Do you know anyone who would kindly loan you their power-washer? My husband uses one on our driveway and sidewalks and it does an amazing job. No chemicals are needed, just the power of the water.

I second the power washer. If you don't have one I think you can rent them, but they are a worthwhile investment. I have a lot of pots on my patio. I wash it with the hose when I'm finished planting but the whole patio gets grungy over the summer. Every spring before we bring out the patio furniture my husband goes over it with thw washer. It not only gets the grunge but any moss that happens to be on them and we have a like new patio.

Straight clorox. dump it on, push it around with a plastic broom, wait 10 minutes and hose it off.
The chlorine dissapates into the air and won't harm your plantings. Works like magic and costs about $1.29 for the supplies...
Just wear old shoes and either white pants or ones you don't care about....because you will splatter some.
I have done it for years and years on my cement patio.
Linda C

You do not have to change soil every year, so cleaning should be cut down. I used the same soil for years I just add fertilizer every spring. I have beautiful plants in my containers.

Thanks so much everyone! Wow, I would never have guessed that bleach wouldn't hurt plants. Will try that while I'm looking into the power washer.

Vala55, good to know about not needing to change the soil each year. My mess is mostly from changing out the plants. I change them with the seasons and also the area starts out shady in the spring but gets an increasing amount of sun as summer progresses.