The sun is shining, and the garden is looking lush; conditions are perfect for that bumper crop of summer vegetables. Yet the tomato flowers are dropping with no sign of fruit, and that baby zucchini you spotted the other day has since turned yellow and shriveled up. This is a scenario that perplexes many gardeners, and even though temperature, moisture levels and plant health can all impact fruit set, the reason is often due to lack of pollination. For some this isn’t a big deal, as many have faith that later in the season things will pick up. I share that optimism, but when the cost of buying a pumpkin sends me into a panicky spin, my goal is to harvest as much produce as I can. I'm sure that is your goal too, so read on, and learn how to solve lack of pollination for your summer fruiting plants, in particular tomatoes, cucurbits and sweetcorn. It may just be easier than you may think!
There are three things to consider when pollinating a plant, the first being flower structure. Some plants grow complete flowers, or flowers that contain both male and female parts, while other plants grow incomplete flowers, meaning its flowers will either be male or female. The second consideration is timing. Pollen is generally released between mid-morning and early afternoon, so make sure you undertake pollination within that timeframe. The last thing to consider is moisture; you don’t want any, so choose a hot dry day once all signs of dew have dissipated.
Tomato flowers fall into the complete flower category, which is the simplest type of flower to pollinate, because the pollen doesn’t have far to travel. I used to think that honeybees were to thank for tomato pollination but actually it is the frantic fluttering of bumble bee wings as they buzz around that vibrates the pollen loose from the flowers. The pollen then falls from the stamen (the male part of the flower) and lands on the female stigma. If bumble bees are scarce, a simple way to replicate this action is by alternating your fingers in a quick up and down motion on the tops of the open flowers. With any luck you will see plumes of yellow pollen puff out – this is a good sign and means you are on the right track.
Not all plants require bees for pollination, and corn - which is wind pollinated - is a good example of this. It is common knowledge that planting corn in a block rather than just a few rows here and there allow the pollen from the tassels to reach as many silks as possible, but I have found that simply relying on this method isn’t enough to give us nice full cobs.
After undertaking a bit of research on this matter, I was intrigued to learn that each thread of silk emerging from an ear of corn is connected to an ovary which has the potential to make one corn kernel. Pollination occurs when pollen from the tassel (the male flower located at the top of the plant) touches a thread of silk and travels down inside it to the ovary. You can assist this process by either clipping off a healthy-looking tassel and gently brushing it over the silks or by capturing some pollen in your hand from a still intact tassel and massaging it into the silk ends. You want to do this while the silks are at their prime. The first method is the easiest and quickest, but because I don’t like to cut too many tassels off, I usually do a combination of the two. Of course, there are other factors at play that may cause poor cob development such as insufficient watering, but if you can keep on top of that you will find that the time spent hand pollinating will markedly increase your yield.
Sometimes you may want to hand pollinate not just to improve the harvest, but to prevent cross pollination. This is especially important in cucurbits (pumpkins, cucumbers, zucchini and the like) if you are wanting to save seeds for next season. Cucurbit flowers are incomplete, so you must ascertain which flowers are female, and which are male. Female flowers are easy to spot because they have a miniature fruit attached to the bottom of them. Male flowers on the other hand grow on long stems and have no fruit attached. If you look inside, you will notice they have a long anther covered in pollen, whereas female flowers have a lobed receptacle - or stigma - with the swelling fruit below it. To pollinate this fruit, simply pick off a male flower and use its anther to rub pollen on the stigma of a recently opened female flower. This type of pollination can feel a bit intrusive at first, but it is a rewarding process, especially when it comes to pumpkin harvesting day.
While hand pollination requires foresight and time, this is nothing compared to the abundance of vegetables it provides. I find if I schedule it in with my morning garden peruse, I often notice other jobs that need attention as I go about my business, helping me to plan the rest of my gardening day. Also, it must be said that spending a sunny morning tapping the odd tomato truss and massaging corn silks is a pretty relaxing affair, and when it keeps the cost of the supermarket bill down, it all feels worth it in the end.
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