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Pre-Harvest Intervals and Safety

A pre-harvest interval is the minimum time between the last pesticide application and harvest. It is on the label, and it protects the people who will handle and eat the crop.

What is a pre-harvest interval?

A pre-harvest interval, or PHI, is the required waiting time between the last application of a pesticide and harvest of a crop. It is listed on the label for each approved crop, and it can be different for each one.

This site does not give any intervals. Read the label for your product and your crop.

Intervals are about the legal and safe time for harvest, not the best flavor or timing. A crop that looks ready may still be inside the interval, and the label governs.

• Check the label for each crop.
• Do not assume one number covers all crops.
• Write it on your spray record.

Why does it exist?

The interval allows residues to break down so that harvested food meets legal limits and is safe to eat. Following it protects consumers, your market access and your reputation.

It also protects workers, who may handle the crop soon after harvest.

Buyers, processors and exporters may have their own limits and requirements. Ask your buyer what documents they want and whether they accept your records.

• Keeps residues within legal limits.
• Protects consumers and your market access.
• Protects workers who handle the harvested crop.

How is it different from the re-entry interval?

The re-entry interval is about when people may enter the field after treatment. The pre-harvest interval is about when the crop can be harvested. Both can apply at the same time, and they can be very different lengths.

Check both before planning labor and harvest. A field may be open for work well before the crop can be picked.

Keep a calendar in the shop that shows the last date each field was treated and the first allowed harvest date. A visual tool can prevent mistakes during a busy week. Some crops are harvested over many days, such as vegetables and berries. Check whether the interval applies to the first picking and each later one, and whether later pickings need a separate treatment schedule.

• Re-entry: when people may enter.
• Pre-harvest: when the crop may be picked.
• Both are on the label.
• Neither can be shortened by choice.

How do I plan around it?

Before you apply, count forward to the earliest harvest date and check that the interval will have passed. Weather, market timing and ripening can shift harvest, so build in a margin and talk with your buyer.

If weather or other events force a change, do not pick early. Ask your extension office about options, such as different products or delaying harvest.

Rain, delays and equipment breakdowns often change plans. When this happens, adjust harvest, not the interval. Early planning leaves room to do that.

• Count forward before you spray.
• Leave a margin for weather.
• Talk to your buyer early.

What records help?

Record the application date, product and crop, then the date harvest began. If a buyer or agency asks, you can show that the interval was followed. Keep the records for the period your state or buyer requires.

Records also help when you grow multiple crops with different labels.

Keep your records on the same page as your harvest log so you can see the dates side by side.

• Application date
• Product and crop
• First harvest date
• Buyer requirements if any

What about multiple applications and grazing?

Labels may also limit the number of applications and may describe waiting periods before grazing or feeding forage. These are separate statements, so read the full label for the crop or use.

Ask your extension office to help you read the label if the crop is unusual.

Specialty and small acreage crops sometimes have fewer approved products and unusual labels. Ask your extension office for current information on what is allowed for your crop.

• Limits on the number of applications
• Waiting periods before grazing
• Rotational crop restrictions

What if the interval was missed?

Do not harvest or sell the crop until you have talked with your state agency or extension office. Selling a crop with residue above legal limits can have serious legal and health consequences. Honest early contact usually leads to the best outcome.

If someone feels unwell after eating or handling a crop, call 911 in an emergency and contact poison specialists for advice.

Last reviewed: November 12, 2026. Written by the Farm Safety Editorial Team. See our editorial policy.