Not all weed killers are created equal or have the same purpose. Some prevent seeds from germinating, others kill established plants.
Some are organic and pet/child safe, and others require plenty of caution when you’re using them.
In this guide, we’ll give you plenty of advice on finding the right weed killer for your garden, what different types of weed killers are, and how to use them safely – along with our top 10 best weed killers.
10 Best Weed Killers for 2021
Different Types of Weed Killer
These are the two main types of weed killer:
Pre-Emergent Weed Killer
This is for killing weeds before they start to grow, preventing seeds from growing by stunting root growth in the very early stages of germination.
Pre-emergent herbicides should be used in very early spring to be effective, as they won’t harm plants that already have an established root system.
This means it’s safe for your lawn and flower beds, but shouldn’t be used near any other new seeds.
Post-Emergent Weed Killer
A post-emergent herbicide is one that kills established, growing weeds. This will only be effective on weeds you can already see.
You can use them any time of year, but be careful not to let the spray or granules come into contact with your lawn or established plants, as it will kill them too.
Weed killers are also categorised by how they work:
Contact Weed Killer
This will kill off any plant it comes into physical contact with, wilting and killing weeds very quickly. You’ll usually start to see results within an hour or so.
They tend to destroy the foliage of the weeds without affecting the root system. This can kill lighter weed growth, but usually means reapplying the weed killer several times to properly kill more established weeds.
Contact weed killer should be used on annual weeds that spread via seeds.
Systemic Weed Killer
These weed killers work by being absorbed by the leaves of the plant and entering the root system, stopping the plant’s ability to get nutrients from the soil. They work more slowly, and you’ll see results in 1-3 weeks.
This is highly effective on perennial weeds that spread through seeds and the soil. Some weed killers are both systemic and contact, and these will usually be marked as general-purpose or all-rounder weed killers.
What are the Best Weed Killers for Lawns?
There are several options for killing weeds in lawn:
- Manual – Manually digging out weeds by hand, using a fork or cultivator
- Pre-emergent weed killer – This will kill weeds before they start growing without affecting established plants and grass. However, it will affect newly sown grass seed.
- Post-emergent weed killer – Although this will kill the grass as well as the weeds, it’s a good option if your lawn is overgrown with weeds and you want to replant that section.
Why is a the best option for weeds in your pavement?
The reason why I recommend using a weed killer to control the weeds in your paved area’s is actually different to why it is useful on large scale gardens.
Simply put, weeds can have very strong root systems and generally speaking, when you try and remove weeds from between pavers, the roots often break off. If you don’t remove the root system, often the weeds can simply just grow back.
The weed killers reviewed below not only kill the root system but will also make it easier to pull the whole weed out after the weed has died.
How Do You Stop Weeds from Coming Back?
This is a gardener’s biggest challenge! Unfortunately, weeds continually get into our gardens from passing birds and wildlife, blown in from other gardens, or even on the soles of our shoes. Luckily, there are some things you can do:
- Keep your existing weeds under control with a post-emergent weed killer
- Use a pre-emergent weed killer in the very early spring before weeds start growing
- Pull out any weeds you do see, especially if they are seeding. Be very careful and dispose of them in your garbage, not your compost.
- Boost your garden’s health by planting native plants, mulching your lawn and flowerbeds, and feeding your plants with the right fertiliser.
The stronger your existing plants are, the harder weeds will have to work to establish themselves.
How to Use Weed Killer Without Harming Wildlife
Some weed killers are very harmful to native ecosystems, wildlife and human health, especially those that are high in glyphosates. If you do need to use a strong glyphosate weed killer, be careful to use it sparingly and avoid pollination times in spring and summer, as this can kill bees and other beneficial insects.
Organic, Pet/Child Safe and Natural Weed Killers
If you have children and pets or are concerned about the natural environment (as we all should be), we recommend that you use a weed killer that is pet safe, child safe, and organic.
In addition to buying these weed killers, you can also try these safe weed removal methods:
- Physical removal – This is the safest but most physically-demanding way of removing weeds. If you don’t have many weeds, and you don’t have back pain, this is a good option. Use a small garden fork to dig down and remove the entire weed with the roots.
Try to spend time doing manual weeding in early spring before the weeds develop seed heads and remember to wear sun protection. It can also help to work when the ground is damp.
- Boiling water – You can effectively kill any type of weed or plant by pouring boiling water onto them. It’s completely safe for the environment, kids, and pets too, as long as you keep them away from where you are pouring and remember to protect your hands too!
- Salt – Sprinkling weeds with salt or adding salt to boiling water will quickly kill weeds, and it’s great for clearing paving or driveways.
If you plan to sow new seed or grow new plants in these areas, just flush it with clean water before you plant to clear out the excess salt.
- 5% vinegar – Vinegar that has an acetic acid level of 5% or more is a key ingredient in natural, organic weed killers. All you need to do is spray it onto the plant (a second dose may be required), and the weed should start to die quite quickly.
- Cornmeal – The gluten in cornmeal is a pre-emergent organic herbicide that works on pre-emergent weeds. You can spread it out over your lawn or flowerbeds in early spring.
How to Apply Weed Killer
When using a weed killer, always follow the manufacturer’s instructions. Don’t be tempted to make the solution stronger if you have to mix it yourself, as this doesn’t make it more effective.
Always apply the weed killer on a dry day when rain is not expected for around 48 hours.
Be sure to wear protective coverings over your eyes, mouth and hands, and to remove pets and children from the area for the entire waiting period (usually a few hours) as specified by the manufacturer.
Best Weed Killer Reviews
If you like the power of Roundup but want to protect the environment, your pets, and children, this is a good option. Made by the same company, this glyphosate-free weed killer is made with 100% natural ingredients and delivers visible results in one hour.
It’s rain safe in 3 hours and the ground is ready for replanting in just 24 hours.
This powerful weed killer is all-purpose and non-selective, so it will kill weeds as well as other unwanted plants. As a result, it’s important to be very careful when spraying or watering in this weed killer, as it can harm other plants in your garden and the environment.
It is not lawn-safe, as it will kill grasses too. It’s affordable, easy to use, and effective.
This Slasher organic weed killer is effective on weeds, moss, and algae, using a nonanoic acid solution to kill weeds effectively. It’s non-selective, so be careful not to apply it to plants you want to keep, as it will damage or kill them.
Slasher organic weed killer is safe to use on paving and in your garden, and it works quickly without leaving any residue.
This is a commercial grade weed killer with a lot of similarities to Roundup, although it’s usually cheaper. The concentrate is easily diluted with tap water, and you can water it onto your weeds or use a weed or garden sprayer - read our article on how to select the best one and our reviews here.
It works on all weed types as well as alien vegetation and unwanted plants – however, it will kill any plant it comes into contact with, so it needs to be carefully applied.
This all-natural weed killer is a great choice for eco-friendly gardening, or if you have children and pets. It comes in a ready-to-use spray bottle, and can kill weeds, moss, and algae.
Tougher, more established weeds may need a second dose to completely kill them off.
This is a broadleaf-specific weed killer for removing dandelions, clover, and bindii. By combining two types of weed killer, it’s effective on a wide range of weed types, and it’s very economical, with 500ml treating 330 square meters. As a systemic weed killer, it shows results within 4 weeks.
This is a great weed killer for killing broadleaf weeds like bindii and clover, and it can be used safely on your lawn without killing your grass.
It’s low toxicity but still effective, and one litre can treat an impressive 1500 square metres.
This pre-emergent weed killer and fertiliser is a great way of giving your lawn essential nutrition in the early spring while suppressing weed germination.
It is used for controlling clover, thistles, flatweeds, and other broadleaf varieties. As a pre-emergent weed killer, it will not affect your lawn – and it will also not kill weeds that are already growing.
This organic, glyphosate-free weed killer is a great way to get rid of unwanted weeds in paving, flowerbeds, vegetable gardens and lawns without harming the environment.
Australian-made, it uses acetic acid and salt to deliver fast results, especially when applied on hot, sunny days. Wilting will usually occur within a couple of hours.
If you like Brunnings Feed ‘n Weed but want something with a bit more power in a liquid form, this is a great option. It’s a selective weed killer that’s safe for most lawn types, killing off broadleaf weeds like clover, bindii, and dandelions without harming your grass.
The fertiliser component helps to nourish your lawn and boost growth, making it harder for weeds to grow.
Best Weed Killer Australia
Top Rated Best Weed Killer 2021
Roundup Naturals Glyphosate-Free Powerful Weed Killer wins as the best weed killer for 2021! Unlike other Roundup products, this is 100% natural and glyphosate-free, making it safe for your pets, children, and the environment. It’s powerful, rain safe in 3 hours, and fully kills weeds in 24 hours.
Best Value Weed Killer
Our best value pick would be boiling water, as it doesn’t cost much at all and is very effective! However, we also recommend Hortico WEED KILLER CONCENTRATE 1L.
It offers commercial-level performance at an affordable price, is non-selective, and doesn’t leave a residue.
Premium Choice Weed Killer
We love the Eco-Organic Garden 1L Slasher Weed killer Concentrate because it’s organic, it’s effective, and it’s proudly Australian, which makes it worth the extra cost.
It’s a non-selective weed killer that controls weeds, lichen, moss, and algae, and it can also be used to spot-spray your lawn (although it will do some damage to the grass). There’s no lasting residue, and it’s safe for children, pets, and the environment.
Enjoy a Weed-Free Garden with the Best Weed Killer in Australia
If you want a neat, beautiful, and weed-free garden, then you need the best methods for controlling annual and perennial weeds. We recommend trying out organic options first, as these are safe for the environment as well as your family and pets.
Whatever your weed killer, remember to apply it on a hot, sunny day when no rain or wind is forecast, and to take appropriate precautions especially when dealing with toxic chemicals.
We hope this article helped you find the best weed killer for your garden!