Box pleated curtains rely on the heading being formed by box pleats. Although this heading style is most often used for valances, table cloths and stools, it can still be used for curtains.
The key to a successful box pleat finish is in planning the spacing between the pleats and their width. You can refer to the page on pleated draperies for more details.
This type of pleating is often used for its simplicity. But it is very attractive when ropes or braids are added to the top edge, and fringes are added to the base. A good fringe to use is a bullion fringe.
The first part of making your own pleats is on this page. This section carries on from there. You may need to adjust the spaces slightly for the headings of box pleated curtains, as they may need more space between the pleats than is required for other types.
It's often a good idea to take a width of scrap material and fold it so it forms the pleats. That way you'll be able to check that the result will be what you intended.
Using the pins as guides (the ones you used to mark out the position of the pleats) flatten out the box sections. To keep the pleats in place, use small stitches to secure the outside edges of the pleats to the main panel.
Use one set of stitches near the top, and another set near the bottom, as shown.
Some fabrics will stay flat once you've folded them in position. Others are more unruly, and you may have to iron them flat.
This type of heading is often used for a valance. The depth of the valance may not give enough room for the pleats to fall naturally into shape. If the pleats don't behave as they should at the bottom of the valance, you can use very loose stitches hidden behind the folds to secure the pleats in position.
The final part of competing your drapes is to attach the hooks. There are a number of ways to do this, which you can learn about on the drapery hooks page.
Box pleated curtains may look best if the hooks are placed quite near the top of the heading. This works well if the curtains are hung from a pole or rod, and the folds of the curtain go both in front and behind the pole.