Rustoelum has some great spray paints that will work for that.
Rustoleum Universal Spray Paint and Primer all in one. Here's a tutorial from someone who has done it! https://greenwithdecor.com/best-spray-paint-plastic-planters/
Hello! Use plastic friendly spray paint! The hard part is deciding what color to use. You can use different sheens satin, glossy or metallic paints there’s so many ...a rainbow of color choices for your consideration.
I recently spray-painted a collection of used mismatched thrift store planters with Rust-Oleum universal (any surface any angle) in an oil rubbed bronze spray paint and they came out fabulous.
I highly recommend the universal paint -both the spray applicator and paint and primer in one worked fabulously. This spray can top nozzle gives a very professional finish. Some of these second hand planters were actually Rubbermaid. They are nicer than you can purchase now at big box hardware barely last year before they start deteriorating/cracking.
Please consider giving your plastic flowerpots an update with spray paint that are labeled plastic friendly. I hope this helps.
Always work in a well-ventilated area. Cover the floor and nearby items with a drop cloth. Lightly scuff any glossy surfaces and wipe clean with a lint-free cloth. Use Painter’s tape to hide any surfaces you don’t want to paint.
Using slow, back-and-forth motions, spray paint each item with several light coats of spray paint, making sure to overlap each stroke slightly. Apply 2-3 coats of spray paint, waiting a few minutes in between each coat.
Let spray paint dry for approximately 1 hour before handling.
Tip: Use of 2X Ultra Cover Primer in White provides better paint coverage and color.
This is something I used from another Hometalk member. BUT I did it on a plastic pot (she used terra cotta), then I sprayed it with a clear sealer. It turned out awesome! You can also do basically the same thing with a sponge. Have fun making some beautiful new pots out of your old ones! Wishing you the best.