Growing under cover in a greenhouse obviously has its advantages – a warmer, more stable growing environment with shelter from damaging wind, frost and heavy rainfall helps plants to grow and flourish far beyond their normal’ growing season.
However, growing plants in the ‘contained’ environment of a greenhouse can pose a few challenges, one of which is the pollination of plants. Fruiting plants, such as tomatoes and melons, will not produce fruit unless their flowers have been pollinated. This is because fruiting is dependent on fertilisation, which cannot occur if the plant hasn’t been pollinated.
As ever, nature is very good at taking care of addressing challenges such as pollination. Some plants are able to self-pollinate, such as peaches, peas and lettuces. However, others get around the challenge of pollination by making the most of their surrounding environment. In the wild, pollination occurs in a number of ways, with the most common being via the assistance of other organisms or ‘pollinators’, such as insects and birds, as well as pollen grains being carried via wind or water. Bumblebees in particular are well-renowned effective pollinators.
However, if plants are removed from a natural setting and grown in a contained greenhouse, obviously the chances of the different types of natural pollination taking place are limited, particularly in smaller greenhouses. Without exposure to nature and the elements, greenhouse owners may well need to step in and ensure that proper pollination occurs!
To assist pollination in your greenhouse, you should first look to nature for a helping hand. Bumblebees are your best bet, so you should try to encourage them into your greenhouse. You can do this by leaving vents and doors open on windless, sunny days to increase the chance of the bees making their way inside.
You would also benefit by planting plenty of nectar-rich flowers such as lavender and other flowering herbs around the outside and inside of your greenhouse, and in the general vicinity. In fact, the more wildlife-friendly your garden is, the more bees will pass by and drop into your greenhouse.
However, if you’re going to encourage bumblebees into your greenhouse, it’s best to stop using any pesticides or insecticides. This is because bees can only thrive in insecticide-free environments. So if you want a helping hand from nature’s most prolific pollinators, then you should probably think about going organic in your greenhouse. If you’ve managed to attract bees to your greenhouse, the chances are that other natural predators such as lacewings and ladybirds will also drop in to help in the battle against greenhouse blights such as aphids.
Another popular method of assisting pollination is via hand pollination. Many people choose to use a soft, small paintbrush tip as a pollinator. However, with some plants such as squash and cucumbers, you’ll need to know the difference between the male and female flowers to ensure successful hand pollination.
Unlike squash and cucumbers, tomatoes and peppers require much less assistance. If you’re growing these plants on a relatively small scale, all that needs to be done is to either gently shake or the plants when they’re in flower.
So you see, pollination in your greenhouse isn’t a difficult task. All you need to do is make sure you know how your plants pollinate so you can give nature a helping hand. And you’ll find that nature will be only too obliging to return the favour!