Growing giant sunflowers - planting out

by Kate Bradbury

Last month, we challenged you to break the World Record for growing the tallest sunflower... Now, in late May, we should all have good, strong sunflowers ready to plant out...

SunflowersLast month, we challenged you to break the World Record for growing the tallest sunflower. Free seeds of 'Russian Giant' were given out with the April issue of Gardeners’ World magazine, and many of you emailed us to register your interest in taking part. We all sowed our seeds, watered, tended and waited.

Now, in late May, we should all have good, strong sunflowers ready to plant out (depending on where we live). Mine have been outside in pots for about three weeks now, but I only planted them in their final positions last weekend. They're roughly 50cm tall and healthy looking, but they're not as tall as Adam Pasco's greenhouse-grown ones. Obviously they'll catch up and take over his soon.

All but one of the sunflowers are planted in well-rotted compost at the back of my south-facing border, close to the wall where they'll be kept warm at night. As an experiment, one is planted in a bucket of semi-rotted compost, like a portable bean trench. All are staked with tall, strong bamboo canes. (They're only about 2m tall, though. I'm still not sure how I'll stake an 8m tall plant.)

I haven't done anything special with my sunflowers yet, I've only watered them. Now I'm upping my game: this weekend I'll be harvesting nettles to make a nitrogen-rich feed, which I'll use regularly when I water the plants. Nitrogen-rich feeds, which include chicken and horse manure, encourage leafy growth and height, as opposed to flowers. I'll avoid using potash-rich fertiliser (such as a comfrey, or tomato feed) for now, as that will encourage flowering, diverting the plant's energy and reducing its height. A potash-rich feed will come in handy when the plants are tall, however, as it will help strengthen the stems, which is essential when growing plants to such heights.

It's all very exciting. I find myself inspecting the sunflowers more than any other plant in my garden - checking for unwanted flower heads and ensuring they're well tied to their stakes. I'm anticipating a growth spurt any day now.

How are your sunflowers coming along? Have you come up with an ingenious way to stake them? Don't forget to send us your photos, and let us know if you think you have a winner.

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Gardeners' World Web User 27/05/2011 at 16:33

The one seed of my seven freebies that germinated is now 61cm tall and looks very healthy. It too has been outside for a month in a big pot. Should it become a monstrous height I will tie it to a drainpipe. just imagine having a sunflower heading for the roof! And the birds would have a very convenient cafe when the seeds were ripe.

Gardeners' World Web User 28/05/2011 at 09:11

Is it too late for me to plant my sun flower seed now? The weather has not been very good up here. I live near Durham.

Gardeners' World Web User 28/05/2011 at 14:07

i have sunflowers on my alloment which are in flower they have been in flower for about a week..too bliming early its cause of warm weather everything is blooming to early.have loads of strawberrys too.

Gardeners' World Web User 28/05/2011 at 16:35

we have sunflowers growing in easy to grow as well..the bees love them too .

Gardeners' World Web User 29/05/2011 at 00:38

Oh yes, mine all germinated well and my 3yr old has been given the job of looking after them which I have to say she is very excited about! Currently she has one planted at the front of my wife's raised vegetable bed!, one in a border at the bottom of the garden and four in pots still until we decide where is best to plant them. As always great plants to get the kids involved in gardening and like most on here they are probably about 40-50cm tall now. Higgy

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