15 Common Problems With Hydroponics (And How To Fix Them)

Hydroponics is a great way to grow plants at home that is challenging, fun and very rewarding. However, there are a number of problems with hydroponics that you may encounter, and it is important to learn to avoid these or deal with them successfully.

Hydroponic growing is a more technical skill than growing plants in soil. You can learn a lot from reading books and articles, and watching instructional videos. However, one of the best ways to learn is from our mistakes. Thankfully, I've made plenty of mistakes while growing plants with hydroponics over the years.

I've put together this article about the most common issues that you may experience. Hopefully this information will prevent you from making some mistakes and give you the knowledge to successfully deal with others.

1. Hydroponics System Leaks

System leaks can occur for a whole variety of reasons. Leaks can occur at any joins or valves in your system. They can also occur if your system gets blocked, such as when the root mass clogs up a NFT system, leading to water backing up and overflowing. Leaks can also occur if you build a system with a reservoir which cannot hold all of the nutrient solution in the system. In this situation, a power cut or pump failure, may lead to back up and overflow of your reservoir.

Solution

Test your system prior to planting anything. Tighten any valves and make sure all connections are tight and secure.

Regularly check your system for problems such as root overgrowth or clogged drains or outlets.

Ensure that you choose a reservoir which can comfortably hold all of the nutrient solution in the system, not just the quantity that is in it when the system is in use.

If you are using an indoor system, consider placing it on a waterproof surface or, if possible, on a drip tray if you are using a small system. This is a good idea to catch leaks, but will also reduce mess when tending to your system.

2. Buying Cheap, Insufficient Or Incorrect Lighting

I like to use my hydroponics systems indoors so that I can grow fresh vegetables all year round. Without sufficient lighting of the correct type, the performance of a system will be very disappointing.

I've made various mistakes with indoor grow lights, such as buying cheap lights that were completely inadequate for what I needed, or buying the wrong type of lighting that led to poor fruit and vegetable yields. 

Solution

For most people, I would strongly recommend looking at LED and T5 fluorescent grow lights. These are typically the easiest to use and will be suitable for most users.

If you are buying LED grow lights, do not go for the cheapest option. Do a bit of research and buy quality lights that will produce light at the correct wavelengths and in sufficient quantities for your system.

Ensure you purchase enough grow lighting for your system. A good rule of thumb is to calculate the square footage of the canopy of your grow area and multiply this by 65. 

Here is a quick example;

A growing area of 4ft by 6ft. Total area = 24 sqft.

24sqft x 65 = 1560 watts

For this growing area, you will need approximately 1560 watts of grow lighting. This is a good rule of thumb, and is what I usually stick to.

3. Using The Wrong Fertilizer

When growing plants in soil, many of the micro nutrients needed are already present in the soil in sufficient quantities. For this reason, fertilizer designed for growing plants in soil does not need to include many of the trace micro nutrients that are essential for healthy plant growth.

Solution

Make sure you purchase nutrients designed for use with hydroponics.

You can make your own hydroponics fertilizer from scratch, but it is much easier to buy a two or three part solution. This can be mixed to produce nutrient solution that can be adjusted to most plants and growth phases. 

4. Not Keeping Things Clean

If you let your hydroponics setup and the area around it become messy and dirty, you may increase the risk of spreading disease or pests to your hydroponic system.

Part of the cleaning process is to stop algae, diseases and pests from being able to establish themselves in your system. Whilst some people do run systems specifically designed to encourage the growth of beneficial bacteria, I think for most home hydroponics setups, it is better to avoid the pathogenic organisms, by regularly cleaning your system and surrounding area.

Solution

Keep the area around your hydroponics setup clean and well organized.

Every 2-3 weeks, drain the system, flush the growing media and roots with water and clean the reservoir, pumps and tubing.  

5. Not Learning As You Go

Every crop of plants in a hydroponics system is different. Some things will go well and you will encounter some problems, either minor or major. You should take the opportunity to analyse what went well and what went wrong, to adjust your practice for future crops.

Solution

Document, photograph and take note of the good and bad aspects of every system you use and crop you grow.

When you encounter a problem, look for a solution. Books, websites and Youtube have so much information available that you will be able to solve your problems or prevent them the next time.

6. Not Monitoring The Health Of Your Plants

If you do not monitor your plants frequently, you will miss the early signs of problems. Whether this is insufficient growth or signs of deficiency or disease, the earlier you realize there is a problem, the more chance you have of correcting it and not ruining your plants.

Solution

Monitor the growth and condition of your plants frequently.

When you see a problem, take the time to find out what the problem is and try to correct it.

If you notice disease or pests, treat early and you may be able to prevent excessive damage to your plants.

7. Not Monitoring And Adjusting the pH Level

The pH level of your nutrient solution is one of the most crucial aspects of hydroponic growing. When growing plants in soil, the soil itself acts as a pH buffer and prevents rapid changes in the pH level. This means that pH issues are slower to develop and can be dealt with more easily.

This is not the case for hydroponics. The pH can change considerably over hours or days due to a range of factors including temperature, rate of absorption of nutrients by your plants, presence of disease, excess evaporation etc.

Solution

When growing with hydroponics, you must monitor the pH of your nutrient solution.

In a new system or when recent changes have been made, you may need to test and adjust the pH on a daily basis. In a stable system, you can reduce testing to once or twice per week. As you gain experience with hydroponic growing, you will begin to understand the factors that can influence the pH and you will get a feel for how often to test.

The best options for testing pH are to use a pH testing kit or a pH testing meter. I generally recommend getting a decent quality electric pH testing meter, as it makes pH testing quick and easy.

8. Nutrient Deficiency and Toxicity

There are numerous factors that can cause nutrient deficiency or toxicity in your plants. It’s not always easy to tell which nutrient is causing the problem or whether deficiency or toxicity is the problem. There are numerous signs to look out for to detect deficiency and toxicity of various nutrients, and you will get better at identifying problems with time and experience.

pH, temperature, plant growth rate, nutrient solution concentration, user error and a whole host of other factors can cause nutrient problems. Don’t forget that excess levels of one nutrient can cause problems with absorption of another.

Solution

Make sure to make up your nutrient solution carefully and accurately.

Ensure that the water you are using to make up your nutrient solution is not excessively hard. If so, consider diluting it with distilled water, or using water that has been through a reverse osmosis filter or activated carbon filter to reduce the level of dissolved solids. 

Monitor the concentration of your nutrient solution with a PPM/EC meter

Monitor and adjust the pH of your nutrient solution.

If your plants begin to display symptoms of nutrient deficiency or toxicity, my advice is to flush your system, discard the nutrient solution and make up a fresh batch. More experienced growers may have the skills to adjust things as they go, but most beginners and intermediates will be better to take the safe approach.

9. Using Hard Water In Your Hydroponics System

As mentioned above, using hard water can cause problems in a hydroponics system. If your water is below 200 PPM, you are likely to be able to use this without major problems, but tap water with a high level of total dissolved solids will cause issues with your nutrient solution.

Firstly, you will not be able to add as many nutrients to the water, as you will be limited by your target concentration for the nutrient solution.

Secondly, you are unlikely to know the exact composition of the dissolved minerals in your tap water unless you have had this privately tested.

The largest components of hard water will be calcium and magnesium salts. Unfortunately, these will typically be large molecule compounds, unable to be absorbed by plants.

Large molecule calcium compounds in your tap water can attract calcium salts that you add to the water, which can lead to your plants being unable to absorb these, and in the worst scenario, resulting in a calcium deficiency state.

Solution

If you have hard water, greater than 200 PPM, I would advise either diluting this with distilled water, or using a filter to reduce the level of dissolved minerals in the water.

An activated carbon filter will reduce the level of some minerals, and is a good, cheap option.

A reverse osmosis filter is a more expensive option, but will reduce the level of dissolved minerals close to zero.

10. Not Monitoring PPM/EC/TDS

Using a nutrient solution that is too dilute will lead to sub-optimal growth of your plants. Excessively concentrated nutrient solution can lead to toxicity or nutrient lock out. Neither are going to result in healthy plants.

As your plants absorb the nutrients and water, and water is transpired at variable rates, the concentration of the nutrient solution will change. The rate of change will depend on the growth rate of your plants, as well as the environmental conditions of your growing environment.

Solution

Use an EC PPM TDS meter to monitor the nutrient solution, both when making up the nutrient solution and over time as your plants grow.

You can adjust the solution to a certain degree as long as your plants do not show any sign of nutrient deficiency or toxicity.

Change the nutrient solution after a maximum of 3 weeks. This must be done, as the proportions of the various nutrients will deviate from the starting concentration due to variable take up by the plants. If using tap water, dissolved solids which cannot be used by the plants will begin to accumulate.

An EC meter will only tell you the electrical conductivity of the solution you are testing. This is converted into an approximation of the total dissolved solids within the solution. It tells you nothing about the various components of the solution.

Make up a fresh batch of nutrient solution every 2-3 weeks, and earlier if you detect any signs of nutrient toxicity or deficiency in your plants.

11. Blocked Or Broken Pumps And Spray Nozzles

Hydroponics systems rely on constant or very frequent delivery of water and nutrients to your plants. If you have a pump or nozzle failure or blockage, these can lead to problems very quickly.

A broken or blocked water pump can lead to plants in most systems being cut off from their water supply. Wick and DWC systems will not have this problem.

For aeroponic systems, it is quite common for the spray nozzles to get clogged over time. If this happens, the exposed roots will dry out very rapidly, leading to your plants wilting and dying very quickly.

Air pumps can also fail. It doesn't take long for the plants to cause the levels of dissolved oxygen in the water to drop to a level that the roots begin to drown, which can result in them dying.

Solution

Check your system frequently.

Consider buying a water or air pump with a built in alarm, which will sound if there is a blockage.

Consider designing your system, so that if there is a blockage or failure, it will not lead to rapid plant death.

For NFT technique systems for example, a good option is to leave the water outlet slightly raised at the end of the channel, which will result in a small pool of water, which will remain in the event of a pump failure.

12. Choosing The Wrong Growing Medium

The choice of growing media is huge and there are many factors to consider when making a choice. I have another entire article dealing with choosing the right growing medium if you want to learn more.

Some growing media are reusable, some are really only suitable to be used once. Some are absorbent and will keep water around the plant roots. Some are minimally absorbent and allow fast drainage. Some are expensive, some are cheap. Many growing media can be adapted to work in different hydroponics systems, and different growers will have their preferences.

Solution

Take a bit of time to think about what you want your growing media to do.

Read around to learn what other people have had most success with.

Consider your budget and whether you want to reuse the media for multiple growing cycles.

Read my article about growing media and you won't go too far wrong.

13. Not Flushing And Refilling the System Often Enough

The challenges of growing plants with hydroponics are totally worth it. Hydroponics has so many benefits and is such a fun hobby. However, If you try to run your system too long between flushing it and changing the nutrient solution, the chance of having problems, or even ruining your crops will increase significantly. The longer you go between changes, the more likely you are to run into problems with disease, pests and nutrient solution issues that you cannot correctly treat.

Solution

While hydroponics is much less labor intensive than soil based gardening, it requires more frequent monitoring and adjustment. Flushing the system and changing the nutrient solution is a bit of a chore, but it's well worth it. Larger produce, faster growing plants, and all year round greens for my kitchen are the benefits I gain. Some simple routine maintenance of my system is well worth it, and as I gain experience, I become more efficient and accurate in my ability to change nutrient solution, flush the system and clean my spare reservoir.

14. Building An Inconvenient Hydroponics System

There are numerous things that can increase the inconvenience of a hydroponics system. Putting a system in a small space without adequate room to work around it or putting it somewhere that your equipment is not close to hand can get frustrating. A system that doesn't have a convenient water source will cause you regret down the line. A poorly built DIY system that is prone to leaks or failure will only cause you frustration.

Solution

Start small. Whether it is a DIY system or a pre-built system, your first few growing cycles should be viewed as a learning experience. If you make bad choices at the outset, you can move on and plan something better next time.

Plan your hydroponics system – You need to have your equipment and water source close to hand and somewhere next to the system that you can prepare nutrient solution or clean your equipment. If you are growing inside, think about what might happen if there is a leak. Is your floor waterproof, or could you put down a drip tray.

15. Plant Diseases

Hydroponic plants are generally less susceptible to disease than plants grown in soil. Without soil, bacteria and fungi have less opportunity to establish themselves. Nevertheless, certain conditions, such as excess humidity, high temperatures and lack of direct sunlight can greatly increase the risk of your plants developing diseases that can threaten your entire crop.

Various features of your system can also cause excess stress to your plants which can make them more susceptible to disease.

Solution

To prevent disease in your hydroponic plants, you should try to avoid conditions that pathogens will thrive in. This means avoiding excessively high temperatures and humidity levels and trying to ensure that your plants receive some direct sunlight or good quality artificial light.

Monitor the pH and concentration of your nutrient solution. Ensure that your nutrient solution contains all of the essential macro and micro nutrients that your plants require for growth.

Monitor your plants frequently for any signs of disease. If you notice a problem, try to identify the cause and treat it as quickly as possible.

Conclusion

I've certainly learned through trial and error a few too many times when growing plants with hydroponics. I think a lot of the issues I experienced could have been avoided with a bit of prior planning and attention to detail. Hopefully this article will prevent you from having as many problems as I did when I first started.