Field-grown produce presented for inspection before or after that date range may be refused entry. However, fresh cucumbers, eggplant, lettuce, squash, and strawberries clearly labeled as having been grown in a commercial greenhouse in Canada may enter the United States year-around.

When entering the U.S. from Canada or Mexico in 2026, the general rule is that most fresh vegetables are prohibited unless they meet very specific criteria. From Canada, most "field-grown" vegetables (like lettuce, carrots, and cabbage) are allowed during the growing season (May–October) if they are commercially labeled as "Product of Canada." However, potatoes and stone fruits are strictly prohibited due to pest concerns. From Mexico, rules are much tighter; most fresh produce is banned to prevent the spread of the Mediterranean fruit fly. Notable exceptions for 2026 include peeled garlic cloves, clean ginger roots, and husked coconuts. All vegetables must be declared to Customs and Border Protection (CBP) agriculture specialists; failing to declare even a single bell pepper can result in a $300 to $1,000 fine. It is a high-priority "pro-tip" to stick to processed or "commercially dried" vegetables, which have a much higher rate of approval, and always "when in doubt, declare it" to avoid being flagged in the global entry system.