Vegetable
Sweet Corn
Zea mays · Poaceae
Also called: Corn, Maize (sweet types)
Sweet Corn (Zea mays) is a high-water vegetable well suited to Tucson and the low desert. It thrives in full sun.
Sweet Corn at a glance
- Water use
- High (established)
- Sun
- Full sun (8+ hours).
- Mature size
- Upright grass, typically 5-8 ft tall; plant in blocks, not single rows.
- Growth rate
- Fast; about 65-90 days to harvest depending on variety.
- Bloom
- Greenish-tan tassels; silks green to brown, Tassels (male) and silks (female) appear about 2 months after planting; ears harvested roughly 3 weeks after silking.
- Cold hardiness
- Frost sensitive; needs warm soil (60 F+) to germinate. Warm-season annual; spring crop must mature before extreme heat, which can disrupt pollination.
- Soil
- Deep, fertile, well-drained soil rich in organic matter; heavy feeder that needs good nitrogen.
- Native range
- Domesticated in Mexico/Mesoamerica from teosinte; sweet corn cultivars grown worldwide. (Field/flour corns have deep Southwest Indigenous roots, but sweet corn itself is not a desert native.)
- Best used as
- Fresh eating vegetable, Wind-pollinated block crop, Three Sisters companion planting with beans and squash
- Wildlife
- Ears attract birds, rodents, and corn earworm; wind-pollinated (not bee dependent).
- Toxicity
- Non-toxic to people and pets.
How to grow Sweet Corn in Tucson & the low desert
Watering
WARM SEASON: direct-sow mid-Feb through April for a spring crop, with a second sowing possible in July-early August for a fall crop (avoid tasseling during the hottest, driest weeks of June). Keep consistently moist; water is critical from tasseling through ear fill. Mulch to reduce evaporation.
Fertilizer & nutrients
Heavy nitrogen feeder. Incorporate compost/aged manure plus nitrogen at planting and side-dress with nitrogen when knee-high and again at tasseling. Watch for chlorosis in alkaline soil.
Pruning & care
No pruning. Plant in blocks of at least 4 rows for wind pollination; do not remove suckers. Harvest when silks brown and kernels are milky.
Notes
Higher water use makes it one of the thirstier desert vegetables; timing matters because heat and low humidity above ~95 F during pollination cause poor kernel fill ('skips'). Plant in blocks for pollination. Isolate super-sweet types from other corn to keep them sweet.
Sources: University of Arizona Cooperative Extension; Pima County Master Gardeners; Tucson Organic Gardeners Planting Guide