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Session Notes: Sustainable Garden Design


Organic Potting Mix for Vegetables – Phil Dudman

▪ 2 x 9l buckets of good quality potting mix
▪ 1 x 9l bucket of garden compost
▪ A few good handfuls of coir/coco peat
▪ 2 scoops (400g can) pelletised chicken manure
▪ ½ scoop blood and bone
▪ A good pinch of trace element mix / rock dust
▪ Mix it all together on a bench and you’ve got a truly magical blend
▪ Keep soil moist and treat the potted veggies to liquid fertilizer every fortnight

What is a Sustainable Gardening?

Sustainable Gardening is about – being part of the wider ecosystem – the environment and working with it; practising closed loop gardening with your resources; taking positive climate action in your patch; connecting into the gardening community. It’s about how garden, just as much as it is about what you garden

What is a sustainable garden?

Can be many things: Food Garden, Wildlife Garden, Thrifty Garden, Climate Action Garden, Community Garden, street garden.

Know your gardens micro climate


These are created by sun, shade, temperature, rain, wind, humidity and will determine what plans you need to put where.

Summer Sun and Shade
Veggie Gardens need 6 – 8 hours of sun, especially in winter so afternoon (western) shade can be beneficial in winter but in summer try:
Using deciduous trees and vines (especially on the western side)
Adding shade structures
Choosing drought tolerant plants

Wind Protection
Hot northerly winds can dry and damage plants; Plants may require extra watering on windy days; Wind on elevated sites can be especially intense; Avoid solid windbreaks as these can strengthen winds. Use wind tolerant plants instead.

The “Whole of Environment” Garden.
We need to look at our garden as a part of nature and tis natural cycles and patterns
Our gardens are an ecosystem and a food chain.

Wildlife Gardening

What does it do?

  • Keeps soil moist for longer
  • Provides habitat for insects, lizards ect.
  • Suppresses weed growth
  • Adds nutrients to the soil and improves soil structure
  • Reduces run-off and erosion
  • Keeps soil friable with reduced compacting
  • Regulates soil temperature

Wildlife Gardening Resources

  • Food – Leaves, fruit, seed, insects etc.
  • Shelter – Dense shrubs, prickly bushes, rock crevices, tree hollows, grasses
  • Fresh water – Ponds, gullies, depressions, rock pools, water bowls etc
  • Breeding sites – Trees, thickets, grasses, leaf litter, rocks and tree hollows, water etc
  • Prevent soil erosion – plant plants, mulch

Garden Structure and Diversity

  • Open gardens provide little food or shelter
  • Think in 3 dimensions and build vertical and horizontal layers in your garden
  • The more layers and variety of plants, the more diversity it will attract and support
  1. Canopy – Large Trees
  2. Mid Storey – Small Trees and shrubs
  3. Understorey – Small Shrubs
  4. Ground Cover
  5. Leaf letter, rocks and logs
  6. Soil fauna

Indigenous Plants

  • Are suited to the local soil / climate and can thrive with low rainfall
  • Help preserve the local plant ecology and contribute to the distinctive character of the area
  • Indigenous wildlife has evolved with these plants that provide perfect habitat, shelter and food
  • Symbiotic relationships between indigenous flora and fauna, especially in the bug world
  • Enhances wildlife corridors and provides habitat steppingstones between fragmented and otherwise isolated communities
  • If your soil is relatively undisturbed, no need to do too much work on amending the soil
  • Keep you compost for the veggie garden

Ground Preperation – Sheet Mulching or Solarisation

Choose your plants

  • Autumn to Spring is the best time to be planting new plants
  • Tube stock are cheaper and often grow quicker than larger potted plants
  • Choose healthy plants and not root bound
  • Squeeze the pot to see if gives (loose) or resists (root bound)

Soak pots before planting

  • Ensure the plant is moist before planting
  • Soak in water with some seaweed solution

Dig a hole

  • Remove weeds from around the hole
  • The hole should be 2 to 3 times wider that the pot
  • Keep soil for backfill. Break up large clumps. Can use potting mix if the soil is poor to help establish the plant
  • Make sure there is some loose soil in the bottom of the hole
  • Check hole drainage by filling with water. If too slow to drain (>4 hours) may have to amend the soil or find another location.

Remove plant from pot

  • Carefully remove the plant from the pot
  • If it is hard to get out, tap or squeeze the sides
  • If the roots are dense / twisting around the shape of the pot, gently tickle to loosen

Place in the hole

  • No need to add nutrients/conditioners
  • Gently place the plant in the hole
  • Ensure the plant isn’t too deep.

Backfill and water

  • Gently push soil back around the roots of the plant and push down firmly
  • Do not compact the soil (no standing on it)
  • Make a little moat around the plant to capture water
  • Give a good soaking water

Potentially install a plant guard to protect from wildlife

  • Plastic, corflute or mesh


  • Chunky bark/wood chip mulch
  • Not around the trunk


  • Water for first 6-12 months to establish
  • Remove weeds
  • Prune after flowering
  • Refresh mulch

Organic Mulch

What does it do?

  • Keeps soil moist for longer
  • Provides habitat for insects, lizards etc.
  • Suppresses weed growth
  • Adds nutrients to the soil and improves soil structure
  • Reduces run-off and erosion
  • Keeps soil friable with reduced compacting
  • Regulates soil temperature

Which Mulch? Tree Mulch of Indigenous Garden

Ground Cover Mulch

  • Chunky with minimal fine particles
  • landscapers/native mulch
  • Slowly breaks down to release nutrients
  • Good water penetration
  • Good air exchange
  • Keeps soil moist
  • Suppresses weeds
  • Reduces run-off and erosion
  • Regulates soil temperature
  • Keep soil friable
  • Reduces compaction
  • Provides habitat for insects, lizards ect

Soil Conditioning Mulch

  • A high level of fine particles
  • Breaks down relatively quickly to feed the soil foodweb
  • Sometimes up to 70% consumed in first 12 months, then 50%, then 30%
  • Improves soil structure when decomposed
  • Reduces run-off and erosion
  • Regulates soil temperature
  • Can become a substrate for weed growth
  • Lets less moisture through

Reduce Chemical Usage

  • A “Whole of Environment” garden is in balance and has inbuilt pest control
  • Many native birds, lizards, micro-bats, insects are the natural predators of pests
  • Insects that have been sprayed with poisons can be harmful to wildlife that eat them
  • SGA’s “Garden Product Guide” identifies garden products that have a low environmental impact rating
  • Use Intergrated Pest Management – IPM
  • Pest Repellent Plants – Penny Woodward

Be a Responsible Pet Owner
Obey local government by laws and contain your animal on your property; Fence off areas such as frog ponds from dogs and cats; Secure dogs and cats, especially at night, so they don’t prey on native animals

Bird Baths
Ensure your bird bath is: Off the ground – suspend from a tree or on a pedestal, Clean – water replaced regularly & has no detergents, Placed in dappled shade, Shallow with a rough bottom or pebbles or a stick, Relatively exposed so birds can see approaching danger but close to safety

Supplementary Feeding – Recommendation is to not supplementary feed.
Increases wildlife dependence on us; Can be an unnatural / unbalanced diet; Exposes them to more disease; Decreases foraging / gleaning skills increasing vulnerability if food runs low; Interrupts migratory behaviour; Wildlife breeds up to a level of food resulting in population booms ; Can decrease diversity by favouring dominate, aggressive species; Attracts unwanted pests / rodents; Can makes birds vulnerable to predators.

Food Gardening

Starting Your Veggie Garden
Grow food like nature does; Feed the soil-food-web; Avoid synthetic chemicals; Compost your organic waste; Encourage garden resilience by growing a diversity of plants; Encourage beneficial insects; Capture rainfall and use water wisely; Include a place for yourself

What do I need for a Veggie Patch?

  • Good sun exposure – Northerly or westerly aspect
    • Fruiting Veggies – min. 8 hours / day
    • Root Veggies – min. 6 hours / day
    • Leafy Veggies – min. 4 hours / day
  • Open friable soil with good organic content; Access to clean water; Compost / vermicast / worm tea; Straw based mulch; Good air circulation

Raised Garden Beds

  • Can be adapted to any area, even hard surfaces
  • Great for growing veggies
  • Saves your back
  • Choose a level spot with full sun
  • Permanency? Moving it will be difficult
  • If it has a base – ensure there are adequate drainage holes
  • If hollow – line with layers of newspapers / cardboard

Productive Potting

  • Using the right pot – big is better
  • A sunny position – 6 to 8 hours Will the location be too hot, too windy, or reflect heat?
  • Place where you will remember to water regularly
  • Good potting mix (ticks)
  • Regular water at the soil level
  • Liquid fertilizer e.g. compost / worm teas
  • Add straw based mulch to reduce evaporation, protect soil

Good Veggies for Pots: Tomato, eggplant, capsicums, cucumbers, asian greens, salad greens, beetroot, potato, bush beans and peas, carrots

Grow your own herbal teas: sage, chamomile, stevia, lemon verbena, thyme, mints, rosemary, lemon balm

Soil Structure
Sandy – Poor water holding ability / Excellent drainage; May be hydrophobic; Poor structure; Leaches nutrients; Easy to cultivate; no structure
Clay – Good water holding ability; Good nutrient retention; Poor drainage; Low aeration; Poor root penetration; Difficult to cultivate
Loam – A combination of fine and coarse particles; Good water holding ability; Good drainage; Easy to cultivate; Good nutrient holding ability
The best way to improve Soil Structure – Add organic matter

Soil Chemistry – pH

  • pH is expressed in terms of acidity and alkalinity and has a role in:
  • A plants ability to access and use nutrients
  • Soil microbial activity
  • pH range for most garden plants is 6.0 to 7.5
  • Use a simple pH test kit (available from nurseries) to test the pH of the soil

Adjusting pH

  • The best was to balance the pH of soil – Add organic matter
  • If the pH is too low (acid), it can be raised with Garden Lime
  • If the pH is too high (alkaline), it can be lowered with garden Sulphur (slow to amend)

Soil Biology – Soil Food Web

  • A universe of unique and diverse organisms that live in the soil and recycle energy, carbon and nutrients
  • The best way to feed the Soil Food Web – Add organic matter

Party or Game of thrones

  • One teaspoon of good garden soil contains one billion bacteria of between 20,000 and 30,000 species, several yards of fungal hyphae, several thousand protozoa and a few dozen nematodes?
  • Teaming With Microbes – A Gardener’s Guide to the Soil Food Web

Activate the Soil Food Web

  1. Add organic matter: Feed the soil food web; Compost, manure, mulch, leaf litter; Plant cover / green manure crops
  2. Avoid garden chemicals: Fertilizers, pesticides, insecticides etc.; Disrupts the Soil Food Web and / or kill microorganisms; Implement Integrate Pest Management
  3. Keep soil moist: Add organic matter; Mulch Mulch Mulch; Creates a good habitat for the soil microbes; Provides water for plants
  4. Minimise Digging; Exposes soil life to UV light; Disrupts Soil-Food-Web; Destroys cavities, created by burrowing critters, for air, water & nutrient cycling
  5. Avoid soil compaction: Destroys cavities for air and water; Avoid stepping on garden beds; Avoid heavy equipment on garden beds; Keep beds an arm reach in width
  6. Prevent soil erosion: Soil-food-web is most active in top 30cm; Mulch / Mulch / Mulch; Always have plant cover

Soil Nutrients

  • Edible gardens need lots of nutrients
  • Existing soil nutrients can be made more available by regulating soil pH
  • Supplement soil conditioners with organic fertiliser
  • Soil conditioner: Food for the soil; Slow release; Bulky organic additives; Macro / micro-nutrients and trace elements
  • Plant fertilizer: Food for the plants; Quick boost for hungry veggies; Macro-nutrients – NPK

Feeding the Patch

  • Soil Conditions: Compost; Vermi-castings; Worm tea; Matured animal manures (cow, sheep, alpaca)
  • Fertilisers: Blood and Bone (N); Chicken manure (N); Nettle tea (N); Pelletised manures (NPK)
  • Note: Leafy greens = N; Fruiting / rooting = NPK
  • Other: Seaweed Solution; Comfrey tea; Rock dust; Dolomite Lime; Crushed eggshells

Best Mulch for Veggie Patch

  • Pea straw / Lucerne / Sugar cane
  • Avoid hay as it will contain seed
  • Avoid bark mulch in the veggie patch
  • Soil should be moist prior to mulching
  • Add mulch after spring rains, before summer drying
  • Apply no thinner than 25mm
  • Apply no thicker than 75mm

Why Recycle Organic Waste at home?

  • Reduce Emissions
  • Feed the Soil Food Web
  • Improve Soil Structure
  • Add Soil Carbon & Humus
  • Grow Healthy Plants

Recycling Organic Waste: Worm Farming; Composting; Bokashi; Chickens

5 Key Ingredients

  • Browns / Dry Inputs / Carbon – Leaf litter, Dead plant material, Twigs, Leaves, Straw, Shredded newspaper or cardboard
  • Greens / Wet Inputs / Nitrogen – Fresh plant pruning’s and garden waste, Household food waste, Tea leaves, Coffee grinds, Animal manure
  • Water – Composting organisms need moisture, but not too much. Moisture from your kitchen scraps should generally be sufficient. The compost should feel damp but not wet Damp Sponge. If too wet, add more dry ingredients
  • Oxygen – Aeration is required to ensure oxygen can enter the compost. Oxygen is required so the aerobic bacteria can breathe. Turn the compost weekly to add oxygen
  • Layering – Use thin layers (3-10cm), Alternate green and brown. Use a diverse range of materials

Avoid Garden Chemicals!

  • You can successfully grow food without the use of chemical based pesticides and fertilizers
  • Many insects in the garden e.g. ladybirds, are ‘good guys’ that will hunt and eat pests such as aphids
  • If you spray lots of chemicals in your garden, you will kill these beneficial insects and make your pest problem harder to control
  • Use natural alternatives such as chili and garlic spray to control pests

Integrated Pest Management

  1. Mechanical Pest Control – Hand Removal (snails); barriers (netting, fencing, copper tape); Traps (Beer traps, pheromone traps, sticky traps)
  2. Cultural Pest Controls – Remove pest habitat from garden; Crop Rotation
  3. Encourage Biological Good Guys – Companion Planting. If you have been using chemical controls in your garden, it will take some time for beneficial insect numbers to increase, so be patient. Remember, without any food, beneficial insects won’t survive either, so you must be able to tolerate a low level of insect pest damage.
  4. Chemical Controls – Last Resort. Think about homemade remedies first:
    • Garlic-chili sprays – leaf attackers, Milk sprays – powdery mildew, Botanical oils – aphids/scale
    • As a last resort – use a low impact chemical solution.
    • Check the SGA website for recommendations

Habitat for Beneficial Insects

  • Beneficial insects include:
    • Pollinators such as bees (native and honey), hover flies
    • Predators include ladybirds, lacewings, hover flies, praying mantids, spiders and predatory mites
    • Parasitoids of pests such as wasps

Plants to Attract Beneficial Insects

  • Open and densely floiwering plants are excellent attractors of beneficial insects:
Carrot Family (Apiaceae/Umbelliferae)Dense flowers arranged in umbels
Particularly good for parasitic wasps
Dill, parsley, anise, garden angelica, caraway, chervil, lovage, coriander, cumin, fennel, carrots, celery, parsnip
Daisy family (Asteraceae/Compositae)Shallow open flower
Popular with lady birds, lacewings, spiders, hover flies and wasps
Absinthe, artichokes, chamomile, tansy, cardoons, chicory, tarragon, fever few, dandelion, yarrow, black-eyed Susans, anthemi, cosmos and salsify

Water Application

  • Water should be delivered directly to the plants root zone, preferably in the early morning
  • Use water efficient systems
  • For soil / ground gardens
    • Water more thoroughly, less often
    • encourage development of deep roots, increasing drought tolerance
  • For container / pot garden
    • Water sparingly, more often
    • Water coming out of the bottom is a waste and a loss of vital nutrients
    • Place a saucer or container under the pot to collect water
  • Above – Sprinkler / Hand Sprinklers – A very inefficient way of watering a garden
  • (Sub)Surface Irrigation – Drip Irrigation – A very efficient way of watering a garden
  • Irrigating from Below – Wicking Beds