How to Turn a Galvanized Metal Trough into a Painted Planter

Posted by John Jennings, Manager


Looking for something really unique to jazz up your poolside, patio, or porch?  Can’t find anything just the right color?  Are you thinking of building a planter out of wood just so you can paint it yourself but don’t want it to rot?  Consider converting a galvanized metal livestock trough into a custom painted metal planter.

Painted Metal Planter using Sherwin Williams exterior latex enamel, a blue called “Commodore” (SW6524) with striping and trim in a yellow called “Honey Bees” (SW9018). The plants added for staging are a desert willow and purple pixie lorapetalum.


Metal livestock troughs can be used in a wide variety of ways.  Imagination is your only limitation!  This article is about custom painting a metal livestock trough to use as a planter.  Of course, it can make an excellent planter, as is, with no painting, provided that holes are punched in the bottom for drainage.  But, many prefer a custom color scheme.  To achieve the look, we took the following steps:


  1. Prepare the surface for primer adhesion.


Coat the entire surface with Zep acidic toilet bowl cleaner, let sit for an hour, coat again with Zep acidic toilet bowl cleaner, let sit for two hours, and then rinse off to remove the zinc coating added during the process of galvanization.  No paint that we know of, except for a paint sold by Benjamin Moore that only comes in three colors, will adhere to the surface well unless the zinc coating is removed, regardless of what the manufacturer says on the container.

Begin with a high quality heavy gauge metal trough like the Tarter products we currently carry.

For example, this author first went to a Sherwin-Williams store and the clerk there insisted that their multi-purpose primer would work without first treating the surface.  He even showed me where it says right on the container that it will adhere directly to galvanized metal, saying nothing about removing the galvanization first.  Alas, against my better judgment, I tried it.  None of it adhered, at all, and we had to strip the entire surface and start over.


Use an acidic toilet bowl cleaner to remove the zinc coating before applying primer.

A gallon of the Zep Commercial Acidic Toilet Bowl Cleaner cost us less than ten dollars and we used about half of it on the approximately 2x2x3 feet trough we painted.  At the time of this writing, a 32 ounce bottle is available at Home Depot in midtown Memphis for $4.49 plus sales tax.


The active ingredient in the Zep Toilet Bowl Cleaner is hydrochloric acid.  This is the same active ingredient in muriatic acid, but likely in a much lower concentration.  Experienced painters or those comfortable with chemicals will likely prefer to use muriatic acid and dilute it themselves but, for consumers, we felt this was a better approach.


Our research also indicated that white vinegar can work, since it too is very acidic, cleaning vinegar in particular, but will take much longer and may not completely remove the coating, leaving spots where paint can come off.  Note that if you just want an aged zinc look, rather than painted metal, an application of white vinegar for 20 minutes, followed by a rinse off, might do the trick.  But, you’ll want to experiment with a cheaper piece of galvanized metal, like a small trash can before trying it on a more expensive, brand new trough.

This is the point at which we pulled off the tape, were pleased with the lines, but realized that the initial primer effort had failed because we had not first removed the zinc coating.

Remember to carefully read the safety instructions on the bottle of Zep and follow them.  Wear goggles and gloves and reduce exposed skin areas as much as possible.  We used disposable latex gloves that offer some resistance to hydrochloric acid but neoprene or plastic might have been better.   Do not mix with any other chemicals, being sure in particular to avoid bleach which will combine with it to create a toxic gas, and be sure to keep baking soda on hand to quickly neutralize the acid and wash it off if any gets on you.  Do this project outside or in an area with really good ventilation.  Keep children and pets away.


  1. Provide proper drainage for plants.


Punch drainage holes in the bottom of the container with a large nail or other pointed hole punch and a hammer or drill holes with a bit specifically for cutting holes in metal.  Be sure to punch holes in the bottom from the outside, with the nail going into the container, to keep the bottom of the surface level.  File down any jagged or sharp pieces that might cut you or others.


When you plant, make sure to put some product in the bottom, like gravel or packing peanuts, wrapped in landscape cloth, to keep soil from packing and plugging the holes you created.   An excellent solution we currently sell is called “Drainit,” disks that come in a variety of sizes, ranging from $4.99 to $12.99 at the time of this writing.  (


Most plants need access to moisture all the time, through their root system, but will die if sitting in too much water.  Very few plants can handle constant or even nearly constant wet feet.  (A few exceptions might include equisetum, Louisiana iris, and papyrus, plants that typically grow in boggy areas or along the edges of bodies of water.)


Be sure to use something like pot feet to raise the planter up enough to preserve drainage and some sort of reinforcement under the trough to provide support.  There are many ways of accomplishing this objective, too numerous to list here; just know that if there is no space between container and ground, there is no drainage.  Water must have an empty space in which to drain.


  1. Prime the surface.


Spray the entire surface with Rustoleum Self-Etching Primer.  There are likely many types of primer that will work but this is the one that works best of the primers we tested.  One can cost $4.76 at the time of this writing at Home Depot in midtown Memphis.  We used only one can but ran just a little short, filling the gap with another primer we liked less.  We could have used another quarter can or so.


Remember that when you removed the zinc coating, you lost the benefit of galvanization, rust resistance.  It is best to coat the entire surface, even the edges of the holes you made for drainage, with both primer and at least two coats of paint to reduce the likelihood of rust.


Allow the primer to dry for 2-24 hours, depending upon temperature and humidity.  Dry to the touch is probably good enough.  We painted 3 hours after applying the primer on a hot July afternoon.


  1. Define the lines with tape.


If you are attempting to do a two tone look, like ours, use painters tape or masking tape to define the lines.  Unless you are an experienced artist or just painting the entire container a single color, don’t try to free hand it.  Make sure the tape is firmly adhered without bubbles along the edges to keep paint from drifting underneath it, distorting what would otherwise be a clean line.


Initially, we taped over every area where we do not want yellow paint, leaving only the stripes and trim exposed. In this image we are about half way through the first round of taping.

When you go to apply the second color, you will have to remove the first round of tape and apply new tape over the area previously painted.  If the first color is not thoroughly dry, the tape may pull it off so don’t be in too much of a hurry to apply the second color.  We waited until the following day but it was a hot time of the year in Memphis, July, despite being very humid.  You might be able to apply the second color after only a few hours on the same day or you might have to wait 2 or 3 days depending upon the temperature and humidity.


  1. Paint it.


We used Sherwin-Williams exterior latex enamel.  In all likelihood, most paints will work if the surface is prepped and primed properly but we wanted the most durable, easily washable coating possible.  We decided that would be an exterior latex enamel and Sherwin-Williams just happened to be the closest most convenient source for us.  For this project, we also wanted a shiny, vibrant look to intensify spring and summer color and balance blander winter tones when trees defoliate, warm season grasses tan, and flowers disappear.

First of 3 coats of yellow, having taped over every area we did not want yellow paint. Later, we took off all the tape and then taped over the yellow before applying the blue.


We waited two hours after the first coat before applying the second coat, and then applied a 3rd coat the next morning.  We repeated the process after removing the first tape and applying new tape to define the field of application for the second color, again applying 3 coats.


  1. Plant it.


Remember that healthy plants start with good soil.   There are many different brands that are good.  We are currently selling Fafard’s Ultra Container Mix with Extended Feed, which we like a lot, but we also sometimes sell Dr. Earth, Vortex, Fox Farms, and Happy Frog, all good mixes.  There are also lots of recipes online for making your own from bulk ingredients, if you need a lot.  Just make sure that the soil is a container/potting mix rather than garden mix.  Garden mixes tend to have too much organic matter and are heavier, retaining too much water for containers that may not drain as well as in-ground planting beds.


When planting in containers, choose plants that are hardy for your area to two zones less than your planting zone.  Remember that plants in outdoor containers must be cold hardier than plants installed in-ground to survive our winters.  For example, Memphis is a Zone 8a (though it used to be classified as 7b).  Therefore, any plant you expect to survive our winter will need to be zone 6a or better unless the winter is unusually mild.   For obvious reasons, plants in containers just aren’t as well insulated from temperature as plants in-ground.

Kelly Myracle, one of our bright and talented employees, did most of the labor associated with this project and is a good person to talk to when you visit us, if you are considering a similar project.

This project will likely take you about 6-8 hours spread out over a few days.  It could be done in one weekend but does not have to all be done at once.  It can be a pleasant stress relief to do alone but it can be an even better experience to do it with partners or children.  Just be sure to exercise every safety precaution and perhaps use the hydrochloric acid (acidic toilet bowl cleaner in this case) before including a child in the project.  As always, don’t be in such a hurry to get to the outcome that you miss out on what you might have gotten from the process.  As Pirsig wrote in his book, Zen and the Art of Motorcyle Maintenance, “We’re in such a hurry most of the time we never get much chance to talk. The result is a kind of endless day-to-day shallowness, a monotony that leaves a person wondering years later where all the time went and sorry that it’s all gone. ”   Garden projects are the perfect vehicle for connecting with others!

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