Jade Plant Prone to Pythium Root Rot: How to Protect
Crassula ovata
Pythium root rot is a serious fungal disease caused by various Pythium species including P. aphanidermatum, P. ultimum, and P. irregulare. These water molds are present in practically all cultivated soils and attack plant roots under wet conditions, causing rapid wet rot that can extend into the stem. The disease is favored by poor drainage, overwatering, and specific temperatures depending on the species.
ð Symptoms
- âĒ Dark brown to black wet rot of roots
- âĒ Roots soften and disintegrate easily
- âĒ Outer cortical tissue pulls off easily exposing vascular strand
- âĒ Brown and dead root tips
- âĒ Stunted growth and undersized plants
- âĒ Wilting during the day with recovery at night
- âĒ Progressive yellowing of leaves
- âĒ Plant collapse and death in severe cases
- âĒ Crown may turn brown-black with soft rot
â Possible Causes
- â Infection by Pythium species (P. aphanidermatum, P. ultimum, P. irregulare)
- â Soil moisture above 70% of available water capacity
- â Poor drainage and waterlogged substrate
- â Overwatering or too frequent irrigation
- â Favorable temperatures (above 77°F for P. aphanidermatum, lower temperatures for other species)
- â Use of non-pasteurized or contaminated substrate
- â Contaminated pots, tools, and surfaces
- â Spread through contaminated irrigation water
- â Transmission by fungus gnats and shore flies
- â Excessive levels of ammonium or soluble salts in substrate
ð Treatment
Quick Fixes
Step 1
Step 2
Step 3
Step 4
Step 5
Step 6
Organic Treatment
Step 1
Step 2
Step 3
Step 4
Step 5
Step 6
Step 7
ðĄïļ Prevention
- â Use well-drained substrate with adequate air pore space
- â Pasteurize or solarize substrate before use (140°F for 30 min)
- â Avoid overwatering and maintain good water management
- â Ensure proper drainage in pots and beds
- â Inspect roots of new plant material before introducing to collection
- â Keep pots, tools, and growing areas clean and disinfected
- â Keep irrigation hose ends elevated off the ground
- â Avoid excessive levels of ammonium and soluble salts in substrate
- â Use substrate with at least 20% composted pine bark
- â Control fungus gnats that can transmit spores
ðą Care Guide: Jade Plant
ð§ How to Water
Allow the soil to dry completely between waterings - wait until it feels bone dry. Water more frequently in spring and summer during active growth, and reduce watering significantly in fall and winter. Avoid letting the plant sit in standing water to prevent root rot.
âïļ Lighting
Place in bright, indirect light near a south or west-facing window. Can tolerate some direct morning sun, but avoid intense afternoon sunlight which can scorch the leaves. The more light it receives, the more compact and vibrant the growth.
ðŠī Ideal Soil
Use a well-draining succulent or cactus mix. Create your own by mixing regular potting soil with perlite or coarse sand in a 1:1 ratio. The soil should never retain moisture for long periods. Slightly acidic pH (6.0-7.0) is ideal.