When you overwater your onions, those leaves and bulbs signal you'll need to help them out. I had once lost 30 plants in rotten soil before noticing the yellow, limp foliage within a day of rain. Stick your finger in the soil before you water - this time I bought a $7 meter that saved my next crop. Remember, onions enjoy dampness, but not soaking wet, as roots will suffocate.
Above Ground Signs
- Yellow leaf tips progressing downward in 48 hours
- Leaves softer than properly watered plants
- Stunted growth compared to neighbors
Below Ground Damage
- White mold on roots visible when gently lifted
- Bulb base feels like overripe avocado
- Foul sulfur smell from decaying layers
Recovery Tactics
- Stop watering for 7-10 days
- Mix 1 inch (2.5 cm) sand into topsoil
- Apply copper fungicide to prevent rot spread
Rescue efforts commence below ground. Carefully pull a bulb to see roots, healthy roots look like white spider webs. If you find a rotted root - you need to act. Right now, I am mixing 50% perlite into the soil for container onions. I adjust my watering weekly - as the necks soften before harvest, the bulbs will need less moisture.
Avoid repeats using smart irrigation. My drip irrigation system puts down 1 inch (2.5 cm) of water weekly in the root zone and not on the foliage. Heavy clay soil takes 3 inches (7.6 cm) of compost annually. Use a gauge to measure rainfall and subtract it from your watering budget.
Read the full article: When to Plant Onions: Expert Guide for Perfect Bulbs
