The most earth-friendly thing you can do is to avoid “eco-friendly” products and just use pre-existing things as much as possible. A secondhand dress, rented or borrowed decorations, the wedding party wearing already owned or secondhand clothes, etc. Most cities have a Facebook group for brides giving away or selling their decorations.

The smaller the wedding the more friendly you can be, as some things get significantly harder or more expensive at a larger scale like whether your venue recycles/composts (or whether you need a venue vs. a park or nice yard), how involved catering would need to be, serving batched cocktails instead of bottled/canned drinks, and so on. I think the biggest things that can be easily cut are paper invites and save the dates, since those are easily done digitally saving paper, printing, and tons of shipping. Serving a vegetarian meal would be another option.

I have been pondering this same thing, I’m glad to see others looking out as well!