Squash fruit rotting (uchiki kuri)

[londongarden16]

Hi there

Wondering if someone can help me with my squash. I have two varieties growing (uchiki kuri and crown prince) which are going nicely.

However, mainly on the uchiki, all the fruit apart from one have gotten to ping pong ball size and rotted off.

I thought we might have a pollination problem as there don't seem to be many bees - so I've been very diligent with using a paintbrush to hand pollinate (taking a bit of the pollen from the male flowers and brushing it into the females.

Not sure why they're rotting, given the hand pollination. Haven't grown squash before, so would live any tips/advice/explanations!

Thanks

[Small pumpkin]

Possibly being a little to delicate with your hand pollinating. I pick the male flower remove its petals and rub all the pollen all over the centre parts of the female.

Welcome to the vine .

[ameno]

It's almost certainly still lack of pollination.
Squash seem not to produce much pollen for some reason, and in order for a fruit to grow it needs most of the seeds inside to successfully fertilise, and each seed needs a separate grain of pollen to fertilise it. This means each flower actually needs a fair amount of pollen to properly pollinate it.

Male flowers a freshly opened, and thus pollen the most abundant and viable, first thing in the morning. Go out and pick off a male flower, remove the petals, and rub the pollen onto the stigma of a female flower. Try to get it all around the stigma, not just in one place.
Also, pollination is more likely to be successful if you use pollen from a different plant, rather than both flowers being on the same plant.

[Snoop Puss]

^That's interesting, Ameno. I don't use the paintbrush technique, just male to female flowers. But I didn't know it was better to use a flower from a different plant. Sometimes not possible if male flowers are few and far between, but I'll bear that in mind.

So, thanks for asking the question, LG. Hello and welcome to the Vine, by the way.

[ameno]

^That's interesting, Ameno. I don't use the paintbrush technique, just male to female flowers. But I didn't know it was better to use a flower from a different plant. Sometimes not possible if male flowers are few and far between, but I'll bear that in mind.

So, thanks for asking the question, LG. Hello and welcome to the Vine, by the way.

With almost any plant, you get a more reliable fruit set when you cross-pollinate, even when the plant is meant to be self-fertile.

[londongarden16]

Thank you everyone for the welcome, and for all the information! That's very interesting - I'll be giving that a go tomorrow morning. I haven't been using more that one flower, and usually from the same plant too.

An additional question - my female flowers are usually open for about 3-4 days, can you pollinate them right up until the end, or is it too late when they're beginning to shrivel?

I have one uchiki fruit so far and am amazed how quickly they grow once they've got going!

[Small pumpkin]

I pollinate every day while the females are open. I have no idea if it helps, but I do it anyway.
Because I pollinate every day, I often use the same male flower on more than one female, especially if it’s a male courgette. Picked at the right time they have a lot of pollen that will easily do 2 or 3 females.

[ameno]

Thank you everyone for the welcome, and for all the information! That's very interesting - I'll be giving that a go tomorrow morning. I haven't been using more that one flower, and usually from the same plant too.

An additional question - my female flowers are usually open for about 3-4 days, can you pollinate them right up until the end, or is it too late when they're beginning to shrivel?

I have one uchiki fruit so far and am amazed how quickly they grow once they've got going!

I usually find you can pollinate them successfully up until the stigma starts to darken and degrade, which usually happens about a day before the petals begin to wilt.

[quanglewangle]

My first time growing squashes also - kabocha in my case. They were turning yellow and dropping of until I overcame my timidity (and feeling the process to be slightly pervy) and got stuck in.

The hardest part for me is finding a just-open male flower: they seem to go from immature to wilted much more quickly than the females.

I peel back and remove the petals and the sepals and use a long pair of forceps (don't ask - long story) to poke the now-exposed stamen (anthers?) into the female and generally wiggle it about the stigma.

The effect was immediate and successful. Now have lots of swelling squashes. As others have said, it's a every morning job.

[Yasai]

I have one uchiki fruit so far and am amazed how quickly they grow once they've got going!

Well, that’s one more than me. Never thought to give them a helping hand, though. Might have to give it a go. Mind you, they’re growing up an arch and unless it collapses (which it may well as, no sooner had I built it out of bamboo and put the plants in the ground, Monty Don came on telly to advise not making a bamboo structure for that purpose), I won’t be able to reach them.