Growing of flowers in boxes for display on window sills, porches, balconies, or terraces has been practiced for several thousand years, but it’’s not conventionalized as most people seem to think. The only conventional feature is the square shape of the box.
The scope for self-expression is almost unlimited. For example, the choice of plant material that can be grown in a window box is so wide that the imaginative window box gardener may change his plant combinations year after year, never repeating the same.
The beginner who believes that all he needs is a box filled with soil to set out plants bought from a florist quickly finds out that succeeding is not as easy as he thought. Even if he waters his box conscientiously every day, he may see his plants languish and flower poorly.
To produce a well-balanced, colorful window box that flowers freely for at least 10 weeks takes both skill and patience.
Sun Exposure Problem
Window box fans should realize that growing plants in boxes is by no means the same as growing them in the garden. Root development is much more restricted, and root competition is much keener in the box.
Also, the plants are much more exposed to the wind and the sun. In a free southern exposure, the sun is also a problem, readily overheating the soil in a small box so that the plants are seriously handicapped in their absorption of nutrients.
Exposure to the sun must also govern the choice of plant material. Some plants need all the sun they can get, while others succeed best in shade or partial shade.
Basic Principles For Success In Window Box Gardening
1. Small boxes are undesirable because they dry out too fast and are subject to overheating. On the other hand, huge boxes are heavy, require more soil than it may be convenient to procure, and present a special problem in fastening them securely.
The most all-around satisfactory dimensions are three to four feet long, eight to 10 inches wide, and eight inches deep. Narrower boxes greatly limit the possibilities for attractive plant groupings. Shallower boxes likewise arc undesirable, while a greater depth is not required.
2. The box should be made of wood, with the ¾” board to 1” inch thick. Such thick boards will provide much-needed insulation against overheating, besides giving the box greater stability. Metal boxes are undesirable because they overheat readily.
3. Screws instead of nails should be used to fasten the boards together, and brass screws which do not rust are preferable to others. Nails are likely to pull out when the boards warp.
4. To preserve the wood, one coat of quick-drying paint should be applied to the inside of the box. Creosote or similar wood preservatives must not be used since they are poisonous to plants.
5. Two alternating rows of drainage holes, about one-half inch in diameter and approximately 6” inches apart, must be drilled into the bottom of the box to allow the escape of surplus water.
Preparation Of The Box
Further preparation of the box includes covering the drainage holes with pieces of broken pots to prevent the soil from falling through as well as from clogging the holes.
Next comes a 1-inch layer of drainage material for which purpose hard coal cinders, broken into one-fourth- to one-half-inch pieces, serve exceptionally well.
Broken bricks may also be smashed with a hammer into similar-sized pieces. Both of these materials can allow surplus water to drain away and be porous.
In consequence, they will absorb some of the water, holding it in reserve – until the plants may need it desperately. In addition, they act as a filter, holding back some of the soil-plant nutrients which otherwise would be washed out with the drainage water.
Soil Consistency
The soil used must be of such consistency that it is not inclined to pack down tight under the copious watering a window box must receive nor to dry out too quickly.
The following mixture serves well:
- 3 parts good garden soil
- 1part granulated peat moss
- ½ part sand
“Good garden soil” is any soil in which sweet corn or cabbage has given good results. To each bushel of this mixture, one three-inch flower pot full of bonemeal and half this quantity of dehydrated cow or sheep manure should be added.
The peat moss must be well moistened before it is incorporated, and all the ingredients must be thoroughly mixed before they are placed in the box. The box is filled to within one-fourth inch from the rim, the soil being pressed down lightly with the fingertips.
The Plants Are Set Out About Six Inches Apart
From the center of the plant to the center of the plant — either in alternating rows or in groups of three to five, depending upon the intended effect.
Thorough watering immediately after planting is important, and after that, the box must be watered regularly, preferably in the evening, until water commences to drip from the bottom. About five weeks after planting, one should apply fertilizer once a week.
Any complete soluble fertilizer may be used, at the rate of one teaspoonful per gallon of water, thoroughly dissolved through repeated stirring. Such supplementary feeding is very important if the plants remain in good health until the end of the season.
Combining Colors
When combining flowers of different colors for effect, one should remember that pure white and pure yellow are bad neighbors and are better not planted together. Simple, always effective contrasts are: red and white, blue and yellow, or orange and mauve.
Red and blue can be brilliant together, provided the red tends to be scarlet and the blue mauve. Red and yellow combine well if the red tends to be scarlet and the yellow-orange. Red, pink, and white are most pleasing when red and pink tend to rise.
Red, white and blue are most satisfactory together when a dark blue is chosen and when one of the three colors is allowed to dominate.
The surest effect with a cheerful mixture of colors is achieved when a type of flower is chosen which offers a wide range of colors, such as annual phlox or petunia.
Annual phlox, by the way, may be sown directly in the flower box at the end of April or in early May, and the seedlings then must be gradually thinned out until they are about five inches apart.
Most Commonly Followed Procedures
All of these directions are for the most commonly followed procedures only. The adventurous window box gardener has a much wider range of possibilities which cannot be treated in this short article.
These include, for instance, the raising of long-flowering floribunda roses, spring-flowering bulbs, and rock garden plants in window boxes — any of which require certain departures from the routine procedure.
The drip-proof window box, which adopts some of the principles of soilless plant culture and which can be left unattended for four to five weekend days, cannot be discussed here, either.
Try These in Full Sun
- Dwarf celosia Fiery Feather (scarlet)
- Verbena Royal (purple-blue)
- Aptenia cordifolia variegata
- Marigold Golden Bedder (golden yellow)
- Ageratum, any semi-dwarf form (purple-blue)
- African daisy (Dimorphotheca aurantiaca) (orange)
- Salvia splendens Zurich (scarlet)
- Baby Orange snapdragon (dwarf orange)
- Festuca ovina glauca or sweet alyssum
- Little Gem with lobelia Sapphire (blue)
- Croton (Codiaeum variegatum) (green, red and yellow)
- Balcony petunia
- Cornflower Blue and White Wonder
- Zinnia Will Rogers (scarlet)
- Marigold Dwarf Harmony or Spry (orange and maroon)
- Sanvitalia procumbens flore-pleno (yellow)
- Lobelia Sapphire (blue)
Ideal for Partial Shade
- Geranium S. A. Nutt (dark scarlet)
- Geranium Beattie
- De Poitevine (salmon pink)
- Geranium Mme. Salleron (variegated foliage)
- Ground ivy (Nepeta hederacea variegata)
- Begonia semperflorens (red, pink and white)
- Ivy Leaved Geranium
- Lobelia tenuior (blue with a white eye)
- Torenia fournieri compacta (deep blue with white)
- Nemesia Sutton’s Orange
- Basket grass (white- and red-variegated)
- Tuberous begonias with dwarf variegated coleus and Vinca major variegata
- Fuchsia O. Monk (red and blue) Hanging fuchsias
- Lysimachia nummularia (golden yellow)
Use Vines for Effect
Particularly pleasing effects may be obtained with a box in front of a window, if a small trellis is built all around the window, and if one or two climbing plants are set out at each end of the box.
- Geranium La Favorite (white)
- Balcony petunias Racy Morn (pink)
- Black Prince (deep crimson)
- Cobaea scandens (purple-blue)
- Petunia White King (white)
- Nolana atriplicifolia Royal Ensign (blue)
- Morning glory Heavenly Blue (blue)
- Marigold Flash (red and yellow)
- Verbena Annapolis Blue (blue)
- Climbing nasturtium (orange)
- Phlox drummondi Red Glory or Ford-hook Crimson
- Balcony petunia
- White Wonder Cypress vine (Quamoclit pennata) (scarlet or pale yellow)
- Tomato Window Box 18″ high (fruits scarlet)
- Curly-leaved parsley Paramount
- Peerless Scarlet runner bean (scarlet flowers)
44659 by Henry Teuscher