How Much Sun Do Cucumbers Need?

If you want to enjoy crunchy, homegrown cucumbers this summer, make sure to provide your plants with enough sun! Join farmer Briana Yablonski to learn how much sun cucumbers need to thrive.

Close-up of a ripe cucumber illuminated by the bright sun among large lobed leaves.

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Cucumbers are some of the most gratifying plants to grow in a home garden. Give them adequate water and well-draining soil, and the tiny white seeds turn into lush, trailing vines loaded with yellow flowers. These flowers eventually give way to crunchy fruits that are ready for you to pickle or snack on.

One key part of growing healthy cukes is providing them with enough light. But just how much light is enough? And is one type of light better than another? Stick with me to learn the answers to these questions.

The Short Answer

Cucumber plants require at least six hours of bright daily light to remain healthy. However, the plants prefer to receive eight to twelve hours of direct light. This amount of light will provide your plants with the energy they need to complete essential processes like cell division and flower production.

If you have to choose between morning and afternoon sun, opt for morning light. This light will dry morning dew that collects on plant leaves and will prevent the development and spread of disease.

If your cucumber plants don’t receive enough light, they’ll have a difficult time growing and producing flowers. Stunted plants and yellowing leaves are two signs that your plants may need more light.

The Long Answer

Providing at least six hours of light is essential if you want healthy and productive cucumbers. So, why is light so essential? And how do you make sure they are receiving enough light? I’ll provide more details about cucumber light needs so you can keep your crops healthy.

The Importance of Sunlight

Close-up of young seedlings with broad, serrated dark green leaves and hairy stems.
Adequate light is crucial for plant health and growth processes.

Cucumbers need sunlight to survive. During the process of photosynthesis, they use energy from the sun to convert carbon dioxide and water into oxygen, water, and glucose. They then use this glucose to power necessary reactions and processes.

When they don’t receive enough light, they can’t make the sugars they need to function! In other terms, a lack of light makes them hungry and weak. That’s why they often appear short, stunted, and generally unhealthy if they don’t receive enough light.

How to Tell Your Cucumbers Need More Sun

If your cucumbers aren’t getting enough sun, they’ll let you know! These symptoms may be barely recognizable when they first appear, but they become impossible to ignore as the plants mature. If you notice any of the following, your cucumber plant may need more light.

Stunted Growth

Close-up of a pear-shaped fruit with pimply skin, transitioning in color from dark green to light green.
Insufficient light limits cucumber growth, affecting essential metabolic processes.

As I mentioned above, cucumbers rely on light energy to help them produce sugars. If they don’t receive enough light, they won’t have all the energy they need to complete processes like cell division and respiration.

This lack of energy often appears as stunted growth. Lack of water, nutrient deficiencies, and poor soil can also lead to small crops, so don’t assume poor sunlight is the cause of stunting.

Lack of Flowers

Close-up of a small bright yellow flower with five petals, showing a star-like shape among large wide dark green foliage.
Ensure adequate light to promote flowering.

Flower production uses a lot of energy. Therefore, if there are only a few hours of light, the cukes are unlikely to receive the energy they need to produce flowers. If you don’t notice any flowers by the time they’re 40-50 days old, there’s a good chance they need more light.

Another common cause of a lack of flowers is too much nitrogen coupled with insufficient potassium and phosphorus. This combination of nutrients causes lots of lush green growth but few flowers.

Morning vs. Afternoon Sun

The large, palmate leaf is dark green with finely serrated edges, covered in grayish powdery spots caused by powdery mildew disease.
Choose a spot with morning sun to prevent fungal diseases.

If you have a spot that only receives six or eight hours of sun each day, the area may receive only morning or evening sun. If you’re stuck between planting in a spot that receives morning sun and another that receives afternoon sun, pick the location with morning sun. This is an important note to take for hot weather gardeners. 

Why? Cucumbers are notorious for developing fungal diseases like downy mildew and powdery mildew. Most of these diseases are more likely to occur in damp conditions, so keeping your cucumber leaves dry increases the chances your plants will remain disease-free. Since morning sun helps dry dew that collects on leaves overnight, it also helps prevent disease.

Tips for Ensuring Your Cucumbers Receive Enough Sun

Since cucumbers grow best when they receive ten or more hours of direct light, aim to provide them with as much as possible. If you’re working with a partially shaded yard or patio, keep the following tips in mind. Remember that hot weather gardeners may opt for less (six to eight) hours of sun.

Look for South-Facing Walls

Close-up of a young plant with heart-shaped, jagged dark green leaves, hairy stems, and bright star-shaped yellow flowers illuminated against a brick wall background.
Opt for the southern side of buildings for optimal sunlight exposure.

If you live in the United States, the sun will always be on the south side of the sky. Therefore, the southern side of houses, garages, and fences will receive more sun than the northern side. If you have to pick a side of a building to start a garden, choose the southern side.

Keep Larger Crops in Mind

Close-up of a plant with large foliage and hanging oblong fruits on a trellis in a garden, with several lush rose bushes in the background.
Plant tall crops on the northern garden edge for sunlight optimization.

Even if your garden is far away from your house and large trees, your cukes may still become shaded by larger plants. Crops like tomatoes and pole beans can grow tall enough to cast shade on the rest of your garden. Planting these tall crops on the northern edge of your garden will limit the amount of shade they cast on shorter ones, like cucumbers.

Consider Planting in Pots

Close-up of two large black pots with young plants climbing their vines, featuring jagged heart-shaped leaves and star-shaped yellow flowers along the supports.
Grow vegetables in containers on sunny patios for optimal growth.

If your lawn and garden are covered with shade, they’re not well-suited for cucumbers. However, this doesn’t mean you have to skip growing this well-loved veggie. An alternative is to plant your cucumber in a container on a sunny patio or deck.

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Final Thoughts

If you want to enjoy lots of crunchy cucumbers this summer, place your plants in an area that receives at least six hours of direct sun. These plants prefer ten or twelve hours of light and just a few hours less in hot climates. Don’t be afraid to place them in a bright, sunny area!

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