What should I plant in December in Philadelphia, PA?

In December in Philadelphia, PA (zone 7a), you can plant Brussels Sprouts, Leek, Onion, and more. These dates are based on local climate data for your area.

When do I plant Brussels Sprouts in Philadelphia, PA?

In Philadelphia, PA (zone 7a), Brussels Sprouts: start seeds indoors Jan 1 – Feb 21 and Nov 1 – Dec 31, transplant outdoors Mar 9 – Jun 30.

When do I plant Leek in Philadelphia, PA?

In Philadelphia, PA (zone 7a), Leek: start seeds indoors Jan 1 – Apr 23 and Dec 17 – Dec 31, transplant outdoors Mar 9 – Jul 16.

When do I plant Onion in Philadelphia, PA?

In Philadelphia, PA (zone 7a), Onion: start seeds indoors Jan 1 – Apr 30 and Dec 17 – Dec 31, transplant outdoors Mar 9 – Jul 23.

What to Plant in December

Philadelphia, PA · Zone 7a

Last frost: Apr 1 Frost-free days: 218

Full year calendar for Philadelphia

The garden rests under snow or mulch. This is planning season — review what worked, order seeds, and sketch out next year's bed layouts.

December at a Glance

Indoor Transplant Direct Sow

1 5 10 15 20 25

Brussels Sprouts

Leek

Onion

Start Indoors 3

Start these seeds indoors under grow lights or on a sunny windowsill.

Plant now

Brussels Sprouts

Nov 1 – Dec 31

1 per sq ft 80–110 days

Later this month

Leek

Dec 17–31

4 per sq ft 90–150 days

Onion

Dec 17–31

9 per sq ft 100–120 days

December Gardening Tips

Start Brussels Sprouts, Leek, Onion indoors now to give them a head start before transplanting outside.
Get a soil test now — results come back fast in the off-season and you can amend before spring.