Seattle in March: what to plant
Over the last 5 years, March in Seattle has run 4.4–11.0°C with about 121 mm of rain across the month. Here is what weather like that will carry to harvest.
Everything above is a five-year average. In the game it is this — the weather Seattle is actually having, today.
Grow one in Seattle's weather right now →❄️ In 3 of the last 5 years, Seattle saw at least one night at or below 0°C in March (record low -1.9°C). Cold-sensitive crops need cover.
🗓️ This month sits inside the frost-free window. Average last spring frost around Mar 1, first autumn frost around Dec 9 — roughly 283 frost-free days. Sow tender crops after the last frost date and make sure they finish before the first.
☀️ About 6.6 h of sunshine a day this month. Within the month it warms by about 2.6°C from the first ten days to the last.
Sow this month — when would you harvest?
Assuming you sow in mid-March, then adding up the warmth Seattle usually gets, one day at a time — which is why some of these run past the end of the month.
| Crop | Days | Harvest around |
|---|---|---|
| 🌿 Rocket | 61 | May 14 |
| 🌱 Microgreens | 8 | Mar 22 |
| 🌿 Spinach | 72 | May 25 |
| 🍒 Cherry Radish | 60 | May 13 |
| 🌿 Coriander | 76 | May 29 |
| 🧄 Garlic | 93 | Jun 15 |
| ⚪ Turnip | 79 | Jun 1 |
| 🫛 Peas | 91 | Jun 13 |
| 🟣 Beetroot | 91 | Jun 13 |
| 🫘 Broad bean | 103 | Jun 25 |
| 🍃 Mint | 30 | Apr 13 |
| 🧅 Chives | 31 | Apr 14 |
🌡️ Tomato, Chili Pepper, Yardlong bean, Bitter melon, Luffa, Winter melon, Aubergine, Okra never accumulate enough heat outdoors in Seattle — not in any month. Locally these need a greenhouse or a warm windowsill.
Best crops to sow now
- 🌿 Rocket Ideal about 101 days to harvest Recent mean 7.7°C — right in the sweet spot
- 🌱 Microgreens Ideal about 8 days to harvest 🪴 Windowsill pot — sheltered from outdoor weather
- 🌿 Spinach Ideal about 118 days to harvest Recent mean 7.7°C — right in the sweet spot
- 🍒 Cherry Radish Ideal about 113 days to harvest Recent mean 7.7°C is too cold (ideal 8–25°C)
- 🌿 Coriander Good about 142 days to harvest Recent mean 7.7°C is too cold (ideal 8–24°C)
- 🧄 Garlic Good about 150 days to harvest Recent mean 7.7°C — right in the sweet spot
- ⚪ Turnip Marginal about 180 days to harvest Recent mean 7.7°C is too cold (ideal 8–24°C)
- 🫛 Peas Marginal about 191 days to harvest Recent mean 7.7°C — right in the sweet spot
- 🟣 Beetroot Marginal about 191 days to harvest Recent mean 7.7°C — right in the sweet spot
- 🫘 Broad bean Marginal about 204 days to harvest Recent mean 7.7°C — right in the sweet spot
- 🍃 Mint Ideal about 30 days to harvest 🪴 Windowsill pot — sheltered from outdoor weather
- 🧅 Chives Ideal about 32 days to harvest 🪴 Windowsill pot — sheltered from outdoor weather
Leave these for another month
- 🌶️ Okra — Recent mean 7.7°C is too cold (ideal 20–33°C)
- 🍆 Aubergine — Recent mean 7.7°C is too cold (ideal 18–32°C)
- 🍈 Winter melon — Recent mean 7.7°C is too cold (ideal 18–32°C)
Other months in Seattle
📍 Somewhere else? Look up your own city →
Temperature and rainfall come from Open-Meteo's historical observations for Seattle, averaged day by day over the last 5 years. Whether a crop finishes in time is worked out from its own starting temperature and heat requirement — those numbers are listed on each crop page if you want to check them.