If you are new to growing cucumbers and are having problems with your baby cucumbers dying on the vine, do not despair as there is a simple explanation. I am sure that by now you have seen loads of horror stories and supposed experts saying that your plants are diseased or underwatered etc. Issues with nutrition and water may well be a problem but at this stage, it is unlikely so read on to see why your baby cucumbers are dying on the vine.
Why Are My Baby Cucumbers Dying on the Vine?
The truth is that in most cases your baby cucumbers are dying on the vine due to not having been pollinated. The small swelling behind the female flower is called an ovary and is not yet an actual cucumber. The female flower requires pollination from the male flower for the ovaries to swell, grow, and become cucumbers. If pollination does not happen, the small swelling that appears to be a baby cucumber will go yellow/ brown and shrivel and die. If this sounds like the problem that you are having, continue reading and we will tell you how we can fix it.
What is Pollination?
Pollination is nature’s way of procreation in plants and occurs when pollen is transferred from the male part of a plant to the female plant, therefore, enabling fertilisation which begins the production of seeds. In nature, pollination is usually achieved with the help of insects and animals or by the wind. Insects such as bees are hugely important for pollination as they will transfer pollen from flower to flower in their quest for nectar. It is quite feasible that your issue with pollination is down to bees or lack of to be more precise. Worldwide the number of bees is decreasing and if you are in an area with a lack of bees and they are not getting to your cucumber flowers to help with pollination, you may have to engage in hand pollination to rectify your problem.
Hand pollination is exactly that, pollinating your female flowers by hand. It may sound difficult and over-complicated, but we assure you that it is extremely easy and can be done in just a few minutes and without any specialist tools or equipment. By pollinating your female flowers manually, you are ensuring that your female flowers are fertilised which means that the female ovaries will begin to swell and turn into cucumbers.
Before you start transferring random pollen from flowers, you will need to recognise which flower is male and which flowers are female.
How to Identify Male and Female Cucumber Flowers
A cucumber plant will grow both male and female flowers and although at a glance they appear the same, there are differences which make them easy to tell apart.
Male Cucumber Flowers
The male cucumber flowers are easily identified as they will usually grow in small groups of 2 or 3 and they have no swelling (ovary) behind the flower.
Female Cucumber Flowers
Female cucumber flowers will grow individually and behind the flower, there will be a small growth around 1 inch long (known as an ovary) which once pollinated will become your cucumber.
Why Aren’t My Cucumbers Being Pollinated?
Cucumber plants may fail to get pollinated for several reasons, which can affect their ability to produce fruit. Here are 9 reasons why your cucumbers are not being pollinated.
1 – Lack of Pollinators
If there are not enough bees or other pollinating insects in the area, pollination can be poor. This can be due to a decline in pollinator populations, the use of pesticides, or environmental changes that affect habitat.
2 – Closed Environment
Growing cucumbers in a closed greenhouse or under row covers without providing access for pollinators can prevent these essential insects from reaching the flowers.
3 – Poor Weather Conditions
Pollinators are less active during cold, rainy, or extremely windy weather. Extended periods of such weather can significantly reduce pollination opportunities.
4 – Time of Day
Pollinators are most active during mid-morning to early afternoon. If cucumber flowers aren’t open during these peak times, or if gardeners are inadvertently disrupting pollinators during these hours, pollination may not occur.
5 – Unattractive Environment
A lack of flowering plants that attract pollinators to the garden can result in a low presence of bees and other insects to pollinate the cucumber plants.
6 – Overuse of Insecticides
The use of insecticides can kill or repel pollinators, reducing the chances of pollination.
7 – High-Stress Conditions
Plants that are under stress from lack of water, poor soil conditions, or disease may not produce as many flowers, or the flowers may not be viable for pollination.
8 – Varietal Issues
Some cucumber varieties are gynoecious (having only female flowers) and require a pollinator variety to be planted nearby. If a gardener plants only a gynoecious variety without a male flower source, pollination will not occur.
9 – Nighttime Lighting
Artificial lighting at night can disrupt the natural behaviour of pollinators, leading to reduced pollination. It is a good idea to attract pollinators by planting a variety of flowering plants, avoiding the use of harmful chemicals, and ensuring that your greenhouse is open to pollinators during key times of the day. Hand pollination is also an option if natural pollination is not sufficient.
How to Hand Pollinate Cucumbers
As we have mentioned, hand-pollinating your cucumbers is easy and can be done in no time at all, but you will want to get started straight away before all your cucumber ovaries have been aborted and died.
Step 1 – Find a Male Flower
The first thing you will need to do is find a male flower to use. These are easily identified by having no ovary attached to the flower and they are usually found in small clumps growing at the same location.
Step 2 – Get to the Pollen
Once you have found your male flower, you should remove all the petals exposing the central nodule (stamen) which is where the male pollen is located.
Step 3 – Pollinate your Female Flowers
Take the stamen that you have removed from the male flower and gently rub it on the central part inside the female flower. By doing this, we are transferring the pollen from the stamen of the male flower to the stigma of the female flower.
Step 4 – Mark Which Flowers have been Pollinated
Once we have hand-pollinated a flower, we like to loosely tie a piece of string around the stem to identify which flowers we have pollinated. This will help you when you check back to see if your pollination was successful.
Step 5 – Results
You should start to see growth in as little as 3 days after pollination and by day 5 the swelling (ovary) should have more than doubled in size and the female flower will have wilted and died.
When you see that the cucumber has started to grow, you will be sure that your hand pollination was successful.
Although you may have been super worried about your baby cucumbers dying on the vine, the issue is extremely likely to be with pollination. The female flowers will naturally abort and die off if they are not pollinated immediately. If you are experiencing this issue, the best way to deal with it immediately is by hand but if you want to grow cucumbers next year, you will need to address the reason that pollinators aren’t visiting your cucumbers in the first place. Hand pollination is so easy that a child could do it and it will help you ensure that you get a good crop year after year even if there are no bees around to help you.
Garden Doctor Tips
“Remove any wilting or dead female flowers to conserve the plant’s energy for those cucumbers that have begun swelling!”
“If marking your female flowers with string, do not tie it too tight as it may damage your cucumber plant when it is growing!”
“Use a cotton bud or soft paintbrush to transfer the pollen from one flower to another so you do not have to remove the male flower!”
“Female flowers only open for 1 day so you will have to ensure that you check back each day and pollinate those that have opened!”
Frequently Asked Questions
How do you pollinate without bees?
Without bees to pollinate your flowers, you will need to hand pollinate. Hand pollinating is the method whereby you transfer the pollen from a male flower to a female flower using a cotton bud or small paintbrush.
How do you do hand pollination?
Distinguish which flower is male and which is female and then using a small paintbrush or cotton bud, transfer pollen from the centre of the male flower to the centre of the female flower.
Why are my baby cucumbers drying up?
Baby cucumbers dry up because they have not been pollinated. The small swelling behind the female flower is known as an ovary and once it has been pollinated, fertilisation will take place and it will grow into a cucumber. If pollination does not take place, the female flower along with the ovary will abort and die.
Trevor Wright is not just a seasoned horticulturist; he’s the esteemed Garden Doctor. With a BSc in Horticulture and years of hands-on experience in the soil, Trevor has become a trusted mentor for all things gardening. As the founder of Garden Doctor, he’s committed to clarifying the intricacies of gardening, offering straightforward advice that’s rooted in years of practice. His writing is a garden of how-tos, savvy insights, and comprehensive guides that enable individuals to nurture and grow their garden dreams. When he’s not knee-deep in garden beds, Trevor is at his keyboard passing on his green-thumbed wisdom to budding gardeners, ensuring that the legacy of sustainable and joyful gardening blossoms far and wide.