Bulb rot usually begins low, down in the soil, where it frequently goes undetected. Last fall, I was diagnosing a client's tulips that had rotted, which upon examination, turned out to be due to soggy clay soil and overwatering. Healthy bulbs can rot and disintegrate into mush within just a few weeks if conditions are bad enough. Mushy bases and rotten odors are early signs to be aware of, and quick action and prevention are important.
Soil & Drainage Issues
- Clay soils retain 40% more water than sandy soils
- Lack of organic matter creates compaction
- Low spots in gardens collect standing water
- Hardpan layers 12" down block drainage
Watering Mistakes
- Watering daily before roots develop
- Using sprinklers instead of drip lines
- Ignoring rainfall when irrigating
- Overhead watering in humid climates
Defective bulbs encourage rot to enter through the injury points. Always check for softened spots or mold on bulbs before planting. For instance, a gardener in New York lost 50% of her daffodil flowers after planting one infected bulb. If you have any uncertainty about the quality of a bulb, isolate it in a 10% bleach solution in case it is in good health. After 10 minutes in the bleach solution, you should plant the bulb.
Tool Sanitation
- Disinfect tools with 70% alcohol
- Replace wooden stakes yearly
- Use separate trowels for sick/healthy plants
- Clean pots with hydrogen peroxide
Organic Treatments
- Drench soil with chamomile tea (antifungal)
- Dust bulbs with cinnamon pre-planting
- Apply neem oil to infected areas
- Use biofungicides containing Bacillus subtilis
Do not use fresh manure because it will burn the bulb and present diseases. A Wisconsin farmer turned to aged compost and reduced rot rates by 80%. For clay soils, try planting bulbs on slopes or berms. Even 6 inches of elevation will improve drainage significantly.
Read the full article: 7 Essential Tips to Plant Bulbs This Fall
