Alpine Garden Plants and Sink Gardens

Alpine Gardening

Sink Gardens

For the beginner there can be no form of gardening more exciting and rewarding than growing a wide variety of plants in containers raised to any chosen level. Several sink gardens take up very little space and each can have a different soil mixture and therefore support a whole range of plants. Moreover, the gardens will last many years. They are particularly suitable for disabled people in wheelchairs or those who are not very mobile, as they do not need to involve bending.

Propagating Plants - Alpine Garden Plants

The original sink gardens were made in sinks carved from solid blocks of stone but these have become scarce and very expensive. With a little ingenuity, people turned to the glazed sinks which replaced the stone ones. No doubt the pressed steel units which have replaced glazed sinks will themselves be put into service.

It is still possible to get hold of glazed sinks but unfortunately many are smashed up. Do try to get hold of one if you possibly can; they are usually free and many are dumped on commons and other open spaces. Your local plumber might know of a source.

Other materials can be used to contain a sink garden and the larger the container, the wider the variety of alpine garden plants you can grow.

Moulded concrete makes excellent sink gardens of any (reasonable) size, although this will be limited if you need to cast in one place and erect in another. Sinks made of bricks or stone laid on a concrete base also can be built to any reasonable size, i.e. any size which can be planted, maintained and observed easily. In fact the possibilities are endless but I would not recommend using plastic or other synthetic materials because they look garish and artificial. This may sound surprising when I have already suggested using concrete but this material can at least be made to look like old stone, whereas plastics can never look other than what they are, with their unnatural colours.

As with any method of growing alpines, preparation is all important and takes time.

Glazed Sink Gardens

Glazed sinks are made in various sizes and depths. The deeper ones are preferable, offering space for a greater range of plants.

To improve the appearance of the sink you will need a cement weld, cement, sand and peat. Clean the sink thoroughly, and remove any piping still attached to the drainage hole.

Mount the sink on a block so that you can reach underneath. Note that it is much easier to carry out the following stage in the cool, frost free autumn months. Paint a cement weld over one end, over the lip and 8cm (3 inches) down the inside and about 10cm (4 inches) underneath. When the adhesive is tacky, apply a prepared mixture made from 1 part (by bulk) cement, 1 part sand and 1 or 2 parts thoroughly moistened moss peat. Pass the peat through a 1.5cm (1/2 inch) sieve before measuring it. Add water to the mix and stir until it is stiff enough to hold without dry crumbling but not so soft that it oozes out.

Then, wearing household rubber gloves, apply the mix in small handfuls to the surface of the adhesive. It may tend to slip off but persevere until you find the knack of making it stick. Spread a layer about 1.5cm (1/2 inch) thick all over, rounding off the inside edges and underneath where it finishes. The proportion of peat you use will affect the texture; the more peat, the darker and rougher it will be. Repeat with the other sides.

To start with make enough of the mixture to fill a standard-sized galvanized bucket and mix a further amount as you need it. The first time you will need to allow at least two hours for the whole job but with practice it will become easier and much quicker.

You can create a stippled finish over the surface by poking it with your fingers and if you leave it unpolished the finish will look even more natural. The following day paint the treated area with a seaweed feed, manure water, or milk to encourage the growth of green algae, which will ’age’ the surface and make it look more like natural stone.

If the sink is standing outside cover it with a plastic sheet to protect it from rain for two days; if it is already under cover take it outside to weather after the two days. Allow the mix to cure for three weeks before planting. Handle the sink with great care when it is being moved because the mix can easily be chipped. Once in position the surface is hard-wearing unless badly knocked.

Sink Gardens from Railway Sleepers

Lengths of railway sleepers can be joined together with aluminium angle brackets (you could use steel but they will rust), see figure 27. The brackets can be painted brown or black to match the sleepers, and make a sturdy and manageable container. The drainage holes should be drilled at 30cm (1 ft) intervals and each one 2.5cm (1 inch) wide.

sink gardens fig 27 and fig 28

Concrete Sink Gardens

Making a concrete sink is a more involved process requiring a wooden mould and A reinforcements to strengthen the finished product. You will only make one size of sink per mould but in compensation alpines can be planted literally all over a concrete sink, because holes can be drilled into its sides. (The sides of sinks made of stones or railway sleepers are too thick to be planted.)

To make a wooden mould for the concrete use 12mm (1/2 inch) thick deal for all parts unless otherwise stated and first make a flat, rectangular base slightly larger than the size-of container you want, then make two sides and two ends to fit exactly inside and on to the base, to the required height (at least 20cm (8inch) and not more than 30cm (1 ft)). Make sure that the sides are shorter by the thickness of the wood at each end, so that the sides fit within the ends, as shown in figure 28.

To make the inside mould, cut the same shaped sides and ends again, but smaller, to allow a gap between the moulds at the sides and ends of 3cm (1% inch) and 5cm (2inch) between the. bases. The base of the inner mould is best in thin wood, cut to fit within the inner mould, not below it. Cut 8 lengths of deal 2.5cm x 2.5cm x 5cm (1 x 1 x 2 inch) for the inner mould, one for each corner, and nail to the sides and ends on the inside of the mould to form a box, leaving the heads of the nails protruding for easy removal later on.

Then cut 8 lengths of 5cm x 2.5cm (2 x 1 inch) deal, 6 20cm (4 inches) longer than the sides of the outer mould and 2 20cm (4 inches) longer than the ends. Next cut 16 blocks 5 x 2.5 x 10cm (2 x 1 x 4inch). Nail one block to each end of the 8 lengths and arrange the pieces as shown in figure 28. do not nail any of the outer mould parts together. Make up the concrete mix. It is one part (by bulk) cement, two parts coarse sand or fine grit and one part sieved peat, with sufficient water to produce a toothpaste-like texture, soft enough to poke into narrow spaces. do not make it too wet or the air spaces created when it dries out will weaken the whole structure.

Fill the base of the mould with a 5cm (2 inches) layer of concrete mix, then fit the inner mould on top. First position the base and then the sides, now nailed together. Weight the base with bricks.

If you want planting holes in the concrete, drill holes 2.5cm (1 inch) in diameter in the sides and ends of the outer mould and slightly larger ones in the inner mould, making sure that they line up. If you fit bungs tapered from the inside outwards, you can plant in the resulting holes in the finished container. Holes tapering in the opposite direction will gradually fill up with debris and eventually block the hole. You must cut one hole 5cm (2 inches) wide in the middle of the base for drainage and use a large bung to fit.

Fill the spaces between the mould with concrete, tamping well down as you do so, leaving the top rough.

To give the concrete added strength, especially at the corners, reinforce it with 2mm (1/12 inch) gauge wire. As long as none of the wire touches the moulds, oxygen will be excluded and the wire will not rust. Fit it in 20cm (8 inch) lengths, particularly around the corners, from the sides to ends and from the sides and ends to the base.

After four days remove the bungs by first gently tapping them from the outside, then remove the outside lengths of wood from the top and sides then the corner blocks from the inner mould by removing the nails. Gently tap down on all the wood of  both moulds and remove them. You will have to leave the inner base where it is because it will be well wedged in.

Turn the newly-made container on its side to remove the last outer lengths of wood at the base. Tap out the base bung and finally, remove the outer base.

With a pointed cold chisel and club hammer, roughen the outside of the container and, when it looks less like a concrete box, paint the sides, ends and top edges with seaweed feed, manure water or milk to age its appearance.

Mount the sink on two lengths of wood and leave it to cure, under cover, for five weeks. If you are doing this in the autumn, the curing time will take longer making the sink stronger as a result.

Brick Sink Gardens

It is far simpler to make a sink from bricks set on a concrete base than an all-concrete one. Carry out the construction on sheets of newspaper larger than the container.

Cut four lengths of wood 5 x 2.5cm (2 x 1 inch) – two of the proposed length of the container and  two of 15cm (6 inch) longer. The wood should be clean and deal is cheapest. Nail blocks of deal 5 x 5 x 2.5cm (2 x 2 x 1 inch) to the ends of the longer pieces. Fit the long pieces within the blocks of end pieces to form a rectangle and put heavy blocks against the ends to hold them in place when the concrete is poured into the frame. Use the same concrete mix as for a concrete sink but reinforce it with strips of metal sandwiched in the concrete in the shape of a series of crosses. The amount of reinforcement needed depends on the size of the base. Small sinks up to 40cm by 30cm (15 in by 12 inch) with a depth of 25cm (10 inch) do not need reinforcement but it is necessary for sinks  larger than these dimensions.

Fit tapered rounds of wood to make drainage holes – roughly one drainage hole, 5cm (2 inches) in diameter, for every square metre (sq yd) of base. Make the base about 5cm (2 inches) thick with the bungs spaced out over the base and leave for four days before removing the frame and bungs, then chip and paint the sides and ends as suggested before. Remember the base will have to be mounted, so the placing of the bungs will depend on the type of mounting.

The base can now be placed in its permanent position, and the bricks or stone built on to it. Mortar them together with a mixture of 3 parts (by bulk) sand to 1 part cement and build up the sides to the required height, never more than 40cm (16inch). Try to use old bricks to give the sink a weathered look.

Leave spaces between some of the end joints of bricks, or at any points between the stones, for vertical planting. Allow the construction to cure for three weeks, then plant.

sink garden

11. September 2010 by Dave Pinkney
Categories: Alpines, Gardening Ideas, Plants & Trees, Rockery Garden, Salads, Sink Gardens | Tags: , , | Comments Off on Alpine Garden Plants and Sink Gardens


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