Knowing when to plant squash in Oregon is the first step to a great harvest. Getting your timing right with Oregons ideal planting schedule makes all the difference between healthy vines and a disappointing season.
Oregon’s unique climate, with its coastal, valley, and high desert regions, means there’s no single perfect date. But by following a few key principles, you can confidently plant your squash seeds at the best possible time. This guide will walk you through the simple steps to success.
When to Plant Squash in Oregon – Oregons Ideal Planting Schedule
This schedule focuses on the two main types of squash: summer squash (like zucchini and yellow crookneck) and winter squash (like butternut and acorn). Both love warm soil and warm air, but their growing needs are slightly different.
Understanding Oregon’s Growing Zones
Your planting dates depend heavily on your USDA Hardiness Zone. Here’s a quick breakdown for Oregon gardeners:
- Zone 8b (Willamette Valley, Portland, Eugene): Last spring frost is typically around April 15. First fall frost is around November 15.
- Zone 9a (Southern Oregon, parts of the coast): Last frost is earlier, around March 15-30. First fall frost is later, in mid-November.
- Zone 7a (Central Oregon, high elevations): A shorter season. Last frost can be as late as May 15-30, with first fall frost in early October.
- Coastal Areas (Zone 8-9): Milder but cooler summers. You’ll need to wait a bit longer for soil warmth.
The Golden Rule: Wait for Warm Soil
The most common mistake is planting too early. Squash seeds will rot in cold, damp soil. They need soil temperatures consistently above 60°F (70°F is ideal for germination). A simple soil thermometer is a great investment.
A good visual cue is when oak leaves are the size of a squirrel’s ear. This old farmer’s saying aligns well with warming soils. Don’t rush it—patience pays off.
Spring Planting Dates by Region
These are target windows for direct sowing seeds outdoors. For starting seeds indoors, begin 3-4 weeks before your outdoor planting date.
- Willamette Valley & Portland Metro (Zone 8b): Plant from mid-May to early June. The soil is usually warm enough by Memorial Day.
- Southern Oregon (Zone 9a): You can often plant earlier, from late April through May.
- Central & Eastern Oregon (Zone 7a): Wait until late May or early June. Protect young plants from late cold snaps with row covers.
- Oregon Coast: Aim for early to mid-June to ensure the soil and air have truly warmed up.
What About Succession Planting?
For summer squash, consider planting a second crop about 6 weeks after your first. This ensures a continuous harvest if your first plants succomb to pests or slow down. Just make sure your second planting has at least 60 days before your first expected fall frost.
Step-by-Step Planting Guide
- Choose a Sunny Site: Squash needs full sun—at least 6-8 hours of direct light daily.
- Prepare the Soil: Work in lots of compost or well-rotted manure. Squash are heavy feeders and thrive in rich, well-draining soil with a pH between 6.0 and 6.8.
- Plant Seeds or Transplants:
- Seeds: Plant 1 inch deep. Sow 2-3 seeds every 3 feet for bush types, or every 4 feet for vining types. Thin to the strongest seedling.
- Transplants: Harden off seedlings for a week before planting. Disturb roots as little as possible.
- Water Well: Water deeply after planting. Keep soil consistently moist but not soggy until seeds sprout or transplants establish.
- Mulch: Once plants are a few inches tall, apply a thick layer of straw or compost mulch. This conserves moisture, suppresses weeds, and keeps soil warm.
Fall Planting Considerations
In Oregon’s longer-season valleys (Zones 8b and 9a), you can plant a second crop in early July for a fall harvest. Count back from your first fall frost date, using the “Days to Maturity” on your seed packet. Choose faster-maturing varieties for this late planting.
For winter squash, ensure you plant so they have enough time to fully mature and harden their skins before cool, wet fall weather arrives. This usually means planting by early June at the latest in most areas.
Protecting Your Young Plants
Oregon springs can be unpredictable. Have these protections ready:
- Row Covers: Use floating row covers to protect seedlings from light frosts and pesky insects like cucumber beetles. Remember to remove them when flowers appear for pollination.
- Cloches or Milk Jugs: DIY cloches from plastic milk jugs (with caps off) can create a warm mini-greenhouse for individual plants.
- Black Plastic: Laying black plastic over the soil a few weeks before planting can help warm it up faster.
Common Mistakes to Avoid
- Planting in Cold Soil: This is the number one reason for seed failure.
- Crowding Plants: Squash need space for air circulation to prevent powdery mildew, a common Oregon problem.
- Overwatering: Once established, water deeply but less frequently to encourage strong roots. Avoid wetting the leaves.
- Forgetting to Fertilize: Side-dress plants with a balanced fertilizer or compost when they begin to vine and again when flowers appear.
FAQ: Oregon Squash Planting
What is the best month to plant squash in Oregon?
For most of Oregon, May is the prime month for planting squash outdoors. In warmer southern areas, late April is possible. In cooler or coastal regions, wait until June.
Can you plant squash in July in Oregon?
Yes, but only for a fall harvest of summer squash in the Willamette Valley or Southern Oregon. Choose a fast-maturing variety and plant by early July. It’s generally too late for winter squash at that point.
How late is too late to plant squash?
Calculate based on your frost date. If the number of days from planting to your first average fall frost is less than the “Days to Maturity” on the seed packet plus about 10 days, it’s too late. The plant won’t have enough time to produce.
Should I start squash indoors or direct sow?
Both work! Starting indoors in April gives you a slight head start, especially for winter squash. But squash seedlings grow fast and don’t like root disturbance, so direct sowing in warm soil is often simpler and just as effective.
What squash varieties grow best in Oregon?
Great choices include:
- Summer: ‘Cosmos’, ‘Eight Ball’ zucchini, ‘Sunburst’ pattypan.
- Winter: ‘Buttercup’, ‘Sweet Meat’, ‘Delicata’ (good mildew resistance).
Always look for varieties with disease resistance, especially to powdery mildew.
Following Oregons ideal planting schedule for squash isn’t complicated once you know the basics. Pay attention to your local frost dates, wait for that soil to warm up, and give your plants plenty of sun and rich food. With a little planning, you’ll be harvesting baskets of squash all season long. Remember, a sucessful garden always starts with getting the timing right.