• Your plant choices depend on your window's sun exposure.WINDOW BOX image by brelsbil from Fotolia.com
  
  Choosing flowers for your New Hampshire window box is dependent on one important issue: the kind of sun you get during the growing season. If your window box is south-facing and gets sun most of the day, you'll want to use sun-loving plants like portulaca and petunias. If you have a window box that gets morning sun but afternoon shade, then your choices would include flowers like lobelia and nasturtium.
  
  

Portulaca

• Opt for portulaca, also known as moss rose, if your window box receives sun at least six hours per day. Portulaca is a heat-loving, drought-tolerant plant that grows to about eight inches in height. This plant is an annual and must be replanted each year. When started in early summer, portulaca will bloom through the early fall in shades of orange, pink, yellow and white. Space plants approximately six inches apart and they will fill in quickly.
  
  

Petunias

• Petunias are well suited to containers and window boxes.Variety of petunias image by Sergey Kolesnikov from Fotolia.com
  
  Choose petunias to go along with portulaca in a window box that gets sun all day long. Both the multiflora and milliflora varieties are good for containers, which means that they'd work well in your window box. Multiflora petunias don't have as large a bloom as the grandiflora but they make up for that by producing many more flowers per stem. Millifloras are more compact than the multiflora but that makes them perfect for a window box.
  
  Another choice for petunias are the trailing varieties called wave petunias. This species will tumble over the edge of your window box in a spray of color.
  
  

Lobelia

• Plant lobelia in a window box that gets some shade during the afternoon.lobelia image by Alison Bowden from Fotolia.com
  
  Plant lobelia in a window box that gets morning sun and afternoon shade. Flowering in shades of deep blue, purple and white, lobelia will trail slightly over the edge of your window box. It blooms from spring through summer and grows anywhere from four to 18 inches in height. This plant does not accept dry soil, though, so make sure to water it regularly, especially when summer days are very hot.
  
  

Nasturtium

• Nasturtiums do well in full sun but can tolerate partial shade.Orange nasturtium in garden image by radarreklama from Fotolia.com
  
  Plant nasturtium for an old-fashioned flower that decks your window box in bright jewel-toned shades of red, orange and yellow. These lightly scented flowers come in three varieties: semi-trailing, climbing and dwarf. For a window box, you'll want to choose either the dwarf or semi-trailing varieties. Easy to grow from seed, nasturtiums germinate and grow quickly. They like full sun but will tolerate partial shade; the size of their seeds makes them the perfect choice for children to plant.