When the danger of frost ends in spring, it’s time to decorate balconies, windowsills and terraces with summer-flowering shrubs and trailing (spreading) flowers with decorative leaves. A miniature flower garden in hanging or standing containers will be bright, colourful and fragrant all summer long, if you choose, plant and look after the plants properly.
Let’s choose the right plants to decorate the right area
On the south side of the house (where the sun shines all day), on a sunny balcony or terrace, the best plants to grow are light-loving plants such as surfinia, petunias, verbenas, Bidens, lantanas, baby’s-breath, Nemesia, Portulaca, sage, Sanvitalia, and marigolds.
On a southeast- or southwest-facing balcony or terrace, good choices include pelargoniums, Diascia, Impatiens (New Guinea or Valero), Lobelia, strawflower, ground-ivy, and Bacopa.
An eastern-facing balcony receives the mild morning sun. Sun-loving trailing (spreading) plants such as surfinia, pelargoniums, verbenas, baby’s-breath, strawflower, Bidens, Diascia and Nemesia grow well here.
A western-facing balcony receives afternoon and evening sunlight. It is also exposed to the wind, so hanging baskets and windowboxes need to be well-anchored and robust, compact plants should be chosen. Shrubby flowers are suitable, such as pelargoniums, verbenas, petunias, ever-blooming begonias, Coleus, sage, ‘Toto’ coneflowers, etc., as well as trailing (spreading) pelargoniums, verbenas, compact surfinia, Bacopa, and strawflowers.
The northern-facing side is almost always in the shade. In semi-shaded and shaded areas, plants lose less water through evaporation, so moisture is retained in the substrate longer. In such a location, a wide range of begonias, Impatiens (New Guinea or Valero), fuchsias, Torenia, Lobelia, Lysimachia, ground-ivy, Bacopa, and mint-nettle-sage will do well.
Let’s use the right substrate for growing flowers
The best substrate for balcony flowers is a peat substrate with a pH of 5.5 to 6.5, enriched with a complex fertiliser with trace elements, made from a medium peat fraction. A soil or substrate with an acidic or excessively alkaline reaction should not be used, because the plants will not absorb the nutrients, will be malnourished and will look unattractive.
Drainage must be prepared
First, holes are punched in the bottom of a new container to drain excess water or fertiliser solution and a drainage layer of about 3 cm is installed. Suitable drainage materials include lightweight expanded clay aggregate (LECA), coarser gravel or clay pot shards. For hanging containers and baskets, LECA is preferable because it is lighter than other materials, but for freestanding pots, this is not so important.
Filling containers with substrate
Windowboxes, hanging baskets or free-standing pots and containers should be filled with the soil blend to a depth of about 2.5-3 cm from the top to prevent the soil from spilling over the edges when planting the flowers, and to prevent water running off over the sides when watering.
Planting
Only healthy plants should be planted in containers, and plants should be deep green (not yellow), compact (not drooping) and have well-developed roots. It is advisable to water the flowers at least one hour before planting, to allow the substrate and the roots to become fully moist. The planting should not be too deep or too shallow, so as not to expose the protruding root ball, and after the planting, the plants should be watered generously.
Watering
Growing flowers in containers where only a small amount of peat substrate is used means that the substrate dries out quite quickly, causing the plants to wilt. In summer, flowers planted in containers need to be watered 2 times a day on hot days. The water should be soft and lukewarm. It is advisable to choose planters with drip trays about 8 cm high as well as hanging flowerpots with drip trays to catch excess water. After watering or adding fertiliser, the substrate will not dry out as quickly and there will be no risk of splashing or dripping onto the walls.
Use moisture-retaining materials
To retain moisture in the substrate for longer, it is advisable to add pellets of a special material called TerraCottem, which helps to keep the substrate constantly moist. Adding 15g of these pellets to 2 litres of substrate produces a substrate ‘gel’ (as the pellets swell, they retain moisture for a long time). The plants then bloom more profusely, with larger flowers and a deep green colour.
Overwatering or soaking plants from prolonged rain
Do not overwater flowers, because if the moisture in the substrate becomes stagnant, the roots of the plants will lack air and will not be able to absorb the nutrients, leading to yellowing of the plants. This also happens after prolonged rain. Do not water or apply fertiliser to flowers until the substrate is well-dried.
Applying fertiliser
Hydrocote, a slow-dissolving complex fertiliser with trace elements, is suitable for the main application of fertiliser to balcony windowboxes and flower arrangements planted in containers.
Once the flowers have established themselves, a 0.2% solution of Nutricomplex, a complex fertiliser, should be applied every 3-7 days, to help the flowers to grow vigorously and bloom more brightly and for longer. It is advisable to apply fertiliser more frequently, every second or third morning, to large-flowered surfinia; less frequently, every 4 to 5 days, to small-flowered surfinia, Calibrachoa, and verbenas; and every 7 days to pelargoniums, begonias and fuchsias.
Protecting plants against diseases and pests
Spray with the insecticides Decis (0.1%) or Actara (0.02-0.04%) against aphids, whiteflies or thrips, and with the fungicides Amistar (0.1%) or Saprol (0.1-0.15%) against powdery mildew. In case of minor plant damage, spray with decoctions of phytoncidal plants (garlic, marigold, wormwood, mugwort, tobacco dust). Spray on a sunless day or in the evening.
To make flowers bloom more intensively, prevent seeds from maturing
Pulling out the overbloomed flowers together with the stalks each day will help new flowers to bloom faster. Removing only the petals leaves the seed primordia, which mature into seeds, resulting in less abundant flowering and less attractive plants.
If a plant has died over the summer, it can be replaced by other flowering shoots to bring your flower arrangements back to life.