🍃When to Plant Spinach in USDA Zone 10a (2026 Guide)
Very cold-hardy. One of the first things you can sow in spring. Here is the cool-season planting schedule for spinach in zone 10a (covering areas like Miami FL, Phoenix AZ). All dates are based on 2026 frost data for your zone.
Direct sow
Dec 27
Harvest From
Feb 5
Because spinach is a cool-season crop, it tolerates light frost and can go out around Dec 27, before zone 10a's average last frost on Jan 31.
- Type: Cool-season
- Method: Direct sow
- Days to harvest: 40
- Spacing: 4" apart
- Sun: Full sun to part shade
- Zone 10a frost: Jan 31 – Dec 30
- Season length: ~333 days
- Companions: radish, strawberry, peas
Growing spinach in zone 10a
Zone 10a has an average last spring frost around Jan 31 and a first fall frost around Dec 30, giving roughly 333 frost-free growing days. That window comfortably fits spinach's 40-day cycle, with room for a second succession planting if you time it right.
Spinach resents transplanting, so direct sow it right in the garden around Dec 27. Give each plant about 4 inches of space in full sun to part shade.
Zone 10a specific growing notes
In zone 10a (Miami FL, Phoenix AZ), your 333-day growing season means spinach should be one of your first spring plantings. Cool-season crops thrive in the mild part of your growing window. Monitor soil temperature — spinach germinates best when soil is 40-75°F.
Your first fall frost around Dec 30 means your last possible harvest is roughly late Dec. For a continuous supply, consider succession planting every 2-3 weeks from Dec 27 through mid-season.
Pro tip for spinach
Soak seeds in water for 12-24 hours before sowing to soften the tough seed coat and speed germination, especially when soil is still cool. Spinach germinates best in soil between 40-70°F.
Troubleshooting spinach
Leaf miners tunnel inside leaves creating winding translucent trails. Remove and destroy affected leaves immediately—do not compost. Row cover at planting prevents the adult fly from laying eggs.
Growing spinach in containers
Shallow 6-inch deep containers are plenty—spinach has a modest root system. Great for windowsill growing indoors year-round. One 12-inch pot provides enough for weekly salads.
Can you plant spinach twice a year?
Yes—sow in late summer (August in zones 5+, September in zones 7+) for a fall and early winter harvest. Spinach thrives in cooling weather and can survive temperatures down to 15-20°F.
Frequently asked questions
When should I plant spinach in zone 10a?
Direct sow around Dec 27. Because spinach is a cool-season crop, it tolerates light frost and can go out around Dec 27, before zone 10a's average last frost on Jan 31.
How long does spinach take to grow in zone 10a?
About 40 days from sowing to first harvest. A Dec 27 planting in zone 10a is typically ready to pick from around Feb 5. Zone 10a has about 333 frost-free days — plenty of time for a second succession planting.
How far apart should I space spinach?
Space spinach about 4 inches apart in full sun to part shade. This gives each plant enough room for roots to spread and leaves to catch sunlight without competing.
What is the best tip for growing spinach?
Soak seeds in water for 12-24 hours before sowing to soften the tough seed coat and speed germination, especially when soil is still cool. Spinach germinates best in soil between 40-70°F.
What are common problems with spinach and how do I fix them?
Leaf miners tunnel inside leaves creating winding translucent trails. Remove and destroy affected leaves immediately—do not compost. Row cover at planting prevents the adult fly from laying eggs.
Can I grow spinach in a container?
Shallow 6-inch deep containers are plenty—spinach has a modest root system. Great for windowsill growing indoors year-round. One 12-inch pot provides enough for weekly salads.
Can I plant a second crop of spinach for fall harvest?
Yes—sow in late summer (August in zones 5+, September in zones 7+) for a fall and early winter harvest. Spinach thrives in cooling weather and can survive temperatures down to 15-20°F.
What grows well next to spinach?
Good companion plants for spinach are radish, strawberry, peas. Avoid planting near warm-season crops that compete for space and nutrients. Spinach also benefits from crop rotation — do not plant it in the same spot year after year.