If you have already grown a seed from any Collection and have acquired 5 duplicates of the same plant, you can trade your duplicates for a random seed pack and Diamonds

1. Open the Nursery:
   Tap the fourth icon at the bottom of your screen, then go to "My Nursery."
   
   
2. Scroll to "Exchange Duplicate Seeds":
   This should be under "Shop Collection Box"
   
   
3. Choose a trade:
   There are three options to choose from, letting you trade 5/10/25 duplicates. Duplicates don't need to be the same seed. Tap the green button under Exchange
   
   
4. Trade:
   Choose the seed packs you want to trade. Your lowest rarity seed packs will be auto-selected first. When you're ready, tap the "Confirm" button

Note: The seed you receive will be randomly selected!