The special orders become available right at the start of fall 2 in your first year, when you'll spot the board near lewis' house. Every monday you'll see two fresh orders posted, and while you can only pick one per week, it's actually pretty nice since you can have multiple active if you grab new ones in following weeks. Most orders give you decent time to finish them, anywhere from a week to almost a month, depending on what they're asking for.

Something worth knowing is that most items need to be collected after you take the order, so don't stockpile crops thinking you'll complete everything instantly. The good news is that if you mess up or run out of time, you can always grab your stuff back from the lost and found at lewis' place.

The rewards are pretty solid, especially for mid-game stuff like the mini-shipping bin you'll get from your first crop order, and some really useful items like mini obelisks that help you zip around your farm faster. You might want to keep an eye out for specific orders like cave patrol or the prismatic jelly hunt, since they open up some interesting possibilities and can net you up to 6000 gold. Once you're further along, these orders even start connecting to ginger island content, so they're worth keeping up with.