Here is a bit of background information and hopefully some helpful hints on making your own
garden tubs and pots.
Hypertufa containers are made from commonly available materials and can be easily made
by most gardeners, thus providing a natural, attractive alternative to expensive purchased
tubs and pots. One of the great advantages of containers and container gardening is that it offers the ability
to provide exact soil mixes and conditions for particular plants. These can be tailor-made by the addition of
specific fertilisers, soil conditioners and change of environment. The containers can be shifted from sun to
shade and moved to protect from frost and wind. Of course they offer an alternative to those gardeners
restricted by lack of garden space in small suburban sections and apartments. Tubs are also excellent for
general use in gardens offering special areas of interest and tasteful features.
Hypertufa is aesthetically compatible with most building material and paving and does not look out of place
in garden situations. It looks old and attracts lichens and mosses and has a natural look entirely compatible
with plants and shrubs in the garden. Hypertufa tubs are very plant friendly. The bulky and porous wall
thickness acts as a reservoir for water from which the plants can drink between showers and waterings.
Being porous it allows for easy passage of air to the root systems - a feature often disregarded when using
terracotta and plastic pots.
Trough gardens are excellent for elderly gardeners who can no longer manage the terrain and conditions of
more conventional gardens. Pots and tubs can be elevated to allow easier gardening. Bringing the plants
closer to eye level and taking the strain off the back the containers may allow us to continue growing our old
plant friends.They can also serve as useful temporary homes for cherished plants for those in transit or living
in rented or mobile homes.
Hypertufa pots are suitable for many sorts of plants and are particularly good for cacti, succulents and alpine
plants. In cool shady areas pots and tubs can provide great little special effects particularly bright glowing
perennials or annuals potted up and tucked into shady green areas as a vivid contrast.
Hypertufa is a man-made substitute for Tufa rock. Tufa is a spongy cellular rock found in limestone country
and especially where water has been involved in the wearing and leaching out of the original materials to
effect a porous spongy consistency. In many countries throughout the world this natural stone has for
centuries been hollowed out and carved for tubs and planters. One of the obvious advantages of the
material for me is its versatility. It can be used for tubs, pots, troughs, steps, benches, sculptures, seats,
stepping stones and bird baths. When properly surface treated it gives the appearance of great age and
ruggedness. No special tools are required and if you are prepared to give it a go yourself they are
inexpensive and entirely original. A little work of art.
How to make your Hypertufa tub: You will need the following:-
Materials and Tool list:
1. For a square or oblong tub you will need two cartons, one of them with smaller overall dimensions by at
least 5 or 6 cm. Place the smaller carton inside the larger. There should be a gap of 5 or 6 cm between the
walls on all sides. These cartons are your moulds. For round containers try different size plastic bags, old
plastic basins, or buckets.
2. Concrete blocks, bricks or short lengths of heavy timber to fit flush against the outsides of the outer
carton for support. This stops the sides bowing out under the weight of the material. For the inside of the
container use any spare sand, soil, potting mix (anything bulky) to stop the inside carton caving in. Fill up
the inside carton progressively as the walls are built up. If you are using plastic bags for moulds, place 4cm
wide adhesive packaging tape around the outside to prevent bowing.
3. Pieces of broom handle, branch or 25mm plastic pipe about 5cm long are used for drainage holes. These
can be carefully removed later on. One or two holes are sufficient for small pots, but for larger tubs and
troughs at least 4 drainage holes are needed.
4. The ingredients in proportion by volume - 2 parts peat, 1 part sharp river sand, moderately fine, but not
beach sand (because of salt and it is too fine) 1 part cement.
5. Tools - Plastic Sheet 1.5 x 1.5 metres, Wheelbarrow (optional), Trowel or spade, Rubber gloves, Tamping
stick, 50 x 50mm about .5 metre long, Wire brush, Old hearth brush, Water container or hose. Well, now we
have it altogether, let's start!
Lay the piece of plastic sheet on the garage floor. Place the large carton in the middle of it.
Place the concrete blocks against the outside of carton. Mix the ingredients in the wheelbarrow or on the
floor. Quantity depends on the size of the envisaged container (use your judgement). After mixing the dry
ingredients thoroughly add sufficient water to make a sticky stiff mix - not runny but about mud-pie
consistency, if you can remember back that far. Now stand the drainage plugs upright on the bottom of the
carton and place a layer of the mix on the base and tamp it down giving special attention to the corners and
around the drainage plugs. Aim for a thickness of 5cm for small to medium size tubs.
Take your smaller carton and place it on the layer of mix in the bottom of the larger carton. Make sure it is
equally spaced on all sides. Then one quarter fill it with sand or whatever you have. This will stop the inside
bowing in and the carton floating up. Now fill up the wall space between the cartons. Use the tamping stick
to work it into the corners as you go to get the air bubbles out. Make sure you tamp the outside walls well.
Keep building up the sides with mix, adding sand to the inside carton for support until you have reached the
desired height. Leave it and don't come back for at least 24 hours.
Finishing: Next morning dash out and have a look at your handiwork. Yuck! Wet cartons. But that's just what
you want. First, scoop out the sand from the inside carton. Then CAREFULLY peel off the inside wet
cardboard and discard. Now the outside. Remove the concrete blocks and carefully finish peeling away the
outside carton but don't worry about the bottom.
DON'T TRY TO MOVE OR TIP THE CONTAINER AT THIS STAGE - YOU WILL LOSE THE LOT !
Now the tricky bit. You will notice that the walls are rather smooth, in fact just like dark wet boxed concrete.
This is not on. We want the walls to look aged and weather worn. This is what we do. Using a wire brush or
a special scraper (see below) we very carefully roughen the sides, top and inside rim. I prefer to round off
the corners and edges as well. Don't worry about a few nicks and scratches and small holes. These help to
give it a natural look. You may wish to carefully scratch in your own design or special texture. Having shaped
the outside to your requirements, gently give it a good brush with a hearth brush.
The container should be left for at least a week to allow it to cure and set hard. Give it a light sprinkling with
water initially 3 hours after moulding and therafter every couple of days to assist the curing process. It is
most unwise to lift it until it's entirely set, but if you have to shift it only do so by sliding or dragging it across
the floor by means of the plastic sheeting. The mix left over can be used for stands for the containers. Either
press it into pottles or plant pots or roll it into flattened balls. Using builders' adhesive these can be attached
to the container base as feet at a later stage.
SO, THERE WE HAVE IT !
A number of interesting points on hypertufa
If you want a really large container try to make it close to where it is to be used. Larger tubs can be made
by joining cartons together with plastic adhesive packaging tape. Line the inside with thin plastic sheet to
prevent the adhesive integrity of the tape being lost when it gets wet. For a large pot you should also add
reinforcing in the form of No. 8 wire, or mild steel rods. Two rings, one just above the base and the other
about 5cm down from the top should be sufficient.
Moulding inside a container
You can also use the same mix by hand moulding it to the inside surface of plastic bowls, buckets or basins
avoid using containers with any undercut. This technique is fine for low sided vessels but not really suitable
for high sided or large tubs etc. It is wise to coat the inside of the plastic mould with silicone spray or a
sheet of thin polythene to act as a release agent. Wearing rubber gloves press the mix firmly into the bottom
and sides of the mould (no less than 30mm thick) having firstly placed the drainage plugs on the bottom.
Leave the container at least 4 days (depending on the weather) to set. Finish as described previously having
carefully extracted it from the mould.
As the pots age in the garden the peat will weather out leaving the surface pitted and porous adding to the
aged effect. Depending on the site you decide to display your trough you can expect in time to have lichens
(dry sites) and moss (wet sites) using the surface as their home. A coating of milk, yoghurt or a slurry of
cow manure enhances the early growth of moss.
Alternative Hyper Tufa mixes can be made by using pine needles, chaff, fine bark mulch, vermiculite and the
fine debris washed up on the beach containing twigs, seaweed, shells and bones etc. All these can be used
in place of peat. Materials originating from the beach should be washed to remove salt. You may also add a
slow release fertiliser into the mix, say Magamp.
The mix proportions can also be altered, for instance one may prefer for the sake of strength to use equal
proportions for very large troughs, especially if they are to be moved. I would also use this mix for
sculptures and steps, maybe adding small metal chips for the steps. Hypertufa gives a soft tread and old
look to steps that you don't get with plain concrete.
Sculptures from a block of hypertufa
To use Hypertufa for sculptures pour the mixture into a carton to form a block. Leave overnight, at least
fifteen hours, to get a partial set - this will depend on the weather. Remove cardboard from the sides and
leaving where it stands proceed to carve away. It won't remain forever in this partially set state, so be
prepared to finish in one sitting. The design should be simple without small detail or thin edges. Use a knife
and wire brush. Work carefully and when finished leave on the spot for a week or so to firmly set. You may
find it easier to work if you cast your original block on a raised bench or box.
Hypertufa Home Grown Stone
Hypertufa modelling is a lot of fun. The materials are
cheap and the art uncomplicated. A little experience -
then let your imagination seek out interesting, useful,
unique forms and images. great fun.
Copyright © 1999 by Efildoog (E.Cosgrove
ALL RIGHTS RESERVED.