Railing Brackets Buying Guide

Railing Bracket + Window Box = Railing Planter
Which comes first, the window box or the railing bracket? The most important thing to remember about choosing railing brackets for planters is that the bracket hardware needs to fit your railing, first and foremost. This practical deck rail bracket guide helps you find brackets that fit your railing while safely and securely supporting your garden in midair. Read on to learn how to choose the best railing brackets for your home.

Step 1: Identify Your Railing Type

Measure your railing. Measure it twice. Wooden railings are nominally measured versus metal rails- meaning a 2x4 wood railing is measured at 1.5"x3.5"- but it is stated as a 2x4.  Measurements of metal rails are true- a 3" width metal rail... is well 3"! Your railing's shape and material type may help you narrow down your options quickly.

Wood Deck Rails

Wooden deck rails come in many shapes and sizes. Standard wood rails are usually 2x4, 2x6 or 2x8 nominal sizes that actually measure 1.5"x3.5", 1.5"x5.5", and 1.5"x7.5". Measure your railing on all sides to determine which nominal size coincides. Don't see your size or shape?  Our heavy duty cable ties with a tensile strength of 250lbs may be the answer.  All of our wood deck rail brackets do not require additional hardware or drilling into the rail itself. Over rail brackets are available in many sizes, and can often be customized if needed. Brackets are listed with dimensions, allowing you to choose the right bracket for your rail and window box.

Flat and Round Metal Railings

Measure your iron railings to determine the exact dimensions and note the shape of your railing, as well as any possible designs or vertical bars in the metalwork that might interfere with installing your railing planter brackets. Keep in mind you may use square-shaped brackets on round railings as long as your planters have some type of surface like balusters to lean on.

Determine How Many Brackets You Will Need

Determine how many brackets are required for your planter box. Longer boxes require more supports due to the weight of soil, plants and water. 1 pair of brackets is will support fully-planted containers up to 48" long. Add another pair for boxes up to 72" in length. Additional supports should be added every 16" for containers 72" and up.

Flower boxes that are 48" or longer will need two pairs of brackets to support fully planted containers. Any balcony railing planter shorter than 48" will only require one pair of brackets.


Now that you've found a bracket that suits your railing shape and size, it's time to choose a window box. Windowbox.com has the largest selection of window box planters, offering 100+ unique designs to suit every style. Here's a quick overview to help you quickly and easily find a window box style that will work on your railing type.

Metal Window Boxes

Deck Rail Brackets for 2x4, 2x6 or 2x8 railings
Heavy Duty Cable Ties
Metal Railing Brackets for rails 3/4" - 5 1/2"

Deck Drape 7"-9"shelf 

PVC and Wood Window Boxes

Railing Shelf Brackets 8 1/2"-11 1/4" shelf
Deck Clamp Bracket for rails up to 2" thick

Stainless Steel Balcony Brackets

Deck Drape 7"-9"shelf 

Fiberglass Window Boxes

Metal Railing Brackets for rails 3/4" - 5 1/2"(excludes Modern)
Deck Clamp Bracket for rails up to 2" thick
Railing Shelf Brackets 8 1/2"-11 1/4" shelf

Deck Drape 7"-9"shelf