Sweet Corn Growing Guide: Planting, Care & Harvest

Zea mays var. saccharata

Growing calendar

Typical timing for central Japan (Kanto region). Shift it for your own climate, and record your actual dates.

JanFebMarAprMayJunJulAugSepOctNovDec

Sow / plantGrowingHarvest

Guides

Common problems

Start from what you can see on the plant.

Wilting Yellow leaves Leaves dying Leaf spots Pests Fruit problems

Pests and diseases (49)

Problems recorded for this plant, most serious first.

Asian Corn Borer

MajorPest

Entry holes and powdery frass appear on the tassel and stalk, and the stalk may snap. Larvae bore down from the tip of the ear and the kernels are eaten and rot.

Helicoverpa Bollworms

CommonPest

Round holes are bored into fruit and buds, the inside eaten out and packed with frass. Rot spreads from the entry hole, leading to fruit and bud drop.

Brown Leaf Spot

Disease

Small light brown to gray-brown spots form on the leaves and enlarge into irregular lesions. When they merge the whole leaf dies and plant vigor drops sharply.

Rust

Disease

Small raised orange-yellow to red-brown pustules form on both leaf surfaces, then rupture and release powdery spores. Heavy infection yellows the leaves and kills them early.

Southern Blight

Disease

The stem rots at soil level and white silky mycelium spreads over the crown and the surrounding soil surface. Brown sclerotia the size of rapeseed then form and the plant wilts and dies rapidly.

Anthracnose

Disease

Light brown to dark brown round lesions with sharp margins form on leaves and fruit, slightly sunken in the center. In wet weather salmon-pink slimy spore masses ooze out on the lesions.

Damping-off

Disease

The stem pinches in at soil level, turning water-soaked to brown and thin, and the seedling topples over. Infection before emergence makes the stand uneven with missing plants.

Root-lesion Nematode

Pest

Elongated blackish brown necrotic lesions form on the root surface and fine roots rot away. Above ground the stand is uneven and plants stay small with pale foliage.

Root Rot

Disease

Fine roots rot brown to blackish brown, growth stops and the lower leaves yellow. The plant wilts easily in the daytime and eventually dies outright.

Root-knot Nematode

Pest

The plant wilts in the daytime and does not recover with feeding or watering. Pull it up and the roots carry beaded chains of galls of varying size with few fine roots.

Bacterial Spot

Disease

Small water-soaked spots appear on the leaves, later turning brown with yellowing around them. Fruit develops water-soaked or scabby spots from which rot spreads.

Leaf Spot

Disease

Small round brown to gray-white lesions appear on the lower leaves, the centers turning gray with tiny black specks. As they multiply the leaf yellows and drops early.

Downy Mildew

Disease

Pale yellow to yellow-brown angular lesions form on the upper leaf surface with a gray-purple mold in the matching spot underneath. Lesions merge, the leaves die back and the plant declines early.

Rice BlastSouthern Corn Leaf BlightBlack-streaked DwarfNorthern Corn Leaf BlightZonate Leaf SpotCyst NematodePythium Damping-offFusarium Stem RotMosaic DiseaseBacterial Lodging DiseaseNorthern Leaf SpotSouthern RustLeaf StreakBacterial Leaf StreakRoot DecaySmudge SpotGray Sclerotial RotScorch DiseaseHead SmutSheath BlightRice StripeStem Snap BlightMagnesium DeficiencyBacterial Stem BlightStem RotBacterial WiltLeaf BlightBacterial Leaf BlightBrown Stripe Downy MildewBrown StripeBrown RotFusarium Head BlightBlue MoldYellowsYellow DwarfSmut

Written byYasuGrowing vegetables and fruit in Chiba, Japan, and building Gadenin. Corrections are welcome. 15 years of growing.