Celsius vs. Solitaire Herbicide (Test)
Celsius WG and Solitaire 70 WG are different post-emergent herbicides, not substitutes. Choose between them only after identifying the weed and turf species, then checking the current product label for that exact use. Their active ingredients, herbicide groups, rates, and restrictions differ. Never transfer a rate, add a tank mix, or use an adjuvant unless the label allows it.
A common mistake is to compare herbicides as if the one with the higher active-ingredient percentage must be stronger or better. That number alone does not tell you which weeds a product controls, whether your grass can tolerate it, or how much to apply. The useful comparison starts with the label and the site, not the package front.
In turf work, I have found that misidentifying a weed or grass species can cause more trouble than choosing between two familiar products. A sound decision follows a simple order: identify the weed, confirm the turf, check the label, then calibrate the sprayer.
What is the difference between Celsius and Solitaire?
Celsius WG and Solitaire 70 WG are water-dispersible granules, or WG products. Granules disperse in water for spraying, but the products contain different active ingredients and act through different herbicide groups. That means their rates, weed-control claims, turf limits, and other directions are not interchangeable.
| Feature | Celsius WG | Solitaire 70 WG |
|---|---|---|
| Active ingredients | 8.7% thiencarbazone-methyl and 6.5% iodosulfuron-methyl-sodium | 70% sulfentrazone |
| Herbicide group | Group 2, ALS-inhibiting | Group 14, PPO-inhibiting |
| Formulation | Water-dispersible granules | Water-dispersible granules |
| Rate | Use the rate on the current product label for the intended use | Use the rate on the current product label for the intended use |
| Weed and turf fit | Confirm both on the Celsius label | Confirm both on the Solitaire label |
Active-ingredient percentage is not a comparison of field strength. Each formulation has its own directions, and no rate conversion between products is safe. A product can be suitable for one labeled turf use and unsuitable for another, even if both are sold for turf.
Herbicide group describes how a product acts on a plant. Celsius is Group 2; Solitaire is Group 14. This difference matters for product choice and resistance management, but it does not prove that one will control a particular weed better at your site. The label’s listed weeds and conditions decide that. Takeaway: compare the labeled use, not just the ingredient percentages.
How do you choose the right product for the weed and turf?
The right product is the one whose current label lists both the weed you are treating and the turf species where it will be applied. A weed-control claim does not make a product suitable for every lawn. Check the site, grass, and target weed before measuring anything.
Start by identifying the weed as accurately as you can. Then identify the turf species. If you are unsure about either, pause and get a reliable identification before spraying. Similar-looking weeds or grasses may have different label directions and may respond differently to a treatment.
Next, check the current product label for:
- The exact turf species and site where use is allowed
- The target weed and any limits on its growth stage
- The labeled rate and maximum seasonal amount
- The minimum time between applications, if repeat treatment is allowed
- Temperature, weather, irrigation, and rain-free restrictions
- Required personal protective equipment, or PPE
- Any required or permitted adjuvant, which is an added product used to change spray performance
Do not assume that a direction on one label applies to the other herbicide. The same applies to a tank mix: do not combine products unless the applicable labels allow the intended site, combination, and rate. If the label does not clearly support your planned use, do not apply. Takeaway: weed and turf identification come before product selection.
How should you prepare and apply either herbicide?
A careful application depends on the label, an accurately measured treatment area, and a calibrated sprayer. Calibration means checking how much spray your equipment applies over a known area. It helps you apply the labeled amount evenly instead of guessing from tank size or using a scoop as a shortcut.
Use this workflow for the product you have selected:
- Read the current label and confirm the use, rate, spray volume, and weather limits.
- Measure the treatment area. Work out the amount of product from the label directions for that area.
- Wear the PPE listed on the label. Use a clean measuring tool dedicated to pesticide use.
- Calibrate the sprayer with clean water. Check nozzle pattern, pressure, and output, and make sure the sprayer covers the planned area evenly.
- Add the WG product to water as the label directs. Keep the spray mixture agitated if directed, including during application.
- Spray evenly at the labeled rate and volume. Avoid overlaps, drift, and runoff, and do not spray under conditions barred by the label.
Do not apply to stressed or wet turf if the label restricts it. Wind can carry spray onto ornamentals or other sensitive plants, so follow label directions that protect people, pets, and nearby plants. Keep people and pets out of the treated area for the label-specified interval.
Never estimate the dose by scoop or assume that the same tank mix works with both products. A calibrated sprayer does not replace label directions; it helps you follow them. Takeaway: measure the area, calibrate with water, and apply only under allowed conditions.
What do practical application scenarios show?
These examples are decision scenarios, not product trials or claims of control. They show how to apply the comparison without guessing at rates or results. In each case, the label for the exact product and site remains the deciding source.
Scenario: You know the weed but not the grass. Do not choose a product yet. Identify the turf species, then check whether the label allows that grass and lists the target weed. If you cannot confirm both, wait rather than risking turf injury.
Scenario: The target weed appears on one label, but the planned site does not. Do not treat the weed based on that listing alone. The label must also allow use on the turf and site in question. A listing for the weed does not override a turf restriction.
Scenario: You have used a Group 2 herbicide repeatedly. Do not assume Solitaire is an automatic replacement just because it is Group 14. Confirm that its label fits the weed and turf, then consider the broader weed-management plan. Repeated reliance on one herbicide group can add resistance risk; group rotation does not excuse off-label use.
Scenario: Someone suggests mixing the two products. Do not combine them solely because both are WG turf herbicides. Check whether both labels permit the intended tank mix and use. If permission is unclear or absent, do not mix them.
Keep an application record with the product name, lot, rate, treated area, date, weather, applicator, and any label-based follow-up interval. Records help you avoid accidental repeat treatments and check seasonal limits. Takeaway: a scenario may guide your questions, but only the label can authorize the treatment.
What should you do after spraying?
Post-application care includes cleaning equipment, tracking treatment limits, and watching the site without rushing to reapply. Visible injury alone does not prove that the treatment has failed. Follow the label’s timing for symptoms, retreatment, and maximum seasonal use.
Clean the tank, screens, boom, hoses, and nozzles exactly as the label directs. Handle rinsate, the water left from rinsing equipment, according to label and local rules. Do not pour it into a drain or waterway. Check for residue, leaks, worn seals, and blocked nozzles before the next use, especially before spraying near sensitive plants.
Store the product in its original, labeled container, tightly closed, dry, and secured from children, animals, food, and feed. Follow the label’s storage directions, and keep the current label and Safety Data Sheet with the product. Do not reuse pesticide containers. Dispose of unused product and empty containers according to label and local requirements.
If turf or nearby plants show severe injury, stop spraying. Check the product, rate, turf species, adjuvant or tank mix, and possible drift or runoff against the label. Do not try to correct a suspected overdose with another chemical. Takeaway: wait for label-based timing, clean equipment as directed, and investigate damage before any further treatment.
Frequently asked questions
These answers cover common points that can be settled without guessing at a rate or making a product claim. Your package’s current label is the final source for legal use, local restrictions, and directions for a specific site.
Are Celsius and Solitaire interchangeable?
No. They have different active ingredients, herbicide groups, labeled uses, and rates. Select only the product whose current label fits both the target weed and turf.
Can I use the same rate for both products?
No. Do not convert or transfer a rate between products. Use the rate and limits on the label for the exact product and use.
Which product controls my weed?
Check the current label for the weed name and the turf species at your site. If either is not listed or you are unsure of identification, do not assume control.
Can I tank-mix Celsius and Solitaire?
Do not mix them just because both are WG products. Confirm that the applicable labels allow the exact tank mix and intended use.
Do I need to calibrate my sprayer?
Yes. Calibrate with clean water and check nozzle pattern, pressure, output, and coverage before applying. Calibration helps you deliver the label rate evenly.
Can I add an adjuvant?
Only if the product label permits or requires it for your use. Do not borrow an adjuvant direction from the other product or another label.
When can people and pets return to the treated area?
Follow the interval on the product label. Do not use a general waiting time in place of that direction.
What if I am unsure whether my turf is safe to treat?
Stop and confirm the turf species and label restrictions before filling the sprayer. If the use cannot be confirmed, do not apply.
Does visible injury mean I should spray again?
No. Follow the label’s timing for symptom development and retreatment. Also check the maximum application and seasonal limits before considering another treatment.
How should I dispose of leftover product or rinsate?
Follow the label and local disposal rules. Do not discharge rinsate to drains or water, and never reuse the pesticide container.
(This article was written by one of our staff writers, Victor Dempsey. Visit our Meet the Team page.)
