GreenlyHow to grow Sweet Corn
Zea mays · corn, maize
A tall, warm-season cereal vegetable grown for its sugary kernels. It is wind-pollinated and requires a block planting for successful fertilization.
Quick facts
| Type | Vegetable |
|---|---|
| Family | Poaceae |
| Light | Full sun |
| Soil pH | 6–7 |
| Frost | does not tolerate frost |
| Soil for sowing | from 12 °C |
| Germination | 7 days |
| Sowing to harvest | 85 days |
| Where it grows | Greenhouse, Open ground |
When to plant
Sow straight into the bed after your last spring frost, once the soil has warmed.
In an unheated greenhouse everything moves about three weeks earlier.
The first harvest comes about 85 days after the shoots appear.
Care
Greenhouse
| Stage | Watering | Temperature | Feeding |
|---|---|---|---|
| Growth | every 3 days | 15…28 °C | nitrogen, 14 days into the stage |
| Flowering | every 2 days | 18…30 °C | balanced (NPK), at the start of the stage |
| Fruiting | every 2 days | 18…30 °C | potassium, at the start of the stage |
Open ground
| Stage | Watering | Temperature | Feeding |
|---|---|---|---|
| Growth | every 4 days | 12…28 °C | nitrogen, 21 days into the stage |
| Flowering | every 3 days | 15…30 °C | balanced (NPK), at the start of the stage |
| Fruiting | every 3 days | 15…30 °C | potassium, at the start of the stage |
Growing notes
Light
Requires full sun to ensure strong stalks and healthy ear development.
Soil
Rich, loamy soil with high organic matter and excellent drainage.
Care
Plant in blocks rather than single rows to ensure wind pollination of the silks. Keep soil consistently moist during the tasseling and silking stages. Apply high-nitrogen fertilizer early in the growth cycle to support height.
How to tell it is ripe
- Silks at the tip of the ear have turned brown and dry while the husk is still green.
- Kernels are plump and smooth and fill the ear right to the tip.
- Peel back a little husk and press a kernel with a thumbnail: milky juice means ready, watery means too early, a doughy paste means over-mature.
- The unhusked ear feels firm and full in the hand.
- Twist the ear downward and pull it off in the cool early morning, then eat or chill it quickly, since the sugar soon turns to starch.
Pests and diseases of Sweet Corn
- Wireworms
Sources
Figures cited from these sources.