Watertight aluminum planters – drainage solution

Aluminum powder coated planters offer an attractive and durable solution for adding landscaping to an existing urban location.  The benefits of aluminum planters are: rustproof, crackproof, frost-proof and pest-proof.  It is important to note, that the soil inside the planters contains minerals which can be carried by water runoff from watering the plants and may stain adjacent materials such as concrete.  For this reason, on a recent project in Seattle, the planters were not allowed to drain onto the adjacent sidewalk.  To work around this restriction, we manufactured the planter boxes with no drain holes and welded all seams to be watertight.  Also, the client built in a clever water collection and monitoring system, which can be pumped out as necessary. A layer of gravel with a geotextile fabric are placed on the bottom of the planters and a PVC pipe extends from the gravel to the soil surface to be used with a kayak pump to remove excess water. To grow healthy plants all planters have to drain. Proper drainage assures optimal soil pH levels and prevents watterlogging, which is harmful to plant roots.

Using Cor-ten planters to create a desert garden

Creating a garden in a hot desert Las Vegas climate has it’s challenges and opportunities.  Utilizing custom Cor-ten steel planters our customer was able to create a low maintenance garden that looks great all year long. The use of succulents and other desert plants in these weathered steel planters reduces the need to water while at the same time increases the home’s curb appeal.  Contemporary trough planters add an element of dimension and create extra space for more plants without being boxy, while oversized Cor-ten steel square planters, placed on each side, create depth.

Expandable Modular Corten Planter Beds

Corten steel garden beds are a durable and attractive option for landscaping in a home or public setting.  Installations of steel planter beds often involve custom metal fabrication with cutting of steel, grinding and fitting, transporting to site and finally welding on-site.  We have designed a raised corten steel planter bed that requires no welding and can be assembled in two popular dimensions: 4 ft x 4 ft x 16 inches high and 4 ft x 4 ft x 16 inches high.  The planter beds ship in a flat pack to your location and can be easily assembled by home owners, gardeners and landscapers with no specialized tools or training.

Another great benefit of our design is that the same packs can be assembled into extra-long continuous gardens.  In the picture you can see two long garden beds assembled from 4 ft sections, in the forefront, 16 feet long garden bed and a 12 foot long garden bed in the background.  This a great and easy way to create a custom corten steel garden at an affordable price and minimum installation time.

Corten planters on the beach

If you are in Southern California take a short ferry ride from Long Beach to Santa Catalina Island.  Looks like an amazing place to relax and take in the views of the water.  When there, make sure to visit the Harbor Sands at the Two Harbors to check out some Nice corten steel planters.  Special thanks to www.VisitCatalinaIsland.com for sharing these pictures.

Corten Steel planters as movable screens and dividers for open floor plans

Open floor plans in homes and offices are becoming very popular.  Here is an example of using extra tall corten steel planters as a way to divide and define the open office space.  Because these planters have casters it is easy to move and reconfigure the work space when the need arises.  Also, having plants as part of the screen and divider systems will reduce employee stress and improve employee health.

Planters with decorative laser cut corten steel privacy screens

Fast and easy way to get some privacy for your deck or patio is to install some corten steel planters with decorative laser cut corten steel privacy screens.   Here are some of our Nice corten planters on casters with screens mounted to the planter box. 

Eliminating staining from corten steel planters through thoughtful design

The look and style of corten steel planters covered in warm brown patina is very popular.

While the patina on the planters is loved nearly by all, the rust run off that may stain stone or concrete surfaces that the planters sit on is not desired by many.

When corten steel planters are exposed to rain and moisture the metal oxidizes and forms the protective patina.  During this oxidation process the rust particles are carried down by water to the surface that the planters reside on.

The best approach to eliminating the appearance of rust staining when using corten steel planters is to design the planter installation in a manner in which the rust does not run off on to concrete, pavers or patio stone.

In this installation the planters are placed directly on pedestals, and the concrete pavers are placed on the sides of the planters leaving a 1/16” of a gap between the paver and the planter. The rust run off drains down to the subfloor and does not come in contact with the concrete pavers.

Corten Steel Planters Roof Terrace 2


Here the planters are installed in a pit and drain onto the soil

corten steel square planters bamboo california


In this installation the planters are placed directly on the subfloor around the perimeter of the patio and the decorative rock is added for aesthetics.


corten steel planter on patio in rock


In this installation the planters are placed on decorative rock allowing the rust run off to filter down to the soil.

corten steel planters in rock


Here a drainage tray is used to contain the rust run off from the corten planter.  In installations where the planters are exposed to rain, additional accommodation should be made to channel the water from the tray via a drain hose.


corten steel planter in drainage tray


Growing bamboo in corten steel planters

Bamboo can be grown in corten steel planters provided a few simple steps are taken to provide the right conditions.  It is important to select the correct species of bamboo for your location, application and climate.  For this you should consult your local bamboo grower.  For this project Spectabilis bamboo was used.

Proper drainage is vital for healthy bamboo.  Our trough corten steel planters come with 6 drain holes that are 1” in diameter.  Also, should it become necessary, it is relatively easy to cut out additional holes for drainage or irrigation tubing.

Because metal absorbs heat we recommend insulating the walls of the planter to protect the roots of the bamboo on hot summer days.  Corrugated plastic can be used to insulate the inside walls of the steel planter.  Corrugated plastic is a good choice as it will create an air gap between the roots of the bamboo and the hot metal.  Plastic sheets can be easily cut to size by a utility knife to fit inside the planter box.  The plastic sheets can be purchased from a local sign supply retailer or online.

The roots of bamboo need room to grow, so choose a container that has space for the roots to thrive.  The 20”Hx46”Lx20”W corten planters have 80 gallons of volume to accommodate many species of bamboo.

Taking care of these few key points can assure that you are successful at growing beautiful bamboo in corten steel planters.

grwoing bamboo in corten steel planters

corten steel square planters bamboo california

Corten steel raised planter beds

Raised garden beds and planters are great for growing plants and vegetables.  Corten steel garden beds are an excellent way to add some modern garden pieces to your backyard and grow some delicious vegetables at the same time.

Our retail corten steel planter bed has perfect dimensions at 14″ high and 40″x40″ long and wide.  Makes for easy weeding and is convenient to reach all plants.  Also, it is big enough to have plenty of soil volume that it will not dry out on a hot summer day. Very sturdy and easy to assemble. It has no bottom and is designed to be placed directly on the ground.  Install the bottom edges of the planter at ground level and do not bury them in the soil completely.

growing vegetables in corten steel planter beds


Also, the same design can be fabricated with custom dimensions.  Here are two such corten steel raised garden beds with custom dimensions of 60″long x 36″ wide x 26″ high

custom corten steel planter beds

Selecting plant colors for metal planters

On my recent trip to San Francisco for our new bench top planter photo shoot I had a dilemma; which plants look good with rust and corten steel and which plants would look good with charcoal gray finish?  Luckily I had the help of my friend and garden designer Dat Pham.  On our trip to the local nursery Dat picked out a cart load of plants and explained that red and orange plant colors would work great with rust accents of the corten steel planter, and green silver colors of plants would look fantastic with the clean look of powder coated charcoal gray.  As a side note, if you need to achieve the wild rust colors that are in these pictures, the only way to do that is to acid wash the corten steel. Naturally, corten steel will form a very even and uniform rust color and texture.

If you are in the San Francisco area and need help with garden design, plant selection, or would like to check out the planters in these pictures, stop by Dalat Design and talk to Dat.  He will blow your funky mind.

corten bench planter gray aluminum planter bench

Rectangular powder coated aluminum planters with gravel rock Arizona


Corten Steel Planters on Casters

Putting casters on planters is not always an easy thing to do.  The planter has to be sturdy enough to handle being rolled around, and the casters have to be tough enough to support hundreds of pounds of soil that is inside the planter.   Our approach was to design a caster frame from angle iron that the casters bolt to, and the corten steel planters sit inside the caster frame.

Here are some pictures of our planters at Blue Line Pizza in Campbell, California.  The city ordinance does not allow for objects to be left outside the restaurant on the side walk.  The planters are used during the day to define a patio space, and are rolled away and stored in the evening. Stop by, have some pizza and beer and check out these planters.

corten planter patio 1 corten planter patio 2 corten planter patio 3

Growing herbs and vegetables in corten planters

Corten steel planters are great for container gardening.  They can be used in areas such as rooftops or patios to create herb and vegetable gardens.  Also, they are ideal for utilizing space along the fence to plant herbs and vegetables.  The area along my fence receives only a couple of hours of direct sun light a day, so I selected shade-tolerant greens: arugula, kale and kohlrabi.   I placed my corten steel planters (16”x46”x16”) along the fence.  I set the planters on top of grey concrete blocks, which allows the planter to sit higher off the ground so I don’t have to bend down as much, and also keeps the planter bottom from being buried in the ground.  I am very happy with how well things are growing in my planters this year.  I have been enjoying some delicious fresh salad.


Corten steel planters herbs vegetablescorten steel planters Kale arugula kohlrabicorten steel planters kohlrabicorten steel planter kale

Will my Corten Planters stain surrounding area with rust or runoff?

We often get asked if the Corten Steel Planters will stain the adjacent area by producing rust runoff or by being in direct contact with the surface the planter sits on.  Below are some pictures of a Corten Planter that has been weathering in the same spot on the patio for about four months.  The outside of the planter is completely covered with rust and the patina will act as a protective layer and prevent any further corrosion on the outside walls of the planter.  From the pictures you can see that there is very little rust run off (virtually none).  At this point the planter is weathered and the weathering steel should produce very little to no rust run off.  A point to consider is that Corten Steel (weathering steel) seals and fully weathers best when it is repeatedly exposed to moisture and then is allowed to dry. Thus the amount of rust run off could vary by climate.  As a reference the planter in the pictures is happily weathering in Seattle.

Also, staining will occur were the planter metal comes in direct contact with the surface the planter sits on.  If you are placing your planter box on grass, lawn or dirt than there is nothing to worry about.  Or if you never plan to move the planter you will never see the marks it leaves underneath the floor.  But if you plant to move the planter and do not want rust marks you should make sure the planter metal does not come in direct contact with the surface that can be stained.  For our planters this can be achieved  by placing a plastic strips on the channel feet/legs the planter sits on.   Another, solution is to place the metal planter box onto casters.  Placing the planter on casters will eliminate direct contact and allow you to easily move the heavy planter.

Generally, If you cannot stand the ideal of the smallest amount of rust on your deck or patio Corten planters are probably not ideal for your application so consider other metal planter options like Stainless Steel or Powder coated aluminum.

corten planter box  rust

Advantages of Powder Coated Aluminum Planters

Aluminum is a very strong yet lightweight alloy that is well suited for construction of large metal planters. Aluminum is naturally rust-resistant and can be powder coated in just about any color. Powder coating is a durable and environmentally friendly coating process that contains no volatile organic compounds.

Unlike some plastic planters that can crack in freezing weather, or bow in hot sunny conditions, aluminum retains its structural integrity. See some pictures below of a 20”x20”x20” aluminum planter enjoying the sunshine, and in the winter being frozen solid. Planting in durable metal planters eliminates the need to winterize the containers by moving them inside to shelter the planters from extreme weather.

red metal planter

red aluminum planter

Rectangular powder coated aluminum planters with pebbles

Corten Steel Planter as a retaining wall or garden hedge

Recently I helped a friend build a brick patio in front of his new house. The court yard area sloped down towards the front entrance so we had to level the patio area by digging up the dirt and installing an interlocking brick retraining wall. The brick patio and the brick retaining wall was a fairly strait forward installation. One issue that came up was that on each side of the retaining wall we had a sloping fence and exposed soil. Extending the retaining wall on each side would have cost more money and a side retaining wall that is just one or two bricks high would look awkward. So we decided to use the rocks that we dug up in the process of leveling to cover up and hedge the exposed dirt. Then we placed a Corten Steel (also known as weathering steel) planter box on each side to cover up the rocks and give the patio a finished look. The combination of the rocks and extra long Corten planers provide a natural transition for the sloping sides which would have been difficult to achieve with brick or other hedging solutions.

corten steel planter wall

Will my stainless steel planter rust?

The two grades commonly used for outdoor planters are 316 grade, known as marine grade, and 304 grade, more commonly used for outdoor planters. Both grades are suitable for use at inland locations whereas 316 grade is recommended for use in coastal, marine or heavily chlorinated environments. Our standard planters come in 304 grade stainless steel with a fine brushed finish.

To periodically clean the planters use non-abrasive cloth and warm water with or without a gentle detergent. Always wipe with the directional grain of the steel. After washing, rinse with fresh water and dry thoroughly.

Salt water air and other chemical may result in small brown spots appearing on the surface of the planter. The spots can be easily removed by gently rubbing the surface of the steel, in the direction of the brushed finish, with a Scotch-Brite pad.

Stainless steel will not rust but it is vulnerable to salt air and chlorine. 316-grade stainless steel is made with molybdenum and is manufactured for costal use. The molybdenum provides higher resistance to pitting and crevice corrosion and gives 316 better overall corrosion resistant properties.

A stainless steel planter will provide you with years of use and enjoyment without rust.

Planting in deep planters / pots and how to make large planters lighter


My neighbor taught me this trick after she purchased one of our Corten Steel planters.  She uses empty plastic water bottles to fill up the planter about half way and then fills the planter up with dirt to the top.

This approach has several benefits:

1) The planter is not as heavy because half of it is filled with air that is inside the empty water bottles.

2) You can use less dirt to plant.

3) Plastic bottles at the bottom of the planter allow for excellent drainage.

4) Plastic bottles at the bottom of the planter promote air circulation and will help to keep the roots of your plant cool.

5) This is a great way to reuse the bottles which may otherwise end up in the trash.

Tip: make sure the water bottle caps are nice and tight on the bottles.  Each bottle should act as an air bubble and keeping the caps tight helps ensure the bottles do not collapse under the weight of the dirt.

How to line the bottom of a planter on the cheap

Say you are filling your planter box or flower pot with dirt on the deck or inside the house and you do not want dirt coming out from the drainage holes, but you still need the planter to drain.  You can run to home depot and get some landscaping cloth (about $10).  But why do that?  Just line the bottom of your planter with newspaper or brown paper grocery bags.  The paper will allow the water to drain while keeping the dirt from falling out.  Also the paper will retain moisture, so less frequent watering needed.

I would stay away from using magazines, as all that paint on magazine pages will most likely prevent water from draining.


We often get asked about the best way to rust a Corten Steel Planter or are there things that can be done to make the planter rust faster.

Our Corten Steel Planters are made to rust and will start showing the signs of rusting if you just put them outside for a couple of weeks and let Mother Nature take its course.

If you do not want to wait for a couple of weeks, wash the planter with warm water and soap when you first receive it.  This will remove any remnants of oil and the water will react with the metal initiating oxidation (rusting).  A periodic mist of water will accelerate the oxidation process, especially if you are in a dry climate.

Spraying vinegar onto the planter will give it the rust look in a matter of minutes.  This rust however washes off, so the next time it rains, your rust will be gone.  The planter really just needs a few months, with or without vinegar, to gain a natural layer of rust and seal.