Have you just Googled "long bench"? (Maybe "long wooden bench" or "long metal bench"?) I did just now and got several result that looked like they'd make great plant shelves.

I don't know where to get them IRL, but it should be pretty easy to find out online or just order it online. I bought some shelves from Amazon a little while ago and the shipping was free because the product was over $25, so that's a good option if Amazon has a bench that looks good to you. I think a lot of other sites have similar deals, too.

Thanks I guess I will try that next. I tried searching for long low shelves
But no luck. I will try benches next.