Your Spring Sowing Calendar: When to Plant Every Seed in Your Garden Pack

There's a reason experienced gardeners talk about timing more than anything else. You can have the best soil, the sunniest spot, and the most carefully chosen seeds — but sow them at the wrong moment, and you'll be fighting an uphill battle all season.

The good news? Getting it right isn't complicated. It just takes a little planning.

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Gardening isn't about doing everything perfectly — it's about doing the right thing at the right time.

Why Timing Matters More Than You Think

Every seed has a temperature range where it germinates best. Sow too early into cold soil and seeds will sit dormant — or worse, rot. Sow too late and your plants won't have enough growing season to produce a decent harvest.

The UK's climate makes this especially tricky. A warm spell in March can tempt you into sowing outdoors, only for a late frost to wipe everything out. That's why understanding the rhythm of the seasons is your single biggest advantage as a grower.

Your Month-by-Month Sowing Guide

February — The Windowsill Start

February is for indoor sowing only. Your windowsill or a simple propagator is all you need.

• Tomatoes — Sow indoors in small pots. They need warmth (18-21°C) to germinate.
• Peppers & Chillies — Start early as they need a long growing season.
• Aubergines — Another slow starter that benefits from an early indoor sow.

Keep seedlings on a bright windowsill and turn them daily to prevent leggy growth. A south-facing window is ideal.

March — Building Momentum

March is when things get exciting. You can start more seeds indoors and, towards the end of the month, begin hardening off your earliest sowings.

• Lettuce & Salad Leaves — Sow in trays indoors for an early crop.
• Broad Beans — These tough plants can go directly outside in mild areas.
• Peas — Start in guttering or root trainers indoors for transplanting later.
• Herbs (Basil, Coriander, Parsley) — Sow indoors on a warm windowsill.

April — The Main Event

April is the busiest sowing month. Most of your Garden Pack seeds can go in now, either indoors or — after the last frost — directly outside.

• Courgettes & Squash — Sow indoors in individual pots. They hate root disturbance.
• French Beans & Runner Beans — Start indoors or wait until May for direct sowing.
• Beetroot — Direct sow outside in rows, thinning to 10cm apart.
• Carrots — Direct sow into fine soil. Don't transplant — they fork.
• Spring Onions — Direct sow in short rows every 3 weeks for a continuous harvest.

May — Full Speed Ahead

By May, the soil has warmed up and you can sow almost everything directly outdoors.

• Sweetcorn — Direct sow in blocks (not rows) for better pollination.
• Cucumbers — Sow indoors or in a greenhouse for best results.
• Sunflowers — Direct sow where you want them to flower.
• Radishes — Quick wins! Ready in just 4 weeks from sowing.

This is also the time to transplant seedlings you started earlier. Harden them off for a week before planting out — move them outside during the day and back in at night.

June — Last Chance Sowings

June isn't too late for plenty of crops. In fact, some do better with a later sowing.

• Second sowings of lettuce, beetroot, and spring onions — Succession sowing extends your harvest.
• Kale — Sow now for autumn and winter harvesting.
• Turnips — A quick crop that thrives in summer warmth.

How Growli Takes the Guesswork Out

Remembering all these dates — and adjusting them for your location — is exactly the kind of thing an app does better than a human brain.

When you scan a Garden Pack seed packet with Growli, it:

1. Identifies the exact variety you're growing
2. Calculates your ideal sowing window based on your postcode and current weather
3. Sends you a reminder when it's time to sow
4. Guides you step-by-step through sowing, potting on, hardening off, and transplanting

No more checking calendars or googling frost dates. Just scan, follow, and grow.