When to Plant Cucumbers in St. George, UT
Published: April 21, 2026
Cucumber Planting Dates for St. George, UT
| Start seeds indoors | March 1–8 |
| Last frost (average) | March 22 |
| Transplant outdoors | March 29–April 8 |
| Direct sow outdoors | March 29–April 8 |
| Minimum soil temperature | 60°F |
| Expect first harvest | May 18 – June 7 |
| Fall crop planting | September 1–11 |
| Fall crop harvest | October 21 |
| First fall frost (average) | November 10 |
Best Cucumber Varieties for St. George, UT
For Zone 6b St. George, the best-performing cucumber varieties are Straight Eight, Diva, and Marketmore — all widely adapted, disease-resistant varieties proven across the transition zone. Lemon is a good alternative where disease resistance matters most, especially in humid summers. These varieties are typically stocked by local nurseries and are the safest bets for gardeners new to cucumber in St. George.
Growing Cucumbers 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. Warm-season crops like cucumber need soil at 60°F or above before transplanting; St. George's frost calendar puts that window clearly in the late-spring to early-fall range.
St. George's moderate climate supports cucumber 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 cucumber. Breaking through caliche for in-ground planting requires significant soil amendment, gypsum application, and deep tilling over several seasons. Water at 1.5 inches per week delivered through drip irrigation for best results in a raised-bed system.
Cucumber Calendar for St. George
| Month | Task |
|---|---|
| March | Start seeds indoors under grow lights |
| March | Transplant outdoors into warm soil |
| May | Expect first harvest window to open |
| September | Start fall crop — transplants or direct sow |
| November | First fall frost — harvest remaining, end of outdoor season |
Cucumber Tips for St. George Gardeners
- •Direct sow after last frost rather than transplanting — cucumbers establish faster from seed in warm soil.
- •Trellis vertically to save space and reduce powdery mildew from soil splash.
- •Succession plant cucumber in St. George every 2–3 weeks through spring to extend the harvest window into summer.
Common Cucumber Pests in St. George
- •Cucumber Beetle — peaks July in Zone 6b (active May–September); yellow and black striped beetles that spread bacterial wilt; trap with yellow sticky traps.
- •Squash Vine Borer — peaks July in Zone 6b (active May–September); sudden wilting with frass at stem base; inject Bt into the stem or use row covers through flowering.
- •Powdery Mildew — peaks July in Zone 6b (active May–September); white powdery coating on leaves; improve airflow and apply milk spray (1:9 milk-to-water).
Check plants every 2–3 days during peak season — early intervention prevents most infestations from becoming serious.
What to Plant with Cucumbers in St. George
In St. George's moderate climate, Radish and Nasturtium are the most beneficial plants to grow alongside cucumber. Radish deters cucumber beetles and matures fast enough to harvest between slower neighbors. Keep cucumber away from Aromatic Herbs — it generally slow cucumber growth when planted too close.
Frequently Asked Questions
When should I plant cucumber in St. George, UT?
In St. George (Zone 6b), start cucumber seeds indoors around March 1–8 and transplant outdoors around March 29–April 8. The city's average last frost of March 22 is the anchor date — count 3 weeks back for seed starting and 1 weeks forward for transplanting.
What zone is St. George, UT for cucumber growing?
St. George is USDA Zone 6b. For cucumber, this means a frost-free growing season of roughly 33 weeks running from March 22 to November 10. This is a comfortable window for warm-season crops like cucumber — standard varieties work well.
When is cucumber harvest season in St. George?
Expect the first cucumber harvest in St. George around May 18, with harvest continuing through June 7. This is based on 50–70 days from transplant or direct sow. A fall crop planted September 1–11 adds a second harvest around October 21.
How long does it take to grow cucumber in St. George, UT?
From transplant or direct sow to first harvest, cucumber takes 50–70 days in St. George's climate. Based on a typical planting date of March 29–April 8, expect your first harvest around May 18. St. George's Zone 6b transition-zone climate produces maturity times right in the middle of the stated range.
What soil does cucumber need in St. George?
St. George's caliche subsoil is effectively rock — traditional in-ground planting of cucumber 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.