How to Grow Popcorn: Planting, Spacing, Care & Harvest

Quick answer

Direct sow after soil has warmed / air and soil above about 60°F (UMN/USU). for default popcorn sowing. Isolate 300 feet from other corn or stagger tasseling (UMN/ISU/USU).

Popcorn at a glance

PlantUniversity of Minnesota: “Direct seed in the garden after soil has warmed.”
SunFull sun, warm-season (USU).
WaterUMN/ISU: about 1 inch water per week until ears are filled, then stop watering to allow drying.
SpacingUMN: seeds 1 inch deep (heavier soils) up to 2 inches (sandy); about 8 inches apart; ≥four rows; rows 18–24 inches.
Days to harvest90–120 days to full maturity (UMN)
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Updated

Planting dates for your ZIP: the ZIP planting planner counts each window from your local frost dates.

Organic pests and diseases: see also organic pest control. Use any product as the label directs.

Not sweet corn: popcorn (Zea mays var. everta) needs isolation from sweet and field corn — cross-pollination hurts popping and sweet-corn quality. See also how to grow sweet corn.

Popcorn ears in a garden
Popcorn ears in the garden. Photo: Geo Lightspeed7, Wikimedia Commons, CC BY-SA 4.0 (resized).

Planting timing

University of Minnesota: “Direct seed in the garden after soil has warmed.” Most types need 90–120 days to full maturity. (UMN growing popcorn) Utah State: soil and air above 60°F for best germination; does not transplant well — direct sow. Optional earlier: “some growers sow seeds 3–4 weeks before frost-free date by planting through or under clear plastic mulches.” (USU popcorn) Default outdoor sow has — cite soil temperature only.

Isolation from other corn

UMN: isolate from other corn types. In ag areas, plant popcorn 300 feet from the nearest cornfield. Time-isolate from sweet corn: plant popcorn first after soil warm; wait three weeks before planting sweet corn (or grow only popcorn). Iowa State: “Do not plant sweet corn in the same garden as popcorn” unless isolated; ≥300 feet between types, or stagger tasseling. (ISU popcorn) USU: same garden only if types tassel at different times.

Depth and spacing

UMN: seeds 1 inch deep (heavier soils) up to 2 inches (sandy); about 8 inches apart; ≥four rows; rows 18–24 inches. USU: 1 inch deep, 7–8 inches in-row, rows 24–30 inches. ISU: 1–2 inches deep; rows 30–36 inches; thin to about 10–12 inches. Present each spacing with its source. Plant in a block, not one long row, for pollination (UMN/ISU).

Sun, soil and water

Full sun, warm-season (USU). UMN/ISU: about 1 inch water per week until ears are filled, then stop watering to allow drying. USU: 1½–2 inches/week critical at tassel, silk, and ear fill — both weekly amounts are labeled by source. Compost for fertility; omit synthetic product rates.

Harvest and storage

Unlike sweet corn: harvest when kernels are hard and shiny and husks are dry, tan, and brittle (UMN/USU/ISU). Leave on the stalk as long as possible; bring inside if rain threatens. Cure husked ears in mesh bags in a warm, dry, ventilated spot. Ideal moisture about 13–14% (UMN/ISU) or 12–15% (USU). Test-pop weekly; when crisp and fluffy, shell and store airtight.

Pests and diseases

Same corn pest and disease complex as sweet corn. Cultural controls for smut and wilt: remove galls and infected plants (USU). See also the pest notes on sweet corn and use any product as the label directs.

Related: sweet corn · ZIP planner · organic pest control

Frequently asked questions

When do I plant popcorn?

After soil is warm / ≥60°F (UMN/USU). Optional plastic 3–4 weeks before frost-free date (USU) is advanced only. No default frost-week planner rule.

Can I grow it next to sweet corn?

Not unless 300 ft apart or tassels do not overlap (UMN/ISU/USU). Prefer a popcorn-only garden or plant popcorn 3 weeks earlier (UMN).

When is it ready?

Dry mature ears — not milk stage. Test-pop while curing (UMN/ISU/USU).

More grow guides: All grow guides

Sources