Cucumbers Falling Off: Pollination and Stress
Cucumbers falling off while small usually trace back to poor pollination or stress on the vine. The University of Maryland Extension says it takes 8 to 12 bee visits per flower to form a straight, full size fruit. It adds that poor set is common with low bee activity.
The short answer
Small cucumbers drop when female flowers are not fully pollinated or when heat, drought or shade stress the plant. Draw bees in, remove row covers once flowers open and give about one inch of water a week. Expect male flowers first.
Why do cucumbers fall off the vine?
The University of Minnesota Extension says cucumber plants have separate male and female flowers and an insect must carry pollen between them. Bees are common pollinators, and Minnesota lists poor pollination as a cause of poor fruit set. NC State Extension adds that poor pollination may lead to misshapen fruit. For bees in a mixed garden, read what roles do bees play in outdoor cannabis.
Why are there only male flowers early?
Maryland Extension says standard cucumbers produce their first 10 to 20 flowers as males, and 10 to 20 males for every female after that. Male flowers appear first, per Minnesota, so early drops of male blooms are normal. Gynoecious types carry mostly female flowers and come with standard seed for pollen, while parthenocarpic types set fruit without pollination.
How does stress affect fruit set?
Maryland Extension lists dry or wet soil for long periods, very high or low temperatures, excessive shade, excess nitrogen and hot, dry winds as causes of poor fruit set. It notes that high temperatures, low sunlight, high nitrogen and close spacing favor male flowers. Minnesota says cucumbers need about one inch of water a week. NC State adds that regular harvest spurs more fruit. For more on plant stress, see the effects of environmental stresses on weed plants.
Cucumber fruit set basics
| Factor | Target | Source |
|---|---|---|
| Bee visits | 8 to 12 per flower | Maryland Extension |
| Early flowers | First 10 to 20 are male | Maryland Extension |
| Water | About 1 inch a week | Minnesota Extension |
| Row covers | Off once flowering begins | Minnesota Extension |
| Sun | 6 or more hours | Maryland Extension |
Sources: University of Minnesota Extension, University of Maryland Extension, NC State Extension.
How to: step by step
- Check whether your variety is standard, gynoecious or parthenocarpic.
- Remove row covers when flowering begins.
- Plant flowers nearby to bring in bees. See companion plants when growing marijuana for ideas.
- Plant in a spot with 6 or more hours of sun.
- Give about one inch of water a week.
- Harvest often to spur more fruit.
Troubleshooting
Tiny fruit shrivels and drops: the flower likely missed enough bee visits.
Lots of flowers, no fruit: these may be male flowers, so look for tiny fruit below female blooms.
Crooked fruit: NC State links misshapen fruit to poor pollination.
Beetles on vines: see cucumber beetles on cannabis for signs to watch.
Help your vines set fruit
Bees, water and steady conditions turn flowers to cucumbers. Kind Seed Co shares more garden notes for growers who raise vegetables and cannabis side by side.
Sources
- Growing cucumbers in home gardens, University of Minnesota Extension
- Cucumbers, University of Maryland Extension
- Poor blossom and fruit set of vegetables, University of Maryland Extension
- Cucumis sativus (cucumber), NC State Extension Gardener Plant Toolbox
FAQ
Do cucumbers need bees?
Standard types do. Minnesota Extension says an insect must carry pollen, and bees are common pollinators. Parthenocarpic types set fruit without it.
Why are my cucumbers misshapen?
NC State Extension says poor pollination may lead to misshapen fruit.
Why are there only male flowers early?
Maryland Extension says the first 10 to 20 flowers on standard types are male.
Do row covers affect pollination?
Minnesota Extension says row covers shut out the beneficial insects needed for pollination, so take them off once flowering begins unless the variety is seedless.
How much water do cucumbers need?
Minnesota Extension says about one inch a week.
