When to Plant Spinach in St. George, UT
Published: April 24, 2026
Spinach Planting Dates for St. George, UT
| Start seeds indoors | Year-round |
| Last frost (average) | March 22 |
| Direct sow outdoors | February 15–25 |
| Minimum soil temperature | 35°F |
| Expect first harvest | March 27 – April 6 |
| Fall crop planting | September 29–October 9 |
| Fall crop harvest | November 8 |
| First fall frost (average) | November 10 |
⚠ One of the earliest spring vegetables — sow 4–6 weeks before last frost. Bolts in heat above 75°F. Plant again in late summer for a fall harvest.
Best Spinach Varieties for St. George, UT
Consult a St. George-area nursery or your state extension office for spinach varieties proven in Zone 6b.
Growing Spinach in St. George
St. George sits in Zone 6b, with an average last frost of March 22 and first fall frost around November 10 — giving a 233-day frost-free growing season. Cool-season crops like spinach benefit from St. George's cooler spring and fall windows, when temperatures stay in the 55–75°F sweet spot that produces the best flavor and least bolting.
St. George's moderate climate supports spinach on the standard transplant calendar with minimal special accommodation. Succession planting — sowing fresh seeds or setting new transplants every 2–3 weeks through spring — stretches the harvest window and gives you a backup crop if pests hit the first planting.
St. George's caliche soil is rock-hard below the surface — raised beds filled with quality potting mix are the most practical approach for spinach. Breaking through caliche for in-ground planting requires significant soil amendment, gypsum application, and deep tilling over several seasons. Water at 1 inches per week delivered through drip irrigation for best results in a raised-bed system.
Spinach Calendar for St. George
| Month | Task |
|---|---|
| Year | Start seeds indoors under grow lights |
| March | Last frost — soil warming, prepare bed |
| February | Direct sow seeds into warm soil |
| March | Expect first harvest window to open |
| September | Start fall crop — transplants or direct sow |
| November | First fall frost — harvest remaining, end of outdoor season |
Spinach Tips for St. George Gardeners
- •Direct sow in very cold soil — spinach germinates at 35°F, earlier than almost any other crop.
- •Succession plant every 10 days until 2 weeks before heat sets in for continuous spring harvests.
- •Succession plant spinach in St. George every 2–3 weeks through spring to extend the harvest window into summer.
Common Spinach Pests in St. George
- •Leaf Miner — peaks July in Zone 6b (active May–September); winding white trails in leaves; remove affected leaves and use row covers.
- •Aphid — peaks July in Zone 6b (active May–September); monitor closely during peak season and treat early.
- •Downy Mildew — peaks July in Zone 6b (active May–September); yellow patches on leaves with fuzzy underside growth; improve airflow and apply copper.
Check plants every 2–3 days during peak season — early intervention prevents most infestations from becoming serious.
What to Plant with Spinach in St. George
In St. George's moderate climate, Pea and Strawberry are the most beneficial plants to grow alongside spinach. Pea improves nearby plant health and pest resistance. Keep spinach away from Fennel — it releases root chemicals that inhibit growth of most neighbors.
Frequently Asked Questions
When should I plant spinach in St. George, UT?
In St. George (Zone 6b), direct sow spinach around February 15–25. Soil must be at 35°F or warmer at 2-inch depth before sowing — cold soil rots the seeds.
What zone is St. George, UT for spinach growing?
St. George is USDA Zone 6b. For spinach, this means a frost-free growing season of roughly 33 weeks running from March 22 to November 10. Cool-season crops like spinach thrive in this zone with both spring and fall planting windows available.
When is spinach harvest season in St. George?
Expect the first spinach harvest in St. George around March 27, with harvest continuing through April 6. This is based on 40–50 days from transplant or direct sow. A fall crop planted September 29–October 9 adds a second harvest around November 8.
How long does it take to grow spinach in St. George, UT?
From transplant or direct sow to first harvest, spinach takes 40–50 days in St. George's climate. Based on a typical planting date of February 15–25, expect your first harvest around March 27. St. George's Zone 6b transition-zone climate produces maturity times right in the middle of the stated range.
What soil does spinach need in St. George?
St. George's caliche subsoil is effectively rock — traditional in-ground planting of spinach produces poor results. Build a raised bed with 12–18 inches of quality potting mix or Mel's Mix for reliable production. Break through caliche only for deep-rooted crops, and expect to add compost each year to offset the alkalinity.