planting lavender or mint will naturally repel spiders.

Yup. And wolfsbane will repel Werewolves, too. Just as effectively.

Guess you've never seen spiders crawling on or weaving webs on Lavender &/or mint, eh? Suggest looking more closely.

peppermint oil with water ... will keep them out.

Sez who?

Of course, you could just squash 'em as you find 'em. Flyswatters work well.