K's Garden

Building a large garden on a budget

Growing Sweetcorn Wednesday 6 May 2009

2009 : I haven’t tried to grow sweetcorn for a long time – and have always had poor results in the UK climate, so this year I’m going to make more effort, and grow some Mini Pops that the kids love.

The problem in the UK is that the Summer isn’t really long enough, but that can be cured, to some extent, by starting them off in the greenhouse and using an F1 variety bred for a shorter season. They don’t like being transplanted so use peat pots (and plant “whole”) – this year I’m growing them in pots I made from newspaper (See How to make Newspaper pots) – these are quite a bit taller than conventional pots, so I hope will provide more root-run.


The new F1 Super Sweet varieties should not be cross pollinated with any other sweetcorn, so plant at least 8M apart – which in practice probably means growing only one variety, and the same variety as your neighbours at that!

Some sweetcorn (especially the Super Sweet which is rather more of a “delicate child”!) is coated with a germination enhancer (fungicide) which is poisonous – it looks like Paprika. Wash hands after sowing, and keep seed out of reach of children. See packet for full details, obviously.

In 2009 I am also trying Mini-pop – picked before they are ripe, and something that my kids like. They can be planted in a row as they don’t need to be pollinated. Keep picking them so that plants form more baby cobs.


Sow in April (min. night temperature 16C/61F) and plant out once all danger of frost has passed (first week of June to be safe). Work in a general fertilizer a couple of weeks before planting out. It must be planted in a rectangular block (minimum areas 4 foot square), rather than a row, as this helps the pollination (which is by wind, rather than by Bee!). Don’t hoe near the plants to avoid root disturbance, and water in dry weather – especially at flowering time. – and tapping the plants, like Tomatoes in the greenhouse, will disperse the pollen and improve pollination (should be around late June or early July). Feed with high Potassium fertilizer (such as Tomato fertilizer)

It may be necessary to put a stake at each corner and string / wire around the block to stop the wind blowing them over.

Most small vegetable plants (such as dwarf French beans, radish, lettuce, etc.) can be grown under the developing plants.


Harvest immediately before cooking – amazing how quickly they loose their flavour, and freshly picked and cooked is a different experience to a cob that has travelled for days getting to the supermarket and then living in the fridge for some while longer. The saying goes that you should take the pan of boiling water to the plot and put the picked cobs in it, rather than the other way round!

Or Barbecue it – pick the cobs and immerse in water for 30 minutes (get the Barbecue going!!) then put on the rack to cook (don’t remove the leaves), for 25 minutes. Then peel and serve.

We give the spent cobs to the chickens after eating – they spend hours pecking the last bits of corn off them!


I keep Sweetcorn as a separate rotation crop – as they need to be planted in a block, and take up quite a bit of space.

2009 Season

05-Apr-2009 : As mentioned above as an experiment this year I am growing my Sweetcorn in pots made from newspaper, and they will be transplanted whole to avoid any root disturbance. A fellow gardener has recommended growing them in the greenhouse. I might try a small block of plants that way this year.

01-May-2009 : well the paper pots have been fine, but I should have used more layers of paper – say 4 “layers” thick. The roots have grown through, and indeed “into” adjacent pots, but the compost was still very open and friable, so I was able to tease them apart with minimal root damage, but I certainly wouldn’t say that planting them was with “no root disturbance”!

I was also surprised how fast they grew, and I have clearly sown them too early. I think 3 weeks, or 4 weeks tops, will be enough between sowing an planting out, including a week for hardening off, so next year I aim to sow one month before the last frost date.

I have planted 12 of each of my two Super Sweet varieties in the greenhouse – I expect they will grow tall enough to raise the roof, we’ll see.

The rest have been planted out on either side of the greenhouse – in the hope that the “barrier” between them will prevent / reduce cross pollination.

2009 Varieties

Sweetcorn Kelvedon Glory F1; Sweetcorn Swift F1; Sweetcorn Minipop F1.

Links and Pictures

For pictures and further details please see my Sweetcorn Crop Notes 2009.


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