Aloe vera root rot: save the plant

Root rot is the disease number one of aloe vera and the leading cause of death of the species in indoor culture. Almost always due to overwatering. Good news: if you intervene in time, rescue is possible in vast majority of cases thanks to fleshy rhizome that can produce new roots.

Recognize the rot

Three combined signs confirm root rot:

Soft floppy leaves. Plant loses characteristic turgidity. Leaves become flexible instead of rigid.

Brown leaves at base (stem side). Rot rises from roots to rhizome then leaves. Affected leaves become translucent and soft.

Soaked substrate, sometimes with smelly odor (rotten eggs). Sometimes gnats (fungus gnats) proliferating.

Confirmation: remove plant from pot. Healthy roots = white or cream, firm. Rotted roots = brown, soft, sometimes black, sometimes smelly.

Why it happens

Three often-combined conditions:

Excess water: too frequent watering, or cachepot with stagnant water. Roots lack oxygen and ferment.

Unsuitable substrate: classic potting soil alone, too dense, retains moisture. Suitable for green plants but not succulents.

Opportunistic fungi: Pythium, Phytophthora, Fusarium. Naturally present in all substrates. Activated as soon as excess water and anaerobic conditions.

4-step rescue

Step 1, remove and examine

Remove aloe vera from pot. Remove all substrate by hand, without pulling on roots.

Rinse root ball with lukewarm water to flush contaminated substrate and see roots well.

Examine roots:

• Healthy: white or cream, firm to touch
• Dead: brown or black, soft, sometimes hollow

Examine rhizome (central zone where leaves emerge). Should be firm and pale green. If soft, brown, smelly, rot has reached center.

Step 2, cut cleanly

Disinfect scissors or knife with 70° alcohol.

Cut all dead roots until reaching healthy tissue. If root partially dead, cut with 1 cm margin in healthy.

If rhizome partially affected, cut rotten zone. If over 80% rhizome soft, rescue difficult but try anyway.

Also cut brown leaves at base at rhizome level. Sprinkle all cuts with cinnamon powder (natural antifungal).

Step 3, dry 24-48 hours

Let plant in open air for 24-48 hours, roots exposed, no pot. Critical step: cuts must heal (protective callus) before contact with new substrate.

Meanwhile, prepare:

• New pot or old pot disinfected with 10% diluted bleach then well rinsed
• Smaller pot than previous (less roots to fit)
• Mandatory drainage holes
• Fresh very draining substrate: 50% cactus mix, 30% horticultural sand, 20% perlite

Step 4, repot and wait

Place plant in pot, spread remaining healthy roots. Pour dry substrate around, lightly tamping. Rhizome should sit at surface, not buried.

No watering for 14-21 days. Plant must reform roots dry. Watch:

• If rhizome stays firm: good sign
• If leaves continue softening: ongoing rot, maybe too late

First light watering after 14-21 days. Resume normal rhythm (14-21 days summer, 30-45 winter) after 1 month.

Visible recovery (new leaves) in 2-4 months.

Extreme case: largely destroyed rhizome

If over 80% rhizome rotten but at least small firm section remains:

Cut, keep only healthy section. Let dry 48 hours. Replant in tiny pot (5-7 cm) with very dry substrate. No watering for 3 weeks.

Sphagnum method (for totally destroyed roots): place rhizome on lightly moist sphagnum bed in closed pot (terrarium effect). New roots in 4-8 weeks. Then replant normally.

Success rate: 30-50% for extreme cases (vs 80-90% for early-detected rot).

Durable prevention

Mandatory finger test before EVERY watering. Substrate dry 5 cm = water. Still moist = wait.

Very draining substrate: 50% cactus mix + 30% sand + 20% perlite. Never classic potting soil alone.

Pot with holes: no exception. If closed decorative pot, keep inner pot with holes.

Cachepot emptied systematically after watering.

Winter = drastically slow watering: every 30-45 days suffices.

With these 5 rules, root rot becomes near impossible.

For other aspects, see the aloe vera complete guide or watering and soft leaves articles.