I have a sunflower plant growing flowers, and I want to grow more sunflowers in my garden.
How do I grow more sunflowers from the current plant?
A sunflower should produce seeds in the middle of the flower, so don't cut off all spent flowerheads. When they are ripe, the seeds can be easily removed or will fall off. The seeds may vary in colour, depending on the breed, but will most likely be in the grey-to-brown range, some may have stripes, some will be solid.
If birds eat the seeds right from the head before you can get them, you might want to protect one head with either a thin netting or a thin piece of cloth, but make sure it can ripen and dry undisturbed. Don't use plastic or you are risking mold.
This is the head I used a few days ago for this year's seeds:
Good seeds should be plump and large. A flower head will yield many seeds, so choose the largest and plumpest for planting.
Just plant the seeds as you would with other plants, at a depth of ca. 1-2 cm and keep the soil humid, but not wet. Some background on your climate and growing seasons might be helpful - if your winters are cold, you should plant the seeds in spring after the last frost date right where you want them to grow. Or you can start them indoors in small pots, transplanting later after the last frost. This may also be helpful if you have many slugs or other animals that may eat the seedlings as larger plants are often less attractive. If planting indoors, make sure to have good lighting and harden them off by putting them outside on mild days (first a few hours in semi shade, gradually increasing to longer time and more sun) before planting outside.
This year, the seeds I planted took only a few days to germinate and are already pushing up through the soil:
If your sunflower really likes the place in your garden, fallen seeds might even germinate on their own, establishing a small colony.
This is most likely a seedling from last winter's bird seed, containing sunflowers. I doubt that it will mature though, we are not past the last frost date, the slugs are are closing in and it's in a bad spot...:
Sunflowers are quite willing to grow from seed and really beginner-friendly (they don't need special treatment of the seeds or very special conditions or a greenhouse), so good luck with your project!
I think you were asking about propagating from the plant rather than the seed. I discovered this year that broken stems will develop roots if you put them in water.
A slug had damaged the young stem badly, and, rather than consign it to the compost heap, I thought I'd see if I could save it. You can imagine how delighted I was when I saw roots starting to grow. I potted the plant up carefully, kept it inside at night, and eventually 9 buds formed. I tried it again last week with another damaged one and, although the roots haven't formed yet, a very healthy bud is developing.
I've decided, just for fun, I'm going to experiment with some more sunflower plants, to see how small I can cut the plants and still get viable growth.