I think that your sunflowers (this variety) would do better if planted in the soil, rather than a container. They have a vigorous, far-reaching root system that will be stifled in most containers. (There are dwarf sunflowers that are suited for container culture.)

Sunflower seeds need to ripen on the plant. The flower will fade, then turn brown. The head usually starts to hang down, too. You can pull out a few of the seeds to see if they have filled properly before cutting the head from the plant.

Sunflowers are annuals. When they have finished making seeds, you need to pull the whole plant up and start again.

I've only grown them one time so my experience is limited, to say the least. I grew them for my stepson because he couldn't believe that a flower could grow to be taller than his daddy....LOL. And mine did indeed grow to be enormous. My stepson was suitably impressed.

I think yours look ok, though I do agree with rhizo that they need to be planted in the ground -- they aren't a pot plant. They need a lot of room and a lot of sun to grow and bloom properly. I virtually had to chop mine down when they were finished blooming -- they wouldn't come up neatly out of the ground without taking lots of soil and grass with them, so I cut them off at the bottom of the stalk and left the roots to rot. I left the spent dried blooms for the birds on a patio table in our backyard -- they were full of seeds and the birds loved them.

The foliage on yours is splendid, from what I can tell. I had every bug in the neighborhood snacking on mine, and the foliage looked ratty, but yours don't seem to be suffering from that problem. It is for that reason that I won't bother to grow them again -- sprays of insecticidal soap didn't work and I've been trying to avoid using any stronger chemicals in my garden.

As far as fertilization goes, I used a water-soluble fertilizer for blooming plants, 1/2 strength, every 2 weeks. I mixed it with water in a gallon-sized container and soaked the soil around the base of each plant.

Renee

I have grown different types of sunflowers for many years.

They do best when planted in the ground. They have root systems that are very large, meant to support the plant that can get well over 6 ft, tall in some cases.

They are fun to grow and come in different colors than yellow.

SG