March marks an exciting time for UK gardeners as the soil begins to warm and daylight hours increase. This month offers the perfect opportunity to start many vegetables, both indoors and out. Whether you have a small windowsill or a large vegetable patch, here’s your comprehensive guide to the best vegetables to sow in March.

Best Vegetables for Indoor Sowing in March

Getting an early start indoors can significantly extend your growing season. Here are the top choices for indoor sowing:

Tomatoes

• Best varieties: ‘Gardener’s Delight’, ‘Sungold’, ‘Moneymaker’
• Sow in small pots or seed trays
• Keep at 18-21°C for germination
• Place on a sunny windowsill or under grow lights
• Perfect for both greenhouse and outdoor growing later

Peppers

• Sweet varieties: ‘California Wonder’, ‘Bell Boy’
• Chilli varieties: ‘Jalapeno’, ‘Hungarian Hot Wax’
• Need consistent warmth (20-25°C)
• Start in small cells or pots
• Require 8-10 weeks indoors before transplanting

Aubergines

• Recommended varieties: ‘Black Beauty’, ‘Early Long Purple’
• Need high temperatures to germinate
• Sow 1cm deep in individual pots
• Keep soil consistently moist
• Require long growing season

Lettuce

• Cut-and-come-again varieties work best
• ‘Little Gem’, ‘Salad Bowl’, ‘Lollo Rossa’
• Perfect for windowsill growing
• Can be harvested within 21 days as baby leaves
• Sow every two weeks for continuous supply

Perfect Vegetables for Greenhouse Sowing

A greenhouse provides the perfect environment for starting these vegetables:

Cucumbers

• F1 varieties like ‘Cucumber Telegraph Improved’
• All-female varieties produce more fruits
• Sow seeds on their edge to prevent rotting
• Keep at 20°C minimum
• Transplant when two true leaves appear

Early Carrots

• Choose early varieties like ‘Amsterdam Forcing’
• Sow in deep containers or greenhouse border
• Keep soil consistently moist
• Thin to 5cm apart when seedlings appear
• Ready in about 12 weeks

Spring Onions

• ‘White Lisbon’ is reliable for March sowing
• Sow thinly in rows 15cm apart
• No thinning required
• Quick growing – ready in 8 weeks
• Ideal for succession sowing

Hardy Vegetables for Direct Outdoor Sowing

These tough vegetables can handle cooler March conditions:

Broad Beans

• ‘Aquadulce Claudia’ is perfect for early sowing
• Sow 5cm deep, 20cm apart
• Double rows with 60cm between
• Protection with cloches helps
• Ready to harvest in about 15 weeks

Peas

• ‘Meteor’ and ‘Kelvedon Wonder’ are reliable
• Sow 5cm deep in double rows
• Provide support for climbing
• Protect from mice and birds
• Start harvesting in 12-14 weeks

Early Potatoes

• ‘Swift’, ‘Rocket’, ‘Foremost’ are good first earlies
• Plant chitted potatoes 12cm deep
• Space 30cm apart in rows
• Earth up as plants grow
• Ready in about 13 weeks

Essential March Sowing Tips

Soil Temperature Guidelines

• Use a soil thermometer for accurate readings
• Most seeds need minimum 7-10°C soil temperature
• Warm soil with cloches or black plastic
• Check weather forecasts for frost warnings

Protection Methods

• Use fleece or cloches for outdoor sowings
• Cold frames help harden off indoor plants
• Mini polytunnels protect rows of vegetables
• Remove protection on warm days

Succession Sowing Advice

• Sow small amounts every 2-3 weeks
• Prevents glut of crops
• Ensures continuous harvests
• Particularly important for salad crops

Planning Your Vegetable Garden

Crop Rotation Basics

• Divide plot into sections
• Rotate annually to prevent disease
• Group vegetables by family
• Consider companion planting

Space Requirements

• Allow room for plants to mature
• Consider vertical growing options
• Plan access for maintenance
• Leave space for succession sowing

Remember to:

• Label all sowings with date and variety
• Keep a garden diary
• Monitor weather forecasts
• Check soil moisture regularly

By following these guidelines, you’ll be well on your way to a productive vegetable garden. March sowing sets the foundation for months of fresh, homegrown produce throughout the summer and autumn.

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