Many of the gardening queries we receive from our readers complain that the flowers on their plants simply drop off without changing into fruit. They have sometimes waited months or even years hoping their efforts would bear fruit and get dispirited when this happens.

There can be a number of reasons that can result in flowers dropping or wilting away before even entering the fruiting phase. These include, but are not limited to, issues such as excessive or lack of watering, a change in watering schedules, changes in sunlight exposure and the wrong duration of exposure in the day, the chemical content of the soil and fertiliser, not switching to the required proportion of the basic ingredients in nitrogen, phosphorus and potassium (NPK) fertilisers for the flowering and fruiting phase, harsh weather and even the size of the container of the plant being grown.

However, in many cases, the main culprit can be the lack of pollination in the first place and nothing else. Broadly speaking, it is the combination of two processes, pollination and fertilisation, that eventually turns flower into fruit.

Both of these processes bring the flowers from the flowering phase into the fruiting phase. Pollination is the first part of the phase-turning event of the flower which we will be discussing today. The second part of this phase-turning event is known as fertilisation, in which the actual fusing of the two male and female gametes occurs. The ultimate goal here is to form fruits and seeds, so as to ensure the continuity of the species in the next generation.

Pollination and fertilisation together bring flowers from the flowering phase into the fruiting phase. Gardeners sometimes need to intervene

The basic process of pollination which eventually leads to fertilisation is very simple. Pollination is the transfer of pollen grains from the anthers, which are the male part of the flower, to the stigma of the pistil, which is the female part. The male and female structures can be part of the same flower, two flowers on the same plant, or two flowers of two different plants. Once the pollen grain is deposited on the stigma, fusion and the process of fertilisation begin.

Just like there are different modes and ways of cargo delivery, the pollen grains from the anther also adopt different ways and modes to get transferred. Those vectors which strongly aid pollination are collectively known as pollinators. The process of pollination is also dependent upon a number of gardening and climate-related factors. Gardeners may need to intervene or provide support if it is difficult for the flowers to commence pollination or if other factors are hampering their process.

The pollination can either be self-pollination or cross-pollination. In self-pollination, the flowers usually have both male and female reproductive parts, and the transfer occurs within the same flower or between two different flowers on the same plant. It is a characteristic feature of some of the staple crops, including rice and wheat.

The second category is cross-pollination. For cross-pollination to occur, the two participating flowers can either be within the same plant species or on two different plants. The participating flower can either be unisexual or have both reproductive parts. The presence and role of pollinators become critical for cross-pollination to materialise.

Insects, animals, birds, wind and water are some of the most common natural pollinators. Common pollinator insects include bees, honeybees, flies, ants, butterflies, slugs, wasps and beetles. Small birds like hummingbirds, which may collect nectar or survive on flowers may also contribute to pollination. Small animals, including rodents, are also considered to be natural pollinators.

Blowing winds help much lighter pollen disseminate into the environment and fly into the female part of the same or other flowers. These floating pollens, a common sight in northern Pakistan, can also result in allergies in susceptible individuals. Finally, very few aquatic plants are likely to adopt water as their pollinating agent.

In the absence of natural pollinators, gardeners usually adopt unnatural ways to pollinate and fertilise their flowers. Sometimes a gentle tap at the base of the bisexual flower can do the trick. In some cases, identification of male flowers comes in handy, as gardeners pluck them and rub their pollen-filled central part on to the female flowers. It is common practice, especially for gourds.

To boost and reap gardening-related results, we should ensure a friendly environment that can promote the process of pollination and ease the course for its vectors as well. In our upcoming articles, we will continue discussing the significance of different types and vectors of pollination in detail.

Please send your queries and emails to doctree101@hotmail.com. The writer is a physician and a host for the YouTube channel ‘DocTree Gardening’ promoting organic kitchen gardening

Published in Dawn, EOS, July 30th, 2023