Pollination is something on which we all depend, but many know little about the important pollination process. As a gardener, it is vital to understand what pollination actually is, why it is so important, and how it occurs.
By gaining a deeper understanding of the pollination process, we can begin to think about how we can ensure that it occurs in our gardens, take steps to improve the natural function in our spaces, or, where necessary, take things into our own hands.
What Is The Pollination Process?
Pollination is an important part of the process that allows plants to produce seeds. It involves the transfer of pollen from a male part (anther) to a female part (stigma) of a plant, enabling fertilization which leads ultimately to the production of seeds.
Is Pollination Important?
The pollination process is an essential part of the timeline by which plants produce their offspring. Fruit and berry producing plants cannot do so without pollination taking place, and flowering plants cannot produce seeds to bring the next generation without this step.
We ignore the pollination process at our peril. Today, it takes place naturally in most instances and is something we usually don’t think too much about. Things will swiftly change if we do not protect the insects and other wildlife upon which a lot of pollination depends.
Understanding the mechanism is also important to us, when we attempt to grow our own food in a sustainable and eco-friendly way. We need to understand the different means by which plants are pollinated, and the steps that we can take in order to ensure this process goes smoothly, in order to achieve the best possible results.
How Does Pollination Occur?
Crops in the Northern Hemisphere are usually either:
- Self pollinating.
- Insect pollinated.
- Or wind pollinated.
Self Pollination
Some plants are self pollinating. This means that they are pollinated internally, or by another flower on the same plant.
Peas and beans are a couple of examples of common garden crops that are usually self-pollinating.
Most plants, however, are not self-pollinating, and need pollen from another plant of the same species in order to be fertilised.
Cross pollination is when pollen is transferred from one flower to another flower on a different plant, not the one it originated from. This can occur between different plants of the same species, but not between plants of different species.
Typically, this is rare with self pollinated plants and you can usually place them close to one another without any risk of this taking place.
Even with self-pollinating crops, however, other mechanisms can also be employed, and yields may be higher when there are insect pollinators around. And plants frequently have mechanisms which prohibit self-pollination.
This is because cross-pollination provides greater genetic diversity. When it occurs, the characteristics of each parent contributes to the progeny produced.
The cross pollination process often leads to greater adaptability. And those plants that withstand change better are better equipped to cope with growing conditions in a specific area.
Pollination By Insects and Animals
Some plants are pollinated by insects and other animal species. Creatures will travel from the flowers of one insect pollinated plant to the flowers of another, transferring the pollen as they seek out the sweet nectar from the blooms.
The flowers of an insect pollinated plant are characterised by enclosed stamens, enclosed stigma, sticky stigma so pollen attaches to insects, bright coloration of the petals and nectar production (to attract pollinators), and larger, sticky pollen grains.
Three quarters of the world’s flowering plants and around 35% of the world’s food crops depend on animal pollinators to reproduce. In the EU, it is estimated that 84% of crops and 80% of wildflowers depend on insects to do this job.
Common garden crops that are typically pollinated in this way are brassicas (cabbage family plants), and cucurbits like squash, courgettes and cucumbers, for example.
If you do not want these types of plants to cross pollinate, and plan on saving seed, then plants within the same species will have to be prevented from flowering at the same time, or separated by quite some distance.
Which Animals Pollinate?
Many plants are insect pollinated in the UK, but small mammals, birds and other creatures can also play a role in pollination.
Important pollinators in the UK include honey bees, bumblebees and other bee species, butterflies and moths, flies, wasps, beetles, and more…
Pollination By Wind
Some plants are wind pollinated, which means that the pollen is transferred from one flower to another through the air, sometimes travelling long distances.
Wind pollinated flowers typically have exposed stamens and stigma. The stigma is usually feathery so that the pollen can be caught and blown by the wind. Nectaries are absent and the petals may be dull/ green. The pollen grains are smaller, smooth and/or inflated, to they travel easily on the breeze.
Wind pollinated crops commonly grown in UK gardens include beetroots, carrots, celery, onions, spinach, sweetcorn and Swiss chard, to name a few examples.
Wind pollinated plants may need to be separated by quite some considerable distance (sometimes even miles) from one another in order to achieve a reasonable rate of seeds which come true to type. However, dense planting between crossing types (of the same species) will often lessen pollen transfer.
Pollination By People
People can also play a role in the process and as a gardener, there are a number of steps that you might take to:
- Promote natural pollinating and ensure that it takes place.
- Encouraging beneficial cross pollination or preventing it where it is not desired.
- Taking pollination into our own hands and transferring pollen ourselves on insect pollinated plants where the pollinators are not present, or are there in insufficient numbers.
How You Can Help The Pollination Process
One important thing to remember as a gardener is that, by working with nature, and with an understanding of the pollination process, we can either help it happen as it should, or manipulate things to achieve our desired goals.
Promoting Natural Pollination
One of the most important things that we do as gardeners to help the pollination process is make sure our gardens are havens for the pollinators on which so many plants depend.
As mentioned above, many plants rely in insects and other animals for the pollination process to happen. Without them, they often cannot fruit or produce seed successfully.
Sadly, human activity, climate change and habitat degradation means that we are currently in the midst of a mass extinction. Many of the pollinators on whom we depend are in decline, or severely threatened.
Many of the pollinators that we take for granted are in danger, and we must take whatever steps we can to halt population declines. We must begin to restore habitat and halt biodiversity losses before it is too late.
By doing all we can to plant for biodiversity and to welcome wildlife in our spaces, growing organically and adopting sustainable, natural, earth-friendly practices in our gardens, we can help make sure we protect precious pollinators and help make sure that plants are pollinated naturally as they should be.
Gardening organically, naturally, and with a wildlife-friendly approach is a must for anyone who understands the vital importance of protecting the natural world around us. We must do so for its own sake, of course, but also for our own survival as a species.
Thinking About Cross Pollination
Understanding which plants cross pollinate and how this occurs is important for those who wish to save their own seeds in their gardens.
People sometimes play a role in pollination by manipulating the pollination process to achieve desired results. They will promote cross pollination where this is beneficial and take steps to prevent this where it is not desired.
Sometimes, the mechanisms of cross-pollination between different crops or other garden plants of the same species are manipulated by growers to create plants with desirable characteristics.
Over the centuries, selective cross pollination has led to many of our most favoured horticultural and agricultural crops. Experimentation in plant breeding means taking a hand in deciding where cross pollination should be allowed to occur and where it should not.
Most tomatoes, for example, are self-pollinating plants and heritage cultivars (not F1 hybrids) will usually come true to type. But gardeners can manually transfer the pollen between different tomato types to encourage cross pollination to occur, and potentially breed new tomato varieties in their garden.
By learning how different plants are related, which cross-pollinate and how they do so, we can avoid this where we want to save seeds that come true to a specific parent plant. And we can encourage cross-pollination where this is beneficial for plant breeding.
Hand-Pollinating Crops
Gardeners and growers sometimes also take pollination into their own hands. This may unfortunately be a necessity for insect pollinated crops where insects are not present in sufficient numbers. It can also be necessary when plants are grown in a polytunnel or other undercover space or, of course, in an indoors growing area.
References:
https://www.nrcs.usda.gov/wps/portal/nrcs/main/national/plantsanimals/pollinate/
Elizabeth Waddington is a writer and green living consultant living in Scotland. Permaculture and sustainability are at the heart of everything she does, from designing gardens and farms around the world, to inspiring and facilitating positive change for small companies and individuals.
She also works on her own property, where she grows fruit and vegetables, keeps chickens and is working on the eco-renovation of an old stone barn.
To get in touch, visit https://ewspconsultancy.com.