It sounds like the tannin from the oak leaves. I would get brown staining on my cement block knee walls and the walkways around my pool every time it rained. It stopped when I removed the oak trees and the sun finally bleached it out over time and returned it back to normal color. If you use oak leaves in your compost mulch then that could be the problem. It had me stymied for a long while wondering where the brown staining was coming from and only when I removed the overhanging oak trees did it stop.

Lou

That makes sense, Lou. When I repot a plant (using home made compost with a lot of oak leaves in it) this happens for the first week or two. Just let it dry as much as the plant(s) will allow, then water copiously until you see a lot of drainage. Then rinse the area around the bottoms of the pots. After a few times, the water should start coming out a lot cleaner. You're right about not wanting the pots to sit in water, that will kill the plants. A small amount of bleach in a bucket of water should get rid of the stains (pour it on the patio.)

Thanks, guys, but I don't think it's tannin, or at least not from oak leaves. I have not used oak leaves in these pots. Just potting soil, and probably not the same potting soil as they were done at different times.

These stains are so bad that chlorox does not get them out, even when I scrub with a brush.

Any other ideas?

Uhoh, that's not good. When the spot on the steps right under the leak in my leaf-filled gutter gets too dark, bleach always clears it up. Just realized I'm assuming it's concrete.

Maybe the potting soil has composted manure in it? Last time I added some of that, it stained the paint on the deck but it didn't really bother me because it was already painted dark green and didn't show up much. Then it was time to paint again. Is paint an option for you? Would using the saucers you got upside-down help? Or some other kind of risers? The runoff water at least wouldn't be in contact with the patio for extended periods. I've seen different types of these in stores and this kind of thing is what they're supposed to help but I always have too many pots to bother doing a few and don't want to spend money on a ton of them. I remember reading on the frugal forum about someone who was using the plastic lids from water or soda bottles as pot feet. At least if they were up, you could rinse the runoff more completely without leaching more from the pots after the pots finish dripping out.

Hmm, you may be onto something, purple. I may well have added compost to these pots. That means I either re-pot without compost or figure out a way to sop the water up quickly.

Maybe I'll re-pot one of them and see if it helps.

Thanks!

I've always had this issue no matter what soil I use

I have always used potting mix from a local hardware store. But only one type is leaving horrible brown stains on the porcelain tile on the back patio (I don't know which one). I tried putting the pot on risers but it doesn't matter if the water doesn't run off the patio, I still have stains. I did buy an organic potting mix once, so I am wondering if this is the one that is causing the stains. It is pretty extreme! I finally had to move the pot to the lawn.

What kind of fertlizer are you using? Manganese, copper and iron will all stain concrete. You can make your own stain removers or buy a ferrous stain remover from a big box store or Amazon.

So pretty!

It could also be salt buildup in your soil. I just flushed a potted ficus tree that had brown rusty looking drainage for quite some time. Flushed it with tap water until the water was clearer then finished flushing with distilled water.

I’ve Never had this problem before. I’ve noticed this recently. It must be a Particular ingredient that is causing this in potting soils. I’ve had this with clients after planting trees in giant pots. The run off is unattractive and annoying!! Going to research this!

I think as someone mentioned earlier it is Ferrous or Iron in the soil. I have had a big problem on my deck which is a Trex deck. I called the manufacture that said basically anything you can use on plastic you can use on Trex. I use A rust remover and it took it right off. I had to scrub a bit where the stain was older. So try a rust stain remover, however, I don’t know how a rust remover impacts concrete. My front patio and courtyard is travertine. I’ve found that scrubbing with soapy water works well after a few days of sunshine.

Thanks for your insight Terry Wilkens! That must be it! I have a large, oddly enough, brown pot that holds the same 3 – 2.5 cu. ft. bags of potting soil I put in it 9 years ago. About 3 years ago I started getting the rusty brown runoff and about the same time I noticed that the water was running straight through. That nasty stain has to be scrubbed well with bleach to get it off the concrete or by pressure washing. I’m finally going to remove all of the potting soil, scrub the inside of the pot, and start over. If that doesn’t solve my problem then the obvious problem is the pot. I hope my plan work!!

I had two big pots with Ivy planted in it. On the entrance way. And suddenly the IVY died, but I think it was getting really old. And now I’m getting the same thing the rusty dark brown stains on the pedestal and the patio cement. It’s really annoying and hard to takeoff. I am wondering if it has something to do with that plant dying?

I planted two new little plants and I don’t want them to die and they don’t seem to be growing very fast. CJ

I was told this could mean too much water, and the water could be settling at the bottom of the pot. This would cause wet feet and the plants will die. I currently have this going on one of my large clay pots. (have 2 identical, only one leaks rust colored water) I may need to rearrange the drainage rocks at bottom of pot. Good luck.

I have used white vinegar with a bit of dish soap, let it sit for approx 20minutes then scrub with a long handled brush. Youmay have to do this a couple of times. There is also a very strong 30% white vinegar used for killing weeds. This may work better but check to see if it is ok on your type of surface

A decade later, I've learned that brown runoff means my pot has worms in it and the worms have turned the "soil" into mud. Great in the ground, but too thick & airless for in a pot.