19 Common Problems In Hydroponics And How To Fix Them

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Since starting out on my hydroponics journey I’ve learned the hard way that there are many, many things that can go wrong. While hydroponics definitely has advantages over traditional soil-based growing methods, it’s not without its fair share of challenges. And, for new growers, it’s certainly a steep learning curve. Getting it right takes time. But after a while, you’ll be able to recognize, prevent and treat the majority of problems that arise within your hydroponics systems.

The most common problems areas to be aware of when growing hydroponically are;

  • Tall, floppy seedlings
  • Wilting
  • Clogging the system
  • System leakage
  • Electrical malfunctions
  • Insufficient lighting
  • Nutrient and pH imbalances
  • Root rot and diseases
  • Mould and algae
  • Plateaued growth

Each of these issues can cause the plants to deteriorate and die if left unchecked. But, thankfully, all these problems have a corresponding solution. It took me quite some time to get my head around it, but I’ll go through each of these common problems in this article which will hopefully save you some time.

19 Common Problems In Hydroponics And How To Fix Them

Problems with seedlings and juvenile plants

Starting seeds in a hydroponic system is a great idea, but it can also be a challenge. Seedlings are generally weaker, which makes them more susceptible to any minor condition. Some common problems that affect seedlings in hydroponics include;

1.  Tall, floppy or ‘leggy’ seedlings

If your seedling stems seem to grow taller and thinner very fast, you have a lighting problem. Plants tend to grow toward the light because they need it for energy. If the lighting is poor or far away, the seedlings will grow faster than expected, trying to reach the light.

Tall, floppy or ‘leggy’ seedlings don’t tend to last and many of mine died (like this cilantro seedling)

This makes the stems long but floppy because they didn’t take time to get healthy. The leaves on these stems also struggle to shoot because the plant has no energy.

Solution: Provide sufficient light in your growing set-up, even if it’s outside. Plants require at least 20-23 watts of light per square foot and it should be close enough to the plants.

I recommend LED grow lights such as these Barrina Grow Lights because they are bright enough without producing heat or using too much power. They don’t cost too much either.

2.  Wilting and drooping

Seedling wilting is caused by poor irrigation or high temperature. You will notice the plants losing their rigidity and starting to dry.

Solution: Do not let the roots dry between irrigations. Keeping the growing area cool and airy is also important.

You can achieve this with proper ventilation and using LED lights because they don’t produce heat and installing a fan.

Problems with your hydroponics system

Hydroponic systems involve many different parts, including pipes, water and air pumps, growing mediums, water reservoirs, and so on. All these parts have to work together to deliver water, oxygen, and nutrients to the plants. If one of them fails, the entire system suffers and plants are affected.

Hydroponic system issues include;

3.  Clogging and blockages

Clogging is a very common problem in hydroponics, especially if you are using a drip system. More often than not, the blockage is caused by pieces of growing medium and roots getting stuck inside the tubes. This affects the circulation of water/nutrient solution. It can also occur due to algae buildup.

Solution: Flush the tubes regularly with warm water to prevent clogging.

Make sure to regularly check your hydroponics system for blockages and excessive contamination from algae

4.  System leakage

Leaks occur for various reasons, causing irrigation problems. For one, if the system is clogged, the water pressure will cause the tubes to disconnect and leak or lead to water backing up and overflowing. Also, if your system reservoir is not big enough to hold the nutrient solution you put in, any power or pump issue can cause the water to back up and leak.

Solution: Test your hydroponic system prior to using it and ensure all the valves and connections are tight. You must also check the system regularly for issues such as clogging and loose valves.

5. Insufficient lighting

Light is one of the most important factors to consider when setting up and running a hydroponics system. Whether the light is natural, or artificial, you must ensure that your plants receive enough of it so that they can photosynthesize, produce energy and grow. Inadequate light can cause your plants to become spindly and weak, seedlings will be ‘leggy’ and thin, and roots won’t develop – to name just a few issues.

Solution: Ensure that your plants receive at least 14-16 hours of natural or artificial light every day. Arteficial lights should be powerful enough to provide enough light for your plants to photosynthesize.

Always use high-quality, energy-efficient LED lights purpose-made for hydroponics. This is so you can ensure the lights produce the right wavelengths and the intensity needed for optional growth.

6. Electrical malfunctions

Unless you are using a passive form of hydroponics system, like Wick Hydroponics, chances are you’ll be running some electricity to your unit to power either a water or air pump, as well as other components like fans or cooling/heating systems. If the power cuts, these components will fail to operate. Over an extended period of time, this can cause issues for your plants. However, this is rare in most cases.

Solution: In most cases, you just have to wait for the power to be restored. However, having a backup battery is always a good idea, particularly if you have a larger system that is more dependent on power.

Environmental factors

7. Lack of nutrients

When plants lack essential nutrients in hydroponics, they are unable to grow and develop. This can lead to a decrease in yields, poor-quality produce, and an increased risk of plant diseases. Many growers daily to understand their plant’s nutrient needs and either over, or under-provide or use nutrients that are sub-optimal for the plants they are trying to grow.

Solution: Research the specific nutrient requirements for the type of plant you are growing in your hydroponics system and take the time to test and monitor nutrient levels in the reservoir regularly.

The General Hydroponics Flora series is still arguably the best nutrient regimens on the market. 

8. pH imbalances

pH is another important factor that is often overlooked by hobbyist growers but one that should be taken seriously. If pH is too low or too high, plants are unable to absorb the nutrients the need to grow. Therefore, keeping pH to between 5.5 and 6.5 is key to healthy growth.

Solution: Invest in a pH meter in order to measure the pH of the nutrient solution. General Hydroponics also offers a great hydroponics pH control kit for all-in-one pH monitoring and management solution.

9. Lack of oxygen or air circulation

Oxygen is an essential element for plant growth and is especially important in hydroponics. Oxygen provides the means needed for plants to convert light energy into chemical energy (photosynthesis).

In hydroponics, plants may not receive enough oxygen if they do not have an air pump to aerate the root system, or a fan to circulate the air around the plants. Or, this equipment may fail or stop working over time.

Solution: Ensure that you have a functioning air pump the aerate the nutrient solution. If you don’t have one, consider investing in one. Make sure you have a simple oscillating fan to circulate the air around the plants.

10. Temperature fluctuations

Air temperature is also very important in hydroponics. I wrote an entire article about it here if you’re interested.

Extremes of temperature can have negative impacts on your plants. It’s therefore important to ensure that temperature in and around the hydroponics system is well-managed.

Solution: Don’t take the temperature for granted. Purchase some good thermometers to test both the air and nutrient solution. Research the temperature requirements for the plants you are trying to grow and ensure these requirements are met.

Disease and sickness

Though the lack of soil eliminates many plant issues, hydroponic plants can still suffer from diseases that include:

11.  Root rot

Root rot is a disease that causes roots to decay and die. The disease is caused by overwatering, lack of oxygen, and poor drainage of damp soil. Root rot is very common in hydroponics because roots are always underwater. However, root rot will not be an issue if the roots are getting enough oxygen.

Root rot manifests as brownish roots instead of white, droopy, yellowish foliage and sometimes odor. The video below gives a pretty good overview of how to recognize root rot, and what to do to fix it.

Solutions: If only a few plants are affected, and the disease has not gone on for too long, you can salvage the situation.

  • Remove each plant from its container to clean and sterilize
  • Rinse the roots and trim off any slimy or infected roots
  • Mix in 3ml of 29% hydrogen peroxide to your reservoir water and allow the plants to sit in for a day
  • Change the water with fresh water and let your plants sit for another day
  • Drain the water again and fill the reservoir with the appropriate nutrient solution
  • Add beneficial bacteria such as Hydro guard to outperform the bad bacteria that cause root rot.
  • If the plants are too affected, take out all the plants
  • Increase oxygen using an air pump connected to air stones.
  • Hide roots from light. You can use a towel or anything else to block light from the roots.
  • Maintain a 60-75 degree Fahrenheit temperature in the grow room. Root rot thrives in warmth.
  • If your system doesn’t have a pump and the water doesn’t move, change the water regularly and clean the containers.

12. Powdery mildew

Powdery mildew is a common fungal disease affecting a plant’s leaves and stems. It looks like someone sprinkled white powder on your plants due to poor lighting, high humidity and poor ventilation.

Solution: you can prevent powdery mildew by investing in better and stronger lighting, providing more air circulation and regulating humidity.

If the disease has started already, make a baking soda solution with 1 tbsp of baking soda, 1 tsp of dormant oil and some liquid soap. Mix this in a gallon of fresh water and spray on your plants.

You can also use potassium bicarbonate or vinegar.

13.  Gray mold

Gray mold is a nasty fungus that affects all plants. It looks like gray or whitish mushy spots on the plant leaves and stems. Like all types of mold, you will find it where there’s high humidity and cooler temperatures.

I’ve written a whole article about mold in hydroponics which covers this topic in more depth.

Solution: Unfortunately, there’s no worthy remedy to gray mold. The best solution is to remove the infected plants completely and hope the rest will be safe.

To dispose of the infected plants, place a brown paper bag over it so it won’t spread mold spores to other plants. You should also spray an organic fungicide such as this PureCrop1 as a precautionary measure. Make sure to also improve air circulation in the growing area.

Problems with leaves

You can often tell how a plant is doing by looking at its leaves. This is no different with hydroponic plants, and any change in the leaves indicates water or nutrient problems. Some of the problems you can expect include;

14. Leaf curling

Leaf curling is caused by too much heat or nutrient imbalance. You can tell the difference depending on which way the leaf curls. If they are dark green and curling downward, you may be overfeeding the plants. But if the leaves are curling upwards and changing color, plants are missing some vital nutrients or suffering from excess heat.

Solution: Once leaves start to curl, there’s not much you can do for them. However, you can do something about the cause to ensure the health of the plant is not compromised.

For one, check that your hydroponic system is not cycling too much or reduce the water-nutrient ratio to avoid overfeeding plants.

If the leaves are curling upward, consult the nutrient blend and ensure you are providing the required nutrients and that the PH level of your solution is balanced. And if the weather has been especially hot lately, try to provide some shade for the plants and introduce a cooling fan.

15. Browning leaves

Leaves browning around the edges indicate dryness or overfeeding.

Solution: Take a closer look at the plants and see if the roots are reaching the nutrient solution properly. If not, add the water level.

If that doesn’t seem to be the problem, adjust the nutrient solution and check the PH level. You may have to pour out and clean the system to avoid salt and nutrient buildup.

16. Yellowing leaves

Yellow leaves indicate a root problem or a lighting issue. Too little or too much light can turn the leaves yellow.

Solution: Check the roots to see if they have changed color, meaning they have developed root rot. If the answer is yes, follow the precautions we outlined for dealing with root rot.

If the roots are fine and the problem is lighting, identify if it’s insufficient lighting or too much. If the lights are too close to the plants, the leaves could be scorching, so you need to pull the lights back a little. More often than not, however, yellow leaves indicate insufficient lighting, meaning you must add some light or bring them closer.

17. Leaf Drooping

Leaf drooping is caused by a lack of oxygen in the roots, and it happens right before the leaves start turning yellow. It can also be because of too much heat.

Solution: If the issue is a lack of oxygen, add an air pump or air stone to the system. You can also adjust the plant so that half of the roots are exposed to air while the other remains in water.

As usual, provide shade for the plants if it’s too hot and introduce a fan to cool the air around.

Pest infestation problems

18. Pest infestations

Pests are not as common in hydroponics as they are in soil-based gardens, but they are still there. Some common hydroponic plant rests include aphids, spider mites, thrips, white flies and fungus gnats.

Solution: the best solution for hydroponic pests is to keep the growing area clean and sterile. Pests and bacteria stick to your clothes, shoes and tools, and then you can easily transfer them to the hydroponics system.

To avoid this, treat the hydroponic area like a hospital theater- you must wear sterile clothes and sterilize your hands and tools when getting in.

But if you already have pests, make an organic pest killer using Neem oil and water and spray it on your plants. A solution of 70% rubbing alcohol, castile soap and water will also work on most pests.

Plant growth problems

19. Slow growth or plateauing

Plant growth issues, where the plant stops growing and doesn’t produce flowers in time are caused by;

  • Insufficient light. Poor lighting will cause plants to grow tall, skinny and weak. They will also struggle to produce healthy leaves and flowers.
  • Water supply issue. If there’s a leak or low reservoir water levels, your roots will not get enough water or nutrients. This makes it impossible for plants to grow healthy and tall.
  • Insufficient or excess nutrients. It’s crucial to have the proper nutrient blend for each plant type. Having too much or too little nutrients is a common reason why plants struggle to grow well.

Solution: Find out the reason for poor plant growth and go from there. Start by checking the water system to see if the levels are okay and if the tube connections are secure.

You should also ensure there’s enough light for the number of plants you have in there. This also means ensuring each plant has enough space around it and it’s getting enough light.

Lastly, learn about nutrient blends for different plants. Nutrient solutions have three numbers in the format N-P-K for nitrogen, potassium and phosphorus. While all plants need all three nutrients, some, like fruiting and flowering plants require more potassium and phosphorus. The growth stage of each plant also determines the nutrient blend.

Once you get the nutrient ratio right, check the PH level of your water. This affects nutrient absorption and deters growth if it’s not balanced. In fact, keeping the PH level balanced is so important that experts recommend checking it weekly or every time you add nutrients or change the solution.

Final thoughts

Many hydroponic problems have simple solutions if you catch them early enough. And because the system is soilless, it’s easy to see the roots and the entire plant as it grows. Keep a close eye on the plants at each stage to know when something is changing.

Rest assured though, that mistakes and problems are normal as you start the journey of hydroponics. You will learn through those mistakes, discover new solutions, and improve. While at it, knowing possible problems by reading posts like this one will help you stay one step ahead and hopefully avoid most of them.

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William, an experienced consultant and passionate advocate for technology and sustainability, is the founder of Smarter Home Gardens. William's journey into gardening began with the purchase of his first home, which came with a small backyard garden. Despite initial challenges brought about by limited space, soil, and sunlight, William's determination to create a vibrant garden led him to research and experiment with innovative gardening technologies and sustainable practices. Driven by his lifelong enthusiasm for technology and sustainability, William explored various gardening methods, including vertical gardening, hydroponics, companion gardening, and composting. Through these efforts, he realized that it was possible to combine his passions with his newfound love for gardening. Smarter Home Gardens was born out of William's desire to share his research and experiences with others, helping them create smarter gardens that leverage cutting-edge technology and contribute to a more nature-positive world. The blog offers in-depth articles on innovative gardening technologies and methods, helpful 'how-to' guides, reviews of the latest gardening technology, and research on cost-effective garden maintenance solutions. William's commitment to sustainable and technologically-driven gardening has made him a trusted voice in the field. His enthusiasm for creating gardens that work with the planet, rather than against it, is evident in every post he shares on Smarter Home Gardens. Through the blog, William hopes to engage with a wider audience, encouraging others to join him on this exciting journey towards smarter, more sustainable gardens.

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