Utah · zones 6a8b

When to plant basil in Utah.

Sow or transplant between May 22 to Aug 7 in a typical year, keyed to Utah's median last frost around May 1. Dates below are state medians; your ZIP code shifts them by days to weeks.

The 2026 windows

Basil dates for a typical Utah season.

1 · Start indoors

Apr 10 to Jun 26

About 6 weeks before set-out. Warm spot, real light.

2 · Set out

May 22 to Aug 7

Keyed to the ~May 1 last frost. Sow 0.25" deep, 8" apart.

Harvest

~40 days later

~0.5 lb per plant over ~12 weeks.

Utah spans more than one climate: Zone 6 is the most common zone, but the state runs 6a to 8b. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.

In Utah: watch for

The pests that find basil here.

A middle-length season, about 157 frost-free days, means basil overlaps aphids for a stretch each summer. Check plants every week or two and treat early.

Aphids

Clusters on the tender tips.

Organic fix: Rinse and use insecticidal soap.

Spider mites

Fine webbing and pale stippling in hot, dry spells.

Organic fix: Spray the undersides with water, then insecticidal soap or neem.

Downy & powdery mildew

Yellowing with gray fuzz underneath, or white powder on top.

Organic fix: Space for airflow, water at the base, spray neem.

Japanese beetles

Metallic beetles chewing basil and mint leaves to lace.

Organic fix: Handpick into soapy water in the morning; neem.

Your season math: Utah gives basil about 157 frost-free days, and it needs roughly 40 days to a first harvest. It's a one-planting crop, so time that single sowing well.

Planting basil in Utah: questions

When should I plant basil in Utah?+

In a typical Utah year, sow basil or set out transplants between May 22 to Aug 7, keyed to the state's median last frost around May 1. Your exact dates shift with your ZIP code and microclimate.

When do I start basil seeds indoors in Utah?+

Start seeds inside about 6 weeks before set-out: roughly Apr 10 to Jun 26 for a typical Utah season.

What USDA zone is Utah?+

Utah spans zones 6a–8b, mostly zone 6. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.

How many basil plants do I need?+

Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.