Choices to Protect You and the Planet

Wisegardening Ratings

Risks of Garden Chemical Products

Risks of garden chemical products for humans, bees, birds, fish, worms and other organisms are important in deciding if you want to use those products to address weeds, pests and disease.  Or you may decide to use lower risk non-chemical better choices.

WiseGardening rates products on the basis of publicly available scientific data on their ingredients’ properties and on other product features. It cannot fully take account of your use of products i.e. how much you use in a particular location, if you spill it on the ground or yourself, if it is degraded or becomes more concentrated by evaporation during storage.  Full details of rating methods are HERE

Use the product ratings below to help you choose! AND ALWAYS FOLLOW MANUFACTURERS’ INSTRUCTIONS.

 

How to Use

WiseGardening Project on Risks of Garden Chemical Products

The WiseGardening project was initiated over 20 years ago to assess and rate garden chemical products for their sustainability.  It was a collaboration between Sustainable Gardening Australia (SGA),  Burnley Horticultural College (now part of the University of Melbourne), the garden centre Bulleen Art and Garden and local government.

SGA is a not-for-profit, non-government organization with a strong interest (passion) for enabling gardeners to grow their own food, protect their health and that of the planet and all that is naturally on it.  It has charitable status under the federal government’s Register of Environmental Organisations and is registered with the Australian Charities and Not-for-Profit Commission (ACNC).

Since 2016, our SGA team has further developed and refined WiseGardening to make it available as part of our web presence.

risks-of-garden-chemical-products

Who Uses WiseGardening to Understand Risks of Garden Chemical Products?

Those interested in garden product risks and safety include home gardeners, managers of Parks and Reserves such as state and local governments, those who maintain public green space, community gardeners and those just concerned with human health and natural life on the planet.

Symbol Guide

Terms of Use

© 2022 Sustainable Gardening Australia. All rights reserved

WiseGardening Terms and Conditions of Use

1. About SGA’s WiseGardening – Protecting You and the Planet

1.1. WiseGardening provides access to an independent database of over 800 chemical garden products available in Australia for Australian gardeners to review each product’s safety for people, and for beneficial insects, birds, aquatic life, earthworms, pets and other non-target organisms (the Services).

1.2. Access to and use of WiseGardening and the Services is provided by Sustainable Gardening Australia Inc (ABN 49 895 542 709 (SGA).  Please read these terms and conditions (the Terms), About WiseGardening and WiseGardening Assessment and Rating Process carefully. Using, browsing and/or reading WiseGardening signifies that you have read, understood and agree to be bound by the Terms. If you do not agree with the Terms, you must cease usage of WiseGardening and the Services immediately.

1.3. SGA aims to include up to date and accurate information about products, their ingredients, and other information on non-chemical approaches to addressing pest, disease and weed problems. SGA cannot guarantee how effective or safe products are, and to the extent permitted by law and as set out in these Terms, is not responsible or liable for any harm, injury, damage or loss resulting from using any product or alternative non-chemical gardening approach described in WiseGardening.

1.4 SGA’s assessment of products is based on the information provided by the product manufacturers/distributors and publicly available scientific assessment of the ingredients stated to be in the products at the time of our assessment of them. However, product details and scientific estimates of ingredient risks may change from time to time and there may be a delay in making updates to our product assessments. Users should confirm for themselves the suitability of a product for their purposes, especially if the product has been purchased before our assessment of the product as the information provided on or pertaining to such products may differ over time. Likewise, chemicals and ingredients in the products that SGA reviews may change from time to time and you should only use SGA’s assessment at the time of publication.

1.5. When precise information is required, we recommend that you contact the manufacturer of the product directly prior to purchase. Importantly, you should always read the product labels and associated information and follow all safety precautions on products you purchase or use.

1.6. SGA does not endorse any product included in the WiseGardening database, nor does it receive any financial benefit from the sale of any of these products.

1.7. SGA reserves the right to review and change any of the Terms by updating this page at its sole discretion. When SGA updates the Terms, it will use reasonable endeavours to provide you with notice of updates to the Terms. Any changes to the Terms take immediate effect from the date of their publication. Before you continue, we recommend you keep a copy of the Terms for your records.

2. Acceptance of the Terms

You accept these Terms by using WiseGardening and by ticking the box on WiseGardening Overview. You also accept the Terms by clicking to accept or agree to the Terms when this option is made available to you by SGA in the user interface.

3. Your obligations as a User

As a User, you agree that:

(a) you will use WiseGardening and the Services only for purposes that are permitted by:

(i) the Terms; and

(ii) any applicable law, regulation or generally accepted practices or guidelines in the relevant jurisdictions;

(b) you will use any product listed in WiseGardening in accordance with any instructions or guide issued by the manufacturer of that product;

(c) you will not use the Services or WiseGardening in connection with any commercial endeavours;

(d) you will not use the Services or Guide for any illegal and/or unauthorised use which includes unauthorised framing of or linking to WiseGardening; and

(e) you acknowledge and agree that any automated use of WiseGardening or its Services is prohibited.

4. Copyright and Intellectual Property

4.1. WiseGardening, the Services and all of the related products of SGA are subject to copyright. The material in WiseGardening is protected by copyright under the laws of Australia and through international treaties. Unless otherwise indicated, all rights (including copyright) in the Services and compilation of WiseGardening (including, but not limited to, text, graphics, logos, button icons, video images, audio clips, codes, scripts, design elements and interactive features) and the Services, are owned or controlled for these purposes, and are reserved by SGA or its contributors.

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(a) use WiseGardening pursuant to the Terms;

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(c) print pages from WiseGardening for your own personal and non-commercial use.

SGA does not grant you any other rights whatsoever in relation to WiseGardening or the Services. All other rights are expressly reserved by SGA.

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(a) business name, trading name, domain name, trademark, industrial design, patent, registered design or copyright, or
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(c) a thing, system or process that is the subject of a patent, registered design or copyright (or an adaptation or modification of such a thing, system or process), to you.

4.4. You may not, without the prior written permission of SGA and the permission of any other relevant rights owners, broadcast, republish, upload to a third party, transmit, post, distribute, show or play in public, adapt or change in any way the Services or third-party Services for any purpose, unless otherwise provided by these Terms. You acknowledge and agree that SGA and/or any other relevant rights owners may refuse that permission in their absolute discretion. This prohibition does not extend to materials on WiseGardening, which are freely available for re-use or are in the public domain.

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SGA takes your privacy seriously and any information provided through your use of WiseGardening and/or Services are subject to SGA’s Privacy Policy, which is available on the SGA website, .

6. General Disclaimer

6.1. Nothing in the Terms limits or excludes any guarantees, warranties, representations or conditions implied or imposed by law, including the Australian Consumer Law (or any liability under them) which by law may not be limited or excluded.

6.2. Subject to this clause, and to the extent permitted by law:

(a) all terms, guarantees, warranties, representations or conditions which are not expressly stated in the Terms are excluded; and

(b) SGA will not be liable for any special, indirect or consequential loss or damage (unless such loss or damage is reasonably foreseeable resulting from our failure to meet an applicable Consumer Guarantee), loss of profit or opportunity, or damage to goodwill arising out of or in connection with the Services or these Terms (including as a result of not being able to use the Services or the late supply of the Services), whether at common law, under contract, tort (including negligence), in equity, pursuant to statute or otherwise.

6.3. Use of WiseGardening and the Services is at your own risk. Everything on WiseGardening and the Services is provided to you “as is” and “as available” without warranty or condition of any kind. None of the affiliates, directors, officers, employees, agents, contributors and licensors of SGA make any express or implied representation or warranty about the Services or any products or Services (including the products or Services of SGA) referred to in WiseGardening, including (but is not restricted to) any loss or damage you might suffer as a result of any of the following:

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(b) the accuracy, suitability or currency of any information on WiseGardening, the Services, or any of its Services related products (including third party material and advertisements on WiseGardening);

(c) costs incurred as a result of you using WiseGardening, the Services or any of the products of SGA; and

(d) the Services or operation in respect to links which are provided for your convenience.

7. Limitation of liability

7.1. SGA’s total liability arising out of or in connection with WiseGardening and the Services or these Terms, however arising, including under contract, tort (including negligence), in equity, under statute or otherwise, will not exceed the resupply of the Services to you.

7.2. You expressly understand and agree that SGA, its affiliates, employees, agents, contributors and licensors shall not be liable to you for any direct, indirect, incidental, special, consequential or exemplary damages which may be incurred by you, however caused and under any theory of liability. This shall include, but is not limited to, any loss of profit (whether incurred directly or indirectly), any loss of goodwill or business reputation and any other intangible loss.

8. Termination of Contract

8.1. The Terms will continue to apply until terminated by either you or by SGA as set out below.

8.2. If you want to terminate the Terms, you may do so by:

(a) [if there is a subscription period] not renewing the Subscription prior to the end of the Subscription Period;

(b) providing SGA with 14 days’ notice of your intention to terminate; and

(c) closing your accounts for all of the services which you use, where SGA has made this option available to you.

Your notice should be sent, in writing, to SGA via the ‘Contact Us’ link on our homepage.

8.3. SGA may at any time, terminate the Terms with you if:

(a) you do not renew the Subscription at the end of the Subscription Period;

(b) you have breached any provision of the Terms or intend to breach any provision;

(c) SGA is required to do so by law;

(d) the provision of the Services to you by SGA is, in the opinion of SGA, no longer commercially viable.

8.4. Subject to local applicable laws, SGA reserves the right to discontinue or cancel your membership at any time and may suspend or deny, in its sole discretion, your access to all or any portion of WiseGardening or the Services without notice if you breach any provision of the Terms or any applicable law or if your conduct impacts SGA’s name or reputation or violates the rights of those of another party.

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You agree to indemnify SGA, its affiliates, employees, agents, contributors, third party content providers and licensors from and against:

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(b) any direct or indirect consequences of you accessing, using or transacting on WiseGardening or attempts to do so; and/or

(c) any breach of the Terms or reliance upon them.

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10.1. Compulsory: If a dispute arises out of or relates to the Terms, neither party may commence any Tribunal or Court proceedings in relation to the dispute, unless the following clauses have been complied with (except where urgent interlocutory relief is sought).

10.2. Notice: A party to the Terms claiming a dispute (Dispute) has arisen under the Terms, must give written notice to the other party detailing the nature of the dispute, the desired outcome and the action required to settle the Dispute.

10.3. Resolution: On receipt of that notice (Notice) by that other party, the parties to the Terms (Parties) must:

(a) Within 14 days of the Notice endeavour in good faith to resolve the Dispute expeditiously by negotiation or such other means upon which they may mutually agree;

(b) If for any reason whatsoever, 14 days after the date of the Notice, the Dispute has not been resolved, the Parties must either agree upon selection of a mediator or request that an appropriate mediator be appointed by the President of the 1 or his or her nominee;

(c) The Parties are equally liable for the fees and reasonable expenses of a mediator and the cost of the venue of the mediation and without limiting the foregoing undertake to pay any amounts requested by the mediator as a pre-condition to the mediation commencing. The Parties must each pay their own costs associated with the mediation;

(d) The mediation will be held in Melbourne, Australia.

10.4. Confidential: All communications concerning negotiations made by the Parties arising out of and in connection with this dispute resolution clause are confidential and to the extent possible, must be treated as “without prejudice” negotiations for the purpose of applicable laws of evidence.

10.5. Termination of Mediation: If 2 months have elapsed after the start of a mediation of the Dispute and the Dispute has not been resolved, either Party may ask the mediator to terminate the mediation and the mediator must do so.

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13. Severance

If any part of these Terms is found to be void or unenforceable by a Court of competent jurisdiction, that part shall be severed and, the rest of the Terms shall remain in force.

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How to use

WiseGardening gives star ratings to garden chemical products on a scale of 0 to 6 Stars where 6 stars are given to those with lowest risks.   Ratings are based on their risks to human health, bees, birds, frogs, pets, earthworms, fish, other aquatic species, soil mobility and persistence.

Data on products and ingredients used to create WiseGardening are the scientifically estimated and publicly reported risks to the health of humans and a range of other living organisms.  Also included are risks from important chemical properties.  For details of how ratings are derived see Our Assessment and Rating Process

Remember: these risks are very important if products are used unwisely.  Always use products strictly according to manufacturers’ instructions on labels and associated documentation.

Notes on Using WiseGardening

WiseGardening is sortable using the Search and Filter boxes.  The Search function can show information not visible on this page e.g. particular susceptible pests.  For some searches a full word such as “fungus” may not find many choices, but the beginning “fung” will show more because many entries might be for “fungicide”. Therefore, for some searches fewer letters may be more effective.

Note that the ingredient risks are based on pure ingredients so the risks are independent of the amount of ingredient in the product.

Some products with high star ratings still show some ingredient risks or other undesirable product characteristics. These products have received a high star rating because aspects of product packaging or being pre-mixed (i.e. not requiring dilution before use, or having robust packaging) reduce the likelihood of spills which could be harmful.

There are a few products which have ingredient risks about which there is conflicting international opinion.  Examples are those containing glyphosate, chlorpyrifos or dicamba.  Because we have only used data which is scientifically widely agreed on, these products may have achieved a higher star rating than some people might expect, especially if their containers and mode of delivery render the likelihood of inadvertent exposure unlikely.

Choices to Protect You and the Planet

Symbol Guide

Risks to Species

H = Human
A = Other Mammals
B = Bees
C = Worms
D = Birds
E = Fish
G = Other Aquatic Organisms
F = Frogs

Other Characteristics

M = Mobile in soil
P = Persistent
S = Carcinogen, Endocrine Disruptor or Genotoxic
Z = Poison S7
W = Biological control
– = No information available for identified ingredients
O = No assessible ingredients listed
Y = Better Choices: WiseGardening options
! = Discontinued product
 ? = Under further investigation

Solid symbols = high risk
Open symbols = moderate risk
No symbol = no or low risk

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Diseases

There are many options available to reduce plant diseases in your garden apart from using manufactured chemicals that have various risks associated with them. Here are a number of better WiseGardening choices.

Bacteria

Avoid Using Seed Which might be Diseased

Use either certified disease-free seed or, if saving seed from your garden, make sure that the plant you are taking it from is healthy.

Crop Rotation

Don’t grow plants of the same family in the same bed for at least 3 seasons to avoid a build up of pathogens in the soil.

Hygiene

Bacteria survive in infected plant debris/litter, seeds and in soils. They are spread by contact, rain splash, vectors and infected seeds.  Before and after harvest, dispose of infected plants/plant parts in sealed plastic bags in bins  – do not compost them.

Disinfect gardening equipment (bleach/methylated spirits).

Fungus

Avoid Moisture on Leaves, Especially at Night

Moisture persisting on leaves allows fungal spores to germinate.  Use drip irrigation rather than sprayers or employ overhead watering early in the morning so that moisture will evaporate.

Exclusion

Prevent pathogens from entering the landscape by only purchasing healthy, vigorous, undiseased plant material. Refuse to purchase any plants showing any sign of disease or poor health.

Hygiene

Completely remove any plants that are either heavily infested with untreatable diseases (remove as much of the plant & root system as possible as well as much infested soil as possible).

Solarisation

Fungus and other pathogens in the top layers of soil can be destroyed by covering the soil with thin, clear or black plastic film and leaving in place for a number of weeks in the summer/hottest months before planting crops. Try to use recycled plastic to avoid the extra pollution of plastic production.

Virus

Plants cannot be cured of viral infections, so prevention is required.

Hygiene

Cleaning of tools (especially cutting tools) with bleach or alcohol between uses and between plants will help prevent transmission of virus.

Some pest insects e.g. aphids can transmit viruses , so control of these pests can reduce the chance of viral infection of plants.

Removal and Destruction of Infected Plants

Place infected plants in plastic bags, seal firmly and dispose of in rubbish bins or burn them.

Crop Rotation

Since viruses can only grow in living organisms for which they are specific, transmission to subsequent plantings can be minimised by practising crop rotation.

Use Virus-Resistant Varieties

Algae

Most approaches listed below can be used to both remove algae and prevent their appearance.

Organisms which consume algae

Add tadpoles or water snails since they use algae as food.

Barriers

Place a net over the pond to catch falling leaves.

Prevent run off from adjacent areas that have been fertilized. This could be achieved by
growing a hedge or dense row of leafy plant species close to the pond.

Reduce nutrients

Fish Food

If the pond contains fish, reduce the amount of fish food which also supports algal growth.

Fish numbers

Removing some fish will decrease the amount of their faeces which after decomposition provide nutrients for algal growth.

Aquatic plants

Add aquatic plants -these will take up nutrients required by algae and thus limit their growth. Up to 60% of the pond surface can be covered with plant foliage.

Barley Straw

As barley straw decomposes it releases chemicals, possibly hydrogen peroxide, which slow algal growth. Use the actual straw (not commercial preparations derived from it). Tie in bundles with string or put in mesh bags placed, if possible, near a waterfall or aerator since it seems to work better if water is oxygenated, but it may take many weeks. Barley straw does not kill algae or other pond inhabitants.

Mechanical

While mechanical approaches to reducing algae are not chemical, they are not as sustainable as the above methods since they require considerable material and energy use in their manufacture and/or operation.

Aerators

In still waters, low oxygen conditions upset the balance of chemical nutrients for pond life and favour algal growth. Aerators help prevent algal growth by increasing dissolved oxygen levels. Make sure to clean any aerator regularly.

Filters

A mechanical filter (or skimmer) draws water in and traps algae. Cleaning the filter to remove the algae should be done on a regular basis.

UV light

Devices are available to shine UV light which kills algae without harming other pond inhabitants – they may be separate or attached to a pump. However, not all algae are susceptible to UV light and it works better if water is moving.

Manual

Although labour-intensive, this is possibly the quickest way to remove algae is manually.

Removal could be done using gloved hands, some sort of brush such as a circular toilet bursh, or a dip net. Manual removal allows easy collection of algae which can be usefully added to the compost heap.

Pests – Insects, Snails and Slugs

There are many options available to reduce pest numbers apart from using manufactured chemicals that have various risks associated with them. Here are a number of better WiseGardening choices.

Traps

Sticky Insect Traps

Commercial ones are available, but you can make your own following instruction/s on many websites.  Hang in locations with problem pests and monitor or replace when necessary.  However, some of these may trap beneficial insects.

Snail/Slug (Gastropod) Traps

For snails/slugs, place cardboard/wooden/plastic board or flowerpot on ground in damp spot in garden. After 1 or 2 days lift and remove snails/slugs congregated underneath.

For slaters and earwigs as well as snails ad slugs make a container with holes near the top. Place it so that the bottom of holes is level with  the ground – cover to keep rain out. Add beer or sweet liquid and vegetable oil to drown pests. Clear out trap regularly.

Bug Zappers

Plug in to 240v power point to attract and then electrocute insects. Locate these away from food preparation/cooking areas.  Please note that the environmental impacts of these are not clear.  Although they do not involve spraying chemicals, they may kill beneficial insects and they may use carbon-emitting electricity.

Provide Habitat for Predators

Increase Plant Diversity

Grow a large variety of plant species, herbs and ornamentals, especially those with brightly coloured flowers and those that are umbrella-shaped.  This will create an ecosystem of interdependent species which keep each other in balance.

Insect Hotels

These can be home-made and are also available commercially.

Nest Boxes

These can be for birds or bats which use insects as food.

Frog Ponds

If you build a frog pond, the frogs will come and they are voracious insect eaters.

Lizard Sun-bathing Rocks

Smooth rocks in the sun attract lizards which eat insects.

Barriers

Fruit Bags

Bag fruit individually or in clusters on trees to exclude pests.

Wood Ash

Mounded around the plants you want to protect, wood ash can be an effective barrier. Create a thick layer around plant for protection. Replace when damp or depleted.  But make sure that the ash was a result of an essential wood burning activity, otherwise it could be the result of an unnecessary carbon-polluting activity.

Netting

Use 5mm x 5mm (or smaller) netting pulled taut over a frame/structure around the plant.

Corrugated Cardboard

Wrap a corrugated cardboard collar around base/trunk of tree/plant and secure with tape or string. Replace periodically over pest breeding season.

Wobbly Fences

Put wobbly wire around plants you wish to protect from possums.

Corrugated Iron on Paths

This deters deer which don’t like walking on  surfaces that are unstable and make noise when trodden on.  Try to use old recycled iron.

Repellents and Attractants

Companion Planting

This approach aims to use nature to attract, repel, enhance plant health and flavour. For example, planting Winter Cress Barbarea verna effectively attracts beneficial insects and entices the cabbage white butterfly to lay its eggs on the leaves.  But the plant kills emerging caterpillars as they try eating it. Marigolds deter the cabbage white butterfly from laying eggs on brassicas as well as repelling root nematodes.

Decoys

Decoy plants may be planted earlier than the main crop to entice insects.  They can then be removed and the main crop planted. They can also be planted around the outside of a crop as insects usually start from the outside.

Artificial cabbage white butterflies can deter live ones for some time.  They should be moved regularly.

Visual Bird Deterrents

Try hanging moving or reflective materials in trees such as lights, mirrors, reflectors, reflective tape, flags, rags, streamers, lasers, dog/human/scarecrow/large hawk models. These will need to be replaced or alternated since birds quickly become used to them and will resume normal activities such as eating fruit.

Manual

Better WiseGardening choices include methods that have subsidiary benefits such as requiring you to do some physical activity, such as those below, which are great for your health.

Removal by Hand

Look for pests and use your fingers to squash or remove them.

For snails and slugs pick them up and put in a bucket of water containing soap or detergent.  This kills any eggs inside the snails and they can later be composted.

Water Jet or Hose

Hose pests off affected plants – e.g. Aphids can be easily removed and will not return.

Fly Swat

Use swat to squash insect against a hard surface.

Pruning

If it is possible, remove the heavily infested section of the plant.

Beneficial Agents

Domesticated Birds

Allowing ducks, chicken or geese to browse in areas of the garden infested with pests can help control their numbers. Such birds are effective predators of snails, slugs, insects and spiders.

Introduce Predatory Insects or Parasites

It is possible to purchase insects and other organisms which will attack pest insects in your garden from a number of suppliers.

Fungus

Avoid Moisture on Leaves, Especially at Night

Moisture persisting on leaves allows fungal spores to germinate.  Use drip irrigation rather than sprayers or employ overhead watering early in the morning so that moisture will evaporate.

Exclusion

Prevent pathogens from entering the landscape by only purchasing healthy, vigorous, undiseased plant material. Refuse to purchase any plants showing any sign of disease or poor health.

Hygiene

Completely remove any plants that are either heavily infested with untreatable diseases (remove as much of the plant & root system as possible as well as much infested soil as possible).

Solarisation

Fungus and other pathogens in the top layers of soil can be destroyed by covering the soil with thin, clear or black plastic film and leaving in place for a number of weeks in the summer/hottest months before planting crops. Try to use recycled plastic to avoid the extra pollution of plastic production.

Repellents and Attractants

Companion Planting

This approach aims to use nature to attract, repel, enhance plant health and flavour. For example, planting Winter Cress Barbarea verna effectively attracts beneficial insects and entices the cabbage white butterfly to lay its eggs on the leaves.  But the plant kills emerging caterpillars as they try eating it. Marigolds deter the cabbage white butterfly from laying eggs on brassicas as well as repelling root nematodes.

Decoys

Decoy plants may be planted earlier than the main crop to entice insects.  They can then be removed and the main crop planted. They can also be planted around the outside of a crop as insects usually start from the outside.

Artificial cabbage white butterflies can deter live ones for some time.  They should be moved regularly.

Visual Bird Deterrents

Try hanging moving or reflective materials in trees such as lights, mirrors, reflectors, reflective tape, flags, rags, streamers, lasers, dog/human/scarecrow/large hawk models. These will need to be replaced or alternated since birds quickly become used to them and will resume normal activities such as eating fruit.

Provide Habitat for Predators

Increase Plant Diversity

Grow a large variety of plant species, herbs and ornamentals, especially those with brightly coloured flowers and those that are umbrella-shaped.  This will create an ecosystem of interdependent species which keep each other in balance.

Insect Hotels

These can be home-made and are also available commercially.

Nest Boxes

These can be for birds or bats which use insects as food.

Frog Ponds

If you build a frog pond, the frogs will come and they are voracious insect eaters.

Lizard Sun-bathing Rocks

Smooth rocks in the sun attract lizards which eat insects.

Weeds

There are many options available to reduce weed infestations in your garden apart from using manufactured chemicals that have various risks associated with them. Here are a number of better choices.

Heat

Solarisation

Cover soil/garden bed with black or clear plastic film. Leave plastic in place for several weeks during the hottest time of the year. This effectively ‘cooks’ the plants and seeds in the soil underneath. This can also reduce soil-borne pathogens.  Try to use recycled plastic to avoid the extra pollution of plastic production.

Steam

Apply water heated to close to boiling point or beyond boiling in some commercially available saturated steam weeding devices to create steam. When applied to a plant it causes the plant cells to rupture then wilt and die.  This treatment needs to be repeated on weed infestations in order to be effective.  Note that heating water to produce steam also requires use of carbon-polluting electricity unless derived from renewable sources.

Hot Water

Apply boiling/close to boiling point water to a plant. This method causes plant cell rupture, followed by plant death. This treatment needs to be repeated on weed infestations in order to be effective. Note that boiling water requires use of carbon-polluting electricity unless derived from renewable sources.

Direct Flame

Apply a direct flame using a fuel powered flame burner to a plant. The flame passes over the plant, increasing the temperature of the moisture in the plant causing cell rupture, followed by plant death.  This treatment needs to be repeated on weed infestations in order to be effective.  Note that this uses carbon-polluting fuel.

Heavy Mulching

Cover with overlapping layers of thick cardboard, ensuring no light can penetrate to the soil.  Then covered with a thick layer of organic mulch e.g. wood chips or bark.

Prevention

Know Your Weeds

Identify the problem plant in order to ensure the treatment is targeted and effective.

Limit Soil Cultivation

Use no-dig gardening methods.

Competition

Reduce the chance of weeds succeeding by using vigorously growing plants and plant close together to restrict light to soil and, therefore,  chances of germination. These plants can out-compete the weeds.

Mulch

Suppresses weeds by preventing light from reaching seeds. This prevents germination of seeds or causes the seed to use up reserves trying to reach surface. Organic and granular mulch has additional benefits of reducing evaporation from soil and capture of rainfall.

Hygiene

Control existing weeds around the garden regularly to reduce weed seed build up. Prevent weeds from being imported to your site/garden by choosing weed free plants from the nursery. Remove any weed seeds that might germinate in the top layer of the planting media. Keep tools and equipment clean.

Care with Fertilisation

Extra fertiliser can give weeds an advantage as many can grow quickly when there is ample nutrition available. Limit fertiliser use to only when necessary.  Use soil testing if possible to determine nutrient needs.

Manual

Removal by Hand

Remove individual weeds by hand pulling or using hand tools is a useful technique in small gardens or for low numbers of weeds. It is highly selective and is most effective on annual weeds and weeds which do not regrow from underground parts – care must be taken to ensure the entire plant is removed. This method is cheap, free and has little to no impact on surrounding plants and animals.

Girdling or Ringbarking

For large or woody weeds too large for hand removal, girdling (ringbarking) is a suitable option. Cut several centimetres of bark from the circumference of the entire plant. This will cause the plant to die.

Mechanical Cultivation (tillage)

Using powered devices e.g. rotary hoe or tractor.  This approach can have the disadvantage of requiring use of carbon-polluting fossil fuel unless the device is driven by human strength.

Refer separately to SGA Better Choices for controlling pests and to SGA Better Choices for controlling fungi.

Traps

Sticky Insect Traps

Commercial ones are available, but you can make your own following instruction/s on many websites.  Hang in locations with problem pests and monitor or replace when necessary.  However, some of these may trap beneficial insects.

Snail/Slug (Gastropod) Traps

For snails/slugs, place cardboard/wooden/plastic board or flowerpot on ground in damp spot in garden. After 1 or 2 days lift and remove snails/slugs congregated underneath.

For slaters and earwigs as well as snails ad slugs make a container with holes near the top. Place it so that the bottom of holes is level with  the ground – cover to keep rain out. Add beer or sweet liquid and vegetable oil to drown pests. Clear out trap regularly.

Bug Zappers

Plug in to 240v power point to attract and then electrocute insects. Locate these away from food preparation/cooking areas.  Please note that the environmental impacts of these are not clear.  Although they do not involve spraying chemicals, they may kill beneficial insects and they may use carbon-emitting electricity.