The easiest way to start saving seeds is from fruiting vegetables grown in the greenhouse or polytunnel. Cucumbers are cross-pollinating plants, which means you need to hand-pollinate a few flowers in order to safely save their seeds. Read on to find out how to save seeds by hand pollination, so that the seeds you save will grow ‘true’ and you get the same healthy cucumbers next year.
Before you continue reading this, first read the basics of saving seeds.
You can save seeds from any open-pollinated variety, but these fall into two categories: cross-pollinating plants and self-pollinating plants.
Cucumbers are cross-pollinating which means that the plant needs both male and female flowers in order to reproduce. So, the pollen from a male flower must enter a female flower, which can be done by wind, insects or by hand. Examples are cucumbers, melons, courgettes and marrows.
Why is hand-pollination important when saving seeds?
You need to make sure that you save seeds from cucumbers whose parent plants are of the same variety in order to get healthy and tasty fruit that are free of mutations. Wind and insects are therefore unreliable because they can bring pollen from a different variety of cucumber or gherkin that someone else is growing nearby.
Of course, this is more of a risk on an allotment site where vegetables grow in close proximity. Even a greenhouse or polytunnel won’t prevent cross-pollination with nearby varieties, so this is when hand pollination is needed. Any cross-pollinating plant can be hand-pollinated.
How to hand pollinate greenhouse or polytunnel cucumber plants
1. Make sure you are growing open pollinating cucumber plants of the same variety.
2. Once you see flowers forming, cover at least two plants with an insect mesh or fabric that excludes insects but lets in light. Cucumbers will cross with any other cucumber varieties or gherkins within a quarter of a mile radius.
3. The first flowers will be male so wait a week or so until the female flowers appear. Male flowers form in clusters, whereas only one female flower will grow per stem.
4. Either using a cotton wool bud or small paintbrush, rub some pollen from the centre of a male flower onto the centre of a female flower.
Alternatively, detach the male flower and remove the petals, leaving the stamen exposed that contains the pollen. Rub this onto the centre of some female flowers. One male flower can pollinate several female flowers. It’s better if you pollinate between two plants if possible.
5. Tie something loosely around the stem of each hand-pollinated female flower so you will know from which cucumbers to save your seeds. Keep them covered until your hand-pollinated cucumbers start growing. You can then uncover your plants.
How to collect, dry and store the seeds
1. Allow the hand-pollinated cucumbers to grow and fatten well beyond the edible stage, allowing them to change colour before harvesting. Green cucumbers will turn brown/yellow and paler varieties will turn yellow.
2. After harvesting, leave the cucumbers to mature for another week.
3. Cut the cucumber open and scoop out all the seeds. Place them in a small glass jar with a little water. Leave on a sunny windowsill for a few days.
4. Now fill the jar fully with water and stir well. The good seeds will sink to the bottom. Now gently pour off the water, refill and repeat. Keep stirring and draining a few times until you are left with clear water and good seeds at the bottom of the jar.
5. Finally, drain off the water and spread out onto a plate to air dry.
6. Once fully dry, store the seeds in a paper (not plastic) packet or envelope in a cool, dark, airy place. Clearly label with the name of the variety and the date you packaged them.
When stored correctly, fully dried seeds from fruiting vegetables will last for several years, so there is no need to hand pollinate these plants every year.
