Sowing seeds indoors is easy and fun, but do bear in mind that the seedlings will need regular care for several months. You’ll also need space in a greenhouse or on a bright windowsill to keep them until they’re ready to be moved outdoors.

Reasons to sow indoors include:

• Frost-free conditions - Some plants need warm conditions to germinate and grow, such as tender and half-hardy flowers and vegetables
• Safeguarding - To provide additional protection, perhaps from slugs or damp weather
• Faster, more reliable germination
• Head start - If you want earlier crops or flowers, sowing seeds indoors gives you a head start
• Additional time - Sowing indoors gives slow-growing plants the additional time they need to flower or crop
• Ensures success - Particularly if you only have a few seeds, or they are rare or expensive  

You can sow a wide range of seeds indoors, including:

• Tender crops - such as tomatoes, chillies and courgettes
• Half-hardy annuals - such as cosmos and nasturtiums
• Hardy annuals and veg - to give them a head start, such as sunflowers and broccoli
• Annual climbers - such as morning glory and sweet peas
• Perennials - such as delphiniums and echinacea, although these may not flower in their first summer
• Tender herbs - such as basil
• Slow-growing crops - such as celeriac

Sowing times vary depending on the plant – check the seed packet for recommended sowing months.

As a general guide:

• Sow in spring – most tender and half-hardy flowers and vegetables, for planting out in late spring and early summer
• Sow in summer – biennial flowers, such as foxgloves, and fast -growing vegetables, such as salads
• Sow in autumn – winter and early spring salads and vegetables, for cropping over winter indoors or planting out in spring
• Sow in late winter – tender and half-hardy flowers and vegetables that need a long growing season, such as chillies

Growing cress

Growing cress

Growing microgreens

Growing microgreens

1. Fill a seed tray, modules or small pots with seed compost or sieved multipurpose compost, and firm down gently to just below the rim 

   Top tip

   Smaller seeds prefer a seed compost as it has a finer texture than multipurpose. It also containers fewer nutrients, which suits young seedlings.

2. Smaller seeds should be scattered as thinly as possible on the surface, while larger seeds can be pressed into the compost individually, at the spacing recommended on the packet.
3. Most seeds should then be covered with a fine layer of compost, vermiculite or perlite. Check the seed packet to see whether and how to cover the seeds you are sowing
4. Water gently using a watering can fitted with a rose (sprinkler head), to avoid dislodging the seeds. Alternatively, stand the container in a tray of water to soak up moisture from below, until the compost is thoroughly damp 

   

5. Label the container, so you remember what you’ve sown and when
6. Cover the container with a clear polythene bag to maintain a humid atmosphere, or place it in a propagator with a clear lid. (Most seeds need a temperature of about 18°C (64°F) for germination, unless the seed packet states otherwise) 
7. Water regularly, aiming to keep the compost just moist at all times
8. Remove the lid or bag as soon as seedlings appear to increase ventilation. Germination usually takes two to three weeks
9. Ensure the seedlings get plenty of sunlight and water regularly to ensure they grow steadily and evenly

It's worth noting that whilst most seeds can be sown direct from the packet, a few with tough seed coats may need to be pre-soaked, scraped or nicked (with sandpaper or a knife) to aid germination – seed packets will provide details. A few others need a period of cold or warmth before they will germinate – see our guide to sowing tree seeds for details
 

Once your seedlings have at least two pairs of leaves, move them into individual pots or modules. Known as pricking out, this ensures they don’t get overcrowded and gives them space to keep growing strongly.

1. Fill several 9cm (3½in) pots or modular trays with multipurpose compost
2. Use ‘dibber’ (a stick, pencil or similar) to loosen the compost around the first seedling
3. Lift it out of the compost, holding it carefully by a sturdy leaf, not the delicate stem, while supporting the roots with the dibber. Try to keep as much compost around the roots as possible
4. Use the dibber to make a hole for the seedling in its new pot of compost, and lower the seedling in place
5. Firm the compost gently around the seedling and water in, taking care not to damage or dislodge the seedling

• Water seedlings regularly, aiming to keep the compost slightly damp and never letting it fully dry out. Seedlings can soon die if short of water, so it’s important to keep a close eye on them
• To encourage strong growth, feed fortnightly with a balanced liquid fertiliser. If seedlings develop pale lower leaves, they may be short of nutrients.
• With flowering plants, pinch out the tips of long shoots to encourage branching – a bushier plant will produce more blooms. If plants grow tall and straggly (leggy), it’s usually a sign they need more light

1. Harden off - a week or two before planting out, start to acclimatise them to outdoor conditions – see our guide to hardening off. This ensures they continue growing strongly and should settle in well
2. Get your planting site ready – check the seed packet to find out whether the plants need sun or shade. Weed the area thoroughly – see our guide to weeding
3. Water well - an hour or so before planting, water your plants so the compost is thoroughly damp
4. Dig a hole - make it a similar size to the plant’s container, and water the base
5. Place the plant - carefully tip the plant out of its pot and stand it in the hole. Make sure the surface of the compost is level with the surface of the soil
6. Fill any gaps - with more soil, fill any gaps around the rootball, firm it in gently, then water generously
7. Plant the rest - repeat with your other plants in the same way, at the spacing given on the seed packet. This will vary depending on the plant’s ultimate size