Fifteen glassine (paper) envelopes, measuring 1.75″ x 2.75″, with a center seam and ungummed flap
These are the same glassine (paper) envelopes I use myself for selling and sharing seeds. They are translucent, so you can easily see the seeds inside, and the seeds roll out easily. I also like that they are biodegradable.
The finish is smooth and glossy, so it is hard to write on them with a pencil or some pens. If I’m writing directly on these envelopes, I usually use a fine-tipped Sharpie (permanent marker) and give it a few seconds to dry before touching it to prevent smudging. Other labeling options: Add a sticky label on the outside and write on that instead, or slip a non-sticky label inside the envelope.
The sealed corners of these envelopes are usually tightly folded, preventing the escape of even tiny seeds, but I suggest checking them before adding your seeds just to make sure. (If there are any gaps, use a bit of tape to seal them.) The open end of the envelope has a fold-over flap that is not gummed, so you will need to tape it closed.
(In the photo here, I included a few baptisia seeds as a size reference; they are not part of this item.)