Common Problems in Growing Hydroponic Cannabis And How To Fix Them

How to Troubleshoot Common Problems in Hydroponic Cannabis Growing

Hydroponics, the future of cannabis cultivation, offers unparalleled control and efficiency, but it certainly has its own share of issues. From finicky pH levels to the ever-present threat of root rot, navigating the world of hydroponics can feel like a constant game of troubleshooting. 

But fear not! This guide will help you with the knowledge to troubleshoot common hydroponic problems. We'll explore common issues like pH imbalances, nutrient deficiencies, and maintaining optimal growing conditions. From troubleshooting wilting seedlings to preventing root rot, we've got you covered. 

1. pH Imbalances and Fluctuations

In hydroponics, getting the ideal pH level is super important for successful cannabis cultivation. Think of it like the lubricant that keeps the machinery running, i.e., making sure the nutrients are readily available to the roots. 

For cannabis, the optimal pH range lies between 5.5 to 6.5. This narrow window allows plants to absorb important nutrients like nitrogen, potassium, and phosphorus maximizing their growth potential.

When the pH strays outside this critical range, nutrient availability can be severely compromised.

In acidic conditions, certain nutrients become less soluble, hindering their uptake. This can lead to deficiencies in essential elements like calcium and magnesium, resulting in stunted growth, chlorosis (yellowing of leaves), and even bud rot.

Conversely, high pH levels can cause a nutrient lockout, where essential nutrients like iron, manganese, and zinc become unavailable to the plant. This can show up as interveinal chlorosis, where the areas between leaf veins turn yellow or brown while the veins themselves remain green.

To ensure your cannabis plants thrive, maintaining a stable pH within the optimal range is crucial. Let's explore some effective strategies to achieve this:

Monitor the pH Regularly 

Make pH monitoring a part of your daily grower ritual and invest in a reliable pH meter. pH test kits also work, but they aren't as reliable and easy to use as a meter. pH never flies off the scales instantly; it gradually fluctuates, and by checking it daily (or at least once every few days), you can catch the fluctuations before it's too late. 

Adjust It When Needed

Even if your pH does wander off course, don't worry just yet — adjusting it is easy when you catch it on time. You can use pH up or down solutions here. These are stronger than household fixes, so even a small amount can make a big difference. 

Start with a few drops and stir the solution before testing it again. Remember, it's always better to take a slow and conservative approach than dumping too much in and overcorrecting — such pH swings can be stressful for your cannabis plant.

If you're using a small hydroponic setup, you can use droppers or syringes for precision. And if your reservoir is small, you can even dilute the pH up or down solution before adding it to your nutrient setup. 

Be Patient 

Once you add the pH adjuster to the solution, let it circulate through the reservoir for a few minutes. This helps stabilize the pH and gives you a more accurate reading. If you're working with a larger setup, you can speed up the process with a pump. 

Do not chase the pH too aggressively, either. You may end up overcorrecting it and sending it swinging back and forth, which will do more harm than good. Instead, aim for small, steady changes. 

Use High-Quality Adjusters

You'll find many growers recommending home remedies like lemon juice or baking soda to adjust the pH — ignore those. They may sound like clever hacks, but they're very unreliable for hydroponics. 

These household remedies can even destabilize your pH and introduce impurities. Instead, stick to proper pH solutions specifically designed for hydroponic systems. 

Be Consistent

Maintaining a stable pH level is crucial for creating a consistent and supportive environment for your cannabis plants. A balanced pH is not just a minor detail; it plays a vital role in ensuring that your plants thrive and grow stress-free. 

By regularly checking and adjusting the pH levels, you can significantly improve the health and overall development of your cannabis plants. This approach ensures that they receive the essential nutrients they need for optimal growth and increases their chances of a successful harvest. 

2. Nutrient Issues: Deficiency, Toxicity, and Lockout

When it comes to solving nutrient issues, you'll feel like Sherlock Holmes because it's nothing short of solving a mystery with little clues. Here, the symptoms don't always paint the full picture. 

Before jumping to conclusions, start with the basics: water temperature, pH, and electrical conductivity. If these are within the correct ranges, you need to go deeper, and here's how. 

Double-Check the Nutrient Mix

Even if you think the conditions are perfect, your plant may still be missing a key element and you may need to start checking for symptoms. 

Your cannabis needs a balanced mix of nutrients, and pinpointing exactly which one is lacking can be tricky. So, you need to start with broad strokes. 

Here, you can even examine your plant's symptoms — yellow leaves, stunted growth, or burnt leaf tips — which can point you in the right direction. Matching the symptoms to the right issue is the first step in solving the issue.

Use Our Grow Guides to Figure Out the Issue 

We've covered many common nutrient deficiencies in our guides, so be sure to cross-check the symptoms your plant is showing with these guides. Once you've identified the issue, follow the recommended solutions to get your cannabis back on track. 

While nutrient issues can vary so much, most fixes come down to balancing the pH, fixing the water quality, or simply adding more of what's lacking. 

3. Wilting or Dying Cannabis Seedlings 

Growing cannabis seedlings in a hydroponic setup is like walking on a rope — the conditions must be precise and right for the seedlings to grow well. However, if your seedling is struggling, don't worry. Here's how you can troubleshoot two common issues: wilting and dying. 

Fixing Wilting Seedlings 

When your seedling starts wilting, it's like your plant is signaling for help. Here, the usual suspects are inadequate water, too much heat, or imbalanced conditions. When seedlings don't get these things, their stems begin to lose strength, and the leaves can end up looking droopy. 

How do you fix this? Well, you do this by making sure your roots get a chance to dry slightly between waterings. In a hydroponic setup, balance is everything — too wet or too dry, and your seedlings will start wilting. 

It's also a good idea to have a backup pump just in case the main one fails. Pump failure is one of the most frustrating issues that can make your plants take a nosedive. 

Fixing Dead Roots 

On the other hand, if your seedling's roots are looking brown or mushy, it's a sign of trouble below the surface. Here, warm water, imbalanced EC levels, or overwatering in dense mediums could be all to blame.

To fix it, start by removing the affected seedling immediately to stop the issue from spreading. Then, adjust the water temperature — the ideal range being between 65°F to 75°F (18°C to 24°C). Finally, monitor the EC levels to make sure the nutrient solution isn't too strong or weak. 

Keep It Clean

Finally, keep your setup clean, especially when growing seedlings. Regularly sanitize your hydroponic system to prevent pathogens and maintain a healthy environment. This step is often overlooked, but it's critical for keeping your seedlings thriving.

4. Roots Rotting in Hydroponic Cannabis

Root rot is when the roots of your cannabis plant start rotting, and it is one of your plant's worst nightmares. It attacks your plant from below and spreads fast if you don't fix the issue on time. So, the best thing to do is prevent it altogether. 

Root rot has three common causes. First, it's pests like fungus gnats or similar critters that bring pathogens straight to your plant. Next is introducing new plants without proper cleaning, which can lead to the spread of diseases. Finally, dormant pathogens can sometimes just hang out for weeks before getting activated. 

If your plant is already showing signs of root rot, don't worry. You might still be able to save your cannabis plant. You simply need to wash the roots with clean water until all the slimy goo is out of it. But remember, flushing may not always work in severe cases. 

To prevent root rot from attacking your cannabis plant, follow these tips:

• Keep the nutrient solution cool by maintaining water temperature below 75°F (24°C) as warm water encourages pathogens. 
• Oxygenate your roots with proper aeration techniques to keep them healthy and resilient. 
• Sanitize your hydroponic setup and tools regularly to limit exposure to harmful microbes. 
• Use dark or thick materials to prevent light from reaching the roots, which can promote algae growth. 
• Regularly inspect your plant's roots for early signs of trouble. 

By staying proactive and keeping your hydroponic system in top shape, you can avoid the headache of root rot and ensure your cannabis plants remain healthy.

5. Biofilm or Algae Growth in Your Setup

Algae and biofilm are other common issues you may face in your cannabis setup. Fortunately, these are easy to manage with the right approach. Algae, being photosynthetic organisms, live in areas exposed to light and nutrients, like your reservoir. 

On the other hand, biofilm is a slimy layer of bacterial buildup that usually harbors other organisms, including algae. If left unchecked, biofilm can pose a serious risk to your plant's health. 

Algae are easy to spot, though. It appears as green or brown slimy patches on surfaces exposed to light, like the reservoir walls and tubing interiors. While green algae are common, brown algae may also show up sometimes, especially if you're using unfiltered tap water. 

On the other hand, biofilm can be trickier to detect. It's usually clear, slimy, or cloudy and often becomes noticeable only when it starts blocking water flow in tubing or emitters. 

Both algae and biofilm can harm your plants directly and indirectly. They compete for essential nutrients like nitrogen and phosphorus, which can lead to deficiencies in your cannabis plants. Plus, they consume dissolved oxygen in the water, which can further stress out the rots. 

They can also create an ideal environment for harmful pathogens like pythium (which causes root rot) and fusarium, as the organic matter they produce allows these fungi to thrive. 

Algae further complicate the matter by influencing the pH balance. During the day, algae consume carbon dioxide, releasing it back at night, which causes fluctuating pH levels. Over time, these shifts can lead to severe issues for your plants.

How to Avoid Algae in Your Cannabis Plant?

Consistency is key to keeping your hydroponic setup clean and free of algae. Plus, you can prevent algae growth in your system by covering all components exposed to light using opaque containers or wrapping transparent tubing with dark or reflective tape to block out the light. 

For areas already affected by algae, scrub them thoroughly to remove the buildup. You should also regularly inspect your system for light leaks and seal any cracks or gaps to maintain a light-proof environment.

Since algae and biofilm thrive in warm water, you should also maintain a water temperature between 65°F to 70°F (18°C to 21°C). This range is ideal for cannabis roots but unfavorable for algae growth.

If you live in warm climates or use high-intensity lights, consider investing in a water chiller to cool the nutrient solution. Insulated reservoirs can also help regulate temperature and prevent overheating.

6. Failing Airpumps in Your Hydroponic System 

Air pumps are crucial to your hydroponic setup, as they make sure the roots get proper amounts of oxygen. When they malfunction, it can lead to serious problems like nutrient deficiencies, root suffocation, and even plant death. 

Without a reliable air pump, your plants could face stress that compromises their health and growth. And since hydroponic plants are submerged in water, they rely only on pumps for the oxygen supply. 

If the pump fails, oxygen levels drop, causing the roots to suffocate. This is why you need to act quickly to prevent damage to your plants, as prolonged oxygen deprivation can be fatal. 

Signs of a Failing Pump

Some times you should look out for a failing pump are:

• Wilting or drooping leaves or the plant appearing lifeless.
• Roots become brown and slimy and start showing signs of root rot due to a lack of oxygen. 
• Nutrient deficiency-like symptoms, including yellowing leaves or stunted growth, are caused due to lack of oxygen. 

Troubleshooting a Failing Pump

If you notice these symptoms, you need to start fixing the issue. Follow these steps to troubleshoot the problem:

Check the Power 

Ensure that the air pump is securely connected to a functioning power source at all times. You should check for loose plugs or power strips that may have been accidentally switched off, as these are common culprits that can lead to power interruptions.

You should also consider testing the outlet by using another device to confirm that it is operational. If necessary, don't hesitate to reset the circuit breakers to restore power and ensure that everything is working properly.

Inspect for Clogs

Next, you should inspect the tubing and air stones for blockages caused by kinks, algae, or debris. Adjust bent tubes or replace them if needed. Algae and mineral deposits can accumulate in the airlines, reducing oxygen flow. Disconnect the tubing and clear it by blowing air through or using compressed air.

If you suspect the air stones are clogged with nutrient salts or algae, they should be cleaned or replaced. Soak them in a diluted vinegar or bleach solution for a few hours, rinse thoroughly, and reinstall them. If cleaning doesn't restore proper airflow, replace the air stones altogether.

Listen for Strange Sounds or Vibrations

A healthy air pump makes a steady humming noise. Clicking, grinding, or banging sounds indicate worn-out parts. Too much vibration could mean misaligned components or improper mounting. 

If the pump becomes unusually hot, it may be overworking or nearing failure. High temperatures are often a warning sign that something isn't functioning correctly.

Preventing Air Pump Failures 

So, how do you prevent this issue and extend the life of your air pumps? Routine maintenance and careful monitoring are key. Also, here are some more tips to help prevent this issue:

• Clean air stones and lines every 1 to 2 months to prevent clogs caused by algae or mineral buildup.
• Keep a backup air pump on hand to avoid disruptions during a failure.
• Place the pump in a dry, well-ventilated area to prevent damage from excessive humidity or dust.

7. Failing Water Pump in Your Cannabis Hydroponic Setup 

The water pump is another critical part of any hydroponic system, which is responsible for delivering the nutrient-rich solution to your plants. If it fails, nutrient flow stops, leading to rapid nutrient deficiencies that can stress or damage your plants.

Symptoms of a Failing Water Pump

Like air pump issues, water pump problems can show up through various plant symptoms. Watch for signs like the following:

• Stunted growth since your plant struggles to develop due to a lack of nutrients 
• Yellowing leaves, which is a sign that your plant is not getting enough nutrients 
• Stagnant water, which leads to low oxygen levels, inviting root pathogens and increasing the risk of root rot

Fixing the Failing Water Pump 

If your plants show these symptoms, troubleshoot the water pump with the following steps:

Check the Power 

Ensure the pump is securely connected to a working power source. To rule out power issues, test the outlet with another device or reset circuit breakers if necessary.

Inspect the Intake Filter and Tubing 

Check for debris, leaves, or algae that might block the pump's intake filter, affecting water flow. Remove any obstructions to restore functionality. Mineral deposits, biofilm, or debris can also block tubing. To clear any blockages, disconnect the tubing and rinse it with warm water or a vinegar solution.

Clean the Impeller

The impeller is a small motor that moves water through the system, and over time, it can collect nutrient salts, algae, and particles over time. To clean it, start by carefully disassembling the pump to access the impeller. Refer to your pump's manual if needed.

Next, soak the impeller in a diluted vinegar solution or scrub it with a soft brush to remove buildup. Finally, rinse thoroughly and reassemble the pump, ensuring all parts are correctly placed to prevent leaks.

Preventing Water Pump Failures 

Water pump failures, when they happen, can wreak havoc on your plant's nutrient routine. So, it's best to avoid them. Here are some tips that can help you prevent water pump failures:

Keep a Backup Pump

Having an extra water pump readily available ensures that you can quickly replace a failing pump, which helps minimize disruptions and allows your plant to continue operating smoothly without significant downtime.

Regularly Maintain Your Water Pump

You should clean the pump, intake filter, and tubing periodically to prevent blockages and mineral deposits from building up.

Properly Install the Pump 

Install the pump in a location that is dry and free of excessive humidity or dust, as these can wear down components or cause clogs.

By being proactive about maintenance and keeping a backup pump, you can ensure that your hydroponic system runs smoothly and delivers the nutrients your plants need to thrive.

8. Pests in Hydroponic Systems

Pests are common in hydroponic setups, despite the controlled environment. There are many pests that can attack your system, but we will discuss only four major pests, signs, and how they affect your plants. Of course, let's also take a look at some solutions to get rid of them. 

Most common pests in hydroponic systems:

• Fungus Gnats

Fungus gnats love wet habitats and can become a big problem in hydroponics systems.

Signs

• Small black flies flying around the growing medium or nutrient reservoir.
• You'll find larvae that look like small see-through worms with black heads in the nutrient solution or near the root zone.
• Plants show signs of stress as the larvae cause root damage. 

Impact

• Larvae eat the roots of the plant, compromising the root system and affecting growth.
• If infestation is severe, nutrient absorption will be hampered and plants will decline.

Solution

• Use sticky traps around the growing medium to trap adult gnats and monitor infestation levels.
• Use beneficial nematodes to kill the larvae.
• Utilize Bt or Bacillus thuringiensis: a bacteria that kills gnats but can't harm plants.
• Improve the drainage and reduce the dampness.
• Do not overwater or oversaturate the growing medium to avoid creating gnat breeding grounds.
• A layer of sand or perlite can serve as a barrier for adult gnats that want to lay their eggs in the medium.

• Spider Mites

Spider mites can cause severe damage to cannabis and can spread easily in hydroponic systems.

Signs

• Fine, silky webbing is visible on leaves, stems, or between nodes.
• As the mites suck on plant sap, you'll probably see yellow or white spots on the leaf surface.
• In case of severe attacks, the leaves will become dry, and brittle and drop off.

Impact

• Draining sap makes a plant weak and unhealthy.
• If left untreated, spider mites will severely depress yields or kill the plant.

Solution

• Introducing predatory mites like the Phytoseiulus persimilis, neoseiulus californicus, and Amblyseius andersoni to control these pests naturally. 
• Use insecticidal soap or neem oil and apply it to the leaves. Focus directly on the underside of the leaves where mites usually live. Repeat every 3-5 days for the best results.
• Make your grow room a little less humid, below 50%. You can also improve airflow with fans to prevent mites from breeding.
• If the infestation is high, isolate one plant and clean it properly so that the mites do not spread. Wash and sterilize all surrounding surfaces and equipment.

• Aphids

Aphid bugs are small sap-sucking insects that reproduce quickly and form large colonies on cannabis.

Signs

• You might see small green, black, or white bugs on the leaves or buds.
• A sticky substance called honeydew on leaves that can promote sooty mold growth.
• Leaves getting weak, curling, or yellowing for nutrient loss.

Impact

• Aphids suck out important nutrients from plants, resulting in weak plants, small plants, and less yield.
• The secretion of honeydew can promote ants and fungus.

Solution

• You can spray the plants with a fine spray of water to shake the aphids off. You can wipe off the aphids with a damp cloth as well.
• Use organic insecticidal soap, neem, or horticultural oils to kill the aphids. Make sure to spray it all over the plant, especially on the underside of the leaves.
• If the infestation is a bit out of your control, don't hesitate to introduce natural predators ladybugs, lacewings, or parasitic wasps (like Aphidius colemani) to help control aphids.
• Check plants daily and take action at first signs of re-infestation as aphids reproduce fast and the population can grow endlessly.

• Thrips

Thrips are really tiny insects that move fast, cause damage to leaves, and spread plant viruses.

Signs

• Silver or bronze marks appear on the leaves with tiny black fecal spots.
• Leaves may be speckled, discolored, or misshapen by feeding.
• To the naked eye, thrips appear like small, thin insects that move fast when disturbed.

Impact

• When plants feed, they damage them and defeat their ability to photosynthesize. 
• Thrips can carry damaging plant viruses which can further endanger your cannabis crop. 

Solution

• You can place sticky traps of different colors to capture the thrips damaging your cannabis crop.
• Insecticidal soap, neem oil, or spinosad is used to spray on plants for effective results. Use again as required, especially after heavy infestations.
• You can release bugs like Orius spp. to control pests on your mums. These predatory mites target thrips and other crop pests by damaging their barrel.

Environmental Management

• Don't fertilize too much as new growth looks good to thrips.
• Make sure plants have good airflow and lower humidity levels so there are not too many thrips.

So, as you can see, you'll have to detect pests early on to manage them in your hydroponic systems. No matter the pest you want to eliminate, you need to monitor regularly, use biological controls, and keep a clean growing space. You can save your plants and cannabis harvest by controlling infestations as soon as they arise.

9. Pathogens in Hydroponic Systems

Pathogens in hydroponic systems typically spread quickly, thanks to the nutrient solution and a controlled environment. Naturally, you need to detect and manage them before they get out of control. Let's take a look at the signs, impacts, and solutions for three common pathogens.

• Pythium (Root Rot)

One of the most common pathogens in hydroponics is Pythium, also known as root rot. This water pathogen flourishes in low-oxygenated and dirty reservoirs.

Signs

• Roots may appear slimy and brown to black rather than the usual white or cream healthy colors.
• Smelly or swampy odor coming from the reservoir or root zone.
• If the plants are drooping, stunted in growth, or yellowing, it may indicate other causes, even if they have enough nutrients.

Impact

• Pythium destroys the root system which can impair the capabilities of a plant to absorb water and nutrients.
• If the disease is severe, plants may wilt, have nutrient deficiencies, and die.

Solution

• First, oxygenate the reservoir using air stones or pumps in the nutrient solution.
• Keep water temps less than 68° F (20° C) to stop Pythium.
• Next, introduce beneficial microbes like Trichoderma harzianum or mycorrhizal fungi to the root zone to prevent harmful pathogens and protect roots.
• You should also sterilize the system after a pest outbreak. Simply clean and sterilize your hydroponic system, tools, and equipment with hydrogen peroxide or bleach.

• Powdery Mildew

Powdery mildew is a fungus that infects cannabis when conditions become too humid and wet, causing cold-stunned growth.

Signs

• You may find white, powdery spots resembling flour on the stems and leaves.
• Leaves that are infected can become yellow, curved, or distorted.
• This disease usually starts at the lower leaves and moves up.

Impact

• Blocks leaf surfaces causing reduced photosynthesis in the plant.
• Reduces the overall strength of the plant and affects its yields. 

Solution

• First, improve the environmental conditions and keep humidity below 50% to prevent fungal cultures and use fans to guarantee air circulation around the plants.
• Next, apply fungicides including sprays made of sulfur or potassium bicarbonate.
• For organic control, spray with diluted milk (1:10) or neem oil.
• Snip the infected leaves and put them elsewhere so they don't affect the remaining plants. 

• Botrytis (Gray Mold)

The disease known as botrytis, or gray mold, can severely damage flowering cannabis plants. Typically, it thrives in humid environments. 

Signs

• Gray fuzzy mold may grow over buds, stems, or leaves if they have been damaged. 
• Buds may get wet or have brown spots that quickly rot. 
• Infected portions smell musty and become soft and mushy.

Impact

• Bud rot affects the plant's buds and makes them unusable
• Grows rapidly if not controlled by conditions.

Solution

• Remove the infected parts and discard them immediately. 
• Make sure you use clean tools so the spores do not spread when you prune the plants.
• You should also control the environment. Remember, these pathogens love humidity, so make sure the humidity doesn't increase above 50%, especially during the flowering stage. Use fans to increase the ventilation. 
• Last but not least, you can apply fungicides to prevent fungal diseases; however, steer clear of them when the plant is in the flowering stage. 

How to Prevent Pest Problems in Hydroponic Systems

It's easier and less labor-intensive to prevent pests and pathogens in the hydroponic system than treating infestation and infection. Use these preventive strategies to create a desirable growing environment. 

• Maintain Cleanliness

Make sure you clean and sterilize the tools and equipment of the system often. Pick up any plant debris, algae, or stagnant water in the growing environment to prevent bugs and diseases from breeding. To eliminate harmful microorganisms in the nutrient solution, use a UV sterilizer in the reservoir.

• Use Barriers

Put insect screens on your vents, intakes, and openings to keep pests out of your growing space. Next, close any cracks or gaps to prevent external threats. You can also reflect more light in your grow space using Mylar and keep some pests at bay. 

• Encourage Beneficial Organisms

If possible, introduce natural predators such as ladybugs, predatory mites, or parasitic wasps. 

• Monitor Regularly

Take a daily look at the plants for any signs of pests and diseases. Always keep track of the pH and EC to ensure the plants don't get stressed as stressed plants are susceptible to diseases. 

Summary: Common Problems in Growing Hydroponic Cannabis And How To Fix Them

By understanding and addressing these common challenges, you'll cultivate healthier, more robust cannabis plants. Remember, patience and consistent observation are key. Embrace the learning process, and soon, you'll be reaping, literally, the rewards of a thriving hydroponic garden.

Along the way, you'll also develop a deep understanding of your plants' needs and preferences. You'll learn to recognize subtle signs of distress and respond accordingly. Essentially, these techniques will help you become a better grower than you already are.