December Garden Jobs by Zone, North to South

Jobs nearly every source lists

• Order seeds and plan. University of Illinois Extension says to make your list from the catalogs, budget it, and sketch next year’s garden on paper. Texas A&M AgriLife says to place seed orders this month so you get the varieties you want, and to try a few new kinds each year. How to plan next year’s vegetable garden.
• Look after tools and engines. Illinois says to detach the garden hose, drain or run gas-powered engines dry or add fuel stabilizer, and get mower blades sharpened; its tip is to sand wooden handles, rub them with linseed oil and keep metal tools off concrete floors, where condensation rusts them. Texas A&M AgriLife says to drain gasoline from power tools and drain and store hoses where you can reach them.
• Check stored bulbs. University of Minnesota Extension says to check dahlia tubers and canna bulbs for soft spots, mold and dryness and remove damaged ones; Oregon State says to check stored bulbs, vegetables and fruits for rot. How to overwinter dahlias and cannas.
• Ease off the houseplants. Oregon State says water and fertilizer needs are generally lower in winter, Texas A&M AgriLife says to reduce feeding indoor plants until mid-March, and Minnesota says to wipe the leaves with plain water and a soft cloth. Houseplant care in winter.

The North: Minnesota and Illinois

University of Minnesota Extension (zones 3a–5a) and University of Illinois Extension (zones 5a–7a).

• Watch for animal browsing on shrubs and young trees (Minnesota). Hardware cloth keeps out rabbits and mice, livestock fencing keeps out deer — but check the base of the plant for a nest first, so you do not cage animals in.
• Read the label on deicing salt. Minnesota says salt built up in the soil dries out roots, and salt spray from plowing browns evergreen leaves until they drop. How to protect shrubs from winter damage.
• Dormant-seed thin lawn. If a warm spell melts the snow, Minnesota says seed can be spread on areas you want to improve any time from now to early spring.
• Bring in the pots. Illinois says a pot left out with soil in it holds water that freezes and expands; clay and ceramic crack most, but plastic cracks too.
• The Christmas tree takes plain water. Minnesota says sugar or sugary drinks in the stand water can grow mold that clogs the tree’s water-carrying tissue. Christmas tree care, and what to do with the tree after Christmas.

The Pacific Northwest: Oregon

Oregon State University Extension Service (zones 5b–9b). It says its tips do not fit every part of Oregon.

• Western Oregon: do not walk on lawns until frost has melted; make sure plants in protected sites still get water; and plant trees and landscape shrubs now.
• Central and eastern Oregon: give plants a deep soaking every six to eight weeks so they do not dry out.
• Protect new plants from wind with stakes, guy wires or windbreaks, and tie up columnar evergreens so snow and ice do not break them.
• Clean up, but not all of it: rake leaves and cut withered perennial stalks, but leave some leaves and standing stems where they cause no disease, for overwintering beneficial insects and pollinators. When to cut back perennials.
• Check for rodent damage at the bases of trees and large shrubs, and do not mound mulch against them, which gives rodents cover.

The Southeast: South Carolina

Clemson Cooperative Extension’s Home & Garden Information Center (zones 8a–9b).

• Irrigation: plants need less water now; controllers can be switched off for the winter months, after checking rain sensors and the outlet they plug into.
• Mulch beds to stop winter weeds, keep soil warm and prevent compaction; Clemson suggests blowing fallen leaves into beds and topping them with pine straw.
• Plant trees as steady rainfall returns, so they need less irrigation to establish.
• Water evergreens deeply over the whole root ball so they do not dry out over winter.
• Harvest the cole crops — collards, kale, spinach, cabbage and lettuce mixes — that are coming on now.

Texas

Texas A&M AgriLife’s December advice, from horticulture specialist Larry Stein (zones 6b–10b).

• Water dormant plants about every 6 weeks if rain is short, and water the landscape before a predicted hard freeze.
• Plant pansies, violas and ornamental cabbage and kale if deer are not a problem; trees and shrubs from now through February (often February or early March in the Panhandle).
• Plant chilled bulbs: tulips and hyacinths kept in the refrigerator can go in any time in December once they have had 60 or more days of chilling. When to plant tulip and daffodil bulbs.
• Do not hurry to prune woody plants: late December through February is usually the best time.
• Prepare rose beds for planting in January and February, with composted manure, pine bark and similar materials.

Florida

UF/IFAS Extension’s three gardening calendars, for north, central and south Florida.

• North Florida: cool-season vegetables such as cabbages, collards, beets and broccoli, and cool-weather herbs including parsley, thyme, sage, dill, fennel, garlic and cilantro. Wait until warm weather returns to cut back cold-damaged plants.
• Central Florida: celery, cauliflower, lettuce, cabbage and carrot; masses of petunia, pansy and snapdragon for winter color; and prepare now to protect tender plants should cold threaten.
• South Florida: broccoli, carrots, kale and green onions; irrigate only if the weather has been warm and dry; and consider a live southern red cedar as a holiday tree, planted out after the holidays.
• All three: amaryllis can be forced to bloom now or planted outdoors for spring flowers (amaryllis care), and fallen leaves make compost and mulch.

California’s Central Valley: Butte County

UC Master Gardeners of Butte County (zones 8b–9b).

• Plant onions, chives, spinach, mustard, peas, beets and radishes, and start brassica and lettuce seeds in a greenhouse to transplant in late January.
• Start amaryllis bulbs in early December, in a sunny south window, for flowers by Valentine’s Day.
• Mulch beds again so winter rains do not sprout weed seeds, and add plenty of compost to beds for spring.
• Prune dormant fruit trees and shrubs, and grape vines; prune large trees ahead of winter storms.
• Plant bare-root plants — fruit trees, asparagus, artichokes, rhubarb, berries and grapes — as soon as you buy them, so they do not dry out.
• Keep a living Christmas tree outside until Christmas week.

Which fruit suits your zone, before you buy bare-root plants: Apple Tree, Blueberry, Raspberries and Blackberries and Grape.

Common mistakes

• Leaving the hose on the spigot. Illinois says take it off before freezing weather.
• Leaving pots of soil outside. The water in them freezes, expands and cracks the pot (Illinois).
• Pruning woody plants too early. Texas A&M AgriLife says late December through February is usually best.
• Cutting back cold-damaged plants right away. UF/IFAS says wait until warm weather returns.
• Overwatering houseplants. They need less water and fertilizer in winter (Oregon State).

Where there is no source here

We found no December calendar from the Mid-Atlantic, the Northeast, the Mountain West or the Desert Southwest that we could read, so those regions are covered here only by the zone table. For your area, ask your county extension office.