Frost Dates for Herndon, VA 20170
Last spring frost April 16 · First fall frost October 21 · 188 frost-free days · USDA Zone 7b
ZIP 20170 has about 43,900 people, one of 2 ZIP codes in Herndon.
Long season: 188 frost-free days. Spring frost risk spans March 30–May 7 (38 days). Fall frost risk spans October 3–November 9 (37 days).
Frost probability for 20170
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 7 | April 16 | March 30 |
| Fall (first frost) | October 3 | October 21 | November 9 |
Dates come from NOAA 1971–2000 freeze probabilities at ROCKVILLE 1 NE (24.1 km away); the 50% date is the median year.
Which crops fit a 188-day season in Herndon
In Herndon (188 frost-free days, a long season), 30 of 56 planner crops fit outright, 25 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 12 | Apr 30–May 7 | 146 | fits: 80 days to maturity, 146 available after Apr 30. | Jun 21 |
| Pepper | Mar 5 | Apr 30–May 7 | 146 | fits: 75 days to maturity, 146 available after Apr 30. | Jun 26 |
| Lettuce | Feb 19 | Mar 19–Mar 26 | 223 | two-plantings: Plant Mar 19 and again by Aug 30; both mature before Oct 28. | Aug 30 |
| Carrots | — | Mar 26–Apr 2 | 230 | fits: 70 days to maturity, 230 available after Mar 26. | Aug 19 |
| Cucumber | Mar 26 | Apr 30–May 7 | 160 | two-plantings: Plant Apr 30 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Beans | — | Apr 23–May 7 | 174 | two-plantings: Plant Apr 23 and again by Aug 1; both mature before Oct 14. | Aug 1 |
| Peas | — | Feb 19–Apr 30 | 251 | fits: 65 days to maturity, 251 available after Feb 19. | Aug 10 |
| Zucchini | Apr 2 | Apr 30–May 7 | 160 | two-plantings: Plant Apr 30 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Onion | Jan 22 | Mar 19–Apr 2 | 223 | fits: 100 days to maturity, 223 available after Mar 19. | — |
| Spinach | — | Feb 19–Apr 9 | 265 | two-plantings: Plant Feb 19 and again by Sep 18; both mature before Nov 11. | Sep 18 |
| Kale | Feb 5 | Mar 19–Apr 2 | 237 | two-plantings: Plant Mar 19 and again by Sep 3; both mature before Nov 11. | Sep 3 |
| Broccoli | Feb 19 | Mar 19–Apr 2 | 223 | fits: 80 days to maturity, 223 available after Mar 19. | Jul 26 |
| Cabbage | Feb 19 | Mar 19–Apr 2 | 237 | fits: 70 days to maturity, 237 available after Mar 19. | Aug 19 |
| Radish | — | Feb 19–May 14 | 251 | two-plantings: Plant Feb 19 and again by Sep 19; both mature before Oct 28. | Sep 19 |
| Beets | — | Feb 19–May 14 | 251 | two-plantings: Plant Feb 19 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Potatoes | — | Apr 2–Apr 9 | 209 | fits: 90 days to maturity, 209 available after Apr 2. | — |
| Garlic | — | Oct 21 | 293 | overwinter: Plant Oct 21 to Nov 11; harvest the following summer. | Nov 11 |
| Strawberry | — | Mar 12–May 7 | 244 | perennial: A perennial: plant Mar 12; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 19 | Apr 23–Apr 30 | 160 | fits: 75 days to maturity, 160 available after Apr 23. | Jul 3 |
| Pumpkin | Apr 2 | Apr 30–Apr 30 | 153 | fits: 100 days to maturity, 153 available after Apr 30. | Jun 8 |
| Cauliflower | Mar 5 | Apr 9–Apr 23 | 202 | fits: 75 days to maturity, 202 available after Apr 9. | Jul 31 |
| Swiss Chard | Feb 19 | Apr 2–Apr 2 | 209 | two-plantings: Plant Apr 2 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Arugula | — | Feb 19–May 14 | 265 | two-plantings: Plant Feb 19 and again by Sep 18; both mature before Nov 11. | Sep 18 |
| Brussel Sprouts | Feb 19 | Mar 19–Apr 2 | 237 | fits: 100 days to maturity, 237 available after Mar 19. | Jul 20 |
| Butternut Squash | Apr 2 | Apr 30–May 7 | 153 | fits: 100 days to maturity, 153 available after Apr 30. | Jun 8 |
| Eggplant | Feb 26 | Apr 30–May 7 | 146 | fits: 70 days to maturity, 146 available after Apr 30. | Jul 1 |
| Okra | Mar 19 | Apr 23–Apr 30 | 167 | two-plantings: Plant Apr 23 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Basil | Mar 12 | May 7–May 7 | 153 | two-plantings: Plant May 7 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Cilantro | — | Mar 19–Apr 9 | 223 | two-plantings: Plant Mar 19 and again by Aug 25; both mature before Oct 28. | Aug 25 |
| Parsley | Feb 5 | Apr 23–Apr 30 | 188 | fits: 70 days to maturity, 188 available after Apr 23. | Aug 5 |
| Celery | Feb 5 | Apr 23–May 7 | 188 | fits: 120 days to maturity, 188 available after Apr 23. | Jun 16 |
| Scallions | Feb 5 | Mar 19–Apr 2 | 237 | two-plantings: Plant Mar 19 and again by Aug 29; both mature before Nov 11. | Aug 29 |
| Turnip | — | Mar 19–Apr 2 | 237 | two-plantings: Plant Mar 19 and again by Sep 8; both mature before Nov 11. | Sep 8 |
| Kohlrabi | — | Mar 5–Mar 19 | 251 | two-plantings: Plant Mar 5 and again by Sep 3; both mature before Nov 11. | Sep 3 |
| Bok Choy | Mar 19 | Apr 9–Apr 16 | 202 | two-plantings: Plant Apr 9 and again by Aug 30; both mature before Oct 28. | Aug 30 |
| Collards | Feb 5 | Mar 19–Apr 2 | 237 | two-plantings: Plant Mar 19 and again by Aug 29; both mature before Nov 11. | Aug 29 |
| Cantaloupe | Apr 2 | Apr 30–May 7 | 146 | fits: 85 days to maturity, 146 available after Apr 30. | Jun 16 |
| Chives | Jan 22 | Apr 23–Apr 30 | 202 | fits: 90 days to maturity, 202 available after Apr 23. | — |
| Dill | — | Feb 19–May 14 | 251 | two-plantings: Plant Feb 19 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Oregano | Feb 5 | Apr 23–Apr 30 | 202 | fits: 80 days to maturity, 202 available after Apr 23. | — |
| Rosemary | Jan 22 | Apr 23–Apr 30 | 188 | fits: 80 days to maturity, 188 available after Apr 23. | — |
| Sage | Feb 19 | Apr 23–Apr 30 | 202 | fits: 75 days to maturity, 202 available after Apr 23. | — |
| Thyme | Feb 5 | Apr 23–Apr 30 | 202 | fits: 90 days to maturity, 202 available after Apr 23. | — |
| Calendula | Mar 5 | Apr 2–Apr 16 | 209 | two-plantings: Plant Apr 2 and again by Aug 25; both mature before Oct 28. | Aug 25 |
| Cosmos | Mar 19 | Apr 16–Apr 30 | 174 | two-plantings: Plant Apr 16 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Lavender | Jan 22 | Apr 16–Apr 30 | 209 | fits: 90 days to maturity, 209 available after Apr 16. | — |
| Marigolds | Mar 5 | Apr 16–Apr 23 | 174 | two-plantings: Plant Apr 16 and again by Aug 4; both mature before Oct 7. | Aug 4 |
| Melons | Apr 2 | Apr 30–May 7 | 146 | fits: 85 days to maturity, 146 available after Apr 30. | Jun 16 |
| Mint | — | Apr 16–Apr 30 | 209 | fits: 90 days to maturity, 209 available after Apr 16. | — |
| Nasturtiums | Mar 19 | Apr 16–Apr 23 | 174 | two-plantings: Plant Apr 16 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Pole Beans | — | Apr 23–May 7 | 167 | fits: 65 days to maturity, 167 available after Apr 23. | Jul 20 |
| Spaghetti Squash | Apr 2 | Apr 30–May 7 | 153 | fits: 90 days to maturity, 153 available after Apr 30. | Jun 18 |
| Sunflowers | — | Apr 16–Apr 30 | 174 | fits: 70 days to maturity, 174 available after Apr 16. | Jul 15 |
| Tomatillos | Feb 19 | Apr 23–Apr 30 | 153 | fits: 75 days to maturity, 153 available after Apr 23. | Jun 26 |
| Watermelon | Apr 2 | Apr 23–Apr 30 | 153 | fits: 80 days to maturity, 153 available after Apr 23. | Jun 21 |
| Yellow Squash | Apr 2 | Apr 30–May 7 | 160 | two-plantings: Plant Apr 30 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Zinnias | Mar 19 | Apr 16–Apr 30 | 174 | two-plantings: Plant Apr 16 and again by Jul 25; both mature before Oct 7. | Jul 25 |
Month by month in Herndon
| Month | What to do |
|---|---|
| January | Start indoors: Chives (Jan 22), Lavender (Jan 22), Onion (Jan 22), Rosemary (Jan 22). |
| February | Start indoors: Celery (Feb 5), Collards (Feb 5), Kale (Feb 5), Oregano (Feb 5), Parsley (Feb 5), Scallions (Feb 5), +9 more. Direct sow from: Arugula (Feb 19), Beets (Feb 19), Dill (Feb 19), Peas (Feb 19), Radish (Feb 19), Spinach (Feb 19). |
| March | Start indoors: Calendula (Mar 5), Cauliflower (Mar 5), Marigolds (Mar 5), Pepper (Mar 5), Basil (Mar 12), Tomato (Mar 12), +7 more. Direct sow from: Kohlrabi (Mar 5), Cilantro (Mar 19), Turnip (Mar 19), Carrots (Mar 26). Transplant from: Broccoli (Mar 19), Brussel Sprouts (Mar 19), Cabbage (Mar 19), Collards (Mar 19), Kale (Mar 19), Lettuce (Mar 19), +2 more. Plant: Strawberry (Mar 12). |
| April | Start indoors: Butternut Squash (Apr 2), Cantaloupe (Apr 2), Melons (Apr 2), Pumpkin (Apr 2), Spaghetti Squash (Apr 2), Watermelon (Apr 2), +2 more. Direct sow from: Potatoes (Apr 2), Sunflowers (Apr 16), Beans (Apr 23), Pole Beans (Apr 23). Transplant from: Calendula (Apr 2), Swiss Chard (Apr 2), Bok Choy (Apr 9), Cauliflower (Apr 9), Cosmos (Apr 16), Lavender (Apr 16), +26 more. Last frost around April 16. |
| May | Transplant from: Basil (May 7). |
| June | Last sowing dates: Butternut Squash (Jun 8), Pumpkin (Jun 8), Cantaloupe (Jun 16), Celery (Jun 16), Melons (Jun 16), Spaghetti Squash (Jun 18), +4 more. |
| July | Last sowing dates: Eggplant (Jul 1), Corn (Jul 3), Sunflowers (Jul 15), Brussel Sprouts (Jul 20), Pole Beans (Jul 20), Basil (Jul 25), +9 more. |
| August | Last sowing dates: Beans (Aug 1), Marigolds (Aug 4), Parsley (Aug 5), Peas (Aug 10), Cabbage (Aug 19), Carrots (Aug 19), +9 more. |
| September | Last sowing dates: Kale (Sep 3), Kohlrabi (Sep 3), Turnip (Sep 8), Arugula (Sep 18), Spinach (Sep 18), Radish (Sep 19). |
| October | Direct sow from: Garlic (Oct 21). First frost around October 21. |
| November | Last sowing dates: Garlic (Nov 11). |
| December | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
Frequently Asked Questions
What is the last frost date for Herndon, VA (ZIP 20170)?
The median last spring frost date for Herndon, VA (ZIP code 20170) is around April 16. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before March 30; one in ten it runs past May 7.
What is the first fall frost date in Herndon, VA?
The median first fall frost date for Herndon, VA is around October 21. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around October 3 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Herndon, VA?
The frost-free growing season in Herndon is about 188 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Herndon (188 frost-free days, a long season), 30 of 56 planner crops fit outright, 25 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Herndon, VA?
Herndon, VA is in USDA hardiness zone 7b (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Herndon, VA?
Start tomatoes indoors Mar 12 and plant out Apr 30 in Herndon. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Herndon?
Two: plant Mar 19 and again by Aug 30; both mature before Oct 28.
When do I plant garlic in Herndon?
Oct 21 to Nov 11; it overwinters and is ready the following summer.
Can I get two tomato crops in Herndon?
Yes: plant out Apr 30 for a summer crop, and set out a second round of transplants by Jun 21 for a fall crop.
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