Vegetable Planting Calendar

How to use the planting calendar

1. Enter your ZIP code. The calendar uses the closest NOAA weather station with frost records, the same one the frost dates tool starts with, unless a freeze can come in any month there.
2. Choose the frost risk. The cautious setting pushes every spring date later and every fall date earlier.
3. Tick the vegetables you grow. Eight common ones are ticked to start, and Select all shows the full list of 30.
4. Read the first line of the result. It names the next job on your calendar, counted from today.
5. Scan the rows. Each vegetable gets a bar for the year and its dates in words. Copy the link to keep your list, since it saves the ZIP code, the risk, and your vegetables.

How the dates are worked out

Every date hangs on two numbers, your last spring frost and your first fall frost at 32 °F, from NOAA’s 1991–2020 normals for the nearest station. At a few cold mountain and northern stations a freeze can come in any month, and NOAA gives no dates there, so the calendar moves to the next closest station that has them and says which one it skipped.

Spring planting

Colorado State’s GardenNotes #720 sorts vegetables into four groups by how much cold they take. We use its timing for each group:

• Hardy crops, such as peas, spinach, and cabbage, go in 4 to 2 weeks before the last frost.
• Semi-hardy crops, such as beets, carrots, and potatoes, go in during the 2 weeks before it.
• Tender crops, such as snap beans, sweet corn, and cucumbers, go in from the frost date to 2 weeks after.
• Very tender crops, such as tomatoes, peppers, and melons, wait until 2 to 4 weeks after.

Colorado State says tender crops go in around the frost date, and we use the two weeks after it. Where sources put a crop in different groups, we chose the more cautious one. Lettuce is hardy to Colorado State but semi-hardy to Utah State and Purdue, so it’s semi-hardy here.

For transplants, seeds start indoors as many weeks before the outdoor window as Rutgers FS787 lists for that crop. The first harvest adds the crop’s days to harvest, counted from setting out plants for transplanted crops.

Fall planting

Virginia Cooperative Extension’s fall gardening guide counts back from the first frost. Add the days to harvest, the length of the harvest, a 14-day fall factor for slower growth in shorter and cooler days, and 14 more days for crops that frost kills. For transplants you grow yourself, add the weeks from seed to transplant. Harvest lengths come from Clemson’s HGIC 1267. Clemson doesn’t list cauliflower or Swiss chard, so those two are our estimate. Days to harvest use the short end of each published range, since late plantings call for fast varieties. Long-season crops such as winter squash, melons, and sweet potatoes get only a spring date.

A worked example

Take ZIP code 43215 in downtown Columbus, Ohio. The closest station is Columbus WCMH, 4.1 miles away, with a typical last frost around April 20 and first frost around October 24.

• Broccoli is hardy. Start seeds indoors February 2 to 9, set out plants March 23 to April 6, and expect the first heads around May 27. For a fall crop, start seeds by May 21 and set out plants by July 9.
• Leaf lettuce is semi-hardy, so sow it April 6 to 20. A fall sowing has to go in by July 28.
• Tomatoes are very tender. Start seeds March 9 to 23, set out plants May 4 to 18, and look for ripe fruit around July 8.
• Spinach for fall needs 40 days to harvest, 3 weeks of picking, and the 14-day fall factor, which is 75 days before October 24. Sow by August 10.

With the cautious setting the last frost moves to May 7, and tomatoes move to May 21 through June 4.

Planting numbers for 30 vegetables

Group sets the spring window. Indoors is the weeks from sowing seeds indoors to setting out plants. Days is the days to first harvest. Harvest is the weeks of picking from one planting, and a star marks our estimate. Numbers in the last column point to the sources listed at the end of the page.

Tips for a better season

• Check the soil, not just the date. Colorado State lists a minimum soil temperature of 60 °F for cucumbers, squash, and melons and 55 °F for snap beans. In a cold, wet spring, wait for it.
• Harden off transplants for about a week before they go out. Rutgers suggests longer outdoor sessions each day and a little less water.
• Sow some crops more than once. Utah State notes that radishes, carrots, sweet corn, and Swiss chard can be planted several times a few weeks apart for a longer harvest.
• Presprout seeds for fall sowings. Virginia Cooperative Extension says sprouting seeds indoors first can cut 2 to 5 days off the fall factor.
• Use your variety’s own days to harvest. If the packet says 75 days where the table says 65, sow 10 days earlier for fall.