When to Plant Garlic in Washington: Counting Back From the First Frost

Seattle’s freeze window runs November 13 to November 30, and that thirty-year band is what sets your planting date, not the calendar month. Count back two to four weeks from it and you land on late October to early November — the stretch when cloves can still root into workable soil before winter rain turns the ground heavy. Half the time frost arrives late, but the other half it doesn’t, and a clove that missed its rooting window waits until spring. Cultivar won’t change this.

The short answer for Washington

For gardens near Seattle, plant garlic late October to early November. That range is anchored on NOAA’s 1991-2020 climate normals for station USW00024233, which place the first fall freeze in a probability band running from November 13 to November 30. Line the two ranges up and the logic is visible: late October to early November falls roughly two to four weeks ahead of that freeze band, which is enough time for cloves to root into soil that’s still workable before winter rain and cold turn the ground heavy and slow to dig.

Treat the November 13-30 figure as a midpoint, not a deadline. It comes from thirty years of records, and in roughly half of those years the first freeze actually lands after November 30, not before it. That works in your favor if you’re running behind. It doesn’t mean you should plan around the later date, because the other half of the time the freeze arrives right on schedule or earlier, and a clove that missed its rooting window doesn’t get a second chance until spring growth resumes on its own.

The cultivar you pick doesn’t move this date. Every variety in the table below, softneck and hardneck, goes into a Seattle-area bed on the same schedule. If you haven’t settled on one yet, Garlic Varieties That Suit Washington Winters covers which types store longest and which handle the wetter west side best.

Working it out for your own garden

The Seattle figure above comes from one station, and Washington’s geography swings the first frost by weeks over surprisingly short distances. It’s worth understanding the calculation rather than just borrowing the date, especially if you garden anywhere but the immediate Puget Sound lowlands.

Find your own frost window first

Elevation moves the date the most. Gain a few thousand feet and the first freeze tends to arrive earlier than it does at sea level, sometimes by two weeks or more. A large body of water works in the opposite direction. Gardens right on Puget Sound, on the Columbia, or near one of the state’s larger lakes often see their first freeze arrive later than gardens a short drive inland at similar elevation, because open water releases stored summer heat slowly through the fall. The Pacific coast strip behaves the same way, staying frost-free longer than the valleys just inland from it.

Count back from whatever window you find

Once you have a frost window specific to your own garden, work the same way this page worked Seattle’s: count back far enough that cloves get several weeks in soil that’s cool but not sodden, before the ground turns properly cold. If your local freeze window runs two weeks earlier than Seattle’s, move your planting window two weeks earlier too. If it runs two weeks later, which can happen right on the water or on a south-facing slope with good air drainage, you have that much more room and can plant into mid-November without much added risk.

Cold air pools, too. A garden at the bottom of a valley or in a known frost pocket will see its first freeze well ahead of a weather station sited on higher, more open ground nearby, even within the same county. If your garden collects cold air on clear, still nights, plant toward the earlier end of whatever range you calculate. If you’re on a slope, near open water, or in an urban heat pocket, the later end is fine.

Soil texture changes how forgiving that window is. Sandy soil drains fast and warms and cools quickly, so a clove planted a little late still finds decent rooting conditions. Heavy clay holds both water and cold, and a wet November in clay ground can mean the difference between a clove that roots well and one that sits in cold mud and starts to rot before it ever sends down roots. Working clay soil, lean toward the earlier half of your calculated window and make sure the bed drains before you plant.

What changes across Washington

The November 13-30 window belongs to the Seattle area and the mild, maritime lowlands around Puget Sound. Move away from that specific climate and the date moves with it, sometimes by more than the two weeks that elevation or a lake can account for on their own.

Eastern Washington is a different climate entirely, not just a colder version of the west side. Once you’re past the Cascades, into the Columbia Basin, the Okanogan, or the Spokane area, the region behaves like high desert: freezes arrive earlier in the fall, the ground freezes harder and deeper, and the growing season overall is shorter. None of the Seattle-anchored figures on this page apply there. A gardener in that part of the state needs a frost window pulled from a station closer to home, not a Puget Sound number stretched across the mountains.

Within western Washington itself, the coast and the lowlands closest to Puget Sound tend to run mildest and latest to frost, buffered by the ocean and the Sound’s open water. Gardens gain elevation toward the Cascade foothills, in places like the hills above Issaquah or the upper Skagit valley, and the first frost there typically arrives earlier than it does down in the lowlands, even within the same county. None of these differences are footnotes. They’re the reason a single statewide planting date doesn’t exist, and why the arithmetic in the section above matters more than the one number this page opened with.

Rainfall timing matters almost as much as temperature on the west side. The Olympic Peninsula and the south Sound tend to get heavy fall rain earlier in the season than the drier northeast corner of the Puget lowlands, and a bed that’s already turned to mud in early October is a bed you can’t work by the time the calculated window arrives. In those wetter areas, a raised bed or a layer of straw laid down ahead of time buys a few extra workable days once the window finally opens.

The mistakes this climate punishes

Assuming the winter’s too mild for hardneck garlic

Western Washington’s winters look mild on paper, and plenty of gardeners assume that means only softneck types like Inchelium Red or Italian Late will perform, skipping hardnecks such as German Red, Chesnok Red or Duganski. The winter cold measured at this same NOAA station runs about 17.4 weeks with air temperatures below 40°F, comfortably clearing the six to eight weeks of chilling the University of Georgia Extension, publication C854, describes as what a clove needs to differentiate properly. Both neck types root and vernalize just fine here. The mistake isn’t the neck type. It’s planting either one too late for that chilling clock to start on schedule.

Planting into ground that stays wet and infected

Western Washington’s wet falls and mild springs line up uncomfortably well with two soil-borne diseases. UC IPM’s Pest Management Guidelines for Onion and Garlic, UC ANR Publication 3453, put white rot‘s active range at 50 to 75°F, a band that covers six months of the growing season here including two months right at its published optimum, and Fusarium basal rot‘s range at 59 to 90°F, covering three months including the planting month itself. Neither of these numbers means the disease is guaranteed. They mean the climate doesn’t rule it out, and the real risk comes from infected seed stock or a bed that’s grown alliums before, not from the calendar alone. Buy cloves from a source that guarantees disease-free stock, and rotate away from any bed that’s carried onions or garlic in the last several years.

Planting too shallow for a wet winter

A clove set an inch deep might survive in a dry climate. In a Puget Sound winter, freeze-thaw cycles and saturated soil heave shallow cloves right out of the ground over the following months. Plant deep enough that the top of the clove sits a couple of inches under the soil surface, then mulch over that with straw once the ground has cooled, both to buffer temperature swings and to keep heavy winter rain from compacting the bed into something closer to concrete by February.

Checking this against your county

Everything on this page is anchored to one station near Seattle. For a frost window specific to your own county, whether that’s Whatcom, Yakima, Spokane, or anywhere between, check with WSU Extension, the state’s land-grant extension service. County offices maintain local planting guidance and can tell you how your area’s frost timing compares to the Seattle figures used throughout this page. This step matters most if you garden east of the Cascades, where the climate has little in common with the Puget Sound lowlands this page is built around, or if you’re in a valley where cold air is likely to pool earlier than nearby stations suggest. For general background on the crop before you get to timing, Growing Garlic in Washington covers bed prep and soil basics.

Common questions

Can I still Plant Garlic in December if I missed the window?

You can, but expect smaller bulbs. By December the ground near Seattle is usually well past NOAA’s November 13-30 freeze window, and a clove going in that late has lost most of its fall rooting time before winter dormancy sets in. It will likely still grow, just with less root mass to draw on when spring growth starts.

What if I want to plant in spring instead of fall?

Garlic planted in fall reliably outperforms spring-planted garlic in this climate because the crop needs an extended cold period to form separate cloves rather than a single round bulb. Spring planting is possible with pre-chilled stock, but for the varieties and timing on this page, fall is the method the whole planting window is built around.

Does the frost date mean it’s safe to plant right up until then?

No. The frost date is the point cloves should already be rooted by, not the deadline for putting them in the ground. Waiting until the days right before the NOAA window opens gives cloves almost no time to establish roots before cold, wet soil slows them down.

Is Seattle’s planting window right for the whole west side of the state?

It’s a reasonable starting point for most of the Puget Sound lowlands, but not an exact match everywhere. Coastal areas and spots right on open water tend to run a little later before frost, while higher ground in the Cascade foothills runs earlier, so treat the Seattle figures as a baseline to adjust from rather than a fixed rule.