Container gardening is a very popular way for many people to enjoy flowers. The smaller containers mean less work and your ability to manipulate the environment, such as providing sun, shade, water and nutrients is much easier than in a larger flower bed. While a variety of containers can be used, for this article we are going to concentrate on window box gardening. Window boxes are a completely different subgroup from other types of containers for a variety of reasons. The window box will generally be enjoyed from the outside of the house looking in, and to some extent, the inside of the house looking out.
Planters that are freestanding on your porch or patio have to be multi-dimensional, while a window box can be two-dimensional. A window box is normally mounted to the side of the house, so there will not be any way to protect it from the elements like you can with a planter. So while there are clear differences between a planter and a window box, and window boxes do have some inherent difficulties, they are very worthwhile. Take the time to do some preparation before you plant and you will enjoy beautiful flowers all season long.
The first step is choosing a window box. Regardless of what type of decorative box you choose, the inside of the box should allow for drainage. Some boxes are lined with sphagnum moss, others have drainage holes drilled in the bottom. Either will work, although the sphagnum moss lined boxes may dry out a little quicker than you expect. They generally work better when the box is in the shade. In a sunny spot you may find that you have to water your box more than once a day. Once you have chosen you box and mounted it on your window sill you are ready to for the fun!
Choosing the plants that you put in your window box takes a little creativity and a little experimentation. If you commonly open the windows in your house, you may want to plant some aromatic flowers of even a few herbs, such as lavender, in your planter. If you can see the box from inside the house, be sure to arrange the plants so that you do not feel like you are looking at the "back" of the box from inside the house. One easy way to arrange your flowers is to plant shorter plants around the exterior edge (front, back and sides), and plant taller flowers in the middle.
When choosing flowers, keep their maturity height in mind, and although you want different heights in your planter, the plants generally look better if they are within six to eight inches of each other in height. This allows the different varieties to blend together. As far as choosing what species of flower to plant, you are limited only to your imagination. Some people like the symmetrical look of only one type of flower in their window boxes, but I would encourage you to be adventurous, combine several heights and complimentary colors in one box for a real showstopping display.
Annuals, or plants that bloom and then die the same season, are most commonly used for window boxes. Their blooms normally last all summer, and at the end of the season, or after the first hard frost, you simple pull them out and toss them in the garbage, or, ideally, a compost pile. The main consideration when choosing which plants to combine is the care requirements. Whether you choose to buy you plants from the garden center at your local superstore or a small nursery, they will come with a tag that gives their care instructions. Take the time to read the tags before you buy, so that your flowers will be compatible. If your window box is in the sun, you need to fill it with sun loving plants. If you decide to plant impatience, which need to be kept in well watered soil, do not plant petunias in the same planter, as they like drier conditions. All of the information you need is available on the plants tag, just be sure you read it before you make your purchase.
Once you have decided on your flowers and brought them home, it is time to plant. If your planters have drainage holes in the bottom, cover them with some large stones to keep the soil from washing out when you water. Next add some potting soil until your planter is about three quarters full. Pop your flowers out of their containers gently and place them where you like. As long as you are gentle with the roots, you can rearrange them until you are happy. One thing to keep in mind is that in their new home, these flowers will really fill out rapidly, so do not pack your window box full. Leave a few inches in every direction for each plant to grow. If it looks a little sparse the day it is planted, you probably have it spaced right. If it looks luscious and bountiful, it may be a little to full.
Now that all your plants are in you can top off your box with some fresh mulch or pebbles. You can just stick with the potting soil if you like, but the mulch or pebbles do a nice job of preventing the potting soil from splashing up on the flower's leaves when you water them or it rains.
So there you are, a beautiful window box to enjoy all spring and summer. As far as maintenance, you really only need to remember two things. The first is that the planter will dry out faster than the ground, so make sure that you check the moisture level often and be prepared to water as necessary. Also, as the flowers bloom and then die off, pinch the spent blooms off with your finders. This process, called dead-heading, encourages the plant to make more flower blooms and extends the blooming season.