Blossom Drop

Why do the flowers keep falling off your tomato, squash, melon, bean plants, and citrus trees?

Blossom drop on tomatoes (Kate Russell)

This condition is called blossom drop. Blossom drop can be caused by several factors, most of which are perfectly normal. Others, not so much. Generally speaking, plants kick unfertilized flowers to the proverbial curb. Here are some species-specific causes of blossom drop. 


Citrus June drop

Most citrus trees produce far more flowers than they could bring to maturity. When the tree decides it has enough fertilized flowers, usually around June, they discard excess blossoms, which is perfectly normal.


Cucurbit blossom drop

The first flowers on your melons, winter or summer squash, and cucumber are generally male. These male flowers drop naturally after a brief appearance. If female blossoms start falling off, it is usually because of thrips damage, poor soil fertility, environmental factors, or inadequate pollination. Adding insectary plants, such as yarrow and bee balm, to your landscape will attract more bees and other pollinators. You can also allow onions, carrots, and fennel to go to seed. These plants will all provide pollen and nectar to beneficial insects that should increase pollination rates. If that doesn’t work, you can always try hand-pollinating.


Bean blossom drop

Temperatures over 90°F will cause bean flowers to abort. Blossoms drop also occurs with insufficient irrigation and poor air quality due to smog or fires. If you know your summer temperatures will exceed that threshold, try planting beans earlier or later in the growing season.


Tomato and pepper blossom drop

Tomatoes and peppers often drop their blossoms when environmental conditions are unfavorable. These conditions might mean any of the following:

• Temperature extremes
• Insufficient irrigation
• Hot, dry winds
• Excessive nitrogen
• Potassium, phosphorus, or nitrogen deficiencies
• Overcrowding
• Tarnished plant bug feeding
• Verticillium wilt
• Fusarium wilt

How to reduce blossom drop

Use these handy tips to reduce blossom drop in your garden:

• Maintain good soil fertility.
• Irrigate regularly.
• Position plants far enough apart that pollinators can find flowers.
• Protect plants from strong, hot winds.

The good news about blossom drop

When environmental conditions cause blossom drop, most plants will produce a second batch of blossoms.