Railing Planters: 5 Tips for Growing Plants

White railing planter with purple flowers on a front porch railing

In many ways, a rail planter is the ideal planter. It has so many practical uses.

First, they're a godsend for people with limited space, like many urban dwellers. For example, a balcony railing planter lets apartment dwellers with no ground space add greenery to their outdoor space.

Second, even for folks with plenty of space, adding a planter to a deck rail creates interest. After all, nothing is exciting about the sides of a railing unless you like the look of raw wood. Beautiful flowers with trailing plants like Creeping Jenny add interest to an otherwise dull space.

Third, there's no limit to what you can grow in railing planters. It's one of the most versatile planters you can own. Flowers are a mainstay, but you can use a deck railing planter for growing vegetables. For instance, if you're a fan of cherry tomatoes, you can grow your crop, considering they're so easy to grow.

So why not take advantage of this do-it-all planter and enjoy its gardening benefits? Here are five tips for growing plants in railing planters to help make you a successful gardener.

Tip #1: Select the Right Railing Planter

There are different styles and sizes of railing planters. Start by finding one that meets your space requirements. At the same time, make sure it's deep enough to sustain your plants' roots.

Generally, a rail planter six to eight inches deep will suffice. However, if you intend to grow vegetables, you might opt for one at least ten inches deep. The added space will give your plants more room for root growth and better yields.

Sage over the railing planter with annual plantings

Look for a Planter for Railings That Mounts Easily

Some require a bit more effort, where you need to mount them using brackets. That's typically the case when using a railing box for window boxes.

Others, like Root & Vessel's over-the-railing planter, require no effort. You plant the box with whatever you like, and its straddle style fits securely over common-sized railings.

What Material Best Suits Your Needs?

Once you decide on the style, you must pay attention to the material. Railing planters come in various materials:

  • Wood: Wooden planters are popular but require mounting brackets to handle their weight. Although durable, you'll have to maintain a wood rail planter, or it will decay with use. Often, it's best to line one with a planter box liner to help preserve the wood. The liner keeps moisture away from the wood to prevent rotting.
  • Metal: Metal rail planters are typically frames with coco liner inserts. The coco liner acts as a container to hold the soil and plants. These planters look nice, but coco liners require more frequent watering.Black deck railing planter with annual plantings
  • Plastic: Plastic planters are readily available and affordable. Moreover, many feature the over-the-railing style we mentioned for quick and easy installation. These planters typically come in a wide range of colors to match your style.

The best plastic rail planters use highly durable, UV-resistant plastic or shatter-resistant resin. Many also come as self-watering planters. They include a water reservoir that gives plants access to water when they choose.

Tip #2: Choose the Right Plants

As mentioned, one of the big pluses of railing planters is that you can grow many different plants. In many ways, the location of your deck railing planter box determines what you can grow.

If your planter gets at least six hours of sun, you can grow anything from vegetables to flowers. Suitable vegetables include:

  • Lettuce
  • Peas
  • Herbs
  • Carrots
  • Tomatoes

You can use annuals or perennials with flowers, so there's virtually no limit. Popular plants include zinnias, geraniums, rudbeckia, coneflowers, snapdragons, and lavender. Trailing plants like vinca, creeping jenny, and calibrachoa add even more interest to a planter.

You'll need to use shade-tolerant plants for rail planters that get four hours or less of sunlight. Ferns, impatiens, begonias, coleus, and hostas are good choices for shady spots on your patio or deck.

Tip #3: Prepare the Railing Planter

Select an excellent potting soil for the planter that provides nutrients and good drainage. The best soil mixes typically include one part soil, peat moss, and perlite. You might also want to have a slow-release fertilizer.

Above all else, make sure your rail planter has drainage holes, or your plants' roots could get root rot. You can use flower box trays to capture water seeping through the drainage holes. That way, you won't have worries about excess water damaging any indoor or outdoor surfaces.

Tip #4: Watering Your Plants

Terracotta railing planter planted with springtime pansies

You have to water your plants. But you run a risk on either side of too much or too little water.

Let's start with when to water. Watering in the morning or late afternoon is best, particularly with outdoor plants. Indoor plants are best watered in the morning.

In either case, avoid watering at night. Your plants are more susceptible to leaf diseases from the moisture.

How to Water Your Plants

Now, let's address how to water. Rather than setting a strict water schedule, focus on when the soil feels dry. Use your finger to check a few inches below the topsoil. If you’re not detecting moisture, it’s time to water.

If you need more security, invest in a moisture meter that tells you when the soil is dry.

Here are four other tips to keep in mind:

  1. Water the plant roots and not the leaves.
  2. Water evenly around the rail planter so roots don't grow in one direction. Water thoroughly until water flows out the bottom of the pot into the saucer.
  3. Wait until the water runs out of the drainage hole and into the tray, then discard any excess water.
  4. Indoor plants need less water in winter, so that you can cut back.

You can eliminate watering concerns with self-watering planters. They’re available as a flower box that can easily be used as a railing planter.

Tip #5: Fertilize Your Plants

Potted plants consume nutrients regularly. Plus, your planter loses nutrients from water seeping through the drainage holes. So, you'll need to fertilize your plants to keep them healthy.

Plants have different fertilizer needs, so pay attention to those of your plants. Some need more nitrogen to thrive, while others need more potassium. When in doubt, use a balanced fertilizer.

The best time to fertilize is when plants emerge from dormancy in the springtime. That's when leaves come out, and plant buds begin to form.

Water your plant before fertilizing it to keep the fertilizer from burning the roots. In addition, the moist soil absorbs the fertilizer better to feed your plants.

White over-the-railing planter with a variety of annual flowers

Root & Vessel Has Decorative Planters for Indoors and Outdoors

If you love plants and gardening in general, we have decorative planters of all types. They match virtually any home decor. Plus, you can use most inside or out. And our popular Artstone planters are self-watering, so you can be more confident that your plants get the right amount.

We guarantee our products, so you'll always be satisfied with your Root & Vessel purchase.