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.

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.

Al

Hi Rain 1950 / others , just saw the comment about coating copper planter with auto undercoat. Aside from from preventing copper toxicity with the above approach, would copper rust or get damaged with the watering? Would you recommend drilling drain holes as well?
MC

Doc, if the plants are to planted directly in the copper vessel, then yes. It if the treated vessel is merely serving as a cache pot, then drilling is unnecessary.

Don't forget to guard against cache pots being filled with water and causing death by inundation.

Only iron and ferrous alloys rust. Copper goes through a three-step
process where the copper oxidizes and forms (you guessed it) copper oxide, then combines with sulfur in the air to form cuprous/cupric sulfide, and then forms copper carbonate, which results in the green colored patina (verdigris) that forms over time. Plants require copper for normal growth, but copper is very toxic at levels only slightly above the adequacy range, so be aware ........

Al

What about using copper mesh to prevent voles from damaging bulbs and roots of non-edible plants? Like this one: http://amzn.to/2BzVWRq

I've been told copper isn't good for plants but I have a string of pearls planted in a little hanging copper bowl and it is very healthy.... been growing in that same container for several years.

I planted my hydrangea in a big copper pot that I sunk into the ground about 1 1/2 feet. The plant was doing great, but this year it looks really bad. So I think I’m going to have to sacrifice it and pull out the pot. How do I neutralize the soil so I can plant something else without the pot?

I have copper indoor planters and I am a complete Newbie so please be kind haha. I've done research but just want to confirm what I should be doing. It is also in a stand, so does not sit on the floor. So I should line it with plastic (are bin bags okay to use?); then I should put drainage in, I've read polystyrene is good; then topsoil, then plant, cover with more soil and press down soil, then water. Is that correct? Do I not need some drainage Holes?Thanks in advance!

"So I should line it with plastic (are bin bags okay to use?" Copper (Cu) itself is very toxic at levels above the minuscule levels plants need for normal growth, to the poison is in the dose. You should use your copper vessel as a cache pot, and nest the pot the plant will actually be growing in inside the copper vessel. The pot you grow in needs to have a drain hole, and since the salts that will be flushed out of the grow medium when you water should never have a pathway by which they can make way back into the grow medium, you should water over the sink, and wait for the pot to stop draining before you return it to its home in the copper vessel. If you like, put a collection saucer in the bottom of the copper pot to protect it, but don't allow the actual pot the plant grows in to sit in the effluent that exits the drain hole. "Should I put drainage in?" Your pot needs a drain hole, and, if you're talking about creating some sort of drainage layer with gravel, packing peanuts, or other coarse material(s), you'll soon discover it's counterproductive. The idea is sterling, but the reality is something altogether different. The pots below are full of grow medium. The shaded area labeled PWT (perched water table) represents excess water that comes as an inherent part of all commercially prepared grow media based on large fractions of fine particles (peat, coir, compost, composted forest products, sand, various meals (like cottonseed meal, feather meal, etc), sand, topsoil. Use the middle image below as an aid to visualize what happens when you use a drainage layer - it simply moves the excess water to a position immediately above the drainage layer.

"I've read polystyrene is good; then topsoil, then plant, cover with more soil and press down soil, then water. Is that correct?" No. Topsoil might have a place in some grow media where weight to prevent blow-over is essential, but by and large all topsoil does is destroy drainage and aeration. What works in the garden (insofar as the soil is concerned) is extremely difficult to grow in when put into service for container culture. It holds much too much water, much too little air, and after a fer waterings will be extremely compacted.

When I plant in an organic-based medium like this,

I make sure the medium is moist but still fluffy, then fill the pot until it's appropriately full. I always correct root problems, especially root congestion, even if the plants are in cell packs. Often, I simply rip the bottom half of the roots off, then work my fingers up into the center of the root mass before I set the plant on top of the soil with the roots spreading away from the stem. Then, I add a bit of grow medium and make sure all the roots are covered and there are no air pockets in the root zone. Finally, I WATER the plant in and avoid compressing the medium. If the plant seems to want to flop over, I figure out a way to secure it just long enough to ensure it's stable.

Al

Thankyou for the info, appreciated

Hi thank you for the info ! i planted two monsteras in a copper tub a few years ago and at the same time i had a 3rd one that i planted in a ceramic pot. They were all about the same size. The two in the copper pot are HUGE while the 3rd one while healthy is no where near their size. I’m wondering if the growth is due to genetics or the copper pot - same grow lights etc - i find it hard to believe the copper pot is the reason for the difference. Thoughts ? and they’re getting transplanted asap.

It's definitely not the copper giving that makes 2 of your plants more vigorous. The only way that could happen is if a copper deficiency was the only thing limiting growth, the soil pH was low enough to make the copper soluble, and the additional solubility fixed the copper deficiency. The odds of that happening are extremely low as copper deficiencies rarely occur (in containers) without a number of other deficiencies that would be attributable to low fertility in general (of all or nearly all nutrients. In that case, it would be far better to fertilize with a product that provides all nutrients essential to normal growth, in the ratio at which the plant actually uses the nutrients. Foliage-Pro 9-3-6 does a remarkably good job at doing that.

It's possible it could be a genetic thing, but since there are 2 plants involved and both plants showing more vigor or vitality (they are different) happen to be in copper pots (are you absolutely sure they are copper and not just plated with a coppery-looking metal?), it's unlikely. Look to other cultural factors like better light, better soil structure, root congestion as a limiting factor, temperature, soil pH, different fertility levels, etc.

Al