How do I keep my planters from leaking?

Plants require proper drainage. You can purchase trays to set underneath them. That would present another issue of standing water. You would have to use a bit of vinegar or mosquito dunks. Or after watering, just hose the entire area down and it will dry up clean and tidy.

I'm gonna assume those planters have drainage hole(s) in the bottom, so I would get some of those plastic saucers and I would get the kind on wheels so you can move them.. https://www.amazon.com/Murilan-Rolling-Outdoor-Planter-Trolley/dp/B07K1CWTVF/ref=pd_cp_86_1?pd_rd_w=H0Pyy&pf_rd_p=ef4dc990-a9ca-4945-ae0b-f8d549198ed6&pf_rd_r=HQ7WR9KW58E3CNBE599Z&pd_rd_r=911c280e-8ca3-11e9-8d50-a7be86592655&pd_rd_wg=2VOA1&pd_rd_i=B07K1CWTVF&psc=1&refRID=HQ7WR9KW58E3CNBE599Z

My husband uses this stuff that comes in a spray can called flex seal. He sprays it in the bottom of his boat to keep it from leaking. So I was thinking you could spray that inside the bottom of your planter. It is called flex seal.

Put a small pan under them to collect water

Plant trays on wheels, as Sharon said. They'll catch the water, but you'll still have to dump the water the tray collects to avoid mosquito larvae.

Hello! I recently purchased a plastic saucer on wheels at Walmart for my large planters. I believe it holds more than 150#. It helps to keep the concrete driveway from being stained.

Additionally a metal support with a few inces of elevation is another idea.

I believe your plants would be unhappy with plugging up the planters bottom drainage hole.

You need these pots to drain if you want the plants to survive. Saucers underneath are a pain to keep emptying. Best to keep some pot risers underneath to allow for proper drainage and it also minimizes staining on the surface beneath.