Do I need inspection and permit to sell plants in Texas and online?
For in Texas sales from a permanent (your backyard) or temporary (a garden show or festival for example) location you do need a Texas Nursery Floral License. Follow the link below to the Texas Department of Agriculture website. They will issue the license and can inspect to insure that you are not spreading plant pests. Online sales are more complicated because each state regulates the shipping of plants into their borders. Before you ship to another state, you will need to find out what they require. Often they will ask for a phytosanitary certificate from your (Texas) department of agriculture. The National Plant Board has a summary of requirements: http://nationalplantboard.org/laws/index.html
Sometimes certain plant species cannot be shipped into certain states due to pest concerns. You will also need a sales tax permit from the state comptrollers office and you will need to collect tax on plants that you sell unless they are sold for agricultural use, in which case you need to get the purchasers Ag/Timber Exemption number. That is also something that you might want to get for yourself.