December planting is a short list for most of the country and a long one for a narrow band of it. North of about zone 8, the ground is cold or frozen and the days are too short for anything new to grow, so what you plant in December is either indoors or deliberately dormant. From zone 9 south it is a different month entirely: the cool season is underway, garlic is going in, and in zones 10b and up you can still sow from seed.
What decides which side of that line you are on is your first frost date, and in December it is worth checking, because a lot of warm-zone gardens have not had theirs yet. Of the 100 largest US cities in our NOAA first frost data, 19 reach their median first frost in December, from Stockton on December 1 to New Orleans on December 31, and Orlando not until January 10. Another 18 do not freeze at all in a typical year.
Check your frost dates first
The zone averages below can be a week or two off for any one garden. Your ZIP code gives you your own zone and dates.
Enter your US ZIP code for your USDA zone, frost dates & planting calendar.
What to plant in December, by zone
| Zone | First frost | Garlic | Sow or set out outdoors | Start indoors for spring |
|---|---|---|---|---|
| 3 to 6 | Sep 15 to Oct 18 | Window closed; mulch it | Nothing; winter sow hardy seed in jugs from Dec 21 | Nothing yet |
| 7a to 7b | Oct 25 to Nov 1 | Window closed late Nov | Nothing; winter sow hardy seed from Dec 21 | Nothing yet |
| 8a | Nov 8 | Through Dec 6 | Winter sow hardy seed from Dec 21 | Nothing yet (onions Jan 14) |
| 8b | Nov 15 | Through Dec 13 | Winter sow hardy seed from Dec 21 | Nothing yet (onions Jan 4) |
| 9a | Nov 30 | Nov 30 to Dec 28 | Transplants of broccoli, cabbage, kale, lettuce | Onions from Dec 21 |
| 9b | Dec 10 | Dec 10 to Jan 7 | Transplants of the cool-season crops; radishes in a cold frame early on | Onions Dec 7; peppers, eggplant, parsley Dec 21; tomatoes Dec 28 |
| 10a | Dec 20 | Dec 20 to Jan 17 | Transplants of every cool-season crop | Peppers and eggplant Dec 6; tomatoes Dec 13; broccoli and kale Dec 20 |
| 10b | Dec 31 | From Dec 31 | Radishes and onion sets to Dec 10; spinach and parsley to Dec 3 | Broccoli and kale Dec 4; lettuce Dec 18 |
| 11 and up | none | Pre-chilled cloves to Jan 31 | The full cool-season list, plus tomatoes, peppers and beans | Not needed |
The garlic windows run from the average first frost through the following four weeks, the same rule as the garlic guide. The outdoor sow-by dates come from the fall planting calendar engine: days to maturity plus about two weeks for slow short-day growth, minus the days a hardy crop keeps going after a light frost. The indoor dates count back from the zone’s average last frost by the weeks each crop needs, the method in when to start seeds indoors.
Why so little grows in December
Cold is only half of it. The other half is light. Below about ten hours of daylight, plants barely grow at all, even in a cold frame that never drops below freezing. On the winter solstice, December 21, Minneapolis gets about 8 hours 46 minutes of daylight, Philadelphia and Denver about 9 hours 20 minutes, Houston about 10 hours 15 minutes and Miami about 10 hours 32 minutes.
That is the real reason a December garden works in Houston and not in Philadelphia. Houston never drops under ten hours, so a lettuce transplant set out in December keeps growing, slowly. In Philadelphia the same transplant would sit and wait for February even if you kept the frost off it. The cold frame guide has the dates for each latitude; the short version is that whatever you harvest in December in the north had to be grown by October.
Zones 3 to 7: plant indoors, sow in jugs, plan
Outdoors, the December job is protecting what is already there. If your garlic went in during October or November, put four to six inches of straw or shredded leaves over it once the top inch or two of soil has frozen. Carrots, parsnips and leeks left in the ground under a deep layer of leaves can still be dug on mild days in zones 5 to 7.
Two kinds of December planting do make sense here.
Winter sowing from the solstice. Hardy seed sown outdoors in milk jugs or clear totes from about December 21 gets the weeks of cold that many perennials and natives need to germinate, then sprouts on its own schedule in spring. Spinach, kale, lettuce, broccoli, poppies, larkspur and most native perennials all work. The winter sowing guide has the cut-off dates for your zone. Tender crops (tomatoes, peppers, basil, squash) do not belong in a jug in December.
Indoor bulbs and greens. Amaryllis bulbs potted in early December bloom in roughly six to ten weeks, and paperwhites in about four to six, so a pot started on the first weekend of the month is in flower for late January. Microgreens (radish, pea shoots, broccoli, sunflower) are ready in one to three weeks on a sunny windowsill or under a basic shop light, and an indoor herb setup keeps parsley, chives and basil going until spring.
What you should not start in December, anywhere north of zone 9, is vegetable seed for the spring garden. The earliest indoor start in zone 7a is onions on January 30, and in zone 6a onions on February 9. A tomato sown in December in zone 6 would be a leggy three-foot plant in a pot by the time it is safe to set out.
Zone 8: the last garlic, then winter sowing
The first frost has passed, on average November 8 in zone 8a and November 15 in zone 8b. The garlic window closes December 6 in 8a and December 13 in 8b, so if the cloves are still in the bag, the first week of December is the deadline. Atlanta (8a) and Dallas (8b) are the big cities in this band.
Kale, collards and cabbage set out in October or November will hold through most zone 8 winters and are the backbone of a December harvest. New outdoor sowings for a harvest this winter are over. From the solstice on, zone 8 can winter sow hardy seed in jugs through mid to late January, and the first indoor start of the year is onions in early to mid January.
Zones 9 and 10: garlic season, transplants, first indoor starts
This is where December is a real planting month. The first frost is around November 30 in zone 9a, December 10 in zone 9b, December 20 in zone 10a and December 31 in zone 10b, and many years it is just a light frost or two before the season turns toward spring.
Garlic goes in now. The window is November 30 to December 28 in zone 9a, December 10 to January 7 in 9b and December 20 to January 17 in 10a. Winters here are too warm to trigger proper bulbing, so put the cloves in the refrigerator (not the freezer) for six to eight weeks before planting, or choose softneck and Creole types that need less cold.
Transplants are the other move. Broccoli, cabbage, kale and lettuce set out in December grow through the mild winter, and a transplant skips the four to six weeks from seed that you no longer have before the heat returns. In zone 10b there is still time for seed: radishes and onion sets through about December 10, spinach and parsley through December 3.
Zones 9b and 10 are also where spring seed starting begins. With a last frost around February 15, zone 9b starts onions about December 7 and peppers, eggplant and parsley about December 21, then tomatoes on December 28. Zone 10a, with a last frost around January 31, starts peppers and eggplant about December 6 and tomatoes about December 13. A basic seed starting setup, a tray, fresh mix and a shop light kept close over the seedlings, is enough.
Houston (zone 9b, first frost around December 9), Austin (9a, December 3), Sacramento (9b, December 16) and Las Vegas (9a, December 10) are all in this band. In the Phoenix area, Scottsdale’s median first frost is December 26 and Phoenix’s airport station freezes in fewer than one year in five.
Zone 11 and warmer: the main season
South Florida, the Hawaiian lowlands and Puerto Rico are in the best vegetable months of the year. The whole cool-season list goes in through January: lettuce, spinach, broccoli, cabbage, kale, carrots, beets, radishes, peas and cilantro. Tomatoes, peppers and beans planted in December fruit through the dry winter, when the heat, humidity and pests that ruin them in summer have eased. Plan for everything to finish by about April, when the heat comes back.
December is planning month
For most gardeners December’s most useful work is on paper. Seed catalogs arrive, last season is fresh in your mind, and nothing in the garden needs you.
Three things are worth doing before January. First, sketch where every crop grew this year, by bed, and use it to decide where each one goes next year: keeping tomatoes, peppers, eggplant and potatoes out of the same bed for three or four years does more against blight than any spray. The crop rotation chart lays out a three and four bed plan for all 24 crops on this site. Second, test old seed before you reorder it: roll ten seeds in a damp paper towel, keep it warm, and count what sprouts in a week. Seven or more is fine to sow; four or fewer, buy fresh. Third, write your frost dates on the calendar and count back from them, using your zone page or the last frost date guide, so the first indoor sowing does not sneak up on you in February. The January planting guide lists those first starts zone by zone.
What not to plant in December
Tender crops outdoors anywhere with a frost date still ahead of it. Zone 9b has its average first frost on December 10 and frost is possible into February, so tomatoes, peppers, beans, squash and basil wait until spring there. In zone 11, by contrast, they are December crops.
Spring vegetable seed indoors north of zone 9. Starting too early is the most common seed-starting mistake there is, and December is too early everywhere north of the Gulf Coast.
Garlic in zones 9 and 10 straight from the store without chilling. It will grow leaves and make a single round bulb with no cloves. If you missed the November and December windows further north, the November planting guide has the rules for a late planting.