Alpine Sink Gardens – Where to Put Them and What to Put in Them
Positioning the Alpine Sink Garden
All sinks and containers must be raised above ground to allow for. The height at which they stand depends on what and whom they are for. The ideal height of a sink garden for a disabled person in a wheelchair or someone who is happier working sitting down rather than standing is 60 – 75cm (2 – 2 1/2 ft) to the top of the sink. Those who operate best standing, must raise the sink garden to suit their own needs, but do not mount it too high or it will become unstable. For the able bodied a height of 15cm (6 inch) from the ground to the base of the sink is perfect and the sink can easily be made stable by placing one or more stones or a few old bricks beneath it.
The choice of mountings for the containers will depend on the overall size and the position of the drainage holes. Any sinks above the dimensions of 60cm by 30cm (24 in by 12 inch) should ideally have supports around the edges and a central drainage hole, whilst those at or below these measurements can be centrally supported with drainage at one end.
Put sink gardens of any size in their permanent positions before adding, stone or plants because they become extremely heavy and difficult to move once filled.
Positioning the sink garden is particularly important. They should be as near to the house as possible and sinks for the disabled and elderly should be on firm foundations, next to a path without any kind of obstruction. A good position is on a paved area, particularly close to a sitting-out area which is ideal for viewing and bringing the garden almost into the home. Where there is no, plant the area immediately around and below the container to soften and broaden its effect, leaving enough room for maintenance of the sink.
A balcony is a good place for a sink garden. There are many advantages, especially if it can be built on the site. The exposed setting is ideal for cushion, rosette and mat plants and even a windy site will not harm these plants – quite the reverse, in fact.
Filling the Alpine Sink Garden
Cover the drainage hole(s) with a piece of perforated zinc, fine-mesh nylon netting, screwed-up chicken wire or any other material which will allow water but not soil out through the drainage hole. If you use nylon netting it must stretch across a large enough area for the soil to hold it taut so that it does not fall through the drainage hole. At the bottom of the sink put a 4cm (1-1/2 inch) layer of thoroughly moistened coarse peat or upturned and well-rotted turves or, if the sink is a deep one, broken clay pots or bricks, or coarse gravel to act as drainage filters. There is no point in using these crocks for a shallow sink where all the space is needed for the roots to grow and, a shallow container is more easily drained.
Add the soil mix, ramming each layer down hard until it reaches 5cm (2 inches) from the top. As always, the soil mix will depend on the plants being used; follow the instructions for the rock garden and, laying slightly more emphasis on drainage because in winter and heavy rains, the sink garden will not drain as freely through one hole as does the base of an open planting. During the growing season more watering will be necessary than with other sites. Use a watering can or a hosepipe with a rose in the end. If, as suggested, the sinks are near the house, this should not present any problems.
Where there are holes in the sides of the container choose plants to suit the direction they will face. Plant when the soil inside is on a level with the hole. Push the plants from the inside outwards, not the other way round, making sure that the roots are always covered. Fill any gaps left around the plants with fresh mortar.
To diminish the flat effect at the surface of the sink garden add one or more large stones to give height, proportion and planting spaces, just like a miniature rock garden. Use any kind of stone that matches the type of soil used and preferably one with some character; for instance put limestone with lime-loving plants. Westmorland is ideal for this.
Tufa is excellent in a sink garden, because holes can be cut, filled with soil and then planted. A big piece can be used as a sink garden in its own right. Other stones though are also very good when used boldly and you can create steep slopes by running them into the soil at a slightly exaggerated angle. There are so many possible arrangements that I suggest you try several ways before committing the plants to their final positions. After all, the sink is, hopefully, going to last for 15 years and even though you will probably make alterations to the planting, to remove stone requires complete renewal of the sink. However, do not bury the stone unnecessarily.
Planting the Alpine Sink Garden
Plan which plants should go where carefully. For instance, do not allow a trailing plant to grow over a cushion and avoid any conical planting right in the middle of the sink. Keep the taller plants towards a corner and limit their number. When the plant is removed from its container, plant it so that the top 5cm (2inch) is above the level of the soil in the sink, thus exposing the roots and topsoil, and the base of the top of the plant is on a level with the top of the container.
To make a better finish, fill the 5cm (2inch) space with matching stone chippings if the garden is in a sunny situation. This not only improves the appearance but also provides perfect drainage round the necks of the plants and creates spaces for water to percolate down without muddy splashes. For the shady setting use fine forest bark instead of chippings.