Seeds for Planting: The Ultimate UK Guide to Sowing Success from Seed to Harvest
Introduction
Planting seeds is one of the most exciting and economical ways to grow a garden. Whether you’re starting vegetables for your allotment, sowing flowers for borders, or growing herbs on a sunny windowsill, seeds offer endless variety, satisfaction, and value.
But to get the best results, it helps to understand which seeds to choose, when and how to plant them, and how to care for them as they grow. This guide walks you through everything you need to know about seeds for planting in the UK, from selecting packets to sowing, germinating, and nurturing your future plants.
Quick Summary: What You Need to Know About Planting Seeds
| Topic | Key Info |
|---|---|
| Best time to start seeds | Indoors: Feb–April / Outdoors: March–June |
| Tools needed | Trays, compost, labels, watering can, warmth |
| Common seed types | Vegetables, herbs, flowers, perennials |
| Where to plant | Indoors (early start), direct sow, containers |
| Germination tips | Warmth, light, moisture, correct depth |
| Mistakes to avoid | Overwatering, planting too deep, lack of light |
1. Why Start Plants from Seed?
✅ Cost-effective — a single packet can grow dozens of plants
✅ Huge variety — access to unusual, heirloom, or rare varieties
✅ Early start — begin growing long before garden centres open
✅ Greater satisfaction — watch life unfold from start to finish
Whether you’re sowing salad greens, sweet peas, tomatoes, or wildflowers, seeds are the heart of every great garden.
2. Different Types of Seeds for Planting
| Seed Type | Best Use |
|---|---|
| Vegetable seeds | Lettuce, tomatoes, carrots, beans, radishes |
| Herb seeds | Basil, coriander, parsley, thyme |
| Flower seeds | Marigolds, cosmos, sunflowers, sweet peas |
| Perennials | Echinacea, delphiniums, lavender |
| Green manure seeds | Mustard, phacelia – great for improving soil |
| Wildflower seeds | Pollinator patches, meadows, biodiversity boosts |
3. Best Time to Sow Seeds in the UK
| Season | What to Sow |
|---|---|
| Late winter (Feb–Mar) | Chillies, tomatoes, aubergines (indoors) |
| Spring (Mar–May) | Broad beans, salads, peas, annual flowers |
| Summer (Jun–Aug) | Carrots, spinach, beets, biennials |
| Autumn (Sept–Oct) | Spring bulbs, hardy annuals, green manure |
| All year (indoors) | Microgreens, herbs, lettuce |
Always check the seed packet for specific timing, spacing, and depth.
4. Where to Buy Quality Seeds in the UK
✅ Trusted suppliers:
- Suttons Seeds
- Thompson & Morgan
- Chiltern Seeds
- Real Seeds
- Premier Seeds Direct
- Kings Seeds
- Higgledy Garden (flowers)
Avoid buying unknown seeds from marketplace sites unless well-reviewed.
5. Tools & Equipment Needed for Sowing Seeds
| Tool/Material | Use |
|---|---|
| Seed trays or pots | For starting indoors |
| Labels and pencil | To track what’s sown and when |
| Fine seed compost | Low nutrient, well-draining base for seeds |
| Watering can with rose or mister | Gentle watering |
| Propagator lid or cling film | Retains heat and moisture |
| Grow lights (optional) | For low-light homes or early sowing |
6. How to Sow Seeds: Step-by-Step Guide
🌱 Step-by-Step Indoor Sowing:
- Fill seed tray or module with seed compost, level off
- Water lightly before sowing
- Sow seeds — either spaced or sprinkled, depending on type
- Cover with fine compost or vermiculite (check packet)
- Label with plant name and sowing date
- Cover tray with clear lid or plastic bag
- Place in light, warm spot (15–22°C)
Check daily and remove cover once seedlings emerge.
7. Direct Sowing Seeds Outdoors
Perfect for:
- Carrots, beets, radish, peas, cornflowers, calendula
🪴 How to do it:
- Rake soil to a fine tilth
- Mark out shallow drills with a cane or stick
- Sow seeds at correct depth
- Cover and gently firm soil
- Water lightly
- Label rows
Keep soil moist until germination. Thin seedlings once they’re big enough to handle.
8. Caring for Seedlings After Germination
| Task | Key Actions |
|---|---|
| Light | Move to bright light or use grow lights |
| Watering | Keep compost moist, not soggy |
| Ventilation | Remove lids once sprouted to prevent damping off |
| Pricking out | Transfer to individual pots when true leaves appear |
| Hardening off | Acclimatise before moving outdoors permanently |
💡 Turn trays daily to stop seedlings from leaning toward the light.
9. How to Store Seeds
Keep leftover or unused seeds cool, dark, and dry.
✅ Storage tips:
- Use envelopes or original packets
- Store in airtight containers
- Keep in a fridge or cool cupboard
- Label with date and expiry (most last 2–4 years)
10. Common Seed Sowing Mistakes
🚫 Sowing too early without enough light
🚫 Planting too deep
🚫 Overwatering and causing damping off
🚫 Using nutrient-rich compost — can “burn” seedlings
🚫 Forgetting to label trays
🚫 Not thinning out overcrowded seedlings
🚫 Letting trays dry out once germination starts
Bonus: Easiest Seeds for Beginners
🌿 Vegetables:
- Radishes
- Lettuce
- Courgettes
- French beans
- Peas
🌸 Flowers:
- Nasturtiums
- Calendula
- Sunflowers
- Cosmos
- Sweet peas
🌱 Herbs:
- Basil
- Coriander
- Chives
- Dill
Conclusion
Starting from seed opens up a whole world of possibilities — from vibrant homegrown veg to blooms not found in garden centres. With the right tools, timing, and care, anyone can turn tiny seeds into thriving, productive plants that brighten borders, fill plates, and support wildlife.
Whether you’re sowing in windowsill trays, greenhouse benches, or raised beds, planting seeds is the most rewarding way to grow.
Top 10 FAQs About Seeds for Planting
1. When should I start sowing seeds in the UK?
February–March indoors, March–June outdoors (check packet dates).
2. Can I use regular compost for seed sowing?
Use seed compost, which is finer and low in nutrients.
3. How deep should I plant seeds?
As a general rule: 2x the size of the seed.
4. Why aren’t my seeds germinating?
Likely reasons: old seed, wrong temperature, or too much/little water.
5. Do I need a greenhouse to grow from seed?
No — a windowsill, propagator, or covered tray works well indoors.
6. What is hardening off?
Gradually introducing indoor-grown plants to outdoor conditions over 7–10 days.
7. How long do seeds last in storage?
Most stay viable for 2–4 years, depending on type and storage conditions.
8. What’s the difference between heirloom and F1 seeds?
Heirloom = open-pollinated, can be saved.
F1 = hybrid, vigorous but can’t reliably be saved for next year.
9. Can I plant supermarket seeds or dried pulses?
Some may sprout, but success is unreliable — better to buy certified seed.
10. Should I soak seeds before planting?
Only for hard seeds like sweet peas, beans, or nasturtiums — 8–12 hours max.