How can I repair an antique planter stand?

A wire brush and/or rust remover (i.e. Naval Jelly, etc.) can remove the rust. Spray paint can restore the old color.

You probably won’t believe this but I have used this method on 4 antique iron beds and two antique iron bridge lamps to get rust off. My hubby has a circular brush like attachment that will go into his electric drill. Not only does it save your elbow grease but it is easy to use. But you do get rusty dust on you. I would then suggest spraying with a rustoleum product and then use the paint color you want. Hope this helps you.

Is the stand wrought iron ? Naval jelly for starter so you do not damage the metal with wire brush attachment(since you said it's an antique; then a hand held wire brush if needed. Brush on liberally, working into pitted areas. Leave on 5 to 10 minutes. Caution: Wipe off painted surfaces immediately, Naval Jelly® Rust Dissolver will remove paint. The rust dissolver should not remain on a surface for more than 15 minutes. Neutralize the Naval Jelly with soda ash or lime. Naval Jelly uses phosphoric acid to strip rust from metal. Soda ash and lime are both "base" compounds, which neutralize acids. Both soda ash and lime can be found in garden shops, where they're sold for use in gardening.use rust inhibiting paint so it doesn't rerust

You might consider hauling it to your local do it yourself car wash and pressure washing it first. It will save you a ton of sweat equity. After that Rustoleum spray paint has never let me down and it comes in a ton of different colors!

You can scrape the rust with a wire brush than spray it with sealer. Next I would paint the plant stand a pretty color and seal it with the sealer one more time.