When to plant mint in Astoria, OR

Plant young mint plants in Astoria Apr 1 – May 27.

Easy Plant young plants

Difficulty: Easy
Sun: Full sun to part shade
Spacing: One plant per pot, or 18 inches apart
Planting depth: Plant at the depth it grew in the nursery pot
Frost: Handles light frost
First harvest: Pick lightly the first summer, then as much as you like

Why these dates

Astoria's typical last spring frost is March 26. On the coast, the soil is usually ready for mint around April 1.

Coast. Mild winters but cool, foggy summers. Frost is rarely the problem; warmth is. Pick early, cool-tolerant varieties of tomatoes and squash.

How to grow mint in Astoria

Pick a sunny spot with soil that drains well, and mix in an inch or two of compost.
Plant young mint plants Apr 1 – May 27, One plant per pot, or 18 inches apart. Plant at the depth it grew in the nursery pot.
Water regularly; mint likes moist soil. Cut it back hard in midsummer for a fresh flush of leaves.
Harvest: Snip stems just above a pair of leaves. Regular cutting keeps plants bushy.

Key numbers

Underground rhizomesSpreads by
Unreliable flavorFrom seed
6.0–7.0Soil pH
Sun to part shadeLight
Just before floweringBest flavor
Every few yearsDivide

How it works

The plant biology behind the advice above, in plain language.

Why mint takes over

Mint spreads by underground stems called rhizomes, plus runners above ground. Each piece can root and start a new plant, so it quickly spreads through a bed. Grow it in a container, or sink a bottomless pot or bucket into the ground with the rim a couple of inches above the soil, and trim runners that creep over the edge.

Growing from seed doesn't work well

Peppermint is a natural hybrid between watermint and spearmint and rarely produces viable seed. Many mint seed packets produce plants with weak or unpredictable flavor. Buy plants or take cuttings from a mint whose smell and taste you like. Cuttings root easily in water.

Flavor

Peppermint's cool bite comes mainly from menthol; spearmint's sweeter flavor comes from carvone. Plants grown in full sun and harvested just before flowering have the most oil. Oregon and Washington, especially the Willamette Valley and the Columbia Basin, grow a large share of the country's peppermint oil.

Soil and water

Mint likes moist, fertile soil with a pH of about 6.0 to 7.0 and grows in sun or part shade. Containers dry out fast in summer, so water them often. Cut plants back hard in midsummer for a fresh flush of tender leaves.

Mint rust and other problems

Mint rust causes orange pustules on the undersides of leaves. Cut infected stems to the ground and throw them out, which removes the spores. Over the years, the center of a clump tends to die out. Divide and replant the healthy outer pieces every few years in fresh soil.

Common questions

When is the last frost in Astoria, OR?

Typically March 26. In 9 years out of 10, frost is over by April 18. These are 1991–2020 NOAA climate normals for Astoria Regional Airport.

Is it too late to plant mint in Astoria?

The spring planting window runs through May 27. Later plantings tend to struggle in summer heat.

How long until I can pick mint?

Pick lightly the first summer, then as much as you like. Snip stems just above a pair of leaves. Regular cutting keeps plants bushy.

Can I grow mint from seed?

Not reliably. Peppermint rarely makes viable seed, and many seed-grown mints have weak flavor. Buy a plant you've smelled or tasted, or root a cutting in water.

What are the orange spots on my mint?

Mint rust, a fungal disease. Cut the plant to the ground, throw out the clippings, and let it regrow. Good airflow and watering at the base help.

How do I stop mint from spreading?

Grow it in a pot, or in a bottomless container sunk into the ground with the rim a couple of inches above the soil. Trim any runners that grow over the edge.

Also plant in Astoria around the same time

Planting dates for mint in nearby areas

Coos Bay and North Bend, OR Apr 1 – May 27
Aberdeen and Hoquiam, WA Apr 1 – May 27
Forks, WA Apr 1 – May 27

Full planting calendar for Astoria · Mint in every city