• OPEN-POLLINATED SEED SUPPLIERS
   
• GARDEN BEDS

 – Types of beds
 – Positioning beds                                                 
 – Bed sizes
 – Pots and boxes

• PREPARING THE SITE

 – Testing the soil texture

• COMPOST

 – Making compost
 – Compost containers
 – Compost supervisor
 – Some composting tips

• WORM FARMS

– Worm farm containers

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Organic gardeners use untreated open-pollinated seed. Open-pollinated seed varieties are selected for vigour, nutrient levels and flavour. Your students can save mature seeds from these species because they reproduce true to type. The benefit of saving seed from your own crops is that the seed will have come from plants that have adapted to your local climate and soil conditions.

This program includes a lesson on saving seed, so check before purchase that seed is open-pollinated because hybrid seed can't be saved. EOG&MP, see pp 138-140 for information on different types of seed.

Open-pollinated vegetable, herb, flowering annual and green manure seeds are available from a range of suppliers, including those on the list provided with this program (see link below). Seed packets are approximately $3.00-$4.25 each. Try to include a few seasonal flowering annual plants in your school garden. Flowering plants encourage beneficial insects to make regular visits to gardens.

Some suppliers have on-line catalogues for easy browsing. The eastern mainland states of Australia can order seed by mail from other states if there are no local suppliers, but Tasmania and Western Australia have restrictions on some species of seed. Suppliers for Tasmania and Western Australia are listed separately.

  You will need a small quantity of vegetable seeds, and a few corn and pea or bean seeds to conduct the experiments in Lessons 1 and 2.

 
Click here for a list of open-pollinated seed suppliers in Australia

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Your choice of garden beds will depend on the area and materials available to your school. The soil in the beds is more important than the bed type, and schools with limited resources will not be disadvantaged in this program.

Types of beds

Beds can be as simple as an area of improved soil without edging, as beds up to about 18 cm above ground level do not require edging. If edging will make ground maintenance easier, untreated hardwood timbers, bricks, concrete blocks, or strips of corrugated iron with a rolled top edge can be used to separate beds from pathways. As stated in Part 1 of the Introduction, CCA treated timber is no longer acceptable for food garden edging, especially where children are in contact with it. See 'Garden Hazards to Avoid' by clicking on the link in the Supervisor's menu.

Slightly raised beds have several benefits. They increase the depth of topsoil, and also assist drainage where soils are heavy. In areas where frosts are mild, raised beds can prevent frost damage by allowing cold air to drain from the bed surface. However, beds that are raised more than 25 cm above ground level can require more frequent watering if the beds do not contain plenty of compost to keep soil moisture-retentive.

In areas where water is in short supply, or where watering periods are very restricted, 'rimmed beds' can help in allowing water to be applied quickly to an entire bed. In this style of bed, a 3 cm wall of soil is formed along the outer edges of the bed to create a shallow moat, see EOG&MP pp 163-4.

Pre-formed corrugated iron beds have become popular at some schools. The bed in the photo (right) is 1 metre wide by 3 metres long. The base of the bed is positioned in a trench for stability, and the height of the bed above ground will depend on how much of the bed is buried.

Before purchasing this type of bed, there are a few points to consider.

• The coloured models are more suited to cool climate gardens, as they tend to absorb heat. The iron becomes hot to the touch and transfers heat to soil in the bed. The original 'silver' bed reflects more heat, and soil in the bed stays cooler.
  

• This type of raised bed can be helpful in preventing frost damage to crops by allowing cold air to drain well below the bed surface.
  

• Corrugated iron beds are available in several heights. The taller models may be too high for young students to comfortably harvest corn or crops that are grown on stakes or trellises.

Instructions for 'no-dig' garden beds have not been included in this primary school program because that type of garden bed usually includes the use of uncomposted manures. Apart from general hygiene concerns, the use of uncomposted manures now carries a risk of contamination with aminopyralid herbicide that can damage plants in affected beds.

Positioning beds

In areas where frosts occur, the position of garden beds can have a marked effect on the amount of plant damage that frosts cause. Cold air, like water, always flows downwards; anything that blocks the downward flow will result in frost damage in that area. Buildings, solid fences and shrubbery, and flat land at the bottom of a slope can all allow cold air to pool, and plants in these areas are more likely to be damaged by frost.

Advice to orient beds in a north/south direction to allow plants to receive ample sunlight comes from northern hemisphere gardening practices and only applies to very cool climates in Australia. Most areas of Australia get more than enough sun to ripen crops. In fact, plants can benefit from some relief from harsh afternoon sun in warmer climates during summer months. It is more important to position beds across any slope in the ground to ensure that all plants in a bed have equal access to water.

Avoid placing garden beds under trees. Trees are very competitive for both moisture and nutrients. 

Bed sizes

Beds should not be wider than a comfortable reach to the middle of the bed for students. If students have to stand or lean on beds to weed or harvest crops, soil structure will quickly deteriorate. For beds that can be accessed from both sides, a width of 85 cm, or less, would probably suit most primary school students.

Do not make beds too long, either. If beds are longer than 5-6 metres, students will tend to take short cuts across the beds rather than walk around them.

You may want to include a passionfruit vine, some perennial berry plants, or a fruit tree in your school garden. A bed along a fence line is a good spot for vines and fruiting canes. For beds with access from only one side, a width of no more than 45 cm would be suitable for students to manage.

If growing fruit trees or blueberry bushes in a lawn area, keep lawn well clear of the canopy area of the plants. Feeder roots for trees lie approximately below the outer edge of the foliage canopy. If lawns are allowed to grow too close to fruit trees, the lawn will compete for fertiliser and water, and growth and fruit production will be poor.

When calculating the area needed for the garden don't forget to allow for pathways between beds. Paths 80 cm in width are wide enough to accommodate a loaded wheelbarrow. When making pathways, remove the topsoil from the path area and place it on the garden beds.

Pots and boxes

For schools that have a limited area available for garden beds, or if beds are not ready in time for planting out seedlings, a range of vegetables and some fruits can be grown in large pots or in vegetable boxes made from polystyrene foam. See EOG&MP pp 145-154 for information on growing food crops in containers – and making your own organic potting mix, if you wish to do so.

Deep polystyrene foam boxes (with slots in the base) that are used to transport fruit and vegetables to market are suitable for growing small quantities of some crops – as long as the boxes are not placed where the growing mix gets very hot.

Polystyrene foam (recycling code 6) insulates the potting mix to some extent, and mulch on top of the box will help to keep the potting mix cool. As far as can currently be established, leaching of chemicals from polystyrene foam is only a problem when in contact with hot substances.

Ask your local greengrocer to save some of these boxes for your students, as most of the boxes get broken into small pieces and end up as landfill.

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You may have to set up garden beds on a lawn area. If the lawn contains couch or kikuyu, digging out the grass will not be sufficient as these two grasses will regenerate from small pieces of runner left in the soil. See EOG&MP pp 440-1 for a guide to turning couch and kikuyu grass areas into garden beds.

On the other hand, you may have to set up garden beds on unimproved soil, or where topsoil has been removed during building construction. Organic gardeners practice minimum cultivation because regular cultivation damages soil structure and accelerates the loss of carbon from soil. However, some initial cultivation may be necessary to break up very compacted ground.

Before you cultivate, it will help if you can identify the texture of the soil in your school grounds. To do this you will need a sample of soil from your garden bed area.

Take a handful of dry soil. If soil in the garden bed area looks hard, try scratching it with the point of a trowel. It may be sandy with a surface crust, but if you need a shovel or trowel to collect your sample – you do not have sandy soil.

Set the sample aside and apply some water to the garden bed area. Take note of how the water behaves. Does it soak in, or bead and run off? Does the soil have a crust when dry, and drain poorly when wet?

Testing the soil texture

Remove any stones from the sample and, using a spray bottle, add just enough water to allow you to knead the soil in your hand. Does it feel, gritty, silky, smooth or sticky?

Roll the soil into a ball. Watch how the soil behaves. Then, roll the ball between your palms to make a log shape. Try to bend the soil log into a curve.

If you were unable to form your soil into a ball, it is very sandy. If the ball broke apart, you have a sandy loam. These soils, and soils that form a crust, need a lot of organic matter in the form of compost added to them for the healthy growth of plants. Adding some bentonite (a volcanic clay) can also help these soils retain moisture.

Did your soil feel only slightly gritty and form a ball and a log, but broke when you tried to curve the log? You have an easily crumbled (friable) loam that probably contains some organic matter. This soil type is good for garden beds, and requires little cultivation. Your soil will benefit from a 3-5 cm layer of compost dug into the top 10 cm of the garden bed, regularly.

If your soil was hard to collect, felt quite smooth, and the soil log cracked but did not break when curved, you have a clay loam. Clay soils retain more nutrients than sandy soils but clay particles are very fine, which restricts water, root and air movement through soil because clay particles sit together like a stack of wet dinner plates. The addition of plenty of compost to topsoil or growing a green manure grain will help improve these soils.

If your soil ball was like hard plasticine, and the log did not crack when bent, you have a clay soil. Clay soils tend to crack when dry and stay sticky when wet. Sticky soils may respond to applications of natural gypsum, preferably organic-allowed gypsum. See EOG&MP, pp 37-8 and pp 442-3 to test your soil's suitability for gypsum application.

If soil in your garden area is in very poor condition, it might be worthwhile to purchase enough compost or organic topsoil to set up one bed to allow students to get started on their gardening, and grow a green manure grain in the rest of the gardening area. Use the slashed green manure as mulch to protect the soil surface. Roots of annual grains break down to provide a lot of organic matter.

Oats, barley and wheat are a good choice as they are fast growing and provide a lot of organic matter. Oats and wheat are also cheap, and usually easy to find. For an easy to follow guide on growing green manures, and a table of which green manure to grow when for each climate, see EOG&MP, pp 14-18.

If your soil forms a crust when dry, feels silky, and the log breaks quickly, you are likely to have a silty soil. These soils can contain nutrients but their very fine particles pack down, excluding air. Silty soils will benefit from green manures that add bulk (e.g. oats). When turned-in they aerate these soils and help them form aggregates. Silty soils are not common, but some soil suppliers combine dredged soil with sand, which produces a poor medium for growing plants. Check the quality of topsoil before purchase.

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As stated in Part 1 of the Introduction, organic gardening and farming focus on maintaining soil health. If soil is healthy, plants are healthy. See EOG&MP pp 5–8, for a detailed explanation on the importance of healthy soil in successful gardening.

Compost is the foundation of garden soil health. Good compost contains all the minerals that plants, animals and humans need for good health, most of the soil's nitrogen, and humus. It provides a habitat for a soil community of millions of beneficial bacteria and fungi and other organisms that help form soil aggregates, increase the depth of topsoil, control soil-borne diseases, and feed nutrients to plant roots through a symbiotic relationship.

Humus, the most stable form of recycled organic waste, stores carbon in soil, keeps soil more moisture-retentive yet better-drained, and buffers plant roots from temperature extremes and unsuitable acidity or alkalinity of surrounding soil.

Making compost

Basically, there are two methods of composting – aerobic (with oxygen) and anaerobic (without oxygen). See EOG&MP p 33 – Organic Fertilisers for further information.

Well-made compost provides perfect conditions for the healthy growth of fruits and vegetables. The vegetable patch and orchard require the most compost because nutrients are continually being removed as crops are harvested. Consequently, we recommend aerobic or 'hot' composting (Indore method) for school gardens, as it is the fastest method of providing a steady supply of compost. With this method compost can be ready to use in 6–8 weeks in most parts of Australia.

Compost containers

EOG&MP pp 42-51 provides information on the different types of containers that can be used for compost making, suitable sites for compost containers, and basic instructions for aerobic composting. You will also find information on ingredients that are suitable and unsuitable for compost making, including reasons why they should, or should not, be used.

Compost can be made in a variety of containers. The examples pictured show a double bin made from recycled timber (above, left), a double bin made from recycled, heavy gauge bird wire covered with knitted polypropylene shadecloth (above, right) and a commercial single bin (below, left) along with a compost tumbler (below, right).

Compost tumblers do the work of aerating the mixture. They are suitable for composting small quantities of fairly soft ingredients quickly, but the mixture may not generate enough heat to kill diseases.

Homemade containers don't require skilled carpentry. What goes into the compost container is more important than how it looks. However, note that the simple wire hoop compost bin demonstrated in EOG&MP is not particularly suitable for school grounds. It is for compost that has moisture levels carefully controlled and is being turned very frequently.

The main points to remember in deciding on the size and site of your compost container are:

• When ingredients form one cubic metre (i.e. 1 m. x 1 m. x 1 m.), aerobic bacteria will generate enough heat to kill diseases and weed seeds
  

• Open-base containers that are in contact with soil allow earthworms to enter the mixture (when it has cooled down) and add worm castings to the compost as they help complete the composting process
  

• Recommendations to position compost containers in full sun do not apply to many parts of Australia, as too much heat can kill off composting organisms
  

• Compost containers need a cover to prevent the ingredients becoming sodden in heavy rain
  

• A container that provides easy access is best.
  
  

Compost supervisor

In primary school gardens, turning and mixing the compost ingredients is a job for an adult. You may need a parent to volunteer as a compost supervisor. A cubic metre of ingredients will gradually reduce in volume to about a quarter of a cubic metre, so turning the heap takes less time as decomposition progresses.

It is advisable to have an adult add or supervise the addition of ingredients to the compost container, as children may add materials that attract vermin or are unsuitable for composting. An adult should check inside compost containers for vermin or snakes before allowing students access to the containers. Snakes are attracted to both vermin and the warmth generated in the early stages of decomposition.

Students and canteen staff can place ingredients into a lidded bin provided in the compost area.

Some composting tips

• If you are new to compost making, don't be intimidated by statements of the ratio of carbon to nitrogen in compost making. Most recommended ingredients contain a mixture of both. With a little practice, you will quickly learn to identify and correct any imbalances

• Chop up tough items using shears, a shredder, or a sharp spade (spread items on soil or grass first to prevent jolting) to assist faster decomposition as bacteria work on the surfaces of organic waste. The more surfaces you can provide  – the faster they can work
  

• The secret to fast composting is regular turning and mixing of the ingredients – weekly turning while the ingredients are generating heat will produce mature compost very quickly
  

• You don't have to wait until you have a cubic metre of ingredients – turning and mixing ingredients will get the bacteria working
  

• If the pile looks grey or contains ants – it is too dry. Turn and mix the ingredients, while adding enough water to dampen the mixture
  

• If the pile has a sharp or acidic smell – turn and mix the ingredients, while dusting with dolomite every 15 cm
  

• If the pile is black with an unpleasant smell – it is over-wet. Air has been forced out, and anaerobic composting has begun. Turn and mix the ingredients, while dusting with dolomite every 15 cm, and adding some straw to the mix. Protect pile from rain
  

• If the pile seems inactive – it may need more nitrogen. Turn and mix the ingredients, while adding some manure every 20 cm. If manures are unavailable, you can substitute a generous sprinkling of poultry-based, organic-allowed fertiliser.

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Worm farms are an excellent way to recycle soft organic waste into organic fertiliser, and many children enjoy looking after these farms. They can be used in conjunction with compost containers or alone for schools that may not have enough ingredients to make compost.

Note that compost worms can be a confusing name for worms that recycle soft waste in worm farms, as they are different species from earthworms that assist decomposition in compost piles, and require different living conditions. See EOGMP, pp 51-53 for information on worm farming, and suitable foods for these worms. We advise not adding manures to worm farms that are tended by students.

Composting worms prefer temperatures around 24� C., but will survive in a temperature range of 10-30� C. The farm needs a shady position.

Worm farm containers

While compost heaps preferably have contact with the soil, worm farms with supporting legs are best to prevent the bedding from becoming water-logged, allow access to the liquid that drains from the worm farm, and provide a comfortable height for collecting castings.

Commercial modular worm farms are suitable for schools that do not have a lot of organic waste or have limited space, and for those in areas with very cold winters. The modules are stackable. You will need a farm with at least two working trays with slotted bases, and one collector tray with a solid base to catch the liquid that trickles through the farm.

The 'Worm Caf�' model is a good size for schools, but very small schools without canteens might find the 'Can-O-Worms' more suitable. Black or green plastic worm farms are portable, and the farm can be moved into a shed or garage to keep worms alive through frost periods. These farms come with a lid, a tap to drain liquid from the base of the farm, bedding materials, and complete instructions for setting up the farm. All you need to do is add some worms, which are available from major nurseries or local worm farmers.

Worm farms made from second-hand, pressed steel bath tubs are now very popular in areas with mild winters. (Cast iron baths need very strong supports.) Old bath tubs can often be obtained quite cheaply from your local tip or building recycling centre. They require a basic timber frame and a lid or cover to keep the surface area dark and prevent water-logging in heavy rain. A layer of fly screen in the bottom of the bath prevents worms and castings falling through the drain hole. Finely shredded coconut fibre makes excellent bedding for these worm farms. A bucket under the drain hole can collect the liquid.


In the farms in the photos right and below, one is a hip bath and the other a full-sized bath. The recycled hardwood timber planks used as a cover allow fast access to as little or as much of the surface as required. A plastic cover over the planks protects the farm from heavy rain. Or, you can use non-PVC plastic, or a sheet of corrugated iron, or dense shadecloth supported in the centre to prevent water pooling. Choose a cover that suits your farm.

If soil is very well-drained, a brick or concrete worm farm can be built on soil, but some of the goodness from the farm will soak into the soil under the farm. This type of worm farm is not suitable for areas subject to wet seasons.

Further details on tending worm farms and collecting castings can be found in Lesson 4.

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