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Par 3 Herbicide Mix Ratio: The Complete Mixing Guide [2026]
Getting the Par 3 herbicide mix ratio right is the single biggest factor in whether your treatment actually works.
Too little product and the weeds laugh at you. Too much and you risk burning the grass you worked hard to grow. This guide gives you the exact numbers — no guessing, no wasted product, no lawn damage.
Whether you have a small backyard in Montreal or a large property, you will find your answer here.
What Is the Correct Par 3 Herbicide Mix Ratio?
The short answer: 55 ml of Par 3 concentrate mixed with 3 litres of water covers 100 square metres of lawn.
That is about the size of a one-car garage, multiplied by five. A typical Canadian residential lawn runs between 300 and 800 square metres, so plan accordingly.
Quick reference: 55 ml Par 3 + 3 litres water = 100 square metres treated
This rate comes directly from the Health Canada approved product label (registration number 27884). It is the minimum amount needed for full weed control — do not go below it.
How Much Par 3 Do You Need for Your Lawn?
Use this simple guide to figure out how much product to mix before you go outside:
- 100 square metres (about 1,000 sq ft) — use 55 ml of concentrate in 3 litres of water
- 250 square metres — use 137 ml in 7.5 litres of water
- 500 square metres — use 275 ml in 15 litres of water
- 1,000 square metres (about one quarter acre) — use 550 ml in 30 litres of water
- 2,000 square metres — use 1.1 litres in 60 litres of water
Not sure how big your lawn is? Open Google Maps on your phone, go to satellite view, tap on your property, and use the measure tool to trace around the grass. You will have an accurate number in under two minutes.
Par 3 Mix Ratio by Sprayer Size
The type of sprayer you use changes how you measure — not the concentration, but the total amount you prepare.
Small handheld pump sprayer (1 to 2 litres)
Perfect for spot-treating a few dandelion patches or weeds along the edges of your garden.
- 1 litre sprayer: add 20 ml of Par 3 concentrate, then fill to 1 litre with water
- 2 litre sprayer: add 40 ml, then fill to 2 litres with water
Backpack sprayer (10 to 20 litres)
The most practical tool for treating a full residential lawn.
- 10 litre sprayer: add 183 ml of concentrate, fill to 10 litres
- 15 litre sprayer: add 275 ml, fill to 15 litres
- 20 litre sprayer: add 366 ml, fill to 20 litres
Golf course or large property tank sprayer
For professionals treating large areas, the rate is 5.5 litres of Par 3 concentrate for every 300 litres of water per hectare. This comes from the official Loveland Canada label.
Step-by-Step Mixing Instructions
Follow these steps every time. The order matters — it prevents foaming and keeps handling safe.
- Put on your nitrile gloves and safety glasses before opening the bottle.
- Fill your sprayer halfway with clean tap water first — never add concentrate to an empty tank.
- Measure the exact amount of Par 3 concentrate using a measuring syringe or small measuring cup.
- Add the concentrate slowly along the inside wall of the tank.
- Fill the tank to the final volume with clean water.
- Close the cap and shake or stir for 30 seconds before spraying.
- Re-shake every 15 minutes during application if you pause.
One thing most people skip: use a syringe or measuring cup every single time. Eyeballing a splash from the bottle is how you end up with dead grass or weeds that survive the treatment.
When Should You Apply Par 3?
Timing matters as much as the mix ratio. Par 3 only works when it can be absorbed through the leaves of actively growing weeds — and then travel down to the roots.
Best time: Spring (May to June)
This is your primary window. Weeds are growing fast, leaves are large and easy to coat, and the product moves efficiently from leaf to root. Apply in spring for the strongest kill of the season.
Second best: Late summer to early fall (August to September)
Weeds naturally start moving energy downward into their roots before winter. Par 3 follows that same path — straight into the root system. Fall treatment is excellent for deep-rooted weeds like dandelions.
Avoid: Hot, dry summer days
When temperatures are above 28 degrees Celsius or during a drought, weeds absorb less product. You also risk drift that can damage nearby flower beds or vegetable gardens.
Never: Winter or dormant season
Par 3 has zero effect on dormant plants. Do not waste product on frozen or sleeping weeds.
Also check the weather: do not spray if rain is expected within 24 hours. Rain washes the product off the leaves before it can absorb.
Common Mixing Mistakes to Avoid
- Eyeballing the amount instead of measuring — even a small difference changes the result.
- Adding concentrate to an empty tank — always add water first.
- Mixing Par 3 with other herbicides or fertilizers — it is not designed for this and may reduce effectiveness.
- Using a sprayer that previously held different chemicals — rinse thoroughly or use a dedicated sprayer.
- Not shaking between pauses — the concentrate can settle at the bottom of the tank.
Frequently Asked Questions
How much Par 3 per gallon of water?
About 68 ml per US gallon for regular lawn coverage, or up to 75 ml per gallon for spot-treating tough weeds.
Can I use less product to save money?
No. Going below the recommended amount means the weeds will not die completely. You will end up re-treating anyway, which costs more in the long run.
What if rain falls within 24 hours of spraying?
If it rained heavily within 4 to 6 hours of application, most of the product washed away. Wait for dry weather and re-apply if weeds show no sign of dying after one week.
Can I store the mixed solution for later?
Mix only what you need for the session. Use the solution within 24 hours. Do not store diluted Par 3 in the sprayer overnight.
Where to Buy Par 3 Herbicide in Canada
Par 3 is available in 1 litre and 10 litre containers at par3solution.is, with nationwide shipping via Canada Post. Payment by Interac e-Transfer or credit card.
The 1 litre bottle covers most residential lawns for a full season. The 10 litre container is the best value for large properties, lawn care professionals, and repeat users.
Order Par 3 Herbicide at par3solution.is — Ships Nationwide Across Canada