Why Haven't My Onions Developed Healthy Bulbs?

Are the bulbs small and soft and the roots pinkish or shriveled?

Have the bulbs rotted in the ground?

Do the bulbs have gray, water-soaked outer layers?

Do the bulbs have bleached, soft patches on them?

Do the bulbs have thick necks that do not cure well?

Do the bulbs have dark green or black, concentrically ringed spots on them?

If roots and bulbs are pinkish, the plant has Pink root disease. Roots infected with this fungal disease shrivel and die. Destroy infected plants. Prevent problems by ensuring good drainage and adding ample organic matter to the soil. ’Crystal Wax Pickling’, ‘Early White Supreme', ‘Hybrid Big Mac’ and ‘JK Special’ are resistant cultivars.

White rot disease causes onion bulbs to rot. Bulbs may be covered with a white fluffy growth. Destroy infected plants; don’t compost them. Prevent problems by providing good drainage and presoaking seeds in compost tea.

Heat or cold injury cause bulbs to have gray, water-soaked outer layers. If temperatures are above 85°F, protect plants with thick straw mulch and keep the soil moist. Protect overwintering onions with mulch, or dig and store just above freezing.

Sunscald often damages curing onion bulbs. Protect onions from direct sun while curing, especially in hot weather. White cultivars are especially sensitive to sunscald.

These symptoms usually indicate either Potassium deficiency or seed stalk formation. Confirm deficiency with a soil test and amend the soil as needed before planting. Onions form seed stalks after any dormant period. Improperly stored sets or cultivars not suited to the day length in your area may go to seed before forming bulbs. Fluctuating temperatures or drying and wetting of soil may cause seed stalk formation.

These symptoms usually indicate fungal disease - Onion smudge. This disease usually appears near the harvest or in storage. Destroy infected bulbs. Tolerant cultivars are ‘Downings Yellow Globe’, ‘Early Yellow Globe' and ‘Southport Red Globe'.

If the bulbs have sunken, dry, brown-black areas around the neck then the cause is a fungal disease - Neck rot. This disease usually appears near the harvest or in storage. Destroy infected bulbs. To prevent problems, cut back on watering as onions begin to mature, especially near harvest. Be careful not to injure bulbs while weeding or harvesting.