Gardening in Eastern Oregon presents unique challenges, including unpredictable spring frosts and a semi-arid climate. Successful vegetable production requires careful planning and precise timing, particularly when starting seeds indoors or sowing them directly in the garden. This guide provides essential recommendations on when to start seeds indoors, when to transplant and when to direct seed outdoors, all based on the region's average frost-free date.
How to use this schedule
- Identify your average frost-free date in column 1 (most gardeners in Eastern Oregon use May 21).
- Use column 2 to count back (or forward) from the frost-free date to determine the appropriate outdoor planting date (column 3).
- Count back further using column 4 to determine the indoor sowing date (column 5) for crops started indoors.
- For example, if your frost-free date is May 21 and you want to start alyssums indoors, sow seeds indoors by April 2.
| Plants | Frost-free date | Weeks to set out | Outdoor planting date | Weeks to grow indoors | Indoor sowing date |
|---|---|---|---|---|---|
| Alyssum | May 21 | -1 | May 14 | -6 | April 2 |
| Beets | -6 | N/A | Direct seed | ||
| Broccoli | -4 | -6 | |||
| Brussels sprouts | -4 | -6 | |||
| Cabbage | -5 | -6 | |||
| Carrots | -4 | N/A | Direct seed | ||
| Cauliflower | -2 | -6 | |||
| Kale | -5 | -6 | |||
| Leeks | -5 | -10 | |||
| Lettuce | -2 | -5 | |||
| Onions | -6 | -10 | |||
| Peas | -4 | -4 | |||
| Spinach | -5 | N/A | Direct seed | ||
| Swiss chard | -4 | N/A | Direct seed | ||
| Radishes | -6 | N/A | Direct seed | ||
| Beans | +1 | -4 | |||
| Corn | +1 | -4 | |||
| Cucumbers | +1 | -3 | |||
| Eggplant | +2 | -9 | |||
| Marigolds | +2 | -7 | |||
| Melons | +2 | -3 | |||
| Nasturtiums | +1 | -4 | |||
| Peppers | +2 | -8 | |||
| Petunias | +2 | -9 | |||
| Squash | +2 | -3 | |||
| Sunflowers | +1 | -3 | |||
| Tomatoes | 0 | -8 |
Frost-tolerant plants
Can withstand light frost (28–32°F) and even heavy frost (below 28°F in some cases).
Frost-sensitive plants
These are plants that are highly susceptible to damage or death when exposed to freezing temperatures (32°F or below) frost.
Hardening off
Before moving transplants outdoors, gradually acclimate them through a process called hardening off. Start by placing them in a sheltered, shady spot for a few hours each day, then slowly increase their time outside and exposure to sun over 7–10 days. This helps reduce transplant shock and improves their chances of thriving in the garden.
By following this seed-starting schedule, you can eliminate the guesswork from planting and give your garden the best chance to thrive in Eastern Oregon’s climate. Remember to adjust based on local microclimates and weather patterns.
Original chart format courtesy of National Gardening Association.
