Window Box Triage (Part 1)

We’ve got a true disaster scene in the window boxes at Chez Perry. It’s a grave emergency and we need to divide and conquer for window box victory before the whole season has past. Here’s a look at the mess we’re in:

Yeah. I wouldn’t exactly call the petrified ornamental cabbages left over from the winter a steal-worthy idea. And in these window boxes we are dealing with another enemy of the state of gorgeousness. That enemy is shade. And lots of it! What you want in a window box is cheerful color and with shade that can be much harder to come by.

But we aren’t the only ones with window box woes. See this reader write-in from Cincinnati, Ohio:

Dear Ask Julia,

I need advice. Every year I plant window boxes and set them outside on the window ledges and for a while they look cute. But then the window sills start to look dirty from inside the house (no matter how much i reduce the dirt in the planter), and the plants start to get overgrown, I need a new approach. I just planted pansies, but a month from now I’ll need to replant. Ideas???

Please steal a good idea for me.

- Carol

Thank you Carol for this thoughtful question. Lots of issues to tackle here. Before we get into the fun stuff of designing an plant combination, let’s pause for a minute and go over the basics of successful window boxery.

DRAINAGE

This is the number one key to window box success. You need to keep an eye on 2 different elements of drainage. First, your container must have drainage holes and plenty of them. You can put something down (like chicken wire or a couple of stones) to make sure that your dirt doesn’t run out but don’t be shy about the drainage holes. The second thing to consider is that you leave drainage space between the box and the side of the house for water to get through. Most window boxes, when installed correctly, will leave 1/2 inch there so that water doesn’t pool and wreak havoc on your wooden window frame.

LIGHT WEIGHT

Choose a light weight container. I do not want to hear from any genius idea thieves who found a gorgeous concrete planter for under the window only to have it break their foot when it gave way under the weight of the concrete, potting soil and water. Choose wooden, fiberglass, or plastic window boxes. Fill them with potting mix (it’s less dense than soil). Make life easy on your brackets.

WATER

Your window boxes are going to need more water than the plants in your yard. They just plain dry out faster and they don’t get the same nutrients. I recommend watering them with a watering can instead of your hose. It keeps the potting mix from eroding out of the container and lessens the water spots on your windows (you can bank on leaving the Windex spending more time under the kitchen sink and less time out front).

FERTILIZE

Pop a little Miracle Grow in that watering can or sprinkle a little Osmocote in the dirt before the plants arrive. Osmocote is my favorite time-release fertilizer. And they just came out with these fun pellets. Haven’t tried them myself yet but from where I sit it’s a genius product extension.

So Carol, with those basics, I think we might have hit on 2 items that could help you to address your issues. It sounds like you are working with window boxes that are not installed on brackets. Rather, they just sit on the window ledges. This is preventing you from getting that good drainage from between the box and the window/wall. Water is pooling, it’s dirty, and it’s splashing. No bueno. In addition, might you be watering with a hose? I think using a watering can would probably help you a ton.

I also recommend PACKING IN THE FLOWERS. It’s a window-box so the standard 6-8″ between plants just isn’t going to cut it. I’ll show you more about this in Part 2 of the Window Box Triage series which focuses on window box design. But aside from being beautiful, packing in the flowers keeps the dirt in place. No washing away, no splashing. Bueno.

Stay tuned … in just a day or so I’ll reveal The Solution to my own window box woes.

posted by Julia on Jun 10th, 2010 in Gardening, Plants & Flowers
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