Written by Jagdish Reddy | Reviewed against USDA, NOAA, University of California IPM, and University of Illinois Extension resources | Updated May 2026

Planting the right crop in the wrong week costs more than choosing the wrong crop entirely. This USDA Zone Planting Calendar for Zones 3–10 helps you match planting dates to frost windows, soil temperatures, and growing season length. A tomato started indoors on February 20 in Zone 6 is ready to transplant around May 1, right when soil reaches 65°F. The same tomato started March 20 misses three weeks of productive season. This calendar is the practical tool for getting that timing right.

Below: monthly lookup table, soil temperature chart, seed-starting dates by zone, month-by-month schedules, season extension tools, and the timing mistakes that end seasons early.

What to Plant This Month: Quick Lookup by Zone

Find your zone and current month. For full monthly detail, jump to the month-by-month section.

Zone	Spring	Summer	Fall	Winter
3–4	Peas, spinach, brassicas, onions	Beans, cucumbers, squash	Kale, radishes, garlic	Planning, seed orders
5–6	Tomatoes, peppers, peas, lettuce	Beans, squash, succession sowing	Broccoli, cabbage, spinach, garlic	Cold-frame greens
7–8	Tomatoes, peppers, beans, cucumbers	Okra, sweet potatoes, succession crops	Fall tomatoes, brassicas, root crops	Greens under protection
9–10	Cool-season greens, tomatoes	Shade cloth, okra, Southern peas	Main fall garden season	Peak cool-season harvests

Want a faster way to check what to plant right now in your zone? Use the interactive planting calendar below to match crops with your local growing season.

USDA Hardiness Zones: What the Numbers Actually Mean

The USDA Agricultural Research Service divides the country into hardiness zones based on the average annual minimum winter temperature over a 30-year period. Each zone spans 10 degrees Fahrenheit. Zone 3 winters drop to -40°F. Zone 10 rarely falls below 30°F.

For vegetable gardening, zones are shorthand for growing season length and frost date range. Sub-zones matter more than the main number: Zone 5a and 5b differ by 5 degrees, shifting the last frost date 7 to 14 days and determining whether an 80-day tomato ripens before fall.

Why Frost Dates Matter More Than Your Zone Number

Two Zone 6 gardeners can have last frost dates three weeks apart based on elevation and proximity to water. Same zone, very different timing.

Last spring frost date = when warm-season planting windows open. First fall frost date = when they close. Every timing decision runs from one of those two numbers.

USDA Zone	Avg Last Spring Frost	Avg First Fall Frost	Frost-Free Days
Zone 3	May 15 – June 1	Sept 1-15	90-110
Zone 4	May 1-15	Sept 15 – Oct 1	110-130
Zone 5	April 15 – May 1	Oct 1-15	130-150
Zone 6	April 1-15	Oct 15 – Nov 1	150-170
Zone 7	March 15 – April 1	Nov 1-15	170-190
Zone 8	Feb 15 – March 15	Nov 15 – Dec 1	190-210
Zone 9	Jan 15 – Feb 15	Dec 1 – Jan 1	240-300
Zone 10	Frost-rare	Frost-rare	330-365

These are historical averages. Keep floating row cover within reach for at least two weeks past your average last frost date in spring.

Not sure when your last spring frost or first fall frost usually happens? Use the frost date calculator below to find your local planting windows more accurately.

Soil Temperature Minimums by Crop

A tomato in 50°F soil turns purple from phosphorus lockout and stalls while a plant put in later into 65°F soil passes it by July. Soil temperature controls germination, not air temperature. A soil thermometer pushed 2 inches deep at 9 AM costs under ten dollars and removes the guesswork.

Crop	Min Soil Temp (°F)	Optimal Range (°F)	Practical Note
Spinach	35	45-65	Germinates in near-freezing soil; bolts fast above 75°F air
Peas	40	55-65	Germinate cold; stop producing above 80°F air
Lettuce	40	60-65	Germination fails above 75°F soil
Brassicas (transplants)	45	65-75	Transplants handle frost; seeds need warmer soil
Carrots	45	60-70	Slow to germinate below 50°F; soil crust blocks emergence
Beets	45	60-75	Water after sowing to prevent germination-blocking soil crust
Beans	60	70-80	Rot in cold wet soil; 60°F is a hard minimum, not a suggestion
Cucumbers	60	70-80	Growth stalls visibly under 65°F even after germination
Squash / Zucchini	60	70-85	Same cold sensitivity as beans
Corn	60	65-85	Cold soil causes patchy germination; replanting is a loss
Tomatoes	60	65-80	Black plastic mulch pre-warms soil 4-8°F faster
Peppers	65	70-85	Slowest to recover from cold soil shock
Melons	70	75-85	Cold soil stunt at this stage is often permanent
Sweet Potatoes	65	75-85	Slips rot in cold wet soil
Basil	60	65-80	Turns black in soil below 50°F

Raised beds warm faster and drain better than in-ground soil, extending the planting season in cold zones by 2 to 4 weeks.

Raised Bed vs In-Ground Planting: Timing Differences

Factor	Raised Beds	In-Ground Beds
Spring soil warm-up	2-4 weeks earlier	Slower, especially in clay
Fall season extension	Drains faster, less frost pooling	Cold air settles in low spots
Soil temp control	Easier with black plastic or mulch	Harder to modify quickly
Watering	Dries out faster; monitor closely	Retains moisture longer
First planting date	Earlier by 1-3 weeks in Zones 3-6	Follow frost dates closely
Fall frost risk	Lower in raised position	Higher in low ground or depressions
Best for	Short-season zones, heavy clay soils	Crops that need consistent moisture

Proper spacing matters more than most beginners expect, especially in raised beds where overcrowding reduces airflow and increases disease pressure. You can estimate spacing needs with our Plant Spacing Calculator.

Raised beds dry and warm faster, but they also need consistent organic matter replenishment each season. Our Compost Calculator helps estimate how much compost to add before planting.

Exact Seed Starting Dates by Zone

Count backward from your last frost date. Zone 5 (May 1 last frost) starting tomatoes 7 weeks back: begin February 11. Zone 7 (March 25 last frost) starting peppers 9 weeks back: begin January 21.

Crop	Weeks Before Last Frost	Zone 3-4	Zone 5-6	Zone 7-8
Onions / Leeks	10-12 wks	Late Jan	Late Jan	Early Jan
Peppers	8-10 wks	Early Feb	Mid Feb	Late Jan
Eggplant	8-10 wks	Early Feb	Mid Feb	Late Jan
Tomatoes (spring)	6-8 wks	Mid Feb	Late Feb	Mid Feb
Tomatoes (fall, Z8+)	6-8 wks	n/a	n/a	Early-Mid July
Celery	10-12 wks	Late Feb	Early Feb	Early Feb
Broccoli / Cabbage (spring)	4-6 wks	Late Mar	Early Mar	Jan-Feb
Broccoli / Cabbage (fall)	4-6 wks	Mid July	Late June	Late June
Basil	4-6 wks	Late Apr	Early Apr	Mid Mar
Squash / Cukes	2-3 wks MAX	Early May	Late Apr	Mar-Apr
Flowers (petunias, impatiens)	10-12 wks	Early Feb	Late Jan	Early Jan

Grow lights should sit 2 to 3 inches above seedling tops. Stretching seedlings need more intensity, not more hours. A heat mat under trays speeds pepper and tomato germination by 3 to 5 days.

For crop-specific indoor timing, our Seed Starting Schedule by Frost Date breaks down when to start vegetables based on your local last frost window.

How to Harden Off Seedlings Without Losing Them

Seedlings raised under lights have never experienced direct UV or wind. Moving them straight outside causes sunscald or collapse within 24 hours.

1. Days 1-3: Full shade, 1 to 3 hours outside. Back inside each night.
2. Days 4-6: Morning sun, 3 to 5 hours. Watch for wilting.
3. Days 7-9: Half to full day outside including afternoon sun.
4. Day 10+: Leave outside permanently. Transplant on an overcast day or in late afternoon.

A cold frame with the lid cracked open handles this automatically, no daily carry-in needed.

If you are new to indoor propagation, our Seed Starting Indoors guide covers grow lights, heat mats, watering, and seedling care in more detail.

Month-by-Month Vegetable Planting Guide

Adjust all timing 1 to 2 weeks based on your local last frost date.

What to Plant in January: Cold Zones Plan, Warm Zones Produce

In Zone 9, January is a peak planting month. Carrots sown now harvest in March before heat arrives. Brassicas, beets, peas, and root vegetables go directly in the ground.

Zone 8: kale, spinach, and mustard greens grow outside. Broccoli and cabbage transplants go in the ground. Use low tunnels below 25°F.

Zone 7 cold frames keep spinach and mache producing through January. Growth slows but does not stop.

Zones 3-6: Start onions and leeks under lights in late January. They need 10 to 12 weeks before transplanting. Miss this window and the harvest shows it.

What to Plant in February: Seed Starting Peaks for Cold Zones

Peppers and eggplant need 8 to 10 weeks indoors before transplanting. A Zone 5 gardener with May 1 as last frost who starts peppers February 15 has plants ready May 10. Start them February 28 and they go out into summer heat without ever fully establishing. That gap shows in harvest volume by September.

Zone 6 tomatoes started February 20 transplant around May 1 when hardened off properly. Cold frames allow direct sowing of spinach in late February when soil hits 35°F.

In Zone 7 and 8, brassica transplants go outside in February. Peas and carrots go directly in the ground. Tomato seed starting begins in Zone 7 by mid-February.

Zone 9-10: Zone 10 sets tomato transplants outside by mid-February. Zone 9 starts warm-season crops indoors for March.

What to Plant in March Before Spring Fully Arrives

Zones 3-4: Nothing outside. Brassicas, celery, and leeks start under lights. Last frost in Zone 3 is still 10 to 12 weeks away.

Zones 5 and 6 get their first outdoor planting. Peas, spinach, kale, arugula, and radishes go in as soon as soil is workable, even with frost still possible. A March 25 pea sowing in Zone 5 gives full pod production in June. Squash and cucumbers start indoors in late March in Zone 6 for a late April or May transplant.

Zone 7 and 8 are in full spring mode. All cool-season transplants go outside. Carrots, beets, and turnips go directly in the ground. Zone 7 tomatoes start indoors in early March.

Zones 9-10 transition to warm crops. Beans and squash direct sow in Zone 10 by late March.

April Warm-Season Window Opens Across Most Zones

Zones 3-4: Kale, peas, spinach, and radishes go outside mid to late April. A late-April frost in Zone 4 is normal. Keep row cover nearby.

Zones 5-6: Full cool-season outdoor production. Warm-season crops start indoors in early April for mid-May transplanting.

Zone 7: Tomatoes and peppers go outside by late April. Succession beans start around April 20, every 3 weeks through July.

Zones 8 through 10 shift to heat management. Okra, sweet potatoes, and Southern peas replace finishing cool-season crops. Shade cloth goes up over remaining greens in Zone 9 and 10 once daytime temperatures hold above 90°F.

May Warm-Season Planting Window by Zone

In Zones 3 and 4, last frost arrives around May 10 to 15. Soil temperature, not the date, is the go signal. A tomato set into 52°F soil on May 12 sulks for two weeks and gets outpaced by one planted May 25 into 65°F ground. Watching the soil thermometer saves more plants than watching the calendar.

Zones 5-6: Beans, corn, cucumbers, squash, and sweet potatoes go out as soil warms. Zone 6 beans typically go in around May 5 to 10 when soil reads 62°F.

Zones 7-8: Succession is the focus. Fall brassica seeds start indoors in late May in Zone 7.

Zones 9 and 10 mulch heavily against heat. Okra and sweet potatoes are the reliable summer workhorses. Tomatoes and peppers need shade cloth once temperatures stay above 100°F for consecutive days.

June: Set Up the Fall Garden Before Summer Peaks

Zones 3-4: Second sowing of beans and cucumbers in early June. Varieties under 60 days finish before September frost in Zone 4.

Zones 5-7: Start fall brassicas indoors. Broccoli started June 25 in Zone 6 transplants in August and harvests in October.

Zones 8 through 10: minimal new planting. Squash vine borers attack in June across the South. Check stems weekly for entry holes with sawdust-like frass. Catch them early or lose the plant.

Mulch becomes essential once summer heat arrives, especially in Zones 8 through 10 where exposed soil loses moisture rapidly. Use our Mulch Calculator to estimate coverage before planting.

July: Fall Garden Setup Month for Most Zones

Zones 3 through 5: Start fall broccoli, cabbage, and cauliflower indoors around July 10 to 15. These transplant outside in August and harvest in September and October. This is one of the most important and most missed seed-starting windows of the year.

Zones 6-7: Transplant fall brassica starts. Final bean sowing in Zone 6 by July 10.

Zone 8: Order fall crop seeds now. The fall garden here often outperforms spring, but setup starts in July.

Zone 10: Start tomatoes, peppers, and eggplant indoors in late July for September transplanting.

August: The Second Growing Season Begins

Zones 3 and 4: Sow turnips, radishes, and spinach in early August. A 50-day turnip sown August 5 in Zone 4 harvests September 24, about one week before average first frost. A 70-day variety sown the same day does not finish. Always check maturity days against your frost date before sowing in August.

Zones 5-6: Transplant fall broccoli, cabbage, and cauliflower. Direct sow kale, beets, carrots, and arugula.

Zone 8: August is the most important planting month for the fall garden here. Tomato and pepper transplants going in now produce from October through December. Fall-planted tomatoes in Zone 8 skip flea beetle pressure and ripen in cooler weather than spring crops. The yields are often better.

Zones 9-10: All brassicas and root vegetables go in the ground. Zone 9 tomatoes transplanted by late August produce through November.

September Planting Schedule: Fall Production Begins

Zones 3-5: Harvest focus. Zone 5 garlic goes in late September. Row cover goes on at first frost warning.

Zones 6 and 7 are in active fall planting. Spinach, arugula, kale, and radishes go directly in the ground now. Kale sown in Zone 7 in September produces through December without protection. September arugula in Zone 6 is often better than April arugula because it never gets warm enough to bolt.

Zones 8-9: Full second-season planting. Zone 9 tomatoes transplanted by September 15 produce through November.

Zone 10: September is the start of the main growing season. Broccoli, cauliflower, carrots, beets, peas, lettuce, and spinach planted now harvest through February.

October Planting Schedule: Garlic Month and Bulb Season

Garlic goes in the ground across Zones 3-8, 4 to 6 weeks before soil freezes. Two inches deep, 6 inches apart, pointed end up. Hardneck for Zones 3-6, softneck for Zone 7 and warmer. Mulch with 4 inches of straw.

Spring-flowering bulbs including tulips, alliums, and daffodils go in Zones 3 through 7. Zone 8 and warmer: refrigerate bulbs 6 to 8 weeks before planting in December or January.

Zones 9 and 10 run full cool-season planting. Onion sets, all brassicas, root vegetables, and peas go in the ground. Cilantro, parsley, and dill planted in October in Zone 9 produce through spring.

November Planting Schedule: Cold Frames Earn Their Keep

Zones 3-6: Cold frames keep spinach, kale, and mache alive into December. A cold frame on a 30°F day can read 55°F inside. Open the lid above 35°F.

Zones 7-8: Low tunnels and row cover carry greens through November. Order next season’s seeds before popular varieties disappear in January.

Zones 9 and 10: Peak fall production. Broccoli, carrots, lettuce, and peas in November in these zones often outperform any spring harvest. No pest pressure, no bolting, no irrigation stress.

December: Winter Harvests in Warm Zones, Seed Planning Everywhere Else

Zones 3-6: Order seeds and review this season while memory is fresh. Check cold storage and remove any rotting root vegetables.

Zones 7-8: Cold frames carry spinach and kale through December. Garlic from October is dormant, waiting for February.

Zone 9: Direct sow carrots, beets, and turnips. Protect tender crops on nights below 28°F.

Zone 10: Beans, squash, corn, and cucumbers go directly in the ground for winter and spring harvest. Cool-season crops are at peak production.

When to Direct Sow vs Start Indoors

Direct sow crops that resent root disturbance: beans, peas, corn, carrots, beets, radishes, turnips, and parsnips. Germination in place produces better root structure and yield than even careful transplanting.

Start indoors: tomatoes, peppers, eggplant, onions, leeks, celery, and basil. These need a head start that outdoor direct sowing cannot provide in most zones.

Squash, cucumbers, and melons can go either way. If starting indoors, cap the time at 2 to 3 weeks. A 5-week squash transplant is rootbound before it hits the ground.

How Late Is Too Late to Plant?

Take the days-to-maturity number from the seed packet. Add 14 days for transplant establishment. Compare to the frost-free days remaining in your season. If the total exceeds what is left, pick a faster variety.

Real example: First fall frost in Zone 6 is October 20. A 75-day tomato transplanted August 1 needs 75 plus 14 days, finishing around October 24. Past the average frost date by 4 days, but most Zone 6 seasons run a bit longer. A 65-day variety transplanted the same day finishes October 5 with two weeks of buffer.

Fast crops with no timing risk: radishes (25 days), arugula (30 days), spinach (40 days), lettuce (45 days), and turnips (50 days) can be sown well into fall because they finish quickly and handle frost.

Adjusting the Planting Schedule for Unusual Weather

Published frost dates are 30-year averages. Any given year can run 2 to 3 weeks early or late. These are the most common deviations and what to do about them.

• Late spring frost: If a frost event is forecast after your average last frost date, cover warm-season transplants that are already in the ground with floating row cover overnight. Do not pull plants. A single late frost on an established tomato covered with row cover causes no lasting damage.
• Early spring heat wave: Resist planting warm-season crops during a warm spell in early April in Zone 6. Soil temperature likely has not caught up to air temperature yet. Check soil at 2 inches before transplanting. One warm week does not change soil temperature reliably.
• Wet, cold spring: Soil stays cold and saturated longer than the calendar suggests. This is the Pacific Northwest pattern every year and a common problem in the Midwest after heavy spring rain. Delay warm-season planting and use raised beds to drain faster.
• Early fall cold snap: Cover warm-season crops if a frost comes earlier than expected. One early frost in September in Zone 6 does not end the season. The next two weeks may be frost-free and productive. Row cover buys that time.
• Extended fall warmth: Take advantage but do not be fooled. Zone 5 sometimes runs frost-free into October. Keep a fall succession planting of spinach and radishes ready to fill beds. But do not use the warm spell to transplant frost-sensitive crops.

Season Extension Tools and What They Actually Do

Floating row cover (frost cloth) adds 4 to 8 degrees of frost protection per layer. One layer protects to 28°F. Two layers push that to near 24°F. Spring use allows 2 to 3 weeks earlier outdoor planting. Fall use carries warm-season crops through the first several frost events.

Cold frames extend planting dates 3 to 4 weeks in each direction. A cold frame built from old window sashes on a raised bed costs nearly nothing. Zone 6 cold frame spinach and kale produce through January.

Black plastic mulch laid 2 to 3 weeks before transplanting warms soil 4 to 8 degrees faster than bare ground. For warm-season crops in Zones 3 through 5, this is the most practical tool for early planting.

Low tunnels, PVC hoops covered with row cover or clear plastic, combine cold frame and row cover benefits across any bed size. Easier to vent and close than cold frames for day-to-day management.

Regional Adjustments for Real Growing Conditions

• Pacific Northwest (Zones 7-9, west of Cascades): Wet cold springs delay soil warming 3 to 6 weeks past what the calendar implies. Many PNW gardeners transplant tomatoes in late June because soil in western Washington and Oregon does not hit 65°F in May. Use a soil thermometer, not the calendar.
• Desert Southwest (Zones 9-10, Arizona, New Mexico, Inland California): Two distinct growing seasons with a dead stop in summer above 110°F. Plant cool-season crops October through February, warm-season crops February through April and again August through October.
• Southeast high humidity (Zones 7-9): Tomato blight, powdery mildew, and downy mildew move faster here than anywhere else. Use disease-resistant cultivars. Wide spacing and morning watering reduce fungal disease pressure significantly.
• High-altitude gardens (any zone): Every 1,000 feet of elevation adds roughly 3 to 5 degrees of cold exposure. A Zone 6 designation at 6,000 feet in Colorado behaves closer to Zone 4. Favor short-season varieties, cold frames, and determinate tomatoes.

Seed Viability and Storage Guide

Not every seed in your collection is worth planting. Old seed with low germination rates wastes bed space and time. Use this as a reference when clearing out stored seeds each winter.

Crop	Avg Storage Life	Quick Viability Test
Onions / Leeks	1-2 years	Test before ordering; replace annually if uncertain
Parsnips	1-2 years	Buy fresh every year; germination drops sharply
Peppers	2-3 years	Viable longer in cool dry storage
Corn	2-3 years	Germination drops fast; buy fresh every 2 years
Beans / Peas	3-4 years	Store well in cool dry conditions
Tomatoes	4-5 years	One of the longest-lived vegetable seeds
Brassicas (all)	4-5 years	Cabbage, broccoli, kale hold well
Lettuce	4-5 years	Germinates poorly if stored in heat or humidity
Cucumbers	5-6 years	Stores very well; often outlasts the packet date
Squash / Zucchini	5-6 years	Can be viable at 6+ years in ideal storage
Radishes	5-6 years	One of the easiest to store long-term
Carrots / Beets	3-4 years	Decline faster than most gardeners expect

Store seeds in a sealed container with a desiccant pack in a cool, dark, dry location. A glass jar with a lid in a refrigerator extends viability by 50 to 100 percent over room-temperature storage. Do a germination test on older seeds: place 10 seeds on a damp paper towel, seal in a bag for 7 to 10 days, and count how many sprout. Under 6 out of 10 means replace the seed.

Succession Planting Schedule by Crop

Crop	Sow Interval	Sowing Window	Zones
Lettuce	Every 2-3 weeks	Mar-May, Aug-Oct	3-9
Radishes	Every 2 weeks	Mar-May, Aug-Oct	All
Cilantro	Every 2-3 weeks	Mar-May, Sept-Oct	All
Bush beans	Every 3 weeks	May-July	3-9
Cucumbers	Every 3 weeks	May-June	5-9
Spinach	Every 2-3 weeks	Mar-May, Aug-Oct	3-9
Beets	Every 3-4 weeks	Apr-June, Aug-Sept	All
Arugula	Every 2-3 weeks	Mar-May, Aug-Oct	All

First-Year Gardener Strategy by Zone

Pick 3 to 4 crops in year one. Fill gaps with radishes. Learn what healthy germination looks like in your soil before managing 12 different crop timelines.

Zone	Best First Crops	What You Learn
3-4	Kale, peas, radishes	Frost tolerance, direct sowing, fast feedback
5-6	Tomatoes, beans, zucchini	Transplanting, warm-season timing, high yield
7-8	Cucumbers, peppers, kale	Long season, succession planting, indoor timing
9-10	Fall lettuce, beans, herbs	Fall garden setup, heat avoidance, cool-season timing

Radishes are the best beginner crop in any zone. They germinate in 3 to 5 days, harvest in 25 to 30 days, and make visible whatever is wrong with your germination setup before you invest in slower, more expensive crops.

Once you know your planting windows, use the garden planner below to map out crop spacing, succession planting, and seasonal bed layouts for your zone.

Pollinator Flowers and Companion Planting Timing

Pollinators do not show up on demand. Cucumbers, squash, melons, and beans all need insect pollination, and poor pollinator timing is why many gardeners get flowers but no fruit. The fix is planting pollinator-attracting flowers before or alongside the crops that need them.

Flower	Start Method	Best Planting Time	Pollinator Benefit
Marigolds	Direct sow or transplant	Same time as tomatoes/peppers	Repels aphids; attracts beneficial insects
Borage	Direct sow	2 weeks before cucumbers/squash	Strong bee attractor; improves nearby yield
Zinnias	Direct sow	After last frost, full sun	Attracts butterflies and native bees all season
Calendula	Direct sow	4 weeks before last frost	Early-season pollinator; deters whitefly
Nasturtiums	Direct sow	After last frost	Trap crop for aphids; edible; attracts hoverflies
Sweet alyssum	Direct sow or transplant	With brassicas and lettuce	Draws parasitic wasps that control caterpillars
Sunflowers	Direct sow	After last frost, north of garden	Late-season pollen source; shelters beneficial insects

A practical companion planting pairing worth knowing: basil planted near tomatoes does not measurably affect yield, but it does well in the same soil and watering conditions, making it a convenient use of space. Borage near squash and cucumbers, on the other hand, has a documented positive effect on bee visitation frequency and fruit set. Plant it 2 weeks before cucumbers go in so it is already flowering when the cucumbers need pollination.

Planting Mistakes That Cost a Full Season

• Planting warm-season crops in cold soil. Beans in 55°F soil rot or stall. The same seed two weeks later in 65°F soil germinates in 5 days and outproduces the early batch by late July.
• Starting squash too far in advance. A 6-week squash transplant is already rootbound when it goes in the ground. Three weeks maximum indoors. It catches up within 10 days of transplanting at that size.
• Missing the cool-season heat cutoff. Spinach and lettuce do not slowly fade. They bolt and turn inedible within a week above 80°F. April-planted spinach in Zone 7 has maybe a 3-week harvest window. Plant it in March or plan fall planting.
• Skipping hardening off. Seedlings moved directly from indoor grow lights to full sun collapse from sunscald within 24 to 48 hours. Ten days of gradual outdoor exposure prevents total transplant loss.
• Leaving beds empty after harvest. Empty beds compact, lose organic matter, and fill with weeds in two weeks. Put in a cover crop or fast succession sowing immediately.
• Overhead watering in the evening. Wet foliage overnight in warm weather is how early blight, powdery mildew, and gray mold start. Water at the base in the morning.

If seedlings yellow, wilt, or stall after transplanting, use our Plant Problem Finder to identify common nutrient, watering, pest, and disease issues.

Common USDA Planting Calendar Questions

What is the best month to start a vegetable garden?

Zones 3-5: April or May after last frost. Zones 7-8: February for cool-season crops, April for warm-season. Zones 9-10: September through November is the most productive window of the year.

What vegetables grow best in Zone 3 and Zone 4?

Kale, spinach, peas, radishes, beets, carrots, potatoes, and short-season tomatoes under 70 days. Bush beans and cucumbers work with proper timing. Choose varieties labeled early or short-season and avoid anything needing more than 75 frost-free days without a cold frame or row cover.

How do I find my USDA zone and frost dates?

Enter your ZIP code at planthardiness.ars.usda.gov for your zone. For frost dates, your county Cooperative Extension office publishes local historical averages that are more accurate than national zone maps. NOAA climate normals are another reliable source.

Can you grow vegetables year-round in Zones 9 and 10?

Yes, by rotating crop families seasonally. Summer is for okra, sweet potatoes, and Southern peas. Fall through spring is for brassicas, leafy greens, carrots, and peas. Zone 8 comes close to year-round with cold frames in winter and shade cloth in summer.

How late can I plant tomatoes and still get a harvest?

Count tomato maturity days plus two extra weeks for transplant establishment, then compare that to your remaining frost-free season. In Zone 6, a 65-day tomato transplanted August 1 usually harvests before early October frost.

How to Build Your Own Planting Schedule Using Frost Dates

Step 1: Get your actual last spring frost and first fall frost dates from your county Extension office or NOAA, not the zone map.

Step 2: Count backward from last frost using the seed-starting table above.

Step 3: Mark outdoor transplant windows. Cool-season crops go out 4 to 6 weeks before last spring frost and 8 to 10 weeks before first fall frost.

Step 4: Set succession planting dates using the succession table.

Step 5: Revisit after the first season. Note what worked. Zone averages are starting points.

Reference Sources

• USDA Agricultural Research Service (USDA Plant Hardiness Zone Map)
• NOAA Climate Normals
• University of California IPM
• University of Illinois Extension
• Cooperative Extension System Resources