GreenlyWhen to plant garlic in Philadelphia
In Philadelphia, garlic: plant around 12 October, a month before the first autumn frost.
Last spring frost around 3 April, first autumn frost around 11 November. Frost-free days: 222 days.
The dates follow the Greenly calendar: open ground a week after the last frost once the soil is warm enough for the crop, frost-hardy crops three weeks before it, an unheated greenhouse three weeks earlier, seedlings sown so they are ready on the day. In a cold year allow a week or two more.