SproutSmart
SproutSmart™ Intelligent Garden Sowing

Pioneer 399

Corn
Zone 11a Save Garden

Planting Schedule

Add Pioneer 399 to your garden to build a schedule and get reminders.
Botanical illustration of Pioneer 399
72d to harvest

Sunlit kernels burst with a buttery sweetness—Pioneer 399 delivers tender, juicy yellow ears that feel silk-smooth at first bite and hold their flavor through the season. Expect plump, well-filled cobs with a bright, even color and a crisp-tender texture that’s ideal for fresh enjoyment and quick roasting, as well as creamy summer sauces and relishes. Grow this 72-day yellow sweet corn for a reliable harvest of garden-fresh ears that taste like pure sunshine.

Crop Dates

Growing note: In frost-free Zone 11a, grow this cool-season crop during the cooler dry season (October–February).
MilestoneDate
Start Indoors—
ClimateFrost-Free Climate
Transplant / Sow OutdoorsOct 1st
Harvest BeginsDec 12th
Harvest EndsFeb 28th

Crop Details

TraitValue
Days to Maturity72
Sun RequirementsFull SunFull sun
Growth HabitUpright
Support NeededNone
Planting DepthNormal
Germination Temp (°F)60
Min Soil Temp (°F)55
Min Night Temp (°F)45
Harden Off (days)Not Required

Today's Conditions

Outdoor planting for Pioneer 399 in Zone 11a typically begins around 2026-10-01. Wait until soil reaches at least 55°F before transplanting Pioneer 399.

Garden Alerts

In frost-free Zone 11a, grow this cool-season crop during the cooler dry season (October–February).

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Frequently Asked Questions

What pest or disease is most likely on sweet corn (Zea mays var. saccharata), and what should I do?
Watch for corn earworm (Helicoverpa zea), which bores into the ear right after silks emerge and often leaves frass near the silk ends. Apply Bacillus thuringiensis (Bt) as directed when silks first appear and again as needed per label, and remove heavily damaged ears early to reduce spread. Also keep the area free of old corn debris between plantings to lower overwintering pest and disease pressure.
How often should I water sweet corn during the main growing phase?
During tassel and ear development, water so the soil stays evenly moist at the root depth (about 6–8 in / 15–20 cm), typically around 1–1.5 in (2.5–4 cm) of water per week depending on weather. Water deeply 1–2 times per week rather than frequent light sprinkling, and avoid letting the soil dry out completely because that can cause poor ear fill and stressed plants. If leaves start to wilt in midday and the soil is dry several inches down, water immediately.
Botanical illustration of Pioneer 399

Sunlit kernels burst with a buttery sweetness—Pioneer 399 delivers tender, juicy yellow ears that feel silk-smooth at first bite and hold their flavor through the season. Expect plump, well-filled cobs with a bright, even color and a crisp-tender texture that’s ideal for fresh enjoyment and quick roasting, as well as creamy summer sauces and relishes. Grow this 72-day yellow sweet corn for a reliable harvest of garden-fresh ears that taste like pure sunshine.

Today's Conditions

Outdoor planting for Pioneer 399 in Zone 11a typically begins around 2026-10-01. Wait until soil reaches at least 55°F before transplanting Pioneer 399.

Garden Alerts

In frost-free Zone 11a, grow this cool-season crop during the cooler dry season (October–February).

Sowing Tips

Soil Temperature

Direct sow or transplant when soil at planting depth holds 55°F for reliable germination and early growth.

Expert Note

For best sweet flavor, grow in blocks (not rows) and keep soil evenly moist after tasseling; harvest when kernels are filled and milky (about 18–22 days after silk).