When to Plant Mint

Spring planting in frost areas

Mint is a hardy perennial, so the timing question is less about frost killing it than about getting young plants established. Penn State sets out starter plants once the danger of frost has passed, and Utah State advises planting early in the growing season. The dates for your zone above cover that window, from your average last frost to about two weeks after.

Hardiness explains why mint can go out earlier than tender herbs like basil. Utah State says established mint is generally hardy to -20°F, and NC State rates spearmint for zones 4-9 and peppermint for zones 5-9. Nursery plants still benefit from being gradually acclimated to outdoor conditions before planting, as Penn State recommends for herb transplants.

Earlier planting has a real payoff with mint: the sooner it roots in, the sooner you can harvest. Utah State starts picking once plants are 3-4 inches tall and well established.

Dividing and replanting

The best times to dig and divide established mint are spring, before new growth begins, and early fall (Utah State). Iowa State likewise names early spring as the standard time for dividing perennial herbs, and Illinois suggests dividing mint every 3-4 years to keep it vigorous.

Mint is rarely started from seed because seedlings often do not come true, so most “planting” is really moving divisions, runners or rooted cuttings. UF/IFAS notes that runners can simply be cut off and transplanted.

Fall planting

In cold climates, fall planting is mainly a matter of dividing and replanting clumps early in the season. Give new plants time to root before the ground freezes, then cover them with about 4 inches of straw, oak leaves or evergreen boughs once it has frozen, as Penn State recommends for perennial herbs. The mulch protects shallow roots from heaving during winter thaws and stays on until growth resumes in spring.

Warm climates

Florida. UF/IFAS gardening calendars list mint for September planting in North, Central and South Florida. The South Florida calendar also lists April and July, noting that small plants do better than seed in summer. These calendars give examples for each month rather than complete windows, and mint is a perennial, so planting outside these months also works if you can keep it watered. UF/IFAS adds that mint does well in Florida’s heat and humidity if it gets moisture-retentive soil and light or part shade.

Desert Southwest. University of Arizona Extension’s Tucson herb guide lists mint for October-November and February-April. It names fall as a good time to start perennial herbs that prefer cooler weather, such as mint, because cooler temperatures relieve heat stress and let roots establish. Avoid planting in early summer if you can; if you must, give afternoon shade and expect to water containers up to twice a day.

Zones 10-11. Mint keeps growing in South Florida even though its hardiness ratings stop at zone 9. Use the South Florida months above and plant small transplants rather than seed.