How can I start up a small plant nursery?

What an exciting idea - best of luck with it! I find this guide that might be helpful

https://www.wikihow.com/Start-a-Plant-Nursery-Business

I would hope that you have lots of experience with horticulture. I would get a job a local nursery to learn how they operate their business. Then you may be able to turn that into your dream. Best of luck.

Here are some sites to get you started.

https://www.profitableplants.com/how-to-start-profitable-backyard-plant-nursery/

http://www.twisted-tree.net/starting-a-nursery-business

https://m.wikihow.com/Start-a-Plant-Nursery-Business

https://howtostartanllc.com/business-ideas/plant-nursery

Be sure to obtain any state, county or city business permits.

Talk to your homeowners insurance carrier to discuss business insurance needs.

Talk to your attorney about any legal ramifications - you need to separate business credit from personal credit.