A Beginner’s Guide to Planting Sweetcorn

Introduction

Sweetcorn is one of the most rewarding crops to grow at home. There’s nothing quite like the taste of freshly picked corn—juicy, sweet, and bursting with flavour. While supermarket corn often lacks sweetness due to time delays between harvest and eating, growing your own ensures peak flavour and maximum freshness.

This beginner’s guide to planting sweetcorn walks you through everything you need to know to grow strong, healthy sweetcorn plants. From choosing the best varieties and preparing the soil to planting, caring, and harvesting, you’ll find easy steps to grow this delicious summer crop, whether in your garden, allotment, or even a large container.

Why Grow Sweetcorn at Home?

• 🌽 Superior taste: Sweetcorn starts losing sweetness the moment it’s picked—homegrown is unbeatable.
• 🌱 Great for beginners: It’s easy to grow with the right conditions.
• 🌿 Impressive and productive: Tall, leafy plants add structure and yield multiple cobs per plant.
• 🐝 Wildlife-friendly: Flowers attract bees and beneficial insects.
• 🪴 Fun for families: Watching corn grow tall is exciting for kids and adults alike.

Best Sweetcorn Varieties to Grow in the UK

Tip: Choose F1 hybrid sweet or super-sweet types for the best taste. Avoid planting different types together to prevent cross-pollination.

When to Plant Sweetcorn in the UK

Step-by-Step Guide to Planting Sweetcorn

Step 1: Choose a Sunny, Sheltered Site

Sweetcorn needs:

• Full sun (at least 6 hours a day)
• Sheltered conditions to protect tall plants from wind
• Moist, fertile, well-drained soil

Avoid exposed areas where wind could knock over tall stalks.

Step 2: Prepare the Soil

Sweetcorn is a hungry feeder and prefers:

• Rich, moisture-retentive soil
• Neutral to slightly acidic pH (6.0–6.8)

How to Prepare:

• Add well-rotted manure or compost in early spring
• Rake in a balanced general-purpose fertiliser before planting
• Water thoroughly before planting and mulch to retain moisture

Tip: Avoid planting where corn or grass crops grew the previous year to reduce disease risk.

Step 3: Sow the Seeds

Indoor Sowing (Recommended in the UK):

• Sow from late April to early May
• Use 7–9cm pots with multipurpose compost
• Sow one seed per pot, 2.5cm deep
• Keep in a greenhouse or warm windowsill (18–21°C)
• Harden off before transplanting outdoors

Outdoor Sowing (If no late frosts expected):

• Sow directly in late May or early June
• Sow seeds 2.5cm deep, 15–20cm apart in blocks

Step 4: Planting Out

• Transplant seedlings from pots once all frost risk has passed (late May to mid-June)
• Water the pots before planting
• Plant 15–20cm apart in a square or block rather than rows—this ensures better wind pollination

Block Planting Layout Example:

 X   X   X
 X   X   X
 X   X   X

Why block planting? Sweetcorn is wind-pollinated. Planting in a square helps pollen reach all the plants more effectively.

Caring for Your Sweetcorn

1. Watering

• Keep the soil consistently moist, especially during flowering and cob formation
• Water thoroughly once or twice a week during dry spells
• Don’t let the soil dry out or waterlog

2. Feeding

• Feed with a high-nitrogen fertiliser every 2–3 weeks until cobs begin to form
• Switch to a high-potash feed (like tomato feed) once tassels appear

3. Weeding and Mulching

• Keep the area weed-free
• Apply mulch around the base to retain moisture and suppress weeds

4. Supporting Tall Plants

• In exposed sites, earth up soil around the base or stake if needed to prevent lodging (falling over)

Sweetcorn Pollination Tips

• Each plant produces male flowers (tassels) at the top and female flowers (silks) lower down.
• Wind carries pollen from tassels to silks—good pollination = full cobs.

Boost Pollination:

• Plant in blocks, not rows
• Shake tassels gently by hand once they appear to help distribute pollen
• Avoid growing different corn types nearby (e.g., sweet, popcorn) to prevent cross-pollination

Common Sweetcorn Growing Problems

Harvesting Sweetcorn

When is Sweetcorn Ready to Pick?

• 18–24 weeks after sowing
• Silks turn brown and shrivel
• Kernels are plump, milky, and tightly packed

The “Squeeze Test”:

• Pull back husk slightly and press a kernel with your fingernail
• If liquid is milky, it’s ready
• If clear, wait a few more days
• If doughy, it’s overripe

How to Harvest:

• Hold the stalk and twist the cob downward to snap it off
• Eat or cook immediately for best flavour

Pro tip: Sweetness declines quickly after harvest—boil or freeze right away!

Storing and Preserving Sweetcorn

Short-Term Storage:

• Keep in the fridge for up to 3 days
• Leave husks on to retain moisture

Freezing Sweetcorn:

1. Remove husks and silks
2. Blanch cobs in boiling water for 4 minutes
3. Cool in ice water, dry, and freeze whole or as kernels

Growing Sweetcorn in Containers

Yes, you can grow sweetcorn in pots—ideal for patios or small gardens.

How-To:

• Use large containers (at least 40–50cm deep and wide)
• Grow 3–5 plants per pot in a cluster
• Use rich compost mixed with loam
• Feed and water regularly
• Stake if necessary to support growth

Sweetcorn Companion Planting

Good Companions:

• Courgettes/pumpkins (Three Sisters planting method)
• Climbing beans
• Marigolds (deter pests)
• Herbs like dill or basil

Avoid Planting Near:

• Tomatoes (similar nutrient demands)
• Potatoes (may compete for space and moisture)

End-of-Season Tips

• Once cobs are harvested, compost the stalks or dig them into the soil to improve structure
• Rotate crops next season to prevent disease build-up
• Clear and mulch soil over winter for a head start in spring

Conclusion

Sweetcorn is a fun and easy crop to grow, even for complete beginners. With a little preparation and regular care, you’ll be rewarded with towering plants and sweet, golden cobs bursting with flavour. Whether you’re planting in a garden bed, raised bed, or large pot, following this guide will help you grow your best sweetcorn yet.

So grab your seeds, start your sowing, and get ready to enjoy fresh, homegrown corn on the cob this summer!

Top 10 Questions and Answers About Planting Sweetcorn

1. When is the best time to plant sweetcorn in the UK?

Sow indoors in late April or outdoors in late May once all frost risk has passed.

2. How many sweetcorn plants do I need?

Grow at least 9–12 plants in a block for good pollination and decent yield.

3. Can I grow sweetcorn in containers?

Yes! Use deep, wide containers and grow in clusters for better pollination.

4. How tall does sweetcorn grow?

Most varieties reach 1.5–2.5 metres tall.

5. Why are my sweetcorn cobs small or missing kernels?

Poor pollination—grow in blocks and shake tassels to help distribute pollen.

6. How often should I water sweetcorn?

Water deeply 1–2 times a week during dry periods, especially when tassels and silks appear.

7. Can I save sweetcorn seeds?

Yes, but only from open-pollinated varieties like Golden Bantam—not F1 hybrids.

8. Do sweetcorn plants need support?

In windy areas, yes—earth up around the base or use bamboo stakes.

9. What’s the best fertiliser for sweetcorn?

Start with a high-nitrogen feed, then switch to high-potash once cobs begin to form.

10. How long does it take to grow sweetcorn?

Sweetcorn typically matures in 18–24 weeks depending on the variety and weather.