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Spray to Swath Interval Calculator

The Spray to Swath Interval is the minimum number of days that must pass between product application and cutting your crop by swathing or straight-cutting. On pesticide labels, you’ll see it referred to as the pre-harvest interval or PHI. Cutting before this interval has lapsed can leave unacceptable residues on harvested seed. To protect the marketability of your crop, always stick to the PHI, for every crop protection product you apply.

Use this tool to calculate the PHI or find a registered product to suit a specific timeline. Don’t see a registered product that you are looking for, or notice an error in the calculator? Please let us know! Contact This email address is being protected from spambots. You need JavaScript enabled to view it..

pdf Spray to Swath Calculator Instruction Sheet (426 KB)

When tank mixing, each tank mix partner is applied in accordance with its registered product label. In cases where information on the tank mix partner labels differs between them, the most restrictive directions must be followed.

Select a Crop Type

Already sprayed? Calculate how long to wait.


Have a deadline? Find a pesticide to suit your timeline.

Sync Your Calendar

If you are using Outlook or an iPhone you can download your swath date ICS file to sync with your calendar.

Embed this calculator on your website

Embed the Spray to Swath calculator on your own site to help protect the quality of your customer's harvest and that of the Canadian canola and pulse industries.

Always read and Follow the Label for every crop protection product that you apply. Along with PHI, the label contains important information, like application rate and timing, that can help you ensure your crop meets the needs of our domestic and export customers.