Container-grown plants need regular attention to maintain them in prime condition and so ensure the best display possible. If you make it a habit to inspect them when you water, you will notice any problems as soon as they arise.
Window boxes and other containers dry out very quickly and regular watering is essential. It should be carried out in the early morning or late evening during summer months. If only one watering is possible, an evening watering is preferable as the plants have the cool night hours in which to absorb the water. A watering can is adequate for small window boxes although a hose will be more effective for larger ones.
Most potting composts (soil mixes) contain sufficient food for only six weeks of plant growth. After that, you will need to feed your plants using a variety of plant foods such as slow release granules and pellets, liquid feed or a general fertilizer. Always follow the manufacturers instructions, as too much fertilizer or liquid feed can burn the plants roots.
These are an efficient means of adding nutrients to plants, as they are added to water. Both organic and chemical varieties are available in many formulations. They may be added to the compost or sprayed directly on to the leaves, depending on the type. Apply liquid feeds bi-monthly in the growing season.
Deadheading And Pruning
Faded flowers will mar your plants and spoil your display. Remove them as soon as they fade. This will also encourage more flowers. Dead or drying leaves and stems also look unsightly and can rot and attract diseases, so remove these regularly.
As your seedlings grow, repot them to grow on before transplanting to the window box. Divide the plants, if necessary, and plant them in pots. Established plants that have outgrown a container can also be transplanted to a pot one or two sizes larger, but with permanent containers just change the top layer of compost (soil mix), or remove the plant, prune the roots and top, then replant with fresh compost.
Evergreen foliage can become grubby over the year. In spring, wash off any accumulated dirt and check for sooty moulds or signs of infection by pests such as caterpillars or grubs. Spray the plants if you find any problems.