No matter where you live, you can have a garden view when you plant colorful summer flowers in a window box.
Many window boxes come with the hardware you’ll need to attach them to your sills, or you can buy brackets to hold them. If you’d rather use the box on your deck, choose brackets that can hang on your deck railing. Just make sure you choose a location that can handle the weight once your box is filled with soil, plants, and water.
Most window boxes look best when they’re within an inch or two of the width of your window, so measure before you buy. With many styles to choose from, you can match the style of your home. Look for a box that is at least 8 inches wide and 8 inches deep, to make sure your plants have enough room to grow.
Skill level: Easy
Time: About an hour
- Potting mix, with or without fertilizer and moisture-control granules
- Optional: moss or bark (to conceal plants left in their pots)
- Slow-release or liquid fertilizer, if not included in your potting mix
The location of your window box will determine whether you can grow plants that like shade or sun. You can use annuals or perennials, bulbs, miniature roses, and even dwarf evergreens.
If you’re shopping for shade-lovers, try coleus, ivies, ferns, impatiens, torenia, browallia, fuchsias,or lobelia. Plants that like sun include geraniums, begonias, marigolds, and zinnias. Stroll around your local Home Depot store and check the tags in the plants to learn about their growing requirements.
If a roof or other feature is going to block the rain from your window box, check regularly to see if your plants need water. If your box doesn’t have a drainage hole in the bottom, go ahead and add one before you mount it.
Next, decide how to plant your window box. One option is to add a good quality potting mix, and plant directly into it. A potting mix that comes pre-mixed with fertilizer and moisture-holding granules is a good choice.
Another option is to drop your plants, still in their pots, into the window box, and fill in around them with moss, bark, or another lightweight material. This makes it easy to switch them if you want to grow something different when the seasons change.
A third option is to put a liner or tray in the box, and then add your soil and plants. We used a coco fiber mat in our 24-inch window box. The mat came with a plastic liner between the fibers, to help keep the the soil from washing out when we water.
Now we come to the fun part – picking out the plants. Garden designers recommend using at least one “thriller,” one “spiller,” and one “chiller” in your arrangement. Spillers are trailing plants, like bacopas or sweet potato vines. Thrillers are tall plants that add vertical interest, like snapdragons or angelonias. Chillers are mid-level filler plants like sweet alyssum or dwarf marigolds. If you put soil around the plants in your window box, leave an inch or so of room, so you can water properly.
You’re done. It’s that easy to plant a summer window box!
Maintain the box by removing spent flowers and leaves, and water regularly during dry spells. If you’re using a potting mix with fertilizer, you won’t have to add any more for 2 or 3 months, depending on how often you water and how fast your plants grow. If you’re using a mix without fertilizer, feed your plants according to the directions on the product you choose.