The Hidden Cause of So Much Stress: Why Are My Plants Dying in Hydroponics?

Why are my plants dying in hydroponics?

According to Mark, hydroponic farmer, “plant roots need oxygen much like we need air. When I first started, drooping leaves had me stumped. 

It wasn’t until nutrients levels showed fine that I realized stale water was the real culprit. Now I change the water every couple days, and my plants are happier and healthier for it.” 

Follow along to learn his simple tricks for avoiding common hydroponic hazards.

Key Takeaway

  • Root rot from poor water oxygenation or changing. Roots need oxygen to absorb nutrients and water, and stagnant water leads to rot.
  • Nutrient deficiency from unbalanced solutions. Hydroponics relies on nutrient solutions for all plant needs, and an imbalance in macros/micros can starve plants.
  • Environmental stress from incorrect pH levels. Hydro plants grow best in a slightly acidic range, as levels fluctuate it causes nutrient lockout or toxicity issues that weaken plants.

Root rot

Diseased roots unable to supply waterWilted leaves, drooping plantChange nutrient solution biweekly, use purified water

After years of trying different approaches in my hydroponic system, I’ve found that root rot from diseased roots is a common cause of plant wilting and death. 

The roots can no longer absorb the water and nutrients needed to keep the leaves hydrated. 

Be sure to change out the nutrient solution every two weeks to prevent bacteria and fungi growth. I also make sure to use purified water from my home reverse osmosis system.

YouTube video

Credit : Khang Starr

Inadequate root moisture

Signs of inadequate root moisture include drooping leaves and overall wilting of the plant. When checking the roots, they may appear dried out or shriveled. 

To remedy this, ensure the roots have ample access to water and nutrients by maintaining optimal water levels. I like to lift the net pots daily and gauge if they feel light or heavy.


Viruses, fungi, and bacteria found in hydroponic systems can wreak havoc on otherwise healthy plants (1). Some diseases to watch for include powdery mildew, botrytis, and pythium root rot. 

To help prevent issues, clean your system regularly and choose disease-resistant varieties when possible. 

I also add a little hydrogen peroxide to the water every few weeks as a natural disinfectant. Communication and isolation are key to disease control in a shared hydroponic system.

Lack of support

Plant TypeSupport Needed
VinesTrellis, stakes
Bushy plantsPlant cages, wires
Heavy fruit plantsTomato cages, plant ties

Providing the right structure for plants to attach to is important, especially for vining types that would otherwise sprawl on the ground. 

Take notes each season on what support methods work best for different plant varieties in your climate and space. 

In my systems, I’ve found lightweight tomato cages perfect for berry bushes and stakes the best for cucumbers to climb.

Insufficient lighting

PlantMinimum Light Needs
Leafy greens300 foot-candles
Herbs500 foot-candles
Fruiting plants1000 foot-candles

Light is the primary source of energy for photosynthesis, so skimping here can starve plants. 

Evaluate lighting levels throughout the grow space using a light meter and adjust fixtures as needed. 

Make sure to match intensities to plant requirements, like my fruiting veggies needing 1000+ foot-candles. Supplementing natural light with LED panels is a sound investment.


Why are my plants dying in hydroponics?

Maintaining a consistent moisture level is key to avoiding either extreme. Some signs of overwatered plants include mushy, darkened roots while underwatered plants wilt severely between waterings (2). 

I like to check the weight of pots daily—if light, a thorough watering is in order. Professional hydroponics growers often rely on moisture sensors for foolproof care.

Imbalanced nutrients

NutrientRoleDeficiency Symptoms
NitrogenLeaf growthYellow leaves
PhosphorusRoot/flower growthStunted growth
PotassiumOverall healthLeaf tips burn

Nutrient composition must meet the dynamic needs of plants as they grow and develop. Use a TDS meter to monitor EC levels and pH strips to check the acidity (3). 

I do monthly nutrient solution replacement and rinses to clear out any accumulated mineral deposits. Proper flushing prevents toxicity issues down the line.

Incorrect pH levels

Most hydroponically-grown plants thrive when pH is held between 5.5–6.5 (4). Values outside this range hamper the availability of nutrients already added. 

Monitor levels frequently with a quality controller or test strips. If levels fluctuate drastically, look for environmental causes before adjusting with acids or bases. 

Stable conditions yield stronger, healthier specimens.

Inadequate oxygen

Roots must respire oxygen to metabolize the array of available nutrients (5). Low dissolved oxygen stresses plants and invites root pathogens. 

Gentle air pumps or sprinklers that break the water surface create advantageous circulation in my systems. Top leeching designs also passively oxygenate without requiring fixtures or electricity.


After years of experience growing hydroponically, I’ve come to better understand how fragile that balance can be between thriving plants and ones in decline. 

However, it’s so rewarding when all the key factors are optimized – the right nutrients, moisture, lights, airflow – and you reap bountiful harvests of healthy greens. 

While challenges may arise, taking the time to methodically assess each potential issue helps get to the root of problems (no pun intended!). 

With the proper preventative care and adjustments outlined here, your hydroponic plants should have what they need to prosper.

I’d love to hear from others in comments – have you successfully solved plant issues using these tips? What further questions do you have? 

Relating experiences and troubleshooting together is so helpful for continuous learning in this hobby. Wishing you green thumbs and full nutrient trays for seasons to come!



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