Hyacinth · Manhattan, New York, United States
When to sow hyacinths in Manhattan
Main outdoor window
23 Sep - 7 Oct
The window this page is built around.
Timed from last spring frost
15 April
In Manhattan, on your chosen risk.
Ready to pick
1 Mar - 30 Apr
If you plant at the start of the window.
The average last frost. Half of all years are later than this.
Step by step in Manhattan
Each window is a range, not a single day. Earlier in the range buys you a longer season; later in it buys you a safer one.
Plant the bulbs
23 Sep - 7 Oct
Four to six weeks before your first frost, so roots form before the ground cools.
In flower
1 Mar - 30 Apr
Hyacinths through the year
Against the frost risk in Manhattan
Why these dates
Plant four to six weeks before the first autumn frost, 12cm deep. For flowers indoors at midwinter, pot prepared bulbs in early autumn and give them ten weeks somewhere dark and around 9C before bringing them into warmth - rushing that cold period is the usual reason a forced hyacinth flowers down inside its leaves.
Hardy to about -25C in the ground. Requires roughly thirteen weeks below 9C, so it is one of the first bulbs to fail in a mild winter. The bulbs irritate skin; handle them with gloves.
Hyacinths are anchored to the first autumn frost rather than the last spring one, so the planting window on this page counts backwards from the end of the season in Manhattan instead of forwards from its start.
Hardiness is not the obstacle here. Manhattan is zone 7a, comfortably inside the range this crop is rated for, so an established plant should come through an average winter without protection.
The median frost-free season here is 203 days, against 150 to 200 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Manhattan
Other flowers to time
Growing hyacinths in Manhattan
When should I plant hyacinths in Manhattan?
Aim for 23 Sep - 7 Oct in an average year. If you would rather not gamble on the weather, wait until 12-26 Sep - by then frost has finished in nine years out of ten.
When will hyacinths be ready to harvest in Manhattan?
Expect to start picking around 1 Mar - 30 Apr, based on 150 to 200 days to maturity from the planting date calculated for this location.
How much frost will hyacinths tolerate?
Hardy to about -25C in the ground. Requires roughly thirteen weeks below 9C, so it is one of the first bulbs to fail in a mild winter. The bulbs irritate skin; handle them with gloves.