Hi annielu and welcome. ;) You'll want to begin by reading through all the FAQ here on saving different types of seeds and seeds in general if you haven't already done so. To get to it just click on the FAQ button at the top of the page and I have linked the FAQ page below for you. Once you read through them feel free to post any questions they raise.

Then you'll want to do a bit of reading on hybrid varieties and the problems that can result from saving their seeds vs. open pollinated varieties that will breed true. Are your varieties of zinnias, coneflowers, black-eyed susans, and daisies hybrids? If not do you still wish to save them to see what the may produce next year? Do you plan to trade seeds?

As to collecting, primarily you'll want to wait until the flower dies and dries and then collect the seed pods that form. With your daisies and cone flowers that seed head is pretty obvious ;) but with zinnias it can be a bit less obvious depending on the variety.

If you don't know which varieties you have the Hortiplex Database here at GW can help you identify them. And lastly, if you do a search here by common name (ie: saving coneflower seeds) you'll find all kinds of previous discussions with tips from experienced seed savers.

Hope this helps get you started. ;)

Dave

Here is a link that might be useful: Seed Saving FAQ

Hi Annielu,
I'm sure from the info Dave supplied, you know you know much of the basic information now. Something to note on the coneflower, black-eyed susan type flowers, beginning seed savers often think the chaff around the seeds is the seed and the seed is the chaff.
Like on coneflowers, there are pointy dark brown parts attached to the flower head base. That stuff is the chaff. The seeds are the lighter cone shaped things nestled between the the pointy dark brown parts.
With black-eyed susans, the seeds are small grey stick things. The chaff surrounding the seeds is the dark larger stick stuff.
Zinnia seeds are a bit odd too. You can break apart the base of a dry flower head and wonder where the seed is, lol. The arrowhead shaped things at the base of the petals is the seed. Viable ones are a bit plump. Sometimes, you will get ones that are flat and bend easy. Those won't make a new plant.
I hope this helps,
Remy

Here is a link that might be useful:

Thanks for the info!! :)