When to Start Seeds: A Month-by-Month Planting Calendar

The Most Important Question in Gardening: When Do I Plant?

“When should I start my seeds?” This is the question I receive more than any other, and I totally get why. Timing your seed starting correctly is the difference between a garden that thrives and one that struggles. Start too early, and you’ll have leggy, root-bound plants begging to go outside while frost still threatens. Start too late, and you’re harvesting green tomatoes in October while your neighbors are enjoying ripe, juicy fruit.

Here’s the beautiful truth: gardening success isn’t about having a green thumb (which, by the way, isn’t even a real thing). It’s about understanding your specific growing conditions and working with nature’s timeline rather than against it. This guide will give you that roadmap.

Whether you’re a brand new gardener trying to figure out your first spring planting or a seasoned grower looking to optimize your schedule, this month-by-month calendar will be your go-to reference. We’ll break down exactly what to start, when to start it, and why timing matters so much.

Understanding Your Growing Zone and Frost Dates

Before we dive into the monthly calendar, you need to know two critical pieces of information: your average last spring frost date and your first fall frost date. These dates form the bookends of your main growing season.

How to Find Your Frost Dates

The easiest way? Visit the National Gardening Association’s frost date calculator and enter your zip code. Look for:

• Last Spring Frost Date: The average date of the last light freeze in spring
• First Fall Frost Date: The average date of the first light freeze in fall

The period between these dates is your frost-free growing season.

Understanding the “Weeks Before Last Frost” Concept

Throughout this guide, you’ll see timing recommendations like “start indoors 6-8 weeks before last frost.” This means you count backward from your last frost date to determine your seed starting date.

Example: If your last frost date is May 15th, and a crop needs to be started 8 weeks before:

• May 15 minus 8 weeks = March 20th
• Your seed starting date is around March 20th

The Complete Month-by-Month Planting Calendar

JANUARY: Planning and Very Early Starts

What to Start:

• Artichokes (in warm climates): 10-12 weeks before last frost
• Onions from seed: 10-12 weeks before last frost
• Leeks: 10-12 weeks before last frost
• Celery & Celeriac: 10-12 weeks before last frost

January might seem early for gardening, but if you want to grow onions from seed (which gives you infinitely more variety options than sets), now’s the time. Onions are slow growers, and starting them in January means you’ll have decent-sized plants ready for spring transplanting.

January Garden Tasks: 1. Order seeds and supplies before popular varieties sell out 2. Inventory leftover seeds and test germination rates 3. Clean and organize seed starting equipment 4. Create your garden plan and map 5. Start compost if you haven’t already Pro Tip: If you’re in a very cold climate (Zones 3-5), January is also the perfect time to build or set up your seed starting station—grow lights, heat mats, and shelving—so you’re ready when the real seed starting season begins in February.

FEBRUARY: The Seed Starting Season Begins

What to Start:

• Peppers (hot and sweet): 8-10 weeks before last frost
• Eggplants: 8-10 weeks before last frost
• Tomatoes (in colder zones): 8-10 weeks before last frost
• Brassicas: Broccoli, cabbage, cauliflower, Brussels sprouts (6-8 weeks before)
• Kale & Collards: 6-8 weeks before last frost
• Lettuce (for early transplants): 4-6 weeks before last frost

February is when the action really starts for northern gardeners. Peppers and eggplants are notoriously slow to germinate and slow to grow, so they need this extra time. If you love spicy food and want to grow habaneros or ghost peppers, definitely don’t wait past February.

Brassicas in February: Broccoli, cabbage, and their cousins can handle cooler temperatures, so starting them now means you’ll have robust plants ready to go out 2-3 weeks before your last frost date. These cold-hardy vegetables actually prefer the cooler temperatures of early spring. February Pro Tips:

• Use a heat mat for peppers and eggplants—these tropical natives need soil temperatures of 75-85°F to germinate well
• Start more seeds than you need; you can thin later and always share extras with friends
• Label everything obsessively—February enthusiasm leads to March confusion

MARCH: The Big Push for Warm-Season Crops

What to Start:

• Tomatoes (in most zones): 6-8 weeks before last frost
• Peppers (if you haven’t yet): 8 weeks before last frost
• Tomatillos: 6-8 weeks before last frost
• Broccoli & Cabbage (second succession): 6-8 weeks before
• Cauliflower: 6-8 weeks before last frost
• Kohlrabi: 4-6 weeks before last frost
• Herbs (basil, parsley, cilantro): 4-6 weeks before
• Swiss Chard: 4-6 weeks before last frost
• Celery (if not started in January): 10-12 weeks before

March is the busiest seed starting month for most gardeners. Tomatoes—the crown jewel of the summer garden—need to be started now. Depending on your zone, you might be starting a second round of brassicas for succession planting.

Understanding Succession Planting: Instead of starting all your broccoli at once, start some in February, some in March, and some in April. This staggers your harvest so you’re not drowning in broccoli for two weeks and then have none for the rest of the season. Direct Sowing Can Begin (In Mild Climates): If you’re in Zones 7-10, March is when you can start direct sowing cool-season crops like:

• Peas (as soon as soil can be worked)
• Spinach
• Radishes
• Carrots (in protected areas)

APRIL: Transplanting Cool-Season Crops, Starting Warm-Season Annuals

What to Start:

• Cucumbers (for early crop): 3-4 weeks before last frost
• Summer Squash & Zucchini: 3-4 weeks before last frost
• Winter Squash: 3-4 weeks before last frost
• Melons: 3-4 weeks before last frost
• Pumpkins: 3-4 weeks before last frost
• Basil (if not started): 4-6 weeks before
• Corn (in containers for early start): 2-3 weeks before
• Beans (in containers for early start): 2-3 weeks before

April is transitional—you’re transplanting cool-season crops outside while starting fast-growing warm-season crops indoors. The key word here is “fast-growing.” Cucumbers, squash, and melons germinate quickly and grow rapidly. Starting them too early leads to root-bound plants that transplant poorly.

April Transplanting (2-4 Weeks Before Last Frost):

• Broccoli
• Cabbage
• Cauliflower
• Kale
• Lettuce (started indoors)
• Onion seedlings

These hardy crops can handle light frosts and even taste sweeter after a touch of cold. Just be ready with row cover if a hard freeze threatens.

Direct Sowing in April:

• Peas (in all zones where ground has thawed)
• Spinach
• Radishes
• Carrots
• Beets
• Turnips
• Potatoes (in many regions)

MAY: The Main Event—Transplanting and Direct Sowing

What to Start (For Summer Succession):

• Second round of cucumbers: For continuous harvest
• Second round of summer squash: Plants started now will produce when early plants fade
• Fall brassicas: Broccoli and cabbage for fall harvest
• More basil: Succession plant every 3-4 weeks for continuous supply

May is when the garden explodes into life. Your last frost date has passed (or is passing), and it’s time to get those heat-loving plants in the ground.

Transplant Outdoors (After Last Frost):

• Tomatoes
• Peppers
• Eggplants
• Tomatillos
• Cucumbers
• Squash and pumpkins
• Melons
• Basil and warm-weather herbs

Direct Sow in May:

• Beans (bush and pole)
• Corn
• Cucumbers (if not started indoors)
• Summer squash (if not started indoors)
• Melons (if not started indoors)
• Okra (after soil warms to 65°F)
• Sweet potatoes (slips)
• Winter squash and pumpkins
• Sunflowers
• Zinnias and other summer flowers

May Garden Tasks: 1. Harden off all seedlings before transplanting 2. Set up supports for tomatoes, beans, and cucumbers 3. Mulch transplants to conserve moisture and prevent weeds 4. Start scouting for pests daily 5. Install drip irrigation if using

JUNE: Maintaining, Succession Planting, and Starting Fall Crops

What to Start for Fall:

• Brussels sprouts: 12-16 weeks before first frost (yes, really!)
• Fall broccoli: 10-12 weeks before first frost
• Fall cabbage: 10-12 weeks before first frost
• Cauliflower for fall: 10-12 weeks before first frost
• Second round of basil: For late summer harvest
• Second round of cucumbers: For fall harvest

June feels counterintuitive—you’re in the thick of summer but starting your fall garden. Brussels sprouts take forever to mature, so if you want them for Thanksgiving, they need to go in now.

June Direct Sowing:

• Beans (succession plant every 2-3 weeks)
• Corn (if you have a long enough season)
• Cucumbers (succession planting)
• Summer squash (succession planting)
• Edamame
• Cover crops in areas you’re done harvesting

June Garden Maintenance:

• Consistent watering is critical as temperatures rise
• Side-dress heavy feeders (tomatoes, corn, squash) with compost or fertilizer
• Stay on top of weeding
• Monitor for tomato hornworms and squash bugs
• Harvest regularly to encourage continued production

JULY: Fall Garden Focus and Heat Management

What to Start for Fall:

• Kale: 8-10 weeks before first frost
• Collards: 8-10 weeks before first frost
• Fall lettuce: 6-8 weeks before first frost
• Spinach: 6-8 weeks before first frost
• Asian greens (bok choy, tatsoi): 6-8 weeks before
• Swiss chard: 8-10 weeks before first frost
• Beets for fall: 8-10 weeks before first frost
• Carrots for fall: 10-12 weeks before first frost
• Radishes: 4-6 weeks before first frost

July is hot, and starting seeds indoors can be challenging because many cool-season crops won’t germinate well in high temperatures. Consider these strategies:

July Seed Starting Strategies: 1. Start seeds indoors in a cool basement or air-conditioned room 2. Use shade cloth over outdoor seed beds 3. Pre-sprout seeds in the refrigerator 4. Choose heat-tolerant varieties of cool-season crops Direct Sow in July:

• Bush beans (last succession)
• Summer squash (if you have 60+ days before frost)
• Cover crops in empty beds
• Buckwheat as a quick cover crop/smother crop

AUGUST: Last Chance for Many Fall Crops

What to Start (For Zones 6 and Warmer):

• Spinach: 6-8 weeks before first frost
• Arugula: 4-6 weeks before first frost
• Mustard greens: 4-6 weeks before first frost
• Turnips: 6-8 weeks before first frost
• Radishes: 4 weeks before first frost
• Kale (if not started): 6-8 weeks before

August is your last realistic window for starting many fall crops. The days are getting shorter, but soil is still warm, which helps with germination.

Direct Sow in August:

• Peas (for fall): Choose quick-maturing varieties
• Beets: For small tender roots and greens
• Carrots: For fall/winter harvest
• Radishes: They mature so quickly, you can plant through September in many zones
• Lettuce: In shade or under shade cloth
• Cover crops: Winter rye, crimson clover, field peas

August Garden Tasks: 1. Remove spent summer crops and compost (if disease-free) 2. Plant fall crops in these cleared spaces 3. Save seeds from open-pollinated varieties 4. Take notes on what worked and what didn’t 5. Order garlic for October/November planting

SEPTEMBER: Winter Garden Preparation

What to Start (In Mild Climates Zones 7+):

• Overwintering onions: For spring harvest
• Spinach (in cold frames or greenhouses)
• Lettuce (in protected areas)
• Asian greens: For late fall/early winter harvest

September is mostly about harvesting and preserving, but in milder climates, you can still get a surprising amount of growth before true winter sets in.

Direct Sow in September:

• Cover crops: Winter rye, hairy vetch, crimson clover
• Radishes: Until 4 weeks before hard freeze
• Spinach: For overwintering with protection
• Lettuce: Cold-hardy varieties with row cover

September Garden Tasks: 1. Harvest and cure winter squash and pumpkins 2. Dig sweet potatoes before first frost 3. Plant garlic (typically late September to October) 4. Clean up and compost disease-free debris 5. Test soil and amend as needed

OCTOBER: Planting Garlic and Cleaning Up

What to Start:

• Garlic: 4-6 weeks before ground freezes
• Shallots: Same timing as garlic
• Bulb onions from seed (in very mild climates): For early spring harvest

October is garlic planting month for most regions. This crop is the complete opposite of most vegetables—you plant it in fall, it establishes roots before winter, then explodes into growth in spring.

October Garden Tasks: 1. Plant garlic cloves 4-6 inches apart, 2-3 inches deep 2. Mulch garlic heavily with straw or leaves 3. Remove all diseased plant material (don’t compost) 4. Cover empty beds with mulch or cover crops 5. Store leftover seeds properly for next year

NOVEMBER & DECEMBER: Rest, Reflect, and Plan

What to Start:

• Microgreens: Indoors for fresh greens all winter
• Sprouts: Alfalfa, mung bean, broccoli sprouts
• Herbs in pots: Parsley, chives, oregano for windowsill

These months are for garden dreaming. Browse seed catalogs, reflect on the season, and make plans for next year. Your only “planting” should be indoor microgreens and sprouts to satisfy that green thumb itch.

Winter Garden Tasks: 1. Review and update garden journal 2. Organize and inventory seeds 3. Sharpen and clean tools 4. Plan next year’s garden layout (rotate crops!) 5. Order seeds early for best selection

Quick Reference: Seed Starting Timeline Summary

Crop	Start Indoors	Weeks Before Last Frost
Artichokes	January-Feb	10-12 weeks
Onions (seed)	January-Feb	10-12 weeks
Leeks	January-Feb	10-12 weeks
Peppers	February	8-10 weeks
Eggplants	February	8-10 weeks
Broccoli	Feb-March	6-8 weeks
Cabbage	Feb-March	6-8 weeks
Tomatoes	March	6-8 weeks
Tomatillos	March	6-8 weeks
Kale	March	4-6 weeks
Lettuce	March-April	4-6 weeks
Cucumbers	April	3-4 weeks
Squash	April	3-4 weeks
Melons	April	3-4 weeks
Basil	April-May	4-6 weeks
Beans	—	—
Corn	—	—
Carrots	—	—
Beets	—	—
Peas	—	—
Spinach	—	—
Radishes	—	—
Brussels Sprouts	June	12-16 weeks before 1st frost
Fall Broccoli	June-July	10-12 weeks before 1st frost
Garlic	October	4-6 weeks before freeze

Frequently Asked Questions

What if I miss the recommended starting date?

Don’t panic! For most crops, you have a 2-3 week window of flexibility. If you start tomatoes a week or two late, they’ll just produce a bit later in the season. For very late starts, consider buying seedlings from a nursery to catch up.

Can I start seeds outdoors instead of indoors?

Many crops can be direct sown—you’ll see “Direct Sow” columns in the table above. Some crops, like tomatoes and peppers, really benefit from the head start of indoor sowing in short-season climates. In long-season areas (Zones 8+), you can direct sow almost everything.

How do I adjust this calendar for my specific zone?

The key is your last and first frost dates. Once you know those, count backward from last frost for spring plantings and backward from first frost for fall plantings. Every gardening decision flows from those dates.

Should I use this calendar exactly or adjust based on weather?

Use it as a guideline, but always watch the weather! If an unseasonably warm spring arrives, you might transplant earlier. If a late cold snap threatens, protect your plants. Gardening is part science, part art, part weather watching.

What’s the latest I can start seeds for a fall garden?

It depends on the crop and your first frost date. Quick growers like radishes and lettuce can be planted 4-6 weeks before frost. Slow growers like Brussels sprouts need 12-16 weeks. When in doubt, check “days to maturity” on your seed packet and add 2 weeks as a buffer.

Can I start seeds indoors in summer for fall planting?

Absolutely! In fact, starting cool-season crops indoors in July and August can be easier than direct sowing in hot soil. Just keep the seed starting area as cool as possible and don’t let seedlings dry out.

How accurate are frost dates?

Frost dates are averages based on historical data. There’s a 50% chance of frost after your “last” frost date. For tender crops, many gardeners wait 1-2 weeks after the official date, or watch the 10-day forecast before planting heat-lovers outside.

Your Personalized Planting Calendar Action Plan

1. Find your frost dates using your zip code 2. Mark your calendar with key dates 8 weeks, 6 weeks, and 4 weeks before last frost 3. Choose your crops for the season ahead 4. Work backward from frost dates to determine your seed starting schedule 5. Set reminders so you don’t miss important planting windows 6. Stay flexible and adjust based on weather and observations

Remember, this calendar is a guide, not gospel. Every garden is unique, and part of the joy of gardening is learning what works in your specific microclimate. Keep a garden journal, note your planting dates and results, and refine your schedule year after year.

Happy planting! May your seeds germinate quickly, your seedlings grow strong, and your harvests be bountiful.

Internal Linking Suggestions:

• Link to “Complete Guide to Starting Seeds Indoors for Beginners” for detailed seed starting techniques
• Link to “10 Easiest Vegetables to Grow from Seed” for beginner crop recommendations with timing
• Link to “Common Seed Starting Mistakes” to avoid timing errors

Related Articles:

• Succession Planting: Maximizing Your Harvest All Season
• Understanding Your USDA Hardiness Zone
• Creating a Garden Journal That Works

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