Sweet corn (Zea mays var. saccharata)

Environment

The bounded range this crop tolerates. Strict on light; outside the DLI band, yields drop sharply.

Temperature

5152535

18–32°C

pH

45.578.5

6–7

EC (hydro)

01234

1.6–2.4 mS/cm

Daily light

5152535

30–45 mol/m²/d

!Light strict; fails outside DLI band

✓Single harvest

Climate and zones

USDA zones: 3–12 (winter low around -40°C)
Frost: frost sensitive (dies at first frost)
Season: warm (summer, frost-sensitive)

·Outdoor year-round (in zone)

✓Outdoor in growing season

·Unheated greenhouse / hoop

·Heated greenhouse

·Indoor (heated home)

·Indoor hydroponics + grow lights

Growing systems

Root mass: heavy. Thin-channel systems can't hold this crop.

·Deep water culture (rafts)

·NFT channels

·Vertical / aeroponic tower

·Drip / Dutch buckets

·Media bed (ebb and flow)

·Wicking bed

✓Soil bed

Growing media

Medium	pH effect	Retention	Bacterial surface
Soil-based mix (Potting soil)	varies	high	high

Nutrient demand by stage

NPK ratios are relative weights. EC targets shift through the plant's life.

Stage	N	P	K	EC (mS/cm)
seedling	2	1	1	1
vegetative	3	1	2	1.8
flowering	2	1	2	2
fruiting	1	1	2	2

Companion-growing notes

Heavy uptake of nitrogen, potassium. Co-grown crops with the same demand will end up deficient even at "correct" EC.
Very high transpiration. Reservoir drops fast; expect daily top-ups and EC creep.

Aquaponics suitability

Not recommended

Fish waste alone doesn't supply enough of what this crop demands. Grows in hybrid systems with supplemental dosing, but expect active management.

Care notes

Not practical for indoor hydroponics (the plants are 1.5–2.5 m tall, need wind for pollination, and require enormous light). For outdoor aquaponics, grow in large media beds or in ground next to the system, irrigated with nutrient-rich effluent. EC 1.6-2.4 mS/cm (a heavy feeder, especially for nitrogen). pH 6.0-7.0. Temperature: 20–30°C (warm-season). Very high light (full sun, DLI 30-45 mol/m2/day). Plant in blocks of at least four rows rather than single rows, because corn is wind-pollinated and block planting ensures pollen reaches the silks. From seed to harvest: 65-100 days depending on variety. Harvest when the silks turn brown and a punctured kernel produces milky liquid (not clear, not starchy paste). Eat or process within a couple of hours of picking for peak sweetness, especially for su types. Each stalk produces 1-2 ears.

Notable varieties

Cultivar	Type	Origin	Days	Notes
Silver Queen	hybrid		92	White-kernel se hybrid, the classic August eating corn in the eastern US for decades. 20-23 cm ears, 14-16 rows. Holds sugar longer than old su types but less than modern sh2. Needs warm soil (18C+) to germinate reliably; don't rush planting. Susceptible to common rust and Stewart's wilt in humid regions.
Golden Bantam	open pollinated		78	The original home-garden yellow sweet corn, introduced 1902 by W. Atlee Burpee. Standard sugary (su) genetics: sugar converts to starch within hours of picking, so eat it the day you harvest. 15-18 cm ears, 8 rows. Short plants (150 cm) compared to modern hybrids. Lower yield but you can save seed, and the flavor when picked and eaten within an hour is what people mean when they talk about real corn.
Peaches and Cream	hybrid		83	Bicolor (mixed yellow and white kernels) se hybrid. 20 cm ears. The grocery-store bicolor standard in the US and Canada. Sugar-enhanced genetics give a 2-3 day harvest window instead of same-day. Good disease package for a home garden: tolerant to northern corn leaf blight and common rust.
Honey Select	hybrid	Burpee / Crookham	79	Yellow triple-sweet (augmented sh2) hybrid. Combines se and sh2 genetics: creamy texture of se with the sugar-holding of sh2. AAS winner. 20 cm ears, 16 rows. Can be planted near other corn types without the starchy cross-pollination problem that pure sh2 varieties have. Good option if you're only growing one corn variety and can't isolate.
Illini Xtra Sweet	hybrid	University of Illinois	85	Yellow supersweet (sh2). The original sh2 hybrid that proved home gardeners could grow supersweets reliably (released 1979). Sugar holds 5-7 days after harvest, a huge advantage over su and se types. Trade-off: sh2 kernels are smaller and crunchier (less creamy), and germination is poor in cold soil. Must be isolated 75m+ from other corn or the sh2 kernels revert to starchy.
Stowell's Evergreen	heirloom		100	White-kernel su heirloom from the 1840s, pre-dates all modern sweet corn breeding. Long season (100 days) but the ears stay in milk stage on the stalk longer than most su varieties, giving a wider harvest window (hence 'evergreen'). 20-23 cm ears, 16-20 rows. Standard sugary genetics so eat it fast. The heirloom seed-saving option for white corn.