Plants that produce once a year

Plants that produce once a season

Somewhat fertile, Fertile, and Very fertile

Items you can use to upgrade your plants

There are three ranks of crops you can produce; B, A, and S. B-rank crops sell for less than the A-rank, and A-rank sell for less than the S-rank. The crop seeds you buy from Besta's farm are always B-rank. If you want to raise S-rank instead, you'll have to work on enhancing them.

If you are in Chapter 1 or you haven't obtained Tartan yet, you can buy Fertilizer to use on your planted crops. Bags of Fertilizer can be purchased at Besta's for 120 G each. To use it just select the bag out of your inventory and press A when the yellow highlight square is hovering over the crop you have planted. One bag will fertilize one square in your field even if there isn't anything growing there, so be careful where the highlight square is.

Fertilizing your crop doesn't automatically raise it's rank. You will have to continue to drop bags of plant food on it until it is harvested. To raise a B-rank to an A-rank, it can take 5 bags of fertilizer. To raise a B-rank up to an S-rank, it might take you 10 or more. The fertilizer will show around the plant's roots. When the Fertilizer has absorbed into the soil, you can add some more.

Raising trees up to an S-rank can take bags and bags of Fertilizer. Since trees take much longer to mature than crops do, plan on buying 30 or more bags just to upgrade one tree into an S-rank.

Happy Lamp Summer season, crop can grow in any season

Gemsoil Fall season, crop can grow in any field

Up Seed Winter season, crop upgrades to S-rank

After you have received Tartan, you can use his abilities to automatically upgrade your B-rank plants into S-rank plants. Around Forget-Me-Not Valley you'll find special flowers you can use to enhance your crops. Just give Tsurudan one of these 3 flowers and your bag of seeds, and he will mix in it's special properties. Tartan can't use flowers on the tree seeds though.

To get your trees to upgrade ranks without the use of even more Fertilizer, you have to mix a high-rank seed with a low-rank seed. For example, if you had given enough fertilizer to your Banana tree to raise it up to S-rank, when you mix it with a B-rank Apple you'll receive an S-rank Appage seed. If you already had a B-rank Appage and you wanted to raise it to an S-rank, mix in that S-rank Banana to bump the Appage seed up to an S-rank. As long as the S-rank tree is part of the mix, it's rank properties will carry over.