[Snoop]

I've just looked through the thread on when to plant sweetcorn but have a different sweet-corn-related question:

How many plants are required for reliable pollination?

I have room for 24 and was thinking of doing them in four lots of six to stagger the crop.

Would six be enough for pollination purposes?

[JayG]

This is a guess!!  

I'd be inclined to go for 3 lots of 8 (although 3 lots of 9 would produce neater blocks!) not for the sake of being awkward but because even in your location I doubt whether you would get 4 follow-on harvests in one summer from sweetcorn so hardly seems worth the extra effort and slight extra risk.

[realfood]

If you are prepared to hand pollinate, even one plant is enough, but I think that JayG is right.

[Kristen]

I never know if hand-pollinating my outdoor sweetcorn does anything - the wind sways the plants all the time and thus they shed the pollen as fast as they make it, so I never see any actually shed when I wiggle them (but the ones in my greenhouse produce a cloud of pollen when I shake them - great fun then trying to manoeuvre the silks lower down into the cascade of pollen!)

Are you planning to plant the batches next to each other?  If so I think you should get benefit from the later planted ones - the earlies will produce pollen over at least a couple of weeks I reckon, so fortnightly planted would probably still benefit their neighbours.  If you are planting 4-weekly then I would do the next-sized bigger block than 6.

You may lose a few plants along the way, so I would grow some "spares", and if you feel like it plant them if they all survive - that will mean, at worst, that you have no "final sowing", but more certainty of pollination.

Give them a wiggle anyway, to help pollination, although I doubt you'll be able to see any pollen

[Snoop]

Thanks, Kristen. I was hoping you'd jump in here.

I was particularly inspired by your remark in the other thread that it takes you two months from planting out to get a harvest. I reckon I could manage that if I start the first batch off now. I was going to do a two-weekly sowing. There are only two of us, but assuming 2 cobs per plant then that would give us around 12 every fortnight or so. Sounds about right to me.

First frosts don't start here till mid October at the earliest. So that should give me plenty of time to get a crop in from the final six plants, even if they're a bit slower than yours. Anyway, it's certainly worth a try. I just love sweetcorn.

I grow mine outdoors and never have any problem with wind pollination. Last year I lost a lot of pollen to bees, but I didn't mind too much, even though lots of the cobs weren't completely pollinated.

Out of interest, I see that you grow Swift. I tried that last year and didn't have much success. Germination was poor (seeds from T&M). So I'm going back to Lark (seeds from Marshalls), which I grew the year before. Have you tried any others?

[Kristen]

My Swift came from Suttons, I have to say that I only buy seed from T&M that I can't get elsewhere as I've had a number of mis-fires with them.

I think Swift, Lark and Swallow are all in the same group of "Tendersweet", and they all suffer from poor germination (probably a side effect of the selective breeding for the things they are GOOD at!) often these new Sweet Corn varieties are coated with a fungicide to prevent them rotting before they germinate (might that be a difference between T&M and Suttons seed I wonder?).

Even so, one of my batches of seed which I chitted on kitchen paper this year all rotted - I decided I had kept the kitchen paper too wet, so now I am only putting the top layer loosely on the corn, rather than snuggling everything down and tucking them all in ...

[realfood]

It looks as if I have almost 100% germination of my 3 different varieties of tendersweet  sweetcorn after about a week of germinating in a propagator. The secret is in the method of sowing. Sow indoors in heat, at 20 C, on top of the compost to prevent the seed rotting, in individual cells in late April. Remember that tendersweet sweetcorn has thinner tender skin on the kernels and thus can rot more easily than normal corn.
I also slightly cover the kernels with mica which allows light to reach the seed which is beneficial.