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
January
Start indoors: broccoli, cabbages, cauliflower, collard greens, kale, leeks, onions, oregano, parsley, petunias, ranunculus, rosemary, snapdragons
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
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
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
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
June
Plant or sow outdoors: bermudagrass, celery, centipedegrass, cosmos, green onions, okra, peanuts, st. augustinegrass, zinnias, zoysiagrass
July
Plant for fall: brussels sprouts, peppers, potatoes, sweet corn, tomatoes
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
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
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
November
Plant for fall: crocuses, daffodils, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips
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.
Planting dates for popular crops in Rockville
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Mar 3 to 17 | Apr 28 to May 12 | Jul 24 to 31 |
| Strawberries | — | Feb 18 to Mar 4 | — |
| Lettuce | Feb 4 to 18 | Mar 25 to Apr 8 | Aug 7 to Sep 11 |
| Cilantro | Feb 18 to Mar 4 | Apr 1 to 8 | — |
| Basil | Mar 10 to 24 | Apr 28 to May 5 | — |
| Potatoes | — | Mar 31 to Apr 7 | Jul 17 to 24 |
| Garlic | — | Feb 18 to Mar 4 | Nov 6 to 20 |
| Onions | Dec 10 to Jan 21 | Mar 4 to 18 | — |
| Cucumbers | Mar 31 to Apr 14 | Apr 28 to May 12 | Aug 7 to 21 |
| Pumpkins | Mar 31 to Apr 14 | Apr 28 to May 12 | — |
| Peppers | Feb 10 to Mar 10 | Apr 28 to May 12 | Jul 17 to Aug 14 |
| Carrots | — | Mar 11 to Apr 1 | Aug 14 to Sep 4 |
| Sweet Potatoes | — | May 18 to 25 | — |
| Watermelons | Mar 24 to Apr 7 | Apr 28 to May 12 | — |
| Sweet Corn | — | Apr 1 to 15 | Jul 31 to Aug 14 |
| Green Beans | — | Apr 28 to May 12 | Aug 14 to 21 |
| Zucchini | Mar 31 to Apr 14 | Apr 28 to May 12 | Aug 14 to 28 |
| Broccoli | Jan 14 to Feb 4 | Mar 4 to 18 | Aug 21 to Sep 18 |
| Peas | — | Feb 18 to Mar 4 | Aug 14 to 28 |
| Spinach | Feb 18 to 25 | Mar 25 to Apr 8 | Aug 28 to Oct 2 |
| Sunflowers | — | Apr 1 to 22 | — |
| Zinnias | May 9 to 16 | Jun 6 to 20 | — |
| Tulips | — | — | Sep 25 to Nov 20 |
| Daffodils | — | — | Sep 25 to Nov 6 |
| Grass Seed | — | Feb 18 to Mar 4 | Sep 25 to Oct 9 |
Nearby cities
- Gaithersburg, MD zone 7b, last frost Apr 2
- Alexandria, VA zone 7b, last frost Mar 24
- Bowie, MD zone 7a, last frost Apr 10
- Frederick, MD zone 7a, last frost Apr 2
- Baltimore, MD zone 8a, last frost Mar 24
- Lancaster, PA zone 7a, last frost Apr 19
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.