Yesterday I signed off to go collect arugula seed from my garden. There’s all kinds of info on the net on how to do it; here is my process. Make sure it’s been about 24 hours since watering, 48 for rain. Do it on a warm dry day (rarely a problem in CA) moisture in the seeds is the only enemy here.
I use a glass jar so I can see what I’m getting. You can use a paper bag or a bucket too. Arugula seed pods when ready to harvest burst open if pinched in the middle. I hold the jar under selected pod and pinch. The seeds, and sometimes parts of the pod fall down into the jar.
Once you are done collecting you will need to remove the seed pod parts. A fork works pretty well.
I let them sit in the jar for a day, stirring a few times to make sure they are all dry and we don’t have any moisture. Now it’s time to store them. You have some options here.
Williams Sonoma offers these awesome seed storage envelopes by a company in England.
Or you can make your own out of regular envelopes or do like I do and use a brown paper lunch sack. I place about a tablespoon of seeds into a packet like this one below for my own use. If I'm gifting, I will fold over again so it's closer to the size of a postcard (and less likely to spill seed) and I'll place a teaspoon of seeds in the sack.
I'll be collecting more seeds soon and if I pack any for gift giving I'll follow up with another photo!