Growing hydroponically is both fun and rewarding. But, there are a number of common problems in hydroponics that can arise when growing plants in water.
I’ve been doing hydroponics for years and am going to share my hands-on experience as well as the knowledge I’ve gained over many hours spent researching.
I put together a list of common hydroponics problems with tips on how to identify and address them.
Common Hydroponics Problem #1: Nutrient Deficiencies
What to look for: poor overall plant health, leaf discoloration, stunted or distorted growth, excessive or slowed growth, delayed flowering or fruit development, or root abnormalities
Getting nutrients right is probably the most common hydroponics problem I see.
Hydroponic plants can and will have problems if your nutrient solution is not properly balanced. This can lead to stunted growth, yellowing leaves, and other symptoms.
Imbalanced nutrient solution can lead to nutrient deficiencies or toxicity. Both can cause stunted growth or plant death.
- Deficiency occurs when you don’t have enough nutrients a plant needs to thrive.
- Toxicity is when a plant gets too many nutrients.
Ensure you are using the right amount of nutrients (not too much, not too little) by following directions on the nutrient packaging and using an EC meter to take readings of your water.
Note: The EC meter I linked to just above is the one I use at home.
Many plants have a preferred EC reading where they grow best. For example, Okra likes an EC of 2.0 – 2.4 whereas some peppers prefer 3.0 – 3.5! Simply use Google to find this information for your plants.
If you take a reading and find out your EC is too high, simply dilute your nutrient solution and remeasure.
If your reading is too low, simply add more nutrients to the reservoir.
Knowing the EC requirements of what you are growing will ensure you stay within the reading and will also help if you are growing more than one type of plant in a single system.
Common Hydroponics Problem #2: pH Imbalance
What to look for: nutrient deficiency/toxicity, strange leaf coloring, slow growth, or mineral buildup in the system
The pH of the nutrient solution can affect the solubility and availability of certain nutrients to the plants.
The plants you’re going to grow will each have pH ranges they prefer. I recommend using Google to research the pH requirements of the plants you’re growing.
Here is a chart of some commonly grown plants to give you a sense of what I mean:
What happens if your pH is out of range?
If the pH is too high (alkaline), it can lead to nutrient deficiencies, particularly for essential micronutrients like iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu).
These nutrients tend to become less soluble and less available to plants at higher pH levels.
Consequently, the plants may show signs of deficiency, such as yellowing leaves, stunted growth, or other visual symptoms.
On the other hand, if the pH is too low (acidic), it can also hinder nutrient uptake. Some nutrients, like phosphorus (P), calcium (Ca), and magnesium (Mg), become less available and less soluble at lower pH levels.
This can result in deficiencies of these elements and negatively impact plant growth and development.
Let’s geek out for a second and talk about what is happening with plants when they can’t absorb nutrients.
The transport of ions across the root membrane is influenced by pH levels. In extreme pH conditions, the functioning of ion transporters and channels can be disrupted which impairs the uptake of essential nutrients even if they are present in the solution.
So, it is very important to maintain optimal nutrient uptake by monitoring and adjusting the pH of the hydroponic solution to keep it within the appropriate range for the specific plants being grown.
This can be achieved by periodically testing the pH levels and using pH adjustment techniques, such as adding acid or alkaline solutions, to keep the pH in the desired range.
By ensuring proper pH balance, you can maximize nutrient availability and promote healthy growth in hydroponic plants.
Here is an article that will teach you how to manage the pH of the nutrient solution.
It may seem difficult at first glance, but it is really very easy!
Common Hydroponics Problem #3: Pest Infestations
What to look for: damaged leaves, residue on leaves, or the pests themselves
Hydroponic systems can be vulnerable to pest infestations, such as aphids, thrips, and whiteflies.
These pests can be difficult to control in a hydroponic system, because there is no soil to use as a natural barrier.
I’ve not had problem with pests myself. I think this is a benefit of growing primarily indoors.
Should you run into pests, there are great resources online to help you navigate the problem.
Common Problem #4: Disease Outbreaks
What to look for: mold, mildew, or root rot
Hydroponic systems can also be prone to disease outbreaks, such as bacterial or fungal infections.
These diseases can spread quickly in the closed environment of a hydroponic system and can be difficult to treat.
Proper cleaning of your system can really help minimize this risk. Follow the advice in that article, and you’ll get your garden started on the right foot.
Common Problem #5: Algae Outbreaks
What to look for: slimy green algae growing in your garden or on planting baskets
To me, nothing is more frustrating than algae growing in my garden. It’s slimy and smelly. It can clog components. It can deprive plants of oxygen.
This could possibly be my number one tip for hydroponic growing: stop algae before it starts by following these steps
- Use hydrogen peroxide or a product like Hydroguard to provide protection.
- Make sure reservoirs do not let in light. Reservoir containers should be painted a dark color.
- Make sure any water drip tubes are not clear.
- Cover the tops of grow baskets to prevent algae growth on items like AeroGarden sponges or rockwool cubes. A cheap way to cover AeroGarden grow baskets is with aluminum foil!
- Thoroughly clean your garden of algae when you see it and/or between plantings.
Common Problem #6: Poor Water Quality
What to look for: stunted growth and nutrient deficiency
If the water you use in your hydroponic system is of poor quality, it can affect the health and growth of the plants.
You know the adage – garbage in, garbage out.
Water that is high in minerals, salts, or contaminants can cause problems. Also, your water will have a natural pH that may need to be adjusted for the plants your growing.
It is not a bad idea to have your tap water tested to understand your baseline.
Common Problem #7: Poor Lighting
What to look for: leggy plants that are reaching for light and/or pale green or yellow leaves
Poor lighting is the second most common hydroponics problem I see.
Plants need sufficient light to grow properly whether you are growing outdoors in natural sunlight or indoors with artificial LED lighting.
If you’re plants are “reaching” for the lights as in the picture above, you’ll know your LEDs are raised too high.
Place your LEDs a few inches above the tops of the plants.
You’ll want to research how much light per day the plants you are growing will need.
A plant that isn’t getting enough light will produce less chlorophyll. You’ll see this result in leaves that are really pale or even yellow.
I do the majority of my growing indoors, so the amount and quality of LED lighting I give my plants is extremely important.
I purchased high-quality, multi-spectrum LEDs and keep them on for 14-16 hours per day for most of my plants.
Poor lighting is a sure way to see poor growth or even plant death!
Common Hydroponics Problem #8: Temperature Fluctuations
Your plants will be impacted if the temperature in your hydroponic system fluctuates too much or is too high or too low.
Remember, it is important to understand both the air temperature and water temperature of your environment.
Tailor the temperatures to your plants’ needs.
For example, lettuce is a low-temperature plant and likes things below 70 degrees. Okra, on the other hand, thrives in warm weather.
I try to get in the habit of using Google to learn about the temperature needs of plants I’m unfamiliar with.
Also, keep in mind your LED lights will naturally increase temps right around your system.
I use a digital thermometer to monitor temps, and I adjust room and water temperatures, as needed.
The EC meter I use includes a water thermometer.
I also use a seed warming mat for some of my Kratky containers just to give the water a few extra degrees of warmth.
I’ve seen others use an aquarium thermometer to elevate water temps, but that is not something I’ve needed in my setup.
If the temperature in a hydroponic system fluctuates too much, the plants can be affected.
Finally, don’t forget to monitor temperatures when growing outdoors, too!
Common Hydroponics Problem #9: Lack of Oxygen
What to look for: wilting at the top of plants
Hydroponic plants rely on oxygen to thrive. So, how do you provide oxygen to your plant’s roots?
Some methods, like the Kratky Method, use exposed roots to allow them direct access to oxygen. Essentially the plants hang down into the nutrient solution, but there is an air gap between the foliage and the top of the water.
AeroGarden’s Bounty countertop models use a couple of different methods. First, they drip water that is naturally full of oxygen directly onto the plant.
Second, the garden is designed to give the roots an air gap for roots hanging down into the reservoir just like with the Kratky Method.
Gardens like Deep Water Culture (DWC) rely on an air pump and air stone to properly oxygenate the nutrient solution.
Learn more about the six different hydroponic systems to see how each oxygenates the water. (link)
Bottom line – If your system is not properly oxygenated, you’ll see poor plant growth.
Conclusion
Hydroponics can be challenging at times even for the experienced grower.
The good news is the problems that generally do arise are common and well-known. I’ve shared some things to look out for and tips and tricks to overcome the challenges before they become a bigger problem.
In addition to the articles on our site, the Reddit hydroponics communities can be quite helpful. I encourage you to hop over there to do research and ask questions.
Finally, feel free to drop us a note if you have any questions or need help with your system!
