Popcorn

Sun

Full sun, with at least 6-8 hours of direct sunlight daily.

Water

Moderate to high; keep the root zone evenly moist, especially during tasselling, silking and kernel development.

Soil

Fertile, well-drained soil enriched with compost; ideally pH 6.0-7.0.

Height

4-8 ft (1.2-2.4 m), depending on variety

Spread

1-2 ft (0.3-0.6 m)

Flowers

Summer: pale green to tan male tassels at the stem tips, with greenish or pinkish female silks emerging from the ears.

Foliage

Long, broad, arching green leaves on upright, jointed stems; turns straw-coloured as the crop matures.

Growth

Fast in warm weather.

Care needed

Medium

• Heat tolerant
• Edible

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Needs looking after

Pick your zone, country, light and whether you have pets.

1. Planting day

   0.7 ft (0.22 m)

2. After 1 year

   6 ft (1.8 m)

   full size

Full size in one season.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Growth rate

Fast

• Plant in a block of at least four short rows rather than one long row for reliable wind pollination.
• Water deeply during dry spells, supplying roughly 1-1.5 in (2.5-4 cm) weekly, including rain; avoid waterlogged soil.
• Incorporate compost before planting and apply a nitrogen-rich vegetable fertiliser when plants are about knee-high, following the label rate.
• Mulch once the soil has warmed, and remove weeds while young without digging deeply around the shallow roots.
• Grow away from other maize, or choose sowing dates that prevent their pollen-shedding periods from overlapping; cross-pollination can reduce popping quality.
• Choose a sheltered site and firm loosened soil around plants after strong winds.

Pruning. Do not prune, remove tassels or routinely remove side shoots. After harvest, cut the stalks at ground level and compost healthy material.

Pick whole ears when the husks are brown and papery and the kernels are hard, leaving them on the plants to dry if weather allows. If prolonged wet weather or a hard freeze threatens, harvest mature ears and finish drying them under cover with good airflow. Test a small batch for popping, then shell and store the kernels in airtight containers once they pop well.

Early spring

Choose a variety suited to your frost-free season and prepare a sunny bed with compost.

Late spring

Sow after frost danger has passed and soil has warmed to at least 61°F (16°C); use a block layout.

Early summer

Thin crowded seedlings, weed carefully, feed when knee-high and mulch warm soil.

Midsummer

Water consistently as tassels and silks appear; watch for caterpillars feeding in the ears.

Late summer

Let mature ears dry on the stalks while checking for bird damage and mould.

Autumn

Harvest dry ears, finish drying under cover if necessary, test for popping and clear spent stalks.

• Plant in rectangular blocks in a potager, giving the vegetable beds height while supporting pollination.
• Use along the sunny northern edge of edible beds in the Northern Hemisphere, or the southern edge in Australia, to limit shading of shorter crops.
• Combine with squash and nearby bush beans in a spacious food garden, allowing each crop enough light and water.
• Grow beside a family growing area where children can follow the crop from seed to dried kernels.

Garden styles it suits: Potager (kitchen garden), Edible landscape, Homestead, Farmhouse, Family-friendly and Cottage garden.

Plant it with: Pumpkins, Winter squash, Bush beans, Nasturtiums and French marigolds.

Wildlife: Seeds and ripening ears attract birds, rodents and, where present, deer. Some insects collect maize pollen, although the crop is wind-pollinated and provides no nectar.

• Poorly filled ears: plant in blocks, avoid drought during silking and keep sowings of the same variety together so flowering overlaps.
• Ear-feeding caterpillars, including corn earworm: inspect silks and ear tips, remove accessible larvae and use only locally approved treatments labelled for edible maize.
• Corn smut: remove swollen, tumour-like growths before they release black spores; avoid injuring plants and dispose of affected material away from the crop.
• Mouldy ears or poor popping: protect mature ears from prolonged damp, discard mouldy kernels and dry sound ears with good airflow; test batches before storage.

Not known to be toxic to people, cats, dogs or horses under normal growing conditions. Hard kernels can cause choking or damage teeth, and swallowed cobs can cause serious intestinal blockage in dogs. Drought-stressed or heavily fertilised stalks can accumulate nitrates and should not be fed to horses without appropriate advice; discard mouldy grain.

• Sweetcorn (Zea mays)

  Plants look much the same, so use labelled seed. Sweetcorn is harvested with soft, juicy kernels at the milk stage; popcorn is allowed to mature into hard kernels capable of popping.

• Dent corn (Zea mays)

  Mature dent corn usually has larger kernels with a noticeable depression in the crown; popcorn kernels are generally smaller and rounded or pointed, without the typical dent.

• Sorghum (Sorghum bicolor)

  Sorghum carries its grain in a clustered seed head at the top of the stem, rather than on husked ears along the stem.

The common name refers to the kernels popping when heated, while the Latin varietal name everta means turned outward.

Propagation. Grow from seed. Direct-sow after frost when soil is at least 61°F (16°C), about 1-2 in (2.5-5 cm) deep; thin to 8-12 in (20-30 cm) apart in rows 24-36 in (60-90 cm) apart.

Accepted botanical name

Zea mays mays Zea mays var. everta is an older name for Zea mays mays.

Sources: GBIF (CC BY 4.0). The care and design notes are LandscapeGPT's own.