 degrees Fahrenheit, and ideal moisture, or humidity, of between 85 and 95 percent.

Choose a container that has at least 4 drainage holes in the bottom. 

An adequate number of holes allows the plant to drain through the soil and not get clogged. 

Also, select plastic or ceramic pots that retain moisture to help the water-loving plant thrive.

You can grow two cucumber plants per one square foot of soil. 

Set up an indoor trellis, and train the plant to grow up the trellis framework.

What kind of soil to use for growing cucumbers indoors?

Instead of picking up a bag of garden soil, select a unique container mix. 

Garden soil isn’t for use in container gardening since it is dense and will clump. 

Worse yet, garden soil could spread bacteria or viruses to your plants.

Choose a specific container mix that provides adequate drainage and fertilizer. 

Look for a combination that contains perlite, coconut husk, or peat.

Every so often, mix fertilizer with watering to provide the cucumber plant with nutrition, especially once they start producing flowers.

Ideal temperature & watering for growing cucumbers indoors

Keep an ideal daytime temperature of between 75 and 80 degrees whenever possible. 

Always maintain a temperature between 70 and 75 degrees Fahrenheit during the daytime and never lower than 65 degrees at night.

Since cucumbers contain the highest water content of any other solid vegetable, ensure you provide the plants with enough water to flourish. 

The plants require about an inch of water every week to produce fruit.

Either commit to watering them daily or set up a drip irrigation system.

If you can’t commit to daily watering by hand, it’s better to water the plants deeply but less frequently than to give them little bits of water every day. 

Too little water will cause wilting, rotting, potentially diseased plants, or bitter produce. 

Put your finger into the soil to determine if the plant needs more water. 

If it feels dry, it needs water.

Growing cucumbers indoors under lights

Of course, natural sunlight is the best option for growing plants. 

However, even a solid glass greenhouse in direct sunlight will need a little help in the winter months. 

That’s where supplemental indoor lighting comes in handy. 

Supplemental lighting works well for growing cucumbers indoors. Set up fluorescent grow lights that provide a full spectrum of colors. Position the lights about a foot above the plants. Let the auxiliary lights shine for about 12 hours daily. 

For cucumber plants to flourish, they require a lot of light. 

Minimally, cucumbers need between 8 to 10 hours of lighting per day.

While you are establishing the seedlings, they will need even more light.

Cucumbers that receive less than 8 hours of light each day will still produce fruit, but less of it so long as they receive at least 6 hours of direct sunlight or artificial light.

Find out how much sun cucumbers need.

Growing cucumbers hydroponically indoors

As long as you have light, water, and plant nutrients, you don’t need soil to grow healthy cucumbers. 

Hydroponics provides the proper level and type of nutrients the plants need to succeed

Hydroponic gardening grows plants using water instead of soil.

It only makes sense that a vegetable containing more than 95% water would thrive growing hydroponically. 

To grow cucumbers hydroponically indoors, you’ll need a lot of space and a hydroponic gardening system. The hydroponic systems that work best for growing cucumbers indoors include an Ebb & Flow or Wick system.

Cucumbers tend to snowball and produce. 

Once they germinate, cucumbers continue providing produce for three to four months, and they don’t need soil for this to happen.

There are different types of hydroponic growing systems. 

Cucumbers grow best in Ebb & Flow/Flood & Drain or Wick systems.

The wick system is an easy type of hydroponic system. 

It does not use aerators, pumps, or electricity.

Place plants directly in an absorbent substance such as vermiculite or perlite. 

Next, place nylon wicks around the plants.

The Ebb & Flow or Flood and Drain system positions the plants in a spacious bed packed with rock wool or perlite as a growing medium. 

The grow bed gets flooded with a nutrient-rich solution, and then the water floods a couple of inches below the top layer of the growing medium. 

A water pump floods the bed and is hooked up to a timer to switch it on and off. 

When the pump switches off, the water drains from the grow bed back into the pump.

Check out our full article: Can You Grow Anything With Hydroponics?

Pollination for indoor cucumbers

Pollination is one aspect of gardening that cannot happen inside unless you have a swarm of bees buzzing around or you tediously do it by hand.

Ensure your indoor cucumbers receive the proper pollination by choosing a self-pollinating plant variety. Usually, European types of cucumber plants provide the best option for inside growing. Plants that produce all female flowers tend to create a great crop without any bee’s help.

Look for cucumbers with the words “gynoecious” or “parthenocarpic” on the seed packet label. 

Gynoecious means the plant produces female flowers. 

While parthenocarpic means it is seedless.

Final Thoughts

Learn how to grow cucumbers indoors throughout the winter with these helpful tips for greenhouse lighting and hydroponics inside your house. 

Start by selecting a hardy, self-pollinating cucumber plant, and prepare for a delicious year-round harvest.

About the author

Greg Volente

Greg Volente holds a Naturalist Certificate from the Morton Arboretum, worked for The Nature Conservancy leading environmental education programs and doing natural areas restoration, and worked in the soil science research & testing lab at Michigan State University. Besides gardening, he's an avid wildflower enthusiast, and loves botanizing, hiking, and backpacking.