I have some old copper containers I want to use for planting. Are there any plants that would not be happy in a copper container?
Hmmm... that's interesting. Were they made for being planted in?
Copper is one of the necessary plant nutrients, but it is toxic beyond small amounts.
The only concern I would have is too much leeching into the moist soil, but I have no idea how big a risk that actually is.
hmmmm. I wonder about this. Copper is used as an application to the inside of nursery containers (woody ornamentals...big sizes) to encourage the healthful growth of roots inside those containers. It does so by killing the fine roots that touch the copper, thus forcing the plant to grow more fine roots towards the inside.
I don't think I would use copper containers......(though have used copper marine paint to control root development).
I think I would plant into containers that fit INTO your copper planers. Copper will kill roots.
I think as long as you don't intend to eat what you plant in there and the soil isn't acidic (that is a trigger for leaching), it should be okay. The downside is that copper is a good heat conductor and also oxidizes very readily (the "verdigris" or green/bluish patina that copper can form, along with other oxides that can cause the copper to brown or form white crystals), but these copper compounds can eventually flake off after awhile and you eventually lose pieces of the container...lol
In excess, copper (like aluminum, etc), can become too readily available in toxic quantities in an acidic environment. If you can't control the pH, what you can do is use the copper container as a decorative one and plant in a plastic container that is sunk in the copper one (or line the copper container with plastic and fill with soil - making sure there are drain holes in both).
Here's a trick I use. Spray the inside surface with a couple coats of automotive undercoating. It seals the surface to prevent leaching and corrosion. Plant away!
Again, you can purchase copper lined containers, copper treated burlap, copper treated root barriers, copper lined grow bags, etc. All are used in the nursery industry because copper kills the fine roots. I don't think it's something you want in a permanent planter. So use our collective suggestions (liner, plastic, coating) just to be safe.
Thanks everybody, I think the automotive sealer is probably the route I will take. They weren't originally planters but I like the idea of using them as planters.
So I'll drill some drainage holes and seal up the inside with the automotive stuff. Obviously I won't use these planters for food crops, just ornamental plants.
Thanks so much. :)
I have used copper pots but have lined them (just a black bin liner) and they look great, I like the look as it discolors, don't forget copper repels slugs and snails so great for Hostas etc that attract these pests ;-)
I put a handful of pennies of the surface of my potted peppermint, because I was told that it would keep away slugs. I don't know for sure, but I suspect that the copper leaked into the soil and killed my plant. It was thriving and made a steady decline. I thought for awhile that it was because it was getting colder outside, so I brought it inside. It's leaves continued to turned yellow and then brown, but not all at once, it happened one stem at a time.
Copper is an element essential to normal growth and good health, but like all of the micro nutrients, it becomes toxic VERY quickly. Post 1982 pennies are 97.5% zinc and 2.5% copper plating. Both copper and zinc would very quickly reach toxic levels if allowed to oxidize in the soil.
If you want to keep slugs away, use a copper wire around the rim of the pot or a length of copper foil used for stained glass projects. It does work.