A colorful window box is the quickest and cheapest way to dress up the outside of any window. A window box planted with the right flower mix adds color, interest and curb appeal to any home, plus when a window box is planted right, it makes an easy care mini-garden.
Window Box Basics
Start with a window box planter that is at least six inches deep so the plant roots will have plenty of room to grow in. The window box should at least be as wide as the window, preferably extending to the outside edges of the window trim. Position the window box a few inches below the window to prevent rain from splattering dirt and debris on the window and always test for clearance on windows that open outward before mounting window box. Mount window box before filling with soil and flowers.
Installing Window Box
Make sure the window box has plenty of drainage holes. If not, drill extra holes in the box bottom (if the box is made of wood or plastic). Mount hanging brackets on house side low enough under the window so no holes need to be drilled in window trim.
Two Planting Options for Window Box
Place a layer or two of newspaper in the bottom of the box to prevent planting soil from washing through the drainage holes. Fill box two-thirds full will potting soil mix, then mix in slow release fertilizer pellets. With plants still in their original containers, set plants on top of soil and play with arrangements until pleased. Remove plants from containers and tuck the root bottoms close together in the window box. Add more soil around the base of each plant until roots are covered, then gently firm the soil with fingertips. Water well.
Another option for planting flowers in a window box is to just leave the plants in their original containers (if larger enough to allow for root growth) or to transplant them into larger pots that will fit into the planter box. Sit individual flower containers into window box in an eye pleasing combination.
Thrillers, Fillers and Spillers for Window Box Planting
To prevent a one dimensional looking window box, plant three heights and shapes of flowers – thrillers, fillers and spillers. ‘˜Thriller’ plants are tall plants used for dramatic effect, ‘˜filler’ plants add bulk to the display and cover the soil with flowers and foliage, ‘˜spiller’ plants cascade over the side of the window box and soften the edges.
Thriller plants should not reach over ten inches mature height so as to not block the view from inside. Salvia, snap dragons and black-eyed susans are good window box thrillers.
Great plants to use as fillers include pansies, impatiens, begonia and verbena. Spillers can be flowering vines like petunias or greenery like ivy. Plant thrillers, fillers and spillers in odd numbers in the window box for most dramatic impact and choose plants that have the same soil, sun and water requirements.
