Fertilizing Daffodils and Iris: Less Is Often More

If your soil is reasonably fertile, daffodils and iris need little to no fertilizer. Over-fertilizing—especially with nitrogen—can cause bulb rot and reduce blooms.

Why Restraint Is Wise

• Bulbs store their own energy; they don't need heavy feeding.
• Excess nitrogen promotes soft, disease-prone foliage and feeds bulb-rotting bacteria.
• High phosphorus can block micronutrient uptake (iron, zinc).

When and How to Fertilize (If Needed)

• Soil test first. Only amend if deficiencies show.
• If fertilizing: Use a low-nitrogen, balanced organic bulb fertilizer (e.g., 3-5-3) at half rate.
• Timing: Apply in early spring as shoots emerge, and optionally after flowering.
• Never fertilize at planting in the hole—burns roots.

Better Than Fertilizer

• Annual top-dressing with compost or leaf mold.
• Allow foliage to die back naturally—it feeds the bulb.
• Divide crowded clumps every 3–5 years.

Bottom Line

Healthy soil grows great bulbs. Fertilizer is a supplement, not a requirement.