Popcorn

Popcorn: plant 25 cm (10 in) apart in the row and 75 cm (30 in) between rows, 1 per square. No known bad neighbours.

Key facts

Spacing in the row	25 cm (10 in)
Between rows	75 cm (30 in)
In a 30 cm (1 ft) square	1 per square
Sun	Full sun, 6–8 hours a day
Root depth	40 cm (16 in)
Height when grown	180 cm (71 in)
Crop rotation group	Anywhere in the rotation
Support	None needed

Sowing and germination

How it is started	Sown straight into the bed
Seeds per hole	2
Plants kept after thinning	1
Seeds per metre of row	8
Sowing depth	3.5 cm (1.4 in)
Soil temperature	from 10 °C, best 18–35 °C
Days to emerge	4–12 days
Light while germinating	Light makes no difference
Before sowing	nothing needed
When to sow	Indoors 7 weeks before the last frost; outdoors after the last frost; soil at least 16 °C

From seedling to plant

Pricking out	sown where it grows
Takes transplanting	Badly, sow where it grows
Hardening off	7–10 days
Life cycle	Annual
Cold tolerance	Tender, hurt by frost
Soil	Rich, with compost, free draining, pH 6–7
In a pot	15 L, 35 cm (13.8 in)
Watering	Water when the soil is dry two fingers down; at flowering, while fruit sets
Feeding	Hungry; at planting, at flowering, while picking
Support and training	A stake; tie in as it grows

Harvest and planning

Days to first harvest	95–120 days, from sowing
Ready when	The kernels are hard and glassy
Harvest window	All at once, 1–2 weeks
Typical yield	0.2–0.4 kg per plant
Botanical family	Poaceae
Watch out for	Aphids, whitefly, blight

Plan Popcorn in your garden

Open the free planner, drop Popcorn onto a bed and see how many plants fit.

Start Planning Your Garden

Sowing and harvest

Sow outdoors	May–Jun
Harvest	Sep–Oct

My dates for this crop

My country Last spring frost where I live

Give the date once and this page, the sowing calendar and the planner all follow it.

Months for a temperate climate: about a month later in the north and a month earlier in the south. Give your own last frost date for exact dates.

What to plant next to Popcorn →

From the same family

Plants of the Poaceae family share diseases and pests, so they follow each other in the rotation only after a break.

Grown much the same way

Crops that need about the same room and care, from another family.

Sources

The values on this page marked as checked come from these sources: spacing, sowing depth, germination, soil, timing and safety notes, each against the source named here.

Seed germination: temperature and timing (Harrington tables) — UC Master Gardener Program, UC ANR for: days to emerge, soil temperature; checked 2026-10-31
Sweet Corn in the Garden — Utah State University Extension for: when to sow; checked 2026-10-31

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