Seeds to sow indoors in January UK

In the UK, seeds you can sow indoors in January include chillies, sweet peppers, aubergines, onions, leeks, parsley, sweet peas and early flowers such as antirrhinums and begonias.

Why Sow Seeds Indoors in January?

I’m looking out the window at the snow-covered ground, the borders and beds are frozen, the soil unworkable. There are no seeds I can sow outside without risking rot or frost damage. Yet January need not be a barren month for us gardeners in the UK. While winter holds the land in its grip, we can start the growing year indoors, on a windowsill or beneath warm artificial light. A heated propagator or bright windowsill, whilst ensuring adequate light is available (grow lights are best for some) and using well-draining seed compost brings on strong, non-leggy plants. 

Vegetables to Sow Indoors in January

January is a month for patience and planning, but also for those crops that need a long growing season. Chillies and sweet peppers are among the top candidates for indoor sowing. They are slow to germinate and slow to grow, especially capsicum chinense varieties such as habanero and scotch bonnet types so starting them early gives them the best chance of fruiting well by summer as these take longer to mature. If like me, you have limited space indoors then other varieties of capsicum annuum or baccatum (bell peppers, jalapeños, cayennes and aji types) can be started later in February and March with good results. Sowing these and aubergines early increases the potential for better cropping providing you can maintain temperature and good light levels.

Onions and leeks grown from seed are also well suited to January sowing indoors. These hardy vegetables benefit from a long season and can be pricked out and grown on slowly until conditions outside improve and the ground clears.

Herbs to Start on a Windowsill in January

Parsley, famously slow to germinate, can be started now too, testing your patience but ultimately rewarding it with fresh leaves later in the year. Chives and early sowings of coriander can also be grown on a sunny windowsill.

Flowers to Sow Indoors in January

Flowers deserve attention in January as well. Sweet peas can be sown indoors to produce sturdy plants ready for planting out in spring. Pelargoniums (geraniums) and antirrhinums can also be started early, while delicate seeds such as lobelia, petunia and begonia benefit from a protected indoor environment and careful watering. They will need good artificial light to grow on before hardening off for your baskets and containers.

Seeds to Sow Indoors in January – Quick List

• Chilli Peppers, Sweet Peppers, Aubergines (Eggplants) - start in propagator as need warmth and light
• Broccoli, Spinach, Kale, Spring Onions, Broad Beans, Peas, Lettuce, Rocket – good to start on windowsill, or in unheated greenhouse/polytunnel
• Herbs Basil, Parsley, Coriander, Chives, Rosemary, Sage, Oregano – ideal for starting on the windowsill 
• Flowers mostly need warmth to germinate, try Sweet Peas, Coleus, Antirrhinum (snapdragons), Dianthus, Japonica (Anemone japonica), Salvia and Iceland Poppies
• Or those hanging basket favourites Begonias, Pelargonium (Geraniums), Petunias, Lobelia, Impatiens (Busy Lizzie), Pansies and Verbena.

Sowing indoors in January is not about rushing the seasons but about working with them. While the garden outside rests under snow, indoors the year’s first promise of growth can begin. Having cleared away the Christmas decorations there is space for pots or trays of compost, carefully labelled, waiting for life to emerge. Each seed sown is a reminder that winter is temporary, and that spring, though distant, is already on its way. With warmth, light, and a little care, tiny green shoots can appear even while frost lies outside.

What might you be sowing this January?