Herb · Lamiaceae
When to plant shiso
Green or purple, with a flavour somewhere between mint and basil. The seed needs light and a cold period before it will germinate reliably.
Start seed indoors
6 weeks before
Counted from your last spring frost.
Plant out
2 weeks after
Counted from your last spring frost.
Sow direct
1 week after
Counted from your last spring frost.
Those weeks become real dates once you name a place.
Timing, in frost-relative terms
Seed packets rarely give calendar dates, because a date that suits one latitude is wrong at another. They give offsets from the last spring frost instead, and those offsets are what make shiso plantable anywhere.
- Start seed indoors 6 weeks before the last frost.
- Plant out 2 weeks after the last frost.
- Sow direct 1 week after the last frost.
- Expect 70–90 days to maturity, counted from planting out.
Frost tolerance
Killed by the first frost, like basil.
Classified as tender, with damage expected below 0°C (32°F)32°F (0°C).