If you live in a condo or have a small yard, you can
exercise your green thumb with a window box — and note
that these containers are trickier than your average
ones. “A window box, because of its small size and
narrow proportions, is more subject to drying out,” says
Kurt Bartel, the vice president of the landscape
management department at David J. Frank Landscape
Contracting Inc. “The soil, water and nutrients are the
three keys to keeping whatever plants you use happy.”
Here Bartel offers specific tips for maintaining a
vibrant window box:
1 “No. 1, you have to have drainage,” he says. “The
water has to be able to percolate through the soil profile.” Either
look for a container with holes in the bottom or drill holes into a
container, he advises.
2 On the flip side, you have to maintain moisture in
the soil, Bartel says. He suggests using Soil Moist, a Jell-O-like
polymer product that absorbs water, expands and slowly releases
moisture back to the plant.
3 Don’t attempt to use regular soil from a garden and
put it into a window box. “It’s way too heavy a soil,” Bartel says.
“You have to use soil mixes to ensure good drainage and make sure
the soil is sufficient for the plants to grow.”
4 Replenish the nutrients that are lost with each
watering. With a soluble fertilizer that you mix with water, you can
water and fertilize your plants at the same time, Bartel says. He
recommends doing this weekly or biweekly for your window box.
5 For a visually pleasing arrangement, you need a
thriller, a filler and a spiller, according to Bartel. “The thriller
is a plant that grows upright, the centerpiece if you will,” he
explains. “Fillers are intermediate-sized plants that add color and
dimension. Spillers hang over the side of the box and cascade down.”
6 Choose plants that like the amount of light your
window box receives. Plants that do well in shade include coleus,
begonias and impatiens, and you can find many varieties of each,
Bartel adds. In full sun, opt for celosia, lantana or succulent-type
plants, he suggests.
7 Don’t be afraid to mix vegetables and herbs with
flowers. Especially if you like to cook and have an easily
accessible window box, your rosemary or basil plant could be happy
right next to a supertunia, Bartel says. Pepper plants — red, yellow
or banana — also make colorful additions to your container.
8 Water often
and consider the elements. A good guide is watering every two to
three days, Bartel says, since window boxes tend to dry out. But, he
adds, how much you need to water depends on the amount of sun, heat,
wind and humidity the container has been exposed to. If your window
box is hard to reach, you may want to invest in an irrigation
system, he says.