One of the sunflowers in my garden has already gone to seed. I can tell this because birds have begun to take take chunks out of the seed head even before all of the seeds have had a chance to develop. This seed head itself is still a couple of weeks away from being ready to harvest to save seeds to plant next year but already the birds have gotten to it. The petals of the sunflower haven't even fallen off completely and the seed head hasn't turned yellow or brown but I'm already losing seeds.
So, I turned to an old gardening trick to protect my seed head from the greedy little birds.
No, this sunflower isn't getting ready to rob a bank. Covering the seed head with a section of pantyhose is a great trick that really works. In place of the pantyhose you could use cheese cloth or another fabric that allows air and water through but doesn't have openings big enough for hungry little beaks. Your plants will look a little funny but at least you'll have seeds for next year.
How long should you leave the sunflower heads covered?
It really depends on a couple of things but generally when the head of sunflower has yellowed or browned is a good time to cut off the head and hang it inside in a cool dry area to dry out. After a week or so you can break apart the seed head with your hands and remove the sunflower seeds inside. Also, by squeezing the sunflower head, while it is on the stem, you'll be able to tell when it is ready because it will be hard and brittle.
Will your sunflowers look exactly like the one you saved seeds from?
I touched a bit on hybrid plants and if your sunflower is a hybrid (a cross between two different sunflowers) chances are that your seeds will not produce an exact replica in the following years. You should still get sunflowers they just may not be as attractive as the ones you originally planted. There is also the possibility that even if your sunflower wasn't a hybrid that it could have been cross-pollinated by urban bees with other sunflowers growing in your area. In which case, you could have a hybrid sunflower all of your own.
Leaving the sunflower seed heads to the birds.
Birds are a great thing to have in your garden, besides adding natural life they help keep garden pests under control. You can help attract birds to your garden by letting the sunflowers go to seed and allowing the birds to eat them. Birds are messy eaters and some of the seeds will inevitably fall to the ground and sprout next year.
Here's a bad picture of a goldfinch in my garden from a couple of years back. Before I planted sunflower seeds I didn't know such a bird could be found in Chicago. I thought the only birds in my neighborhood were pigeons, until one day I heard a big ruckus out in the garden and I opened the door to discover dozens of these black and gold birds feasting on the sunflowers I had planted that year in my garden. Now the sunflowers come back on their own and the goldfinches visit every year and put on a spectacular show in the garden.
Protecting sunflowers from squirrels.
To be 100% honest I'm not sure if the fabric over the seed head trick will work with urban squirrels. But it can't hurt to try. If you have experience with this feel free to speak up in the comments.