Risks and Pleasures of Planters on Decking


I am a little giddy with excitement to write this article because it involves two things I love, Decks and Plants. A match made in Heaven, I am assuming there are decks in heaven. In Revelation, there is definitely a garden, so safely assuming plants. But till we get there, can you put planters on decking?

Yes, Yes, and Yes, putting planters on your deck is a wonderful idea. The microenvironment on a deck can be an excellent growing space for plants. There are some risks with planters on decking, like water and fungi but you can put planters on decking. These risks can be minimized allowing you to enjoy your deck plants.

First, let’s discuss why planters on a deck is an excellent idea, then some of the risk of planters on decking, followed by solutions. I hope that in the end, you will be inspired to have plants on your deck, all while protecting your deck to be enjoyed for years. Grab a water, stretch out on your sun chair, we are about to make your deck better. Can you believe that? Making your deck better.

Goods thing about growing plants on a deck

A deck is like an open greenhouse. Without all the glass hindering the sound of birds singing in the background.

A deck’s Micro Environment is excellent for growing plants.

The very things that you enjoy about your deck, so do plants. It is a warm, sheltered area to enjoy the sun. Plants love, need the same. A warm and sheltered area to soak up the sun’s rays.

The very reflective nature of decking, both composite and wood, increase the surface air temperature, your deck is warmer than your yard. More warmth spurs plant growth and extents the growing seasons. If you have had no luck growing tomatoes, your deck may be the answer with both warmth and a longer growing season.

Also, the very placement of your deck helps to protect the plants from the environment, mainly the blowing wind. Backyard decks are protected by your house, which often helps to warm the deck but also stops the wind. In Calgary, it’s the cold blowing north winds that freeze and the howling west wind that dries.

If you are so fortunate to have a south face deck. The house will stop the freezing north winds. A privacy fence along the West side of the deck will shelter the plants and you from the west wind. Creating a mini greenhouse without the roof. Along the house wall and privacy fence are wonderful areas for planters and hanging plants.

I love plants, but I am no expert, but Antonia Colgrove is. If you wish to learn more about the technical parts of growing plants on your deck, check out here website,  Beside the Front DoorOpens in a new tab. to learn more. But before you do that, let’s get back to what I am an expert in, decks.

Plants bring life and colour to your deck

As creatively as a deck can be built, nothing can match the beauty of plants. Adding plants breaks up the mundane of wood or composite. Regardless of how it’s laid out, decking is row upon rows of the same material and design. Adding a planter on the decking adds a splash of life on your deck.

A wisely selected flowerpot will bring change, colour and beauty to the deck. As the seasons’ change, so does the planter. In spring small shoots of life springing forth. Breaking into a jungle of green leaves, then springing forth flowers and colour. Regular deadheading extending the flowers for days and possibly weeks. Becoming the focal and pleasure point of the deck.

Planter on your Deck bring your Garden conveniently to you

As I have said before, your deck is a bridge between your house and nature. Putting plants on your deck brings nature just one step closer to your house. Without gearing up to go work in the garden, you can stroll barefoot with your robe on and enjoy nature. Plants are life and they give life to those who enjoy them. What’s that saying?

“take time to smell the roses.”

Not sure who first said it, but taking time just to enjoy plants and life, makes life worth it. Planters on a deck make this that much easier. The “roses” or whatever else you decide to grow are just a short walk out your door. Planters on a deck are a convenience for enjoying life and relaxing. 

Speaking of relaxing, I am not sure about you, but I find it hard just to sit and enjoy it. Laying in a sun chair for hours appeals little to me. But bringing pleasurable, relaxing activities draws me in or out as your deck would have it.

Planter provides Pleasurable work on your deck

Planters on your deck give you something relaxing to busy yourself with while enjoying your deck. Going from planter to planter watering the plants. Like an old farming strolling along your deck inspecting your plants, crop. Enjoying the beauty and life they bring. If you go with vegetables, you can even eagerly watch and enjoy your produce. As the fruit ripens on the vine. Anticipation building every day as it grows and matures.

But more importantly, you have something to immerse yourself in as you enjoy then sun. Your body soaking in vitamin D, raising your mood and releasing life’s tensions. As you nurture your plants, they, in turn, can nurture you. With the regular rhythm of water, trimming and feeding plants on your deck, bringing you meaningful but relaxing work to do.

I hope you are all excited now about growing plants. I know I am. But planters on decking bring with them some risks. The very things that help plants grow can damage your deck. Destroying your outdoor oasis. I have a larger article about preventing joists from rotting, Opens in a new tab.click the link to read. It goes to greater lengths to explain what causes rot and how to prevent it.

In short, water and fungi are the biggest risks to your deck. The two essentials to growing plants. The more I learn about plants the more I discover that it’s the microorganism in the soil that makes all the difference to healthy plants. But when talking about decks, we call this “Fungi” the number cause of rot and deck failure.

Risks with Planters on a Deck

Risk of Water Damaging your decking

Plants grown in planters will require regular watering. More so then garden plants as the container both limits water and increase evaporation. But ever time you water your plants, you are possibly damaging your decking.

Increased water increases the potential of wood rot, destroying the decking. Moisture is one of the essential elements for rot.

Also, water can stain your decking; both wood and composite can develop unsightly stains. With wood decking, it will discolour and swell the decking. With composite, it will be more a surface-level discolouration. Both making your beautiful deck, ugly.

Risk of Fungi rotting your deck

As I already said, plants require a healthy level of fungi in the soil to feed the plants. Breaking down the organic material into nutrients for the plant. This fungus is good. No, it’s great, it’s essential for your plants. But your deck is also organic material. The very thing that is causing your plants to thrive by breaking down the compost can do the same to your deck. The fungi know no difference between a twig, mulch or decking. To the fungi its all food to be broken down.

Risk of Freezing of Plants in planters on the deck

Not so much a risk for your deck but more for your plants. Most planters are small and will freeze in the winter. Remember that the frost level that the decks footing need to be below. That’s how far the cold can go. In Calgary, that’s four feet. Meaning any planter less than four feet deep and wide can freeze in the winter. That’s every planter on your deck.

Which is fine for annual plants or even perennials growing in your yard. They can survive the cold and sprout up after. The problem is with plants from warmer climates who are not designed for winter.

Also, the microenvironment that makes your deck so great for plants can kill them if not managed. Plants don’t have calendars; they know not when its spring. They only know when it’s warm. When a few sunny days come in winter, warming your deck. Thawing the frozen planters They are like hey, its springtime, time to grow. Throwing all their reserves into producing leaves. But when the weather turns and freezes again, all is lost. The poor plants can only do this so many times before there is nothing left, and they die.

As you can see, these are our three risks to planters on a deck. Water and fungi damaging the decking along with freezing of plants.

Preventing Planter from Damaging Decking

We will divide this into two categories protecting decking and plants. With some solutions to help you enjoy your deck and plants for years to come.

Protecting Decking from Water and Fungi

First, a call for regular deck maintenance. With all decking, but especially wood decking, regular maintenance is essential to compacting water and fungi from damaging your deck. Decking needs to be regularly cleaned removing any build-up of dirt between decking or anywhere moisture can be trapped.

With wood decking, sealing and staining are essential. Only keeping a deck free of debris will protect and extend its life more regular staining. Planters increase the amount of water on your deck. Increasing sealing and satin will help to preserve the decking. Make a point of staining your deckOpens in a new tab. every year. For you may enjoy your deck and plants longer.

Along with regular cleaning and staining, here are a few things that will help your decking under planters.

Move Lightweight Planters Around

Have a plan to move planter around the deck every seven days. Allowing the decking under the planter to dry. Reducing water damage to the decking as the water will quickly evaporate once exposed to the sun. This will also reduce fungi from spanning on the decking with the decking drying out before it can germinate.

“It is recorded in laboratory culture experiments that spores can germinate between 7-10 days following suitable wetting

TimberWiseOpens in a new tab.

You can do this by picking up each planter and moving it a few feet ever week, but a more convenient option is pot caddies. Pots with wheels allow you to move the planter with ease ever week without any stain in lifting. Also reducing the risk of spilling the planter when lifting.  Wheels also double to allow air movement under the planters our next suggestion.

Create Airflow Under Planters will save the decking

Raising the planter a few inches of the decking creates airflow allowing the decking to dry. Dry decking hinders rot and limits fungi as its no longer a damp unventilated area. Not just under your deck but also under your planter ventilation is a good thing. Ventilation doesn’t have to be a complicated thing, just space between the decking and planter. Here are a few ways.

Pot caddies. The reason I like pot caddies is they allow both airflow and movement. The wheels allowing you to regularly move the planters to clean under while increasing air movement when even when not moved.

Amazon has some good caddies that double as planter saucer collecting runoff water. With 4 wheels the caddie can hold a 10 5/8” (270mm) diameter pot. Strong enough for 125 lb (56kg) planter.

Off Cuts of Cedar. If your decking is cedar, this is gold. While building your deck, you will have small cuts of decking which can be used to raise the planters off the decking. Gather these up, cut them to fit under the planters. Spacing them to allow air to flow under the larger planter. Over time they may become wet and damaged themselves but can be easily replaced compared to replacing the actual decking from water damage. The larger pieces will provide

good support for heavier planter while not imprinting the decking. But they can trap water so regularly moving will help to allow the decking to dry. A dolly can conveniently help with lifting and rolling.

Bottle caps. For smaller planters placing bottle caps under the planters is a cheap way to increase overflow at no extra charge. Small in size making them hardly noticeable under the planters. Either rest the planters on top or for a more permanent solution hot glue them to the underside of the planter. Don’t use with heaver planters as the weight will leave imprints in the decking but for a light planter and excellent means of airflow.

Wrought-iron Planter. Can raise the planter providing airflow with class. There is just something about the look of wrought iron. It just looks good.

Etsy has a good selection of wrought-iron planters if you are looking for ideas or to buy. Here’s the link to Etsy’s page.

A limiting factor with wrought iron is you should buy the holder before the planter as they are limited in what size and shape of planter you can use. But they do look good while drying the decking.

Surface Savers. For round planters, another option is ringed spacers. Lifting the planter ¾” (18mm) to allow air to circulate while still providing a larger base to minimize imprinting on the deck. Here’s a link to Gardener having 8” (200mm) surface savers which may work for your planters.

Hanging Planters. Now, this is taking airflow to a whole new level, literally. By hanging planter of a pergola, privacy fence or house wall. Any water that may spill can easily evaporate with the sun. Preventing water from pooling under the planter. Also, the distance between the decking and soil limits any spreading of fungi from the planter to decking. Maybe for you hanging your plants is the best way to enjoy your plants and keep your decking dry and clean.

Protecting decking from excess planter water

Regular watering of potted plants is essential with water evaporating so quickly from the planter. Planter also need to allow the water to run through the soil without drowning the plant’s roots. Meaning that the potential for water damage on your deck is high with planters. Having a basin to catch excess water could save your decking. Either inside or outside the planter.

Saucers or Drip trays. Provide a basin to catch water flowing through the planters. Preventing the water from damaging the deck while watering the plants. There are many types of saucers or drip trays, but with all of them, the planter sits inside the tray, catching the water before it runs unto the deck.

The key is size and depth. The saucer needs to be deep enough to catch all the dripping water from the planter. Amazon has some nice deep ones if you have round planters. Here is the link for some durable saucers on AmazonOpens in a new tab.. Of course, there are many other options on Amazon and your local gardening centres.  

Planter Liners.  Switching to the other side, plant liners protect your decking from the inside of the planter box.Opens in a new tab. Collecting the water inside the planter, preventing water from spilling on your deck, rotting the decking. One of the biggest advantages of liners over saucers is the liners reservoir. Not only do the liners protect the deck, but they also hold water. Allowing the plants to draw water from the reservoir for days. A big advantage on hot days as the heat wilts dry plant. Plant’s with liners can draw from the reserve, keeping them alive through the heat.

Another advantage of liners in wood boxes is when growing edibles. One of the concerns with treatment from the planters leaching into your food. Contaminating your precious homegrown food. Liners prevent all this by separating the wood and treatment from the soil. Ensuring nothing in the wood gets into your food.

A small note, some liners have drainage holes to prevent drowning of plants. Except these holes destroy the hole advantage of liners as the water will drain unto the decking. Use solid liners with a reservoir on the bottom or fill with a few inches of gravel, allowing water to drain from the soil while still protecting your deck.

Here is a liner with a watering reservoir on Amazon. You can either set it alone on the deck or dress it up with a nice box matching the deck. This one on Amazon is 31”x7”x7”, click hereOpens in a new tab. if you want to order one. There are other sizes also available to suit your deck.

Protecting your deck plants over Winter

Plant on your deck is wonderful in the summer, but when winter blows in the planter will freeze. Which is fine with annual plants. If you enjoy planting your planters every spring, this is fine. Move the planters to the side to allow you to clean off your deck in spring and your set. Fresh plants in the spring to enjoy.

With perennials, it’s a different story. The freeze, thaw on a deck, will kill almost any plant over winter. Leaving you with two options.

Non-dormant plants will need to be brought inside to a similar environment of both light and warmth as your deck before it freezes. Keep them in their containers as not to shock them and settle them into your house as if nothing has changed.

With dormant winter plants, they will need to do exactly that. They need to be winterized in a way as not to be mistakenly woken in the winter but to remain dormant to spring has truly sprung. Keeping the soil around their roots frozen is the key.

Move the dormant plants off your deck. Storing them in an unheated garage or shed where they will stay frozen all winter. Some people claim its better to winterize them in the ground where they belong. Take them containers and all and bury them in your garden to remain all winter.

Another option is to move them to a sheltered, cold, protected area of your yard. Possible your north-facing wall, sheltered from the warming sun. Pile all the containers closely together and cover with a tarp and insulating material like straw to sleep through the winter. The key is no light, consistent cold temperature for they don’t prematurely sprout.

Either way, live plants must be taken off your deck for the winter. Either in your house to be nurtured through the winter. Or sheltered outside, to sleep the winter out. Giving you a nice open deck to clean in the spring before brining your garden back out.

For a larger discussion from people with more expertise with gardening here is a link to Walter GardensOpens in a new tab. site about perennials in containers. I learned a few things reading this article and hopefully you will to.

Now armed with the tools to protect your decking, I hope you are inspired to put planters on your decking. Plants are simply amazing. Improving any space, including your deck.

Ryan Nickel

A Red Seal carpenter, passionate about building decks to be enjoyed.

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