Aroids are incredibly rewarding plants - but also sensitive to subtle shifts in their environment. For collectors and growers using soilless or semi-hydro substrates, mastering EC (electrical conductivity) and understanding how it relates to humidity and root health is key to unlocking the marvellous growth rate coco soilless mixes can provide.
Here’s how to stay in control - and how to help your aroids bounce back when things go wrong.
- Understand EC - And Why It Matters for Aroids
EC measures the total dissolved salts in your nutrient solution or substrate. Aroids are not heavy feeders, especially when grown indoors or in lower light. In most setups, they prefer a moderate to low EC range, typically between 1.2 and 1.8 mS/cm.
If EC is too high, salts can build up in the root zone, leading to leaf burn, stalled growth, or root tip dieback - especially in young or recently repotted plants.
- Always Check EC Runoff
Even if you’re feeding at the right strength, excess salts can accumulate over time - especially in mixes with coco, bark, or LECA. That’s why checking runoff EC is essential.
How to do it:
Water your plant until a small amount runs out the bottom. Use an EC meter to test that runoff. If the EC is significantly higher than what you’re feeding in (e.g. feed = 1.0, runoff = 2.5), it’s time to flush the pot with clean, pH-balanced water until the EC comes down.
Regular monitoring prevents silent salt buildup and keeps the root zone safe and active.Â
When you flush your aroid’s pot to remove excess salts, you’re not just washing out the bad - you're also clearing out the good. Coco- and bark-based mixes don’t hold nutrients the way soil does, so after a heavy flush, the substrate is essentially reset to zero.
That’s why it’s crucial to feed again immediately after flushing, using a gentle, balanced nutrient solution at the appropriate EC (usually around 1.2–1.8 for recovery).
Failing to refeed can leave your plant in a nutrient void, delaying recovery or causing deficiencies and if left for too long can lead to root rot - especially in active growers like Philodendron, Anthurium, or Monstera.
The goal: flush out the excess, then reintroduce a clean, controlled baseline - not leave the plant starving.
- Adjust EC Based on Humidity
Humidity and EC go hand-in-hand.
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Low humidity = lower EC needed
When air is dry, aroids transpire more, pulling water (and salts) through the plant faster. High EC in low humidity can quickly cause burn. Keep EC mild — around 1.0 –1.4 in these conditions. -
High humidity = plants can handle more
In 80%+ humidity, transpiration slows, and roots can tolerate higher EC without stress. EC of 1.6–2.0 may be suitable for mature plants or fast growers in peak season.
⚠️ Struggling with Transitioning to Room Conditions?
If your aroid looks amazing in a humidity bin or grow tent but starts to decline once moved into ambient room air, EC is often the hidden culprit.
The shift from 80–90% humidity to 40–60% dramatically increases transpiration. If the plant is still being fed at a high EC suitable for high humidity, it may begin pulling in too many salts too quickly - leading to tip burn, leaf curl, or even root damage.
Solution: When transitioning to room conditions, always dial EC back - aim for the lower end of the range (around 1.2–1.4) and observe how the plant responds.
Gradual acclimation, proper airflow, and a drop in feeding strength make the move much smoother.
For many growers, this single adjustment is the difference between thriving ambient plants and constant setbacks.
- Aroids don’t need a soaked pot after transplanting
When you transplant an aroid, its root system initially occupies only a small volume near the stem. Roots grow gradually to explore the new soil, so they don’t immediately need water throughout the entire pot. Overwatering at this stage can cause low oxygen levels and increase risk of root rot.
Providing a moderate amount of water ensures moisture reaches the young roots, encouraging healthy root expansion without suffocating the plant. This careful balance supports strong root establishment and overall plant vigor.
- What to Do When a Plant is in Shock
Signs of shock after repotting or overfeeding include:
- Droopy leaves
- Sudden Yellowing
- Loss of root mass
- "Stuck Growth"
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Steps to recover:
âś… Flush the substrate with clean, pH-balanced water (no nutrients) to remove excess salts.
âś… Reduce light for a few days - too much can stress a compromised plant.
âś… Maintain high humidity - use a dome, humidifier, or keep it grouped with other plants.
In most cases, aroids bounce back well once root pressure returns - especially in a breathable, airy mix like HiGrow’s Aroid AirLite™, Aroid Classic™ or Aroid AquaMax
Final Tip: Start Light, Build Up
With aroids, it’s always better to underfeed than overfeed. Healthy roots can grow into nutrients, but burned roots can’t recover as easily. Monitor, adjust, and keep conditions steady - and your plants will reward you with lush foliage and active growth.