How to grow sunflowers

Sunflowers can be grown in pots or sown directly into the ground. They can be started off indoors in early spring and will grow quite happily on a window sill for a time. Alternatively, seeds can be planted outside directly once the risk of frost has passed.

Sowing indoors

To begin growing your sunflower, fill a pot with compost to 1cm below the rim. Anything that will hold compost will make a good pot. If you don’t have a plant pot consider using yogurt pots, tin cans, plastic cups, old bottles (with holes in the bottom for drainage) or toilet rolls which are biodegradable and can be planted into bigger pots or into ground soil later. Sow one seed per pot and water so that the compost is moist. If you are growing different varieties of sunflower remember to label your pots.

Sunflowers started off indoors grow rapidly and tend to grow tall and leggy because of the warm environment – you should see them begin to shoot within about a week to ten days of sowing your seeds. Supporting them with a cane will keep them upright until they are big enough to support themselves – if you don’t have any canes you could consider using pencils, chopsticks or knitting needles.

Sunflowers started off indoors are tender and should be introduced to the outside world slowly to harden them off – a couple of hours outside during the day before returning them inside overnight over a period of time helps to prepare them for being outside permanently.

Sowing outdoors

Sowing seeds outdoors is best done after the threat of frost has gone. Seeds can be sown directly into the garden border or in pots as described above. If you are sowing your sunflowers outdoors (and when your sunflowers are small), be aware that slugs, snails, mice, rabbits and other animals have a healthy appetite for baby sunflowers.

There are measures you can take to protect your sunflowers. Plastic bottles make good sunflower protectors – try cutting a plastic milk bottle in half, cutting off the base and putting it over the top of your sunflower will deter anything that thinks your sunflowers might be dinner, while allowing the sunflower room to grow out the top. Throwing gravel or egg shells around the base of your sunflowers makes an uneven surface which it is difficult for slugs and snails to move on.  You can also buy copper tape or bands in garden centres.

Young boy and tall sunflower

Watching your sunflower grow

Sunflowers like plenty of sun but also like to be kept moist. Choose a sunny spot for maximum exposure to sun when planting your sunflower. Ensure you water it regularly too but make sure it doesn’t get water logged.

When sunflowers are well established you can feed them with lawn feed or tomato feed but be careful not to get this on the leaves as it can cause the plants to rot.  The thick stems mean your plants should not need to be staked but if they look as if they need some help, they can be tied to canes with string or ribbon providing it is not tied so tight as to cut into the stem.

Further information

For further information about growing sunflowers, watch the short films below from Dobbies Garden Centres.

Please note: a printable version of this page can be found in the resources area of this website

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