Crop type: Sweetcorn
Zea mays ‘Lark’ AGM
Common name: Sweet corn ‘Lark’
Crop slug: sweetcorn
This Allotment Pro editorial draft summarises the cited RHS cultivar profile. Check the source and adjust cultivation decisions for local conditions.RHS cultivar profile
1 - Overview
‘Lark’ is an extra-tender tendersweet sweetcorn with soft, sweet cobs. This early- to mid-season cultivar produces good yields and performs particularly well in cold soil, where its germination is more reliable than that of many supersweet varieties.
The profile schedules indoor sowing from April to May, planting or sowing outside from May to June and harvest from August to September. Its combination of tenderness, dependable establishment and useful yield makes it a practical choice for cooler UK sites.
2 - Size
- Ultimate height
- 1.5–2.5 metres
- Ultimate spread
- 0.5–1 metre
- Time to ultimate size
- 1 year
The upright plants need enough space to form a compact block. This layout allows wind-borne pollen to reach neighbouring silks and helps the kernels fill evenly.
3 - Growing conditions
- Suitable soils
- Chalk, clay, loam or sand
- Moisture
- Moist but well drained
- Soil pH
- Acid, neutral or alkaline
Prepare fertile soil with well-rotted organic matter. Maintain even moisture while the crop establishes and while the cobs are filling, without leaving roots waterlogged.
4 - Position and hardiness
- Light
- Full sun
- Aspect
- East-, south- or west-facing
- Exposure
- Sheltered
- Hardiness
- H2 — tolerant of low temperatures but not freezing, approximately 1–5°C
Cold-soil performance refers to germination and establishment, not winter hardiness. Grow ‘Lark’ as a frost-tender annual in a sunny sheltered place and transplant only after the last frost.
5 - Colour and seasonal interest
| Season | Flowers | Foliage | Fruit |
|---|---|---|---|
| Spring | — | Green | — |
| Summer | — | Green | Tender sweet cobs developing |
| Autumn | — | — | Mature cobs into September |
| Winter | — | — | — |
The RHS profile records green foliage in spring and summer. Its main identifying qualities are the tender kernels, reliable cool-soil germination and productive early- to mid-season crop.
6 - Botanical details
- Family
- Poaceae
- Native to Great Britain and Ireland
- No
- Foliage
- Deciduous
- Habit
- Columnar and upright
- Name status
- Accepted
- Award
- RHS Award of Garden Merit
Genus
Zea contains large flowering grasses. Male flowers form terminal tassels, while the female flowers and cobs develop in clusters in the leaf axils. Growing several plants in a block improves pollination.
7 - How to grow
Cultivation
Grow in a sunny sheltered position in soil enriched with well-rotted organic matter. Sweetcorn tolerates several soil types but prefers well-drained ground with a pH between 5.5 and 7.0. Harvest ‘Lark’ from August to September as its sweet soft kernels reach eating maturity.
Propagation
Sow in pots or modules under cover from April to May, harden plants off and set them outside in May or June after frost. Direct sowing from late spring to early summer is also possible. Use a grid rather than a row to aid wind pollination.
Pruning
No pruning is required.
Pests
Birds, slugs, mice and badgers may damage seed, seedlings or cobs.
Diseases
Smut may form large galls on cobs and stalks in hot weather.