Root and soil problems are among the most serious and often overlooked issues in ornamental plants. While leaves may show signs of illness, the origin of the problem is frequently hidden beneath the surface. In this article, we’ll explore the main causes of root problems, how to recognize symptoms early, what to do in each case, and how to maintain a healthy soil environment for your indoor plants.
1. Root Rot
Cause: Excessive moisture, poor drainage, and the presence of fungi (e.g., Pythium, Rhizoctonia, Fusarium) are the main causes.
Symptoms:
- Wilting even with moist soil.
- Yellowing or drooping leaves.
- Foul odor from the soil.
- Roots appear dark, soft, and mushy.
Treatment:
- Remove the plant from the pot and wash the roots.
- Cut off all rotten roots with sterile scissors.
- Let the roots dry for a few hours.
- Repot in a clean pot with new, well-draining soil.
- Apply cinnamon or Trichoderma-based fungicide to prevent recurrence.
2. Soil Compaction
Cause: Over time, organic matter breaks down and compresses, reducing aeration and water infiltration.
Symptoms:
- Water pools on the surface and takes time to absorb.
- Roots cannot “breathe” properly.
- Slow or stagnant growth.
Treatment:
- Loosen the topsoil carefully.
- Repot using a lighter, more aerated mix (e.g., add perlite, vermiculite, or bark).
- Consider mixing coarse sand or coconut fiber to improve structure.
3. Accumulation of Salts and Fertilizers
Cause: Frequent use of chemical fertilizers and watering with hard water.
Symptoms:
- White crust on the soil surface or pot edges.
- Leaf tips turning brown.
- Plant becomes more sensitive to pests and diseases.
Treatment:
- Rinse the soil with abundant water (leaching) once every 2–3 months.
- Repot every 1–2 years, removing part of the old substrate.
- Use filtered or rainwater if possible.
4. Soil pH Imbalance
Cause: Inappropriate substrate for the plant species or accumulation of organic matter.
Symptoms:
- Nutrient deficiencies even with fertilization.
- Yellowing between leaf veins (chlorosis).
- Poor root development.
Treatment:
- Test the pH with a simple soil test kit.
- For acid-loving plants (e.g., azaleas, gardenias), lower the pH with pine bark or coffee grounds.
- For plants that prefer neutral to alkaline soil, raise the pH with lime.
5. Poor Drainage
Cause: Pots without drainage holes or substrates that retain too much water.
Symptoms:
- Waterlogged soil.
- Smell of rot.
- High incidence of fungi and root rot.
Treatment:
- Always use pots with drainage holes.
- Place a layer of gravel or expanded clay at the bottom of the pot.
- Use appropriate substrates for the type of plant (succulents, for example, need sandy, quick-draining soil).
6. Nutrient-Poor Soil
Cause: Substrate depletion after months or years without renewal.
Symptoms:
- Pale or small leaves.
- Little or no growth.
- Weak flowering.
Treatment:
- Replace part or all of the old substrate.
- Enrich with organic matter (compost, earthworm humus).
- Begin regular fertilization using organic or mineral products appropriate to the species.
How to Identify Root Problems Without Uprooting the Plant
- Observe the base of the plant: if the lower stem is dark or mushy, it’s a warning sign.
- Smell the soil: bad odor indicates anaerobic decomposition.
- Use a moisture meter to assess if the substrate stays constantly wet.
- If possible, examine through transparent pots or gently remove the root ball.
Ideal Soil Mixes for Indoor Plants
- General-purpose plants (peace lily, pothos, philodendron):
- 50% organic soil + 25% perlite + 25% coconut fiber or pine bark.
- Succulents and cacti:
- 40% coarse sand + 40% composted soil + 20% gravel or pumice.
- Ferns and orchids:
- 40% pine bark + 30% coconut fiber + 30% sphagnum moss.
Natural Soil Additives
- Cinnamon powder:
- Antifungal and antimicrobial.
- Use when repotting or treating root wounds.
- Charcoal powder:
- Absorbs toxins and helps with drainage.
- Mix into substrate for orchids and ferns.
- Crushed eggshells:
- Slowly release calcium.
- Also help raise pH slightly.
- Worm castings:
- Rich in nutrients and beneficial microorganisms.
- Strengthens plant immunity.
Maintenance Tips
- Repot every 12–24 months.
- Remove 2–3 cm of surface soil every 6 months and replace with fresh soil.
- Rotate pots to promote even root growth.
- Avoid excess water, even in hot seasons.
A healthy plant begins with healthy roots, and good roots require suitable, balanced soil. Paying attention to the substrate’s structure, composition, and drainage is just as important as watering or fertilizing. By understanding what’s happening below the surface, you’ll be able to prevent serious problems and keep your ornamental plants strong and beautiful. Root care is an invisible but essential part of plant health.