Hypertufa%20 v.2

A DIY Guide for the home-gardener

Dave Allen

2002

Make A Hyper-Tufa Garden Planter

i

Table of Contents

WHAT IS TUFA? 1

WHAT IS HYPER-TUFA? 1

BEFORE YOU BEGIN 2

WHAT YOU WILL NEED 3

MAKING A PLANTER MOULD 4

MAKING A RETARD MIXTURE 5

THE HYPER–TUFA RECIPE 6

MAKING THE HYPER-TUFA MIXTURE 7

MAKING A HYPER-TUFA PLANTER 8

FINISHING YOUR HYPER-TUFA PLANTER 10

AGING YOUR HYPER-TUFA PLANTER 11

GLOSSARY OF TERMS 12

Make A Hyper-Tufa Garden Planter 1

What is tufa?

Tufa exists in nature. It is a typeof rock. It builds up over time as adeposit from water carryingchemicals in solution such ascalcium carbonate or silica.

You can see tufa deposited:

• in limestone caves asstalactites and stalagmites

• around hot or cold watermineral springs

• as concretions aroundvolcanic blowholes or geysers

Natural tufa was once carved and made into ornaments for gardens. But,today most natural sites are protected and tufa cannot be extracted.

What is hyper-tufa?

Hyper-tufa is a homemade replicaof real tufa. It is just as good forgarden ornaments and does notrequire destruction of theenvironment to produce.

Hyper-tufa is made from Portlandcement. Cement is used to makeordinary concrete and it comesready bagged from the hardwarestore.

Sometimes, real tufa contains lotsof foreign and organic matter: bitsof harder rock and stones, twigs,branches, leaves, and eveninsects. These ‘additives’ can alsobe mixed in with the cement tomake authentic looking tufareplica.


Before you begin

Making hyper-tufa is similar to making concrete. To be successfulat making hyper-tufa garden features you first need to learn somethings about concrete.

Here are some important points you should know about concrete.

• To make concrete, cement, aggregate and water are mixedin specified amounts to produce ‘wet’ concrete.

• ‘Wet’ concrete is a liquid. It can be poured to fill spaces orshapes.

• Concrete ‘sets’ (goes hard) over time, not by drying out, butbecause crystals grow within the concrete.

• As the crystals grow, they interlock to make the concretestrong and go hard.

• The speed at which this setting process occurs depends onthe temperature. When it is warm, the setting process isfast. If it is cold, particularly if it is frosty, the concrete maynot set at all.

• Once the concrete starts to set it will continue to harden fora month or more, providing it is kept moist.

• Hard aggregate materials (stones, rock chips, etc) added toconcrete will STRENGTHEN the mass.

• Soft aggregate materials (wood, bark, peat, etc) added toconcrete will WEAKEN the mass.

• The finer the aggregate particles then the more cement isneeded. This is so that each particle is covered withcement.

This is not only hard oyour eyes, or lungs glasses, a mask ov

Another considerationcaution around a pond,

WARNINGCEMENT IS CAUSTIC

n your hands, but could cause serious injury toif you breathe it in. Consider wearing safetyer your mouth and nose, and rubber gloves.

is your garden pond, plants, and the fish. Use so that bits or chuncks of cement do not fall in.


What you will need

Now that you know something about concrete, you are almostready to make your first hyper-tufa planter.

First, you are going to need some tools to do the job.Here is a checklist of the things you will need:

! A pair of gloves (thick rubberis best.)

! Large shovel for heavymixing of ingredients.

! Smaller shovel, for examplea coal shovel, for putting themix into the mould.

! A wheelbarrow in which tomix the ingredients.

! A short stick about 450 mmlong for tamping the mix.

! Some plastic sheet (blackgarden polythene).

! A selection of “moulds” of theshape you want to make ahyper-tufa pot or feature(cardboard boxes of variousshapes, plastic pots, plasticrubbish bags, buckets, oldlampshades, or anything thattakes your fancy!).

! A wire brush or very stiffscrubbing brush.

! Some bags of cement. (Justbuy 1 or 2 to begin with.)

! Some aggregate. This isthe “hard stuff” to givestrength to the mix. It couldbe regular “builders mix”which is a mixture of sandand shingle; available in bulkfrom most hardware orbuildings supply yards.

! Some peat This is the “softstuff” to give the mixturesome texture. It can bebought as bags of coarsepeat at a garden centre or itcan be any organic materialfrom the table below.

Some alternatives you could use for:

AGGREGATE PEATAny combination of:• river gravels• road chips of various sizes• fancy coloured pebbles• lime chips• pumice• scoria

You may want to start simply, thenexperiment with different materials tomake your own distinctive aggregate.

Any of the following, either alone orin combinations:• granulated pine bark (fine)• chopped straw, broken twigs• coarse untreated wood shavings• chopped flax flower stems and

chopped flax fronds• spaghnum moss• chopped fern trunks and

shredded fronds• bits of coal or coke, charcoal• pine needles• chopped bamboo, coconut fibre


Making a planter mould

Before you start making the hyper-tufa mixture, you first need tomake a mould of the shape and size you would like for yourplanter.

You can use almost any container that will form a mould: plasticbags, cardboard boxes, buckets, etc. As you gain experience withmaking planters you can experiment with different containers tofind ones of a shape or size you like the best.

A good, simple way to begin is with ready-made cardboard boxes.For your first planter find two boxes; one large one and anotherslightly smaller so that it will fit inside the larger one with at least50 mm clearance all around.

An ideal large outside box is the “banana-box.” This is the strongcardboard box in which bananas are shipped. They are generallyavailable from supermarkets or fruit shops. These boxes make anideal sized planter that is about as large as one person can lift withdifficulty when finished.

For the smaller inside box you will need to find one that gives therequired 50 mm or more clearance all round when placed insidethe banana box.


Making a retard mixture

Once you have made your planter and the mixture has set, youwill remove the boxing. You then have to scour the surface toexpose the various ingredients and show the texture to its fullestadvantage.

Now this can be a difficult job. If you strip the boxing off too soonthe whole lot collapses, or at the very least cracks appear. Orelse, you leave the boxing on too long and by the time you cometo strip it off, the planter is so hard you will find scouring thesurface very difficult.

What is needed is something that you can paint onto the surfacesof your boxing, to delay the setting of the hyper-tufa mix at thesurface of your planter, before you make them.

Various commercial products are available. You can get themfrom most building supply stores. Alternatively, you can makeyour own retard from wallpaper paste using the recipe below.

Paint the inside of your banana box with the retard mixture andallow it to dry. For greater retarding, paint on a second or thirdcoat.

Retard Recipe

• 3 or 4 level teaspoons ofcellulose wallpaper powder

• 500 ml water

• ½ cup of sugar


The Hyper–tufa recipe

Now that you have gathered all the tools together, found theboxes for a banana -box mould, made up a mixture of retard andpainted the inside of the banana-box, and have all the basicingredients on hand, you are ready to start making a hyper–tufagarden planter.

There are many different recipes for hyper-tufa.

These are the two most commonly used recipes:

NOTE: All parts are by ‘volume’ or ‘bulk’ of the ingredient. For example,you could use a bucket as your bulk measure.

Then, for the basic recipe you could mix:

• 6 buckets of cement• 6 buckets of aggregate• 12 buckets of peat• water

Basic Recipe

• 1 part cement

• 1 part aggregate

• 2 parts peat

• Water

Stronger Mix

• 2 parts cement

• 1 part aggregate

• 2 parts peat

• Water


Making the hyper-tufa mixture

Making hyper-tufa planters is quite hard work. Considerrecruiting a helper before you begin. Start with a small quantity foryour first attempt!

To make the hyper-tufa mixture for your planter using the basicrecipe, follow these three steps:

1. Carefully measure out thedry ingredients and putthem in the wheelbarrow.

2. Use the large shovel tothoroughly mix the dryingredients.

3. SLOWLY add a smallquantity of water andcontinue to mix theingredients thoroughly.Watch carefully theappearance of the mixturewhile adding smallamounts of water andblend to an even greycolour.

Pay particular attention to the corners of the wheelbarrow tomake sure all ingredients are thoroughly mixed.

Water must be ad

Thoroughly blend al

Be careful not to m

IMPORTANT

ded SLOWLY as you mix the dry ingredients.

l ingredients until the mixture looks an even greycolour.

ake the mixture too wet; it should be about theconsistency of thick porridge


Making a hyper-tufa planter

Now that you have finished mixing the ingredients, you can makeyour first hyper-tufa planter.

For the “banana-box planter” follow these five steps:

1. Place the larger cardboard banana-box onto a flatsurface and place bricks or concrete blocks around theoutside of the box to support the box walls.

2. Place one or more 50 mm wooden spacers (to act asdrainage holes in the finished pot) on the base of thebanana-box.

3. Shovel in the hyper-tufa mix to the thickness of thespacers, ie 50 mm, and pat the mix flat with your hand.


4. Place the smaller box inside the larger banana-box sothat there is an even gap all around of about 50 mm.

5. Fill the inside box with bricks, rocks, soil etc to hold it inplace, then fill in the gap between the two boxes with thehyper-tufa mix, tamping down with a piece of stick as yougo.


Finishing your hyper-tufa planter

Leave the planter to set for about 24 hours; longer in winter.

Peel off the outer banana-box. Because it will be very soggy bythis time, it should peel off easily.

Use a high-pressure garden hose to scour the planter walls toexpose the texture of aggregate and peat. If water scouring is noteffective, you may need to use a stiff brush to scrub the walls.

After a week or more, you can remove the inner box and its fill.Knock out the 50 mm wooden spacers to provide the necessarydrainage holes for the planter.

Your planter is now ready for planting!

Enjoy!

WARNING

Resist the temptation to remove the inner box and its fill too soon.

Do not try to move the planter; it will break!

Wait for at least a week before you attempt to move the planter.


Aging your hyper-tufa planter

Hyper-tufa is called a living stone because, in time, a garden ofmosses or lichens will grow on the surface. However, this takestime because fresh concrete is highly caustic and inhibits thegrowth of plants on the surface.

In time, the caustic nature of the concrete will disappear withnormally weathering. The process can be speeded up by treatingthe surface with various acids such as sour milk, vinegar, yoghurt,etc. You do not need to buy these specially but when old stock isavailable, use it.

Another technique is to mix up a custard of animal manure andpaint it on the hyper-tufa surface. This will not only provide asource of nutrients but may also contain spores or seeds ofvarious plant life. Stir up a sloppy mix in a bucket and slap it on!

If you leave your pot in a shady, damp spot, moss will soon growon the surface. However, if you are forever moving the pot fromsun to shade, from damp to dry, then nothing or little will grow.

Remember a rolling stone gathers no moss!


Glossary of Terms

A

aggregate ∙ A mass of inorganicrock-like materials mixed togetherin various combinationsaccording to their diameter.Commonly reffered to as'Builder's Mix'.

B

builders mix ∙ A mixture of fineand coarse aggregates, usuallycontaining crushed river-stonesand sand.

C

caustic ∙ Capable of corroding, oreating away tissues; burning;corrosive.

concrete ∙ A mixture of cement,fine aggregate, coarseaggregate, and water.

concretions ∙ The act or processof growing or coming together;solidifying.

H

Hyper-tufa ∙ a home-madeequivalent of natural tufa rock;made from cement, aggregateand peat.

P

Portland cement ∙ A finely-groundpowder commonly made of amixture of limestone and shale;used in the making of concrete. Itnormally develops its designstrength in twenty-eight days.

R

retard ∙ A chemical product whichdelays the setting of the concretemix.

S

scoria ∙ Refuse or slag remainingafter a metal has been smelted;loose, clinkerlike pieces ofvolcanic lava.

T

tamping ∙ Forcing down or packcloser together by firm repeatedblows.

tufa ∙ A chemical sedimentary rockcomposed of calicium carbonateor of silica, deposited fromsolution in the water of a springor lake.

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Hypertufa%20 v.2