This weekend it snowed again – a return of the snow meant that my hardening off was put back yet again. It also means that plants I sowed at the start of the year, that I was expecting to get into the garden soon, are not in the garden and are starting to bloom.
Also on the weekend, my six on Saturday was about tiny fruit and a few plants that are already growing female flowers that will eventually turn in to fruit hopefully.
This is how to hand pollinate – and not just because you are terribly impatient and you sowed all your warm weather plants wayyy too early. Hand pollination can be done because you have plants in a greenhouse and there are not as many pollinating insects as you would like. You can also hand pollinate if the weather is cool and insect activity outside is low – sometimes you might be getting fruit but it is misshapen or tiny/rotten; this is a sign of poor pollination and hand pollination can up the odds of good fruit.
The other reason is for seed purity; if you are collecting seed for next year you have to make sure that the seeds you are collecting were pollinated by the same variety of plant as some will cross-pollinate (example The Cucurbit family). This post is about courgette flower hand pollination but the same technique could be applied to most hand pollination of fruits that have separate male and female flowers.
So with no further ado: First work out the female and male flowers – the female will have a tiny fruit behind the flower the male flower will be on a longer stem and have no fruit.
Once you have found the female and male the next step is to work out which ones will open the next day. Flowers of both sexes are only viable for one day and by noon the chances of good fertilisation/pollination are pretty low. The key is to catch the flower opening in the morning and complete the hand pollination first thing (it doesn’t have to be dawn but the earlier the better)
Both flowers that are about to open are pointy; look quite yellow/orange but have green stripes (that look like thick veins) and in the evening they may crack open a little. Old flowers will be twisty or curly and will be darker orange. When you find new ones you can mark them for tomorrow – if you are trying to keep seed purity also tape or bag the flower shut so insects can’t pollinate before you wake up.
When the flowers open the next day they will be very bright orange and mostly open – if it is late in the day the flowers will have wilted a little and fully opened with petals bend back and have become darker orange. There is no death knell that means you can’t try in the afternoon to pollinate; it just may be less successful the later in the day.
If you are just pollinating to eat the fruit and don’t have any male flowers of the same variety open, you can use flowers from the same group, knowing that the seeds will not be anything like you have planted. Today, I pollinated a pumpkin with a courgette because I wanted fruit but I will know not to keep the seeds from that one (or you could take a chance and get something cool like collecting seeds from an F1 fruit)
The male flowers house the pollen on the anthers
and the female flowers house the receptors for the pollen called stigma.
The technique is to fake insect interaction between the two flowers – where normally the insect would visit the male flower pollen sticks to their body hairs while they are moving around collecting nectar and pollen and then when they visit female flowers for more nectar the pollen stuck to the hairs is rubbed onto the stigma for pollination.
You can do this one of two ways using a paint brush or cotton bud or by physically touching the male anthers to the female stigma. I did both just to make sure; usually the best pollination will occur when using the pollen from a couple of male flowers to one female but I only had one male flower open at the time. If you have male flower on the same plant as the female that is fine but it is better to use other male flowers if you can.
Using the paint brush collect the pollen on the side of the brush as if you are a bee; I collected the pollen that had fallen on the petals first. Make sure the paint brush is super dry – if you need to wash it do it a couple of days before as damp brush will hold onto the pollen.
Then place the brush alongside the stigma in the female flower; the bee would normally bury right down behind the stigma to get the nectar and her body would rub on the side of the stigma depositing pollen as she goes.
The other option is to pick the male flower and remove the petals to expose the anthers; try to cut away the petals without touching or knocking the anthers so the pollen remains intact and attached.
Using the same action as the paint brush; touch the anthers alongside the stigma all the way around. I also touched the top and the middle for good luck; when you are finished you will see the anthers no longer look fluffy.
You can also use a paint brush to collect any pollen that has fallen off and place that in the female as well.
The last step is to mark the fruit so you know that is the one you pollinated – this is not essential but if you do a few it is nice to know that you were successful. If you are collecting seed then it is a good idea to mark the fruit as then you know to not pick that fruit before it is mature and seeds are ready (especially true for courgette and cucumbers that are normally eaten small/immature)
The flowers will then closes and twist up and if pollination was successful the fruit at the base will start to swell in three to five
I had the flu this week so was not able to finish the post for the start of the week but that means we get to see the result of the pollination.
Its a little hard to see but the fruit is plumper and the stem is a little thicker; the F has also faded a little as it stretched. It was hard to get the same perspective and framing as the photo above as everything had grown out of place.
Hoepfully, the fruit continues to grow and remains on the vine so I can collect the seeds when they are mature (when the skin is too hard to press in with a finger nail); long after you would normally pick a courgette.
Another hope, is that all your gardens are warming up (or cooling down for the southern hemisphere perhaps) so that you might finally get around to the next season of growing and gardening. I planted out my cool weather vegetables this week, Easter snow be damned.