No smoking

This may be kind of harsh, but I would very clearly just say 'no smoking'. I'm getting married in September and have already had a couple of discussions about this. It's your wedding day, and if you simply don't want people smoking during the few hours they're celebrating with you, that's okay. Even if it has nothing to do with you getting sick - I don't get sick but I HATE the smell and hate that even though I'm not smoking, I will smell like it all night if I'm around it.

In my opinion, you don't really need a magical phrase to say you don't want smoking, if you don't want it, that's plenty!

The trouble with "smoking areas" is that if you're in a small yard, it won't stick to one area. and lingers to clothes!

Since the tent is going up in your backyard you can absolutely tell people no smoking in the tent. If they want to smoke they can go to the front away from the tent to smoke.

If anyone puts up a fuss say that the people you're renting the tent from have a strict rule about it. Enough cigarette smoke will yellow the inside of their tent, so.

I would just have a cute sign somewhere that says "no smoking please." It's your backyard and you have the right to say no smoking! I certainly wouldn't do a designated smoking area because that just encourages smoking in that area and encourages the smokers to congregate there. Your guests are adults--they can make do for several hours without smoking (unless you know someone who's extremely addicted). If I were having a backyard wedding, I would not allow smoking on my property whatsoever.

I completely agree with this! You don't need a fancy phrase to say 'no smoking'.

I agree with this too. I'd just have a "no smoking" sign that applies to your entire property.

As with a lot of other things, you honestly don't owe guests an explanation for why smoking isn't allowed. For my wedding there will be absolutely no smoking (of any sort) or vaping allowed because my mom and I are asthmatic and I get migraines typically within a few seconds of smelling weed or cigarette smoke. I don't know if anyone invited smokes, but I know quite a few of them vape so it will definitely need to be mentioned.

If you have an FAQ section on your wedding website, that would be a great place to mention it. I might phrase it like, "We appreciate you not smoking at our wedding. If you'd like to take a smoke break, please do so at your vehicle." As for the venue itself, a simple "No Smoking" sign is never a bad idea.