How To Grow Hydroponics Cucumbers (Ultimate Guide)


Hydroponics is highly effective and beneficial at producing plants and delicious foods such as cucumbers. That is, provided you know what to look for and how to provide appropriate care for hydroponic cucumbers. As your hydroponic system needs change and your garden flourishes, some important aspects should be kept in mind to ensure your cucumbers thrive. 

Here’s the ultimate guide on how to grow hydroponic cucumbers:

  1. Select the best hydroponic system. 
  2. Choose the best variety.   
  3. Select the growth method.
  4. Provide the right space. 
  5. Provide the proper amount of light. 
  6. Determine the best temperature.
  7. Use the best nutrients. 
  8. Use vine training method.  
  9. Harvest frequently.  
  10. Proactively prevent pests and diseases.    

In this article, I’ll discuss all of these steps in great detail. Everything you need to consider before growing cucumbers using hydroponics is covered, from all the basics a beginner may need to references for additional sources for more advanced growers. Let’s get started!

1. Select the Best Hydroponic System

Cucumbers are tropical native veggies that thrive in warm weather and lots of water. However, they’re susceptible to cold and frost. Because these veggies are water lovers – essentially, cucumbers are all water – growing them in a healthy hydroponic system just makes sense.

Before growing cucumbers hydroponically, it’s essential to first determine the type of hydroponic system you want to install, or assess what type you’re currently utilizing to deem it appropriate. 

In general there are two main hydroponic growing methods: ebb and flow systems and DWC systems.  

The main difference between DWC and ebb and flow systems is the amount of time the plant roots are submerged. In particular, in an ebb and flow system, the roots go through dry periods (the drain phase), whereas in a DWC system, your plant’s root system is continuously submerged. 

Both of these growing systems are relatively easy to learn, making them beginner-friendly, and – perhaps more importantly – both have shown success in production and yield.

Ebb and Flow Systems

Ebb and flow systems are popular hydroponic system setups for hobbyists, novices, and commercial growers. It’s considered to be a beginner and intermediate level in complexity. While relatively simple in design, ebb and flow systems do require some setup and attention to detail. 

Ebb and flow systems –or as they’re more commonly known, flood and drain methods – are widely recognized and versatile in cost, skill requirements, and design. The flood and drain method is named because it involves two continuous phases of flooding the growing area with water and nutrients, then draining the water back into the reservoir. 

To set up an ebb and flow hydroponic system, you’ll need four main components:

  • Plant tray
  • Reservoir
  • Submersible pump
  • Timer

Be sure to find a good-quality, reliable timer, as it controls when the water in the system is in flood and drain mode. When the timer goes into flood mode, the water and nutrients are pumped into the plant tray through the submersible pump. The nutrient solution flows up to the container and soaks the plants’ roots until they reach the water limit.

When the timer goes off, the pump stops, and the water and nutrients cease to flow and begin draining into the reservoir through a drainage system. 

Providing enough aeration in your ebb and flow system is crucial to success. You can include an air pump or let the roots become completely dry and oxygenated during the drain phase.  

To see some diagrams of this system, check out this article from trees.com. 

Using this method, the same water can be cycled through for about a week. After about a week, though, you will need to change the water and renew the nutrients. The timer in this system is excellent for customization to precisely meet your crop’s needs.  

If you elect to use an ebb and flow system for your hydroponic setup, be sure to properly clean and sanitize the parts involved each growing season to prevent algae growth, mold population, and insect infestations. These potential problems can ruin your harvests if not maintained or controlled.     

Hydroponic DWC Systems

Hydroponic DWC systems are also popular choices for many gardeners, both professional and hobbyists. DWC systems stand for Deep Water Culture and sound a lot more intimidating than they’re. However, DWC systems are straightforward and beginner-friendly methods of hydroponic setups. 

In a DWC system, the cucumbers – or any plant you’re growing – have their roots suspended in a well-oxygenated solution made of water and nutrients. Using an air pump and air stone, the water in which the roots are submerged is highly oxygenated to prevent the plant from drowning. 

The water in a DWC system ensures your plants are appropriately hydrated. The nutrient component contains all of the micro and macronutrients the cucumbers need to flourish or whatever plant you’re growing. Without soil, nutrient supplication is key to healthy plant production.

Many experts on hydroponic systems believe DWC systems are the simplest and easiest to install and maintain. However, these systems can be challenging to control in small systems. In particular, when you’re trying to keep the proper pH, water, and nutrient levels, which tend to fluctuate in small systems more than in commercial-grade operations.  

For more information about DWC systems, including pros and cons, and a video overview, check out this article from Epic Gardening.

Other Hydroponic Farming Methods

Ebb and flow systems and DWC systems aren’t the only hydroponic methods in existence, but they’re the easiest to implement and maintain. However, if you’re a more advanced gardener, you may want to research other hydroponic growing methods.  

This article from Hydro Pros discusses six methods for hydroponic farming that could be helpful to you when determining the suitable method for you.        

2. Choose the Best Variety 

Once you’ve selected the type of hydroponic method you want to implement, it’s time to determine the species or variety of cucumbers you want to grow.

Cucumbers are members of the Cucurbitaceae family and have two distinctive subgroups: slicing and pickling. The main difference between the two is size and length when they reach maturity. 

Slicing varieties are wider and longer than pickling cucumbers. They’re nearly double the measurement of their pickling cousins at almost 12 to 13 inches (30.48 to 33 cm) in length, while pickling types are short and stout and, on average, reach a maximum height of about six inches. 

The varieties don’t stop there. Within each subgroup of the cucumber Cucurbitaceae family, over ten types of cucumbers exist, and all of them are unique. Here’s a list of 33 kinds of both slicing and pickling cucumbers from Gardeners Path for more details. 

Nearly any type of cucumber can flourish in a hydroponic system, but the choice is vital for you and your unique garden. Some of the best cucumber varieties to grow hydroponically are bush types, including apple and lemon cucumbers.

Other resources suggest using seedless cucumbers in your hydroponic system. For example, you can test out the different flavors and sizes of cucumbers at your local grocery store or market and determine your preferred type by taste. 

3. Select the Growth Method

There are three ways to start your hydroponic cucumbers. One option is seeds, a popular selection among expert and novice gardeners. The other ways are by cloning cucumbers or transplanting them from the dirt.

Each option has its challenges and benefits. Use the information below to help you determine the best method for you.  

Germinating Seedlings

Hydroponic cucumber seeds have high germination rates, making seedling germination the most popular choice among many horticulturalists. Propagation of cucumber seedlings requires close attention to detail, though, mainly to temperature.  

If you elect to germinate seeds to grow cucumbers hydroponically, you should use tiny seedlings and directly sow them individually in about 4 inches (10.16 cm) of a suitable hydroponic substrate.  

Hydroponic substrates are anchoring systems for the plant’s roots. They’re soilless media that support the plant and allow the roots to attach for increased aeration, moisture retention, and growth. 

Because cucumbers grow so well, especially in hydroponic systems, the type of substrate you use is more about personal preference than anything else.   

Clone Plants and Transplants 

Another way to propagate cucumbers in your hydroponic system is by cloning or transplanting other cucumber plants. 

To clone a cucumber plant, trim it and place it in water. Remember to change the water daily and keep it in full sunlight until you see roots. They need a considerable amount of light, but too much, and they could bolt. Some partial shade is suitable for pruned cucumbers being cloned.   

This process takes a few weeks before they begin to root. Once they root, you can then move them to your hydroponic system. To see a video of this process, check out this YouTube video:

Another similar option to cloning is transplanting your cucumber plant from the soil. If you have a traditional garden producing cucumbers, you can transplant them similarly to cloning. Or, you can purchase a cucumber plant already potted and growing to transplant.

Many people find cloning and transplanting are more costly and time-consuming options than germinating seeds, so these tend to be less popular choices.  

4. Provide the Right Space

Cucumbers take up lots of room, so it’s essential to provide them adequate space to grow. Providing the right amount of space for your hydroponic cucumbers ensures they fully mature and thrive.  

In traditional gardens, cucumbers grow in patches. Typically, this is no different in a hydroponic system. Thus, just like in a conventional soil-based garden, it’s best to space out the cucumber patches several feet to promote proper growth.  

Most growers advise novices to space cucumber patches about 2 to 6 feet (0.60 to 1.8 m) apart, depending on the type of cucumber and the growth method you’re training.  

Sometimes, you may need to trim and prune your cucumber plants to control the growth, but this is a simple and easy process to complete.      

5. Provide the Proper Amount of Light 

Most green veggies love the sun and require a lot of light for proper growth. Cucumbers, in particular, need plenty of sufficient light to flourish, but be careful. If you give them too much light, they can suffer.  

Cucumbers sometimes die with clones or transplants if over-exposure to sunlight occurs. Therefore, if you’re cloning or transplanting a cucumber plant, partial shade is optimal to ensure it roots quickly.  

It also depends on the type of light you’re offering to determine how much the cucumbers need. If it’s sunlight, cucumbers generally require 12 to 14 hours of light, followed by a total of 10 to 12 hours of darkness. This ratio of the sun and night is true if your cucumber plants are outside.  

However, if your cucumbers are indoors or you’re relying on artificial grow lights, you may need to provide more light to the plants. Artificial light needs will depend on the intensity and brightness of the artificial lighting and could take some trial and error and adjustments to get your cucumbers what they need.  

If you notice your cucumbers start to pale in their vibrancy, curl in on themselves, wither, or brown, they could be getting too much sun. Cucumbers that don’t get enough light won’t produce as many veggies and will have an overall reduced yield compared to those getting enough light.    

6. Determine the Best Temperature

As I mentioned previously, cucumbers are native to more tropical zones and thus love warmer weather. Therefore, when planted traditionally in soil-based gardens, cucumbers need to be planted during the warm seasons and require higher temperatures to survive.

One benefit of hydroponic systems is you have more control over the growing conditions and can adapt and adjust the requirements to create a higher production yield.  

Ideally, cucumbers need to stay at a temperature ranging from 65 to 75°F (18 to 23°C). However, as tropical natives, they don’t like to be too hot. Therefore, the temperature shouldn’t exceed 90°F (32°C) if they’re to survive.  

One potentially dangerous condition for cucumbers is cold and frost. Cucumber plants can become injured or die from frost, so it’s essential not to let the temperature drop below 55 to 60°F (12 to 15°C) at the lowest.  

Cucumber plants suffering from frost injury tend to have looks of decay and water-soaked spots.   

7. Use the Best Nutrients

Proper nutrient solutions are crucial to the healthy development of all plants, and cucumbers are no exception. Cucumbers need the right mixture of nutrients to prosper and grow. But, how do you know which one to use in your hydroponic system? 

For cucumbers grown hydroponically, nitrogen, potassium, phosphorus, and pH levels are essential for vegetative growth. Therefore, when selecting a nutrient solution, you should look for one geared explicitly toward fruit and vegetable growth.  

Hydroponic nutrient solutions aimed toward vegetative growth are usually high in nitrogen. Nitrogen gives plants the necessary nutrients during their vegetative state to promote photosynthesis and encourage them to produce chlorophyll. This leads to healthy stem and leaf growth.

Health stem and leaf growth add to a plant’s overall size and health. Without nitrogen in your nutrient solution, you’ll notice the leaves on your cucumbers turn a sickly yellow, and the plant’s growth will come to a halt. 

When your cucumbers begin to flower and produce initial cucumbers, more phosphorus and potassium must be added to your nutrient solution while decreasing the amounts of nitrogen.

pH levels also play a critical role in hydroponically grown cucumbers. Every plant has a preferred pH level required to reach its maximum growth potential. The pH levels and nutrient solutions work together to ensure healthy plant growth and maximum yield.

8. Use Vine Training Method 

Training your cucumbers to grow in the way you want them to is a great way to control the growth and have the hydroponic system of your dreams. I recommend using a vine training or trellis training method for several reasons.

For starters, vertical growth saves a ton of space in your system, greenhouse, or garden. However, vine training tends to only work on certain types of cucumbers. If you’ve elected to grow a bush growing cucumber plant, they won’t be able to be trained to climb a trellis and can’t grow vertically.  

Notably, vining varieties are climbing cucumbers and can quickly grow vertically. Vining cucumbers aren’t only space savers, but they also prevent disease and pests. In addition, growing cucumbers vertically can increase airflow and be more accessible to harvest than bush varieties. 

Generally, you can use any type of support you prefer to train cucumbers to climb. Just be sure to pick a support tall and sturdy enough to support your plant. Usually, something between 4 and 6 feet (1.21 and 1.82 meters) tall is sufficient to support the growth of most cucumber plants.  

Cucumber vines tend to prefer to sprawl out rather than climb, so it does take a little bit of training to get them going in a vertical direction. This requires regular observations and gently moving vines to help them attach to the support.   

9. Harvest Frequently

Cucumber plants must be harvested frequently to prevent excessive crop loads and maintain average veggie yields. Usually, cucumber plants take several months or about 60 days to mature.  

Generally, cucumbers grow to be about a foot long or 14 inches (35 cm) in length when they’re ready to harvest, depending on the variety you’re growing. However, some pickling cucumbers are matured and ready for harvest at half that length – about 6 inches (15 cm).

Other than by length, you can tell if a cucumber is ready for harvest by carefully observing the skin of the cucumber. If it’s thick and hard to penetrate with your fingernail or thumbnail, it’s ready to be harvested.

Harvesting cucumbers is easy. All you need to do is snip the individual vegetable about 1/4th of an inch (0.635 cm) above the vine. Avoid tugging on the cucumber, as this risks damaging the plant.  

Rinse your veggies, and they’re ready to eat or store. Slice them and top them on salads, or make your unique dish.

10. Proactively Prevent Pests and Diseases 

Growing cucumbers hydroponically is a great way to have delicious and fresh vegetables on hand, but it’s essential to be vigilant about preventing pests and diseases from invading your crop.  

Powdery Mildew

One common issue that tends to arise with hydroponic cucumbers is powdery mildew. This white-colored fungus grows on the leaves, flowers, and veggies that bloom on the cucumber plant.  

While powdery mildew won’t kill your cucumber, it will compete with it for nutrients needed to grow. This can cause your cucumber to grow and mature more slowly, weaken, and may even prevent it from yielding and producing. 

If you notice this disease spreading on your plant, you should get an organic fungicide. A fungicide with sulfur as the main active ingredient is best for this issue. Also, trim and prune the infected leaves and thoroughly clean and sanitize the shears after you’ve used them on the diseased portions of the plant.  

Spider Mites

Cucumber plants are also susceptible to spider mites. These pests are attracted to cucumbers because of the warm environment to thrive. Spider mites can be a significant issue in production and yield capacity as they prevent your cucumber plant from fully engaging in photosynthesis.  

You can tell if your cucumber plant has spider mites through careful observation. Spider mites will appear as tiny black spots on the underside of the cucumber leaves and tend to leave the leaves looking yellowish and with slow growth.  

Spider mites spread quickly, so it’s essential to crush the issue as soon as you find it to prevent continued breeding and decay of the plant. 

To get rid of these pests, you can apply a miticide and scrub the plant’s leaves with an insecticide soap.  

You can be proactive about preventing disease and pests by selecting more resilient cucumber variations such as Japanese Taurus and ensuring adequate spacing between each patch or plant.    

Final Thoughts

Growing a plant made chiefly of water entirely in water can be a rewarding and fun experience. Hydroponic systems allow gardeners to grow plants in a controlled environment without the use of soil.  

Many plants excel in this form of growing, especially cucumbers. However, it’s crucial to maintain proper conditions to ensure cucumbers survive and flourish. In particular, sufficient light and temperatures are keys to success.

It’s also important to pay attention to details to prevent pests and diseases, and to harvest quickly and frequently for fresh and delicious produce.

Alexander Picot

Alexander Picot is the principal creator of TheGrowingLeaf.com, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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