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Rockville, Maryland planting calendar and frost dates

Rockville is in USDA hardiness zone 7b. The last spring frost typically comes around April 1 and the first fall frost around November 6, giving about 219 frost-free days a year.

Hardiness zone
Zone 7b
Typical last frost
April 1
Typical first frost
November 6
Frost-free season
219 days

Frost dates in Rockville

Last spring frost

  • March 19Risky: frost later than this in 9 years out of 10
  • April 1Typical: a later frost in half of years
  • April 15Safe: a later frost only 1 year in 10

First fall frost

  • October 24Risky: frost earlier than this 1 year in 10
  • November 6Typical: an earlier frost in half of years
  • November 21Late: frost before this in 9 years out of 10

The growing season between the typical last and first frosts is about 219 days. Frost here means a low of 32°F at the weather station. A hard freeze (28°F), which damages most hardy crops too, typically ends around March 22 and returns around November 19.

NOAA U.S. Climate Normals 1991-2020 for Rockville 1 Ne, 1.9 miles ENE of the city center. Low-lying and rural spots often frost later in spring and earlier in fall than airports and city centers.

What to plant each month in Rockville

  1. January

    Start indoors: broccoli, cabbages, cauliflower, collard greens, kale, leeks, onions, oregano, parsley, petunias, ranunculus, rosemary, snapdragons

  2. February

    Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, celery, chives, cilantro, collard greens, eggplants, ginger, leeks, lettuce, marigolds, nasturtiums, oregano, parsley, peppers, petunias, ranunculus, rosemary, sage, snapdragons, spinach, swiss chard

    Plant or sow outdoors: black-eyed susans, blueberries, garlic, grapes, grass seed, hollyhocks, kale, onions, peas, poppies, raspberries, rhubarb, strawberries, turnips, wildflowers

  3. March

    Start indoors: basil, cantaloupes, celery, cilantro, cucumbers, eggplants, marigolds, nasturtiums, peppers, pumpkins, ranunculus, tomatoes, watermelons, winter squash, zucchini

    Plant or sow outdoors: asparagus, beets, black-eyed susans, blackberries, blueberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, dahlias, dill, figs, garlic, gladioli, grapes, grass seed, green onions, hollyhocks, kale, leeks, lettuce, onions, parsley, peas, poppies, potatoes, radishes, ranunculus, raspberries, rhubarb, roses, snapdragons, spinach, strawberries, swiss chard, turnips, wildflowers

  4. April

    Start indoors: cantaloupes, cosmos, cucumbers, okra, pumpkins, watermelons, winter squash, zucchini

    Plant or sow outdoors: asparagus, basil, beets, cantaloupes, carrots, chives, cilantro, cucumbers, dahlias, dill, eggplants, figs, garden mums, ginger, gladioli, grapes, green beans, green onions, kentucky bluegrass, lavenders, leeks, lettuce, lilies, marigolds, mints, nasturtiums, oregano, parsley, peppers, perennial ryegrass, petunias, potatoes, pumpkins, ranunculus, rosemary, roses, sage, snapdragons, spinach, sunflowers, sweet corn, sweet peas, swiss chard, tall fescue, thyme, tomatoes, watermelons, winter squash, zucchini

  5. May

    Start indoors: zinnias

    Plant or sow outdoors: asparagus, basil, bermudagrass, cantaloupes, celery, centipedegrass, cosmos, cucumbers, eggplants, green beans, green onions, okra, peanuts, peppers, pumpkins, st. augustinegrass, sweet potatoes, tomatoes, watermelons, winter squash, zoysiagrass, zucchini

  6. June

    Plant or sow outdoors: bermudagrass, celery, centipedegrass, cosmos, green onions, okra, peanuts, st. augustinegrass, zinnias, zoysiagrass

  7. July

    Plant for fall: brussels sprouts, peppers, potatoes, sweet corn, tomatoes

  8. August

    Plant for fall: bearded irises, beets, broccoli, brussels sprouts, cabbages, carrots, cauliflower, collard greens, cucumbers, green beans, lettuce, peas, peppers, radishes, snapdragons, spinach, sweet corn, swiss chard, turnips, zucchini

  9. September

    Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, carrots, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hydrangeas, kale, kentucky bluegrass, lettuce, lilies, ornamental alliums, peonies, perennial ryegrass, radishes, roses, saffron, snapdragons, spinach, swiss chard, tall fescue, tulips, turnips

  10. October

    Plant for fall: cabbages, cauliflower, crocuses, daffodils, daylilies, grass seed, hostas, hyacinths, kale, kentucky bluegrass, lilies, ornamental alliums, peonies, perennial ryegrass, radishes, saffron, spinach, tall fescue, tulips

  11. November

    Plant for fall: crocuses, daffodils, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips

  12. December

    Start indoors: onions

Frost dates and zones by ZIP code in Rockville

Rockville's 4 main ZIP codes take their frost dates from 2 different NOAA stations: the typical last frost ranges from April 1 in 20850 to April 15 in 20854. Every one of them is in zone 7b.

ZIP codeZoneWeather stationTypical last frostTypical first frost
208507bRockville 1 Ne, 1.9 mi ENEApr 1Nov 6
208517bRockville 1 Ne, 2.2 mi NWApr 1Nov 6
208527bRockville 1 Ne, 3.7 mi NNWApr 1Nov 6
208547bWashington Dc Dulles Airport, 14.5 mi WSWApr 15Oct 24

Planting dates for popular crops in Rockville

PlantStart indoorsPlant or sow outdoorsFall planting
TomatoesMar 3 to 17Apr 28 to May 12Jul 24 to 31
Strawberries—Feb 18 to Mar 4—
LettuceFeb 4 to 18Mar 25 to Apr 8Aug 7 to Sep 11
CilantroFeb 18 to Mar 4Apr 1 to 8—
BasilMar 10 to 24Apr 28 to May 5—
Potatoes—Mar 31 to Apr 7Jul 17 to 24
Garlic—Feb 18 to Mar 4Nov 6 to 20
OnionsDec 10 to Jan 21Mar 4 to 18—
CucumbersMar 31 to Apr 14Apr 28 to May 12Aug 7 to 21
PumpkinsMar 31 to Apr 14Apr 28 to May 12—
PeppersFeb 10 to Mar 10Apr 28 to May 12Jul 17 to Aug 14
Carrots—Mar 11 to Apr 1Aug 14 to Sep 4
Sweet Potatoes—May 18 to 25—
WatermelonsMar 24 to Apr 7Apr 28 to May 12—
Sweet Corn—Apr 1 to 15Jul 31 to Aug 14
Green Beans—Apr 28 to May 12Aug 14 to 21
ZucchiniMar 31 to Apr 14Apr 28 to May 12Aug 14 to 28
BroccoliJan 14 to Feb 4Mar 4 to 18Aug 21 to Sep 18
Peas—Feb 18 to Mar 4Aug 14 to 28
SpinachFeb 18 to 25Mar 25 to Apr 8Aug 28 to Oct 2
Sunflowers—Apr 1 to 22—
ZinniasMay 9 to 16Jun 6 to 20—
Tulips——Sep 25 to Nov 20
Daffodils——Sep 25 to Nov 6
Grass Seed—Feb 18 to Mar 4Sep 25 to Oct 9

Nearby cities

Planting in MarylandAbout zone 7bPrintable calendar for Rockville

Questions

When is the last frost in Rockville?

Around April 1 in a typical year, based on NOAA's 1991-2020 records for Rockville 1 Ne. There is still a 1 in 10 chance of frost after April 15.

What planting zone is Rockville in?

USDA hardiness zone 7b (2023 map). The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.

When should I plant tomatoes in Rockville?

Start seeds indoors March 3 to 17 and set plants out April 28 to May 12.

When is the first frost in Rockville?

Around November 6 in a typical year, and before October 24 about 1 year in 10.