African Milk Tree with Soil pH Imbalance? Rare but Treatable
Euphorbia trigona
Soil pH imbalance occurs when soil becomes too acidic (low pH < 6.0) or too alkaline (high pH > 7.5), preventing plants from absorbing essential nutrients. The ideal pH range for most plants is 6.5-7.5. When pH is outside this range, nutrients become chemically locked in the soil, leading to deficiency symptoms even when nutrients are present.
ð Symptoms
- âĒ Yellowing of older leaves with low pH (acidic soil)
- âĒ Interveinal chlorosis on young leaves with high pH (alkaline soil)
- âĒ Stunted or slow growth
- âĒ Brown spots or tips on leaves
- âĒ Curled, twisted, or withered leaves
- âĒ Purple or red cast on leaves in cool weather (phosphorus tie-up)
- âĒ Poor root development
- âĒ Reduced flowering and fruiting
- âĒ Moss growth on soil surface (acidic conditions)
â Possible Causes
- â Natural soil composition (sandy, peaty, or chalky soils)
- â Use of hard water for irrigation (increases alkalinity)
- â Over-application of lime or wood ash
- â Excessive use of acidifying fertilizers
- â Heavy rainfall leaching nutrients (causes acidity)
- â Decomposing organic matter affecting pH balance
- â Geographic location with naturally acidic or alkaline soil
ð Treatment
Quick Fixes
Step 1
Test soil pH immediately
Step 2
For acidic soil: Apply agricultural lime at recommended rate (typically 5-10 lbs per 100 sq ft)
Step 3
For alkaline soil: Apply aluminum sulfate (1-2 lbs per 100 sq ft for faster action than elemental sulfur)
Step 4
Water deeply immediately after application
Step 5
Retest pH after 2-3 weeks
Step 6
Apply foliar fertilizer to address immediate nutrient deficiencies
Step 7
Repeat amendment at half-rate if pH still not in range
Organic Treatment
Step 1
Test soil pH to determine if acidic (<6.5) or alkaline (>7.5)
Step 2
For acidic soil: Mix 2-3 tablespoons ground limestone per gallon of soil
Step 3
For alkaline soil: Mix 1-2 tablespoons elemental sulfur per gallon of soil
Step 4
Add 2 inches of compost to buffer pH and improve soil structure
Step 5
Water thoroughly to help amendments penetrate soil
Step 6
Retest pH after 4-6 weeks
Step 7
If needed, repeat with half the original amendment dose
Step 8
Maintain with monthly compost top-dressing
ðĄïļ Prevention
- â Test soil pH regularly (every 6-12 months) using a reliable pH meter
- â Use filtered or rainwater instead of hard tap water
- â Choose plants suited to your natural soil pH
- â Apply amendments gradually in small doses
- â Monitor water quality and adjust irrigation practices
- â Maintain proper drainage to prevent nutrient leaching
- â Add organic matter to buffer pH fluctuations
ðą Care Guide: African Milk Tree
ð§ How to Water
Water only when soil is completely dry, typically every 3-4 weeks. Reduce watering in winter. Wrinkled leaves indicate thirst. Yellowing or browning may signal overwatering and root rot.
âïļ Lighting
Prefers bright indirect light to direct sunlight. Can tolerate some direct morning or afternoon sun. Avoid harsh midday sun which may cause scorching. Also adapts to medium light conditions.
ðŠī Ideal Soil
Use well-draining sandy or cactus mix. A 2:1:1 blend of cactus soil, perlite, and coarse sand works well. Good drainage is essential to prevent root rot.