When to Plant Sunflower in Unknown

Growing Sunflower in Unknown: Complete Guide

Sunflower (Helianthus annuus) is a crop that grows best when sown directly in the garden. In Unknown, the right time to direct sow is around Tuesday, February 17, 2026, once soil temperatures are consistently warm enough for germination.

Because Unknown stretches across 6 USDA hardiness zones (5a, 7a, 7b, 8b, 9a, 9b), planting windows can shift by as much as six to eight weeks from one end of the state to the other. Gardeners in the warmer southern zones can start earlier, while those in cooler northern zones should wait until the zone table above shows their last frost has passed.

With 80 days to maturity, Sunflower fits comfortably within Unknown's growing season in most zones. In the warmest parts of the state, a second planting later in the season may be possible.

Sunflower requires full sun (6-8 hours) and low-moderate (1 inch/week) moisture. Most of Unknown receives adequate sunlight during the growing season, though gardeners in humid eastern regions should watch for fungal issues and ensure good air circulation.

For the most precise planting dates tailored to your exact location, enter your ZIP code on our planting calendar or use the zone table above to find the schedule for your area of Unknown.