December Gardening Looks Very Different Depending on Your Climate
More than almost any other month, December gardening tasks depend on where you live. In cold-winter Northern Hemisphere climates, the vegetable garden is typically dormant or close to it, and December is mostly about protection, tidying, and planning rather than active growing. In warm-winter regions (parts of the southern US, the Mediterranean, and similar climates), some crops may still be actively growing through December. And in the Southern Hemisphere, December falls in summer, so the task list looks more like what a Northern Hemisphere gardener would do in June. Treat the guidance below as written primarily for cold-to-mild-winter Northern Hemisphere gardens, and adjust heavily for your own climate.
Putting the Vegetable Garden to Bed for Winter
For gardeners in climates where the growing season has ended, December is commonly treated as a cleanup and soil-building month:
- Working compost, well-rotted manure, or other organic matter into vegetable beds is a frequently mentioned December task, giving it time to break down before spring planting.
- Clearing spent plant debris, especially from crops that had disease or pest issues, is commonly recommended to reduce problems carrying over into next season.
- Checking stored fruit and vegetables (from a root cellar, garage, or pantry) for early signs of rot, pest damage, or disease is often suggested so problems don’t spread to the rest of what’s stored.
- Labeling or marking where dormant perennial herbs and vegetables are planted is sometimes recommended, since it’s easy to forget exact locations once foliage has died back, and accidentally disturb them in spring.
Protecting Plants, Pots, and Beds From Winter Weather
In colder climates, protecting what’s still outdoors is a common December focus:
- Brassicas like cabbage and other cold-hardy crops still in the ground are sometimes netted to protect them from birds, which can be more aggressive foragers once other food sources are scarce.
- Bare-root trees, hedges, and shrubs are often planted in December in milder climates where the ground isn’t frozen, since the dormant season is generally considered a favorable time for establishing bare-root stock.
- Mulching over perennial roots and some bulbs can help buffer against temperature swings in areas with cold but not extremely harsh winters; practices vary considerably by zone, so it’s worth checking regionally specific advice for anything borderline-hardy in your area.
- Watching for fungal issues like downy mildew on cool-season ornamentals is sometimes mentioned for damp winter climates; affected leaves are generally removed and disposed of promptly since there’s often no effective fungicide treatment once it’s established.
Indoor, Greenhouse, and Windowsill Tasks
Even where the outdoor garden is largely dormant, there’s often still gardening to do indoors in December:
- Forcing herbs like mint or chives indoors on a sunny windowsill is a commonly mentioned way to have fresh herbs through winter.
- Taking root cuttings of certain herbaceous perennials is sometimes done in December in mild-winter regions, though success varies by plant type and isn’t guaranteed.
- In a heated greenhouse or indoors, some gardeners continue tending cool-tolerant crops like certain lettuce varieties through winter, though this generally requires supplemental light or a reasonably warm, bright location in most climates. This guide to winter greenhouse growing covers heating options and what’s realistic to grow in an unheated versus heated structure.
What Plants Can You Start in December?
In most cold-winter climates, December is not a typical month for starting new outdoor vegetable crops, since cold soil and short daylight hours generally work against germination and growth. That said, a few options are sometimes available depending on your setup and climate:
- Fast, cold-tolerant herbs or greens grown indoors under supplemental light.
- Bare-root trees, shrubs, or hedging, in regions where the ground isn’t frozen (this is a planting task rather than a seed-starting one).
- In warm-winter or Southern Hemisphere climates where December falls in an active growing season, a much wider range of crops may be appropriate, but that’s effectively a different gardening calendar entirely and worth checking locally rather than assuming anything from a Northern Hemisphere-focused list.
The “70/30 Rule” and the “3-Hour Rule,” Explained
Both of these come up occasionally in general gardening discussion, and in the sources we reviewed, neither has one standardized, widely agreed-upon definition tied to an official horticultural body. They appear to function as informal rules of thumb — sometimes the “70/30 rule” is used loosely around watering practices or dividing effort between soil care and plant maintenance, and the “3-hour rule” sometimes gets used around limiting a single gardening session to avoid overexertion, though phrasing and intent vary by source. Given the inconsistency, it’s reasonable to treat both as casual heuristics rather than precise, verifiable standards.
Planning Ahead for Next Spring
December is also a reasonable time to do planning that doesn’t require being outside:
- Reviewing notes from the past growing season — what thrived, what struggled, and what pests or diseases showed up — can inform next year’s plans while it’s still fresh.
- Ordering seeds for spring can make sense in December, since some popular varieties sell out earlier in the season.
- If you’re new to gardening or planning next year’s vegetable garden, our guide to what to plant in May covers many of the common warm-season crops and timing considerations you’ll likely be working with once spring planting season arrives.
FAQ
What to do with a garden over winter? In cold-winter climates, this generally means cleaning up spent plant debris, working organic matter into beds, protecting any remaining cold-hardy crops, and checking stored produce periodically. In warm-winter or Southern Hemisphere climates, the garden may still be actively growing, in which case normal seasonal maintenance continues.
What is the 70/30 rule in gardening? It’s an informal heuristic without one agreed, standardized definition across the sources reviewed for this guide — it tends to come up loosely around watering habits or dividing gardening effort, so it’s best treated as a casual rule of thumb rather than a precise standard.
What is the 3-hour gardening rule? Similarly, this doesn’t appear to be a standardized horticultural guideline; it seems to be used informally, sometimes in reference to limiting how long a single gardening session should run. Treat it as general advice rather than an established rule.
What plants can I start in December? In most cold-winter climates, few new outdoor vegetable crops are realistically startable in December; indoor herbs under supplemental light and bare-root tree/shrub planting (in unfrozen ground) are the more commonly cited options. Climate makes a large difference here.