Cute little environment with a fun idea. The tetris aspect was a nice surprise when I first started planting and I liked the potion making/selling aspect.
I would love to see more around the tetris puzzly part. The optimizer in me wishes I could actually fill every plot using the shapes. I think being about to see the shape of each arrangement (get it) when buying would also be a nice thing to have.
At some point I did get poor and have the wrong potions for the job due to experimentation. Perhaps a way to help people at the beginning is to make the seeds priced at a discount the first couple times you buy them. Overall I think there's a lot of potential for the idea and you've laid a lot of great groundwork to build upon!