Zone 4 Planting Calendar: What to Plant and When

Zone 4 runs on a short clock. The last spring frost holds on well into May, the first fall frost can turn up in September, and what sits between them is only about 110 to 140 days of open ground. At that length the things gardeners in milder zones treat as optional stop being optional here: seedlings raised under lights indoors, row cover over the beds in spring, a low tunnel or cold frame to hold the fall crop a few more weeks. Crop choice carries the rest of the load. Fast, cold-hardy vegetables are the backbone of a Zone 4 garden, and the heat lovers only earn their space when you grow short-season varieties of them and give them a head start. This Zone 4 planting calendar sets out what to plant and when, month by month, from the first onion flat in January to the last kale pulled out of the snow.

Zone 4 planting calendar

Use this month-by-month Zone 4 planting schedule as your season map. It shows when to start seeds indoors, when to move transplants outside, what you can direct sow, and what should be ready to harvest. Dates shift with the weather each year, so pair it with your local last and first frost dates from the ZIP code planting calendar.

Zone 4 planting schedule at a glance

The Zone 4 year moves in four steps. You start seeds indoors from January through March, onions and leeks first, then peppers and celery, then tomatoes and eggplant roughly six to eight weeks before your last frost. Peas, spinach, radish, and the other cold-hardy crops go straight into the ground in April as soon as the soil can be worked, while tender transplants wait for the frost risk to pass in the second half of May or early June. The main harvest runs from July into September, and the fall sowings that fill it out go in during July and August so they mature before the first freeze.

A dash means there is little to plant or harvest that month in Zone 4. Cold months are for planning, ordering seed, and starting the earliest crops indoors under lights.

The best crops for Zone 4

The most reliable Zone 4 vegetables are cold-hardy and quick to mature, the kind that handle a short, cool season and even shrug off a light frost. Lean on these and you will fill your beds with far less risk:

Vegetables

• Leafy greens and lettuce. Fast, frost-tolerant, and perfect for spring and fall. Browse lettuce seeds, spinach seeds, and kale seeds.
• Root crops. Carrots, beets, and radishes mature quickly and store well. See carrot seeds, beet seeds, and radish seeds.
• Peas and beans. Peas love the cool shoulder seasons; bush beans give a fast summer crop. Try pea seeds and bean seeds.
• Brassicas. Broccoli, cabbage, and their cousins thrive in the cool weather this zone does best. Explore broccoli seeds and cabbage seeds.
• Warm-season crops, started early. Tomatoes and peppers ripen here if you start seeds indoors in late winter and choose shorter-season varieties. See tomato seeds and pepper seeds.

Herbs and flowers

Hardy herbs like chives, dill, parsley, and cilantro do well in Zone 4, and cold-tolerant flowers such as calendula, nasturtium, and sunflowers add color and pull in pollinators. Start with our herb seeds, and for the full range see all of our vegetable seeds.

When are the frost dates in Zone 4?

Your last spring frost is the average date of the final freeze before summer, and your first fall frost is the average date of the first freeze after it. In Zone 4 the last frost typically falls around mid to late May and the first fall frost around mid to late September, leaving a growing season of about 110 to 140 days. Those two dates drive everything: you start most warm-season seeds indoors weeks before the last frost, plant tender crops out only after it, and count backward from the first fall frost to know how late you can sow.

These are averages for the whole zone, and your yard can run a week or two earlier or later. For the exact last and first frost dates at your location, enter your ZIP code in our interactive planting calendar and plan your Zone 4 garden around your real local dates.

Zone 4a vs 4b: last and first frost dates

Every USDA zone is split into an a half and a b half that sit about 5F apart in average winter low. Zone 4a is the colder half, and Zone 4b is the milder one. On paper that is a small gap, but on the calendar it shows up at both ends of the season: in 4b the last spring frost lets go of the garden earlier and the first fall frost arrives later, so a 4b gardener works with a couple of extra weeks that a 4a gardener simply does not have.

Treat the numbers below as a planning baseline, not a forecast. Local microclimate moves them more than the half-zone does. A low spot that collects cold air, a valley bottom, or a garden at higher elevation can run one to two weeks behind these averages, while a south-facing slope or a site near a large lake can run ahead of them. Keep your own frost records for a season or two, and confirm your dates by ZIP code with our planting calendar tool.

Whichever half you garden in, the date you work backward from is your own last frost, and the job it drives is when to start seeds indoors. For tomatoes and peppers, count six to eight weeks back from that date, which lands in late March or early April for most of Zone 4 and a little earlier in 4b than in 4a. Onions, leeks, and celery need longer and go under lights in January or February. Hold every tender transplant until the frost window has fully passed, and keep row cover within reach for the cold night that always seems to come after you plant.

What does USDA Zone 4 mean?

USDA Plant Hardiness Zones are based on the average annual coldest winter temperature. Zone 4 means your average extreme winter low lands between -30 to -20F. That number tells you which perennials, shrubs, and trees can survive the winter in the ground, so it is a measure of winter hardiness, not frost dates or season length. When a plant is labeled hardy to Zone 4, it means the plant can normally live through a Zone 4 winter. For annual vegetables you plant fresh each spring, your frost dates and season length matter more than the hardiness number, which is why this calendar leans on both.

Not sure this is your zone? If your winters are colder, see our Zone 3 planting calendar. If they are milder, check the Zone 5 planting calendar. And for your exact dates, always confirm with the ZIP code planting calendar.