Why do melon plants flower without producing fruit?
Written by
Michael Sullivan
Reviewed by
Prof. Martin Thorne, Ph.D.Dropping melon flowers that don't set into fruit is a major pain for many gardeners. This problem, known as flower abortion, can often be solved by addressing environmental or care issues rather than assuming a defect on the part of your melon plants. I've dealt with this while freezing in spring and dying of heat exhaustion at the same time! It affects both male and female flowers, but knowing the causes leads to the cure. Your harvest depends on it.
Pollination Failure
- Lack of bees due to pesticide use
- Rainy weather preventing bee activity
- Isolated plants with no pollen sources
- High humidity making pollen sticky
Temperature Extremes
- Nights below 50°F halt pollen function
- Days above 95°F desiccate flowers
- Sudden temperature swings shock plants
- Soil temperature fluctuations affect roots
Nutrient Imbalances
- Excess nitrogen promotes vine over flowers
- Potassium deficiency weakens flower retention
- Calcium shortage causes blossom-end drop
- Micronutrient gaps in boron and magnesium
Hand-pollination. Actually, pollinate female flowers with pollen from male flowers, either with a small brush or some other means. It helps if this is done in the early morning when the flowers are completely open. I usually mark the female flowers that I want to pollinate beforehand with ribbons. Do this every other day during the period when the flowers are open. The success rate is typically above 90%.
Temperature control protects blooms. On cold nights, cover plants with a frost cloth to protect them from frost damage. In a heatwave, provide afternoon shade. I have some portable frames made of chicken wire and otherwise rigged up, over which I throw a shade cloth. Keep your soil sufficiently moist, and it goes a long way toward keeping the rootstock temperate. Such flowers stand the season's change better.
Modify feeding practices to achieve a balanced nutrient profile in the soil. Before fertilizing, get a soil test. After establishing vines, reduce nitrogen levels. When flowering begins, increase potassium levels. I use foliar sprays of calcium every week to strengthen the flower stem and prevent wilting due to mechanical damage.
Consistent watering helps keep flowers on the plants. Conserve soil moisture but don't saturate. Drought forces flowers to drop immediately. I water with drip irrigation on timers. If I fail to check my soil 4" down every day, my plants wilt, but I know their feet are well cared for. I don't hear anything since this splashes pollen off the plants.
Read the full article: How to Grow Melons: Expert Tips for Success
