5 Tips for Growing Plants in Railing Planters

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

Railing Planters Are Perfect for Small Spaces

Railing planter boxes are 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.

“Railing planters are ideal for anyone short on square footage but big on creativity,” says Andrew Berger, Product Manager at Root & Vessel. “They make gardening accessible year-round, whether you’re growing herbs for the kitchen or adding greenery to a city balcony.”

Deck and Railing Planters Brighten Outdoor Spaces

Even for folks with plenty of space, adding a planter to a deck rail creates interest. Beautiful flowers with trailing plants like Creeping Jenny add appeal to an otherwise dull space.

Whether you’re growing herbs, flowers, or vegetables, a few basics can make all the difference.

Remember These Tips

• Railing planters maximize small outdoor spaces like decks and balconies.
• Choose planters 6–8 inches deep (10 for veggies) with good drainage.
• Mix upright and trailing plants for color and dimension.
• Water in the morning and use self-watering planters for convenience.
• Fertilize regularly for healthy, long-lasting blooms.

You Can Grow Almost Anything in a Railing Planter

There's no limit to what you can grow in porch railing planters. They’re one of the most versatile planters you can own. Flowers are a classic choice, but you can use a deck railing planter for growing vegetables.

For instance, cherry tomatoes are a favorite. They thrive in railing planters and are easy to maintain.

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 Planter: Depth, Material & Mounting

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.

“When in doubt, go deeper,” says Berger. “Planters at least eight inches deep support better root systems and moisture control.”

Look for a Railing Planter That Mounts Easily

Some installations require a bit more effort and need mounting brackets, especially when you’re attaching window boxes to a railing.

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.

“Our over-the-railing planters eliminate the need for tools or brackets,” says Berger. “They fit securely on most standard railings, so setup takes seconds—not hours.”

Choosing the Best Material

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

Wood Deck Planters

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 Railing Planters

Metal 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 are porous and don’t retain water as well as other materials.

For that reason, they require more frequent watering as they dry out quickly. You might have to water your plants twice a day.

Coco liners also decompose so you’ll have to replace them every year.

Plastic Railing Planters

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 for Sun or Shade

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.

Vegetables for Planters

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

Flowers for Deck Planters

You can use annual or perennial flowers. Popular plants include:

• Zinnias
• Geraniums
• Rudbeckia
• Coneflowers
• Snapdragons
• Lavender

Trailing plants like vinca, creeping jenny, and calibrachoa add even more interest to a planter.

Shade Tolerant Plants

You'll need to use shade-tolerant plants for rail planters that get four hours or less of sunlight. Some top choices include:

• Ferns
• Impatiens
• Begonias
• Coleus
• Hostas

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: How to Water Plants in Railing Planters

Want to guess what one of the top challenges is for gardeners, especially those with limited experience? Watering. You run a risk on either side of too much or too little water.

“If you’re concerned about watering, self-watering planters make care effortless,” suggests Berger. “The hidden reservoir keeps plants hydrated even on hot or windy days.”

Want to learn more about self-watering planters? Read our blog, How Self-Watering Planters Work.

When to Water Your Plants

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.

Rather than setting a strict 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.

4 Steps to Water Successfully

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.

Tip #5: How to Fertilize Plants in Railing Planters

Potted plants consume nutrients regularly. Your planter loses nutrients from water seeping through the drainage holes. That means 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, generally a 7-7-7 or 10-10-10 ratio of nitrogen, phosphorus, and potassium.

When to Fertilize Plants

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.

Add the Finishing Touch with Root & Vessel Planters

Whether you’re working with a cozy balcony or a spacious deck, railing planters make it easy to grow beautifully in any space. They turn ordinary railings into living displays of color and life.

Root & Vessel offers a full range of decorative and self-watering planters for both indoor and outdoor use, including our easy-to-install over-the-railing style. Each one is crafted for durability, style, and simplicity, helping you create a space that thrives season after season.

Let’s grow together.

FAQ: Railing Planter Basics

What can I grow in a railing planter?

Almost anything, from herbs to flowers to small vegetables, depending on light and planter depth.

How often should I water railing planter plants?

Typically when the top 2 inches of soil are dry, or every 1–2 days in summer.

Do railing planters need drainage holes?

Yes. Without them, roots can rot from standing water.

What’s the best soil for railing planters?

Lightweight potting mix with peat moss and perlite ensures proper drainage.