What Seeds To Sow In January In The UK: Your Complete Guide

January feels like a bit of a dead month in the garden, doesn’t it? Everything’s grey and cold, and you’re stuck inside watching the rain. But here’s the thing – January is actually brilliant for getting a head start on your growing season. There are loads you can be doing indoors right now that’ll pay off massively come spring and summer.

I’ve been gardening for years now, and January has become one of my favourite times because you can sit at the kitchen table with a warm cuppa, planning what to grow whilst actually sowing seeds on your sunny windowsill. No muddy knees, no freezing fingers, just you and your seed packets.

This guide covers everything you can sow in January in the UK, from vegetables and herbs to flowers and fruit. Let’s get stuck in.

Why Sow Seeds in January?

Right, before we get into the what, let’s talk about the why. January sowing gives you a massive head start on the growing season. Plants like aubergines, chillies and sweet peppers need a long growing season to produce a good crop in our cooler climates, so starting them now means they’ll actually have time to ripen before autumn arrives.

Even quick-growing things like salad leaves benefit from an early start. You can be eating fresh lettuce and rocket whilst it’s still freezing outside, which is lovely when shop-bought salad costs a fortune.

Plus, there’s something deeply satisfying about seeing green shoots appearing when everything outside is still dormant. It gives you something to look after during these dark winter months.

What You’ll Need to Get Started

You don’t need loads of fancy equipment to start sowing seeds in January. Here are the essential tools:

A heated propagator – This is brilliant for heat-loving crops like chillies, peppers and aubergines. It keeps the compost at the right temperature for germination. If you haven’t got one, don’t worry – you can often get away with a warm windowsill above a radiator.

Seed compost – Don’t use regular potting compost or garden soil for seed sowing. Seed compost is finer and contains fewer nutrients, which is actually what you want at this stage. It may be cheaper to just sieve normal compost.

Small pots or seed trays – Individual pots work well for larger seeds like broad beans, whilst seed trays are perfect for sowing lots of smaller seeds. You can also use old plastic fruit tubs to sow seeds.

A bright spot – Seeds need good light once they germinate. A sunny windowsill that faces south is ideal.

Labels – Trust me, you’ll forget what you’ve sown within about three days. Label everything.

Vegetables to Sow Indoors in January

Let’s start with the vegetables. These all need to be sown indoors because they’re either tender (can’t handle frost) or need the extra warmth to germinate.

Aubergines

Aubergines need an early start because they have such a long growing season. In the UK’s short growing season, if you don’t start them in January, you’ll struggle to get ripe fruit before the cold weather arrives in autumn.

I sow aubergine seeds in individual pots filled with seed compost, then pop them in my heated propagator. They need night-time temperatures of around 18-21°C to germinate, so a heated propagator is pretty much essential unless you’ve got a very warm house.

‘Black Beauty’ is a reliable variety for UK gardens and produces lovely glossy purple fruits. Once they’ve germinated and grown a bit, you can move them to an unheated greenhouse, but they’ll need that initial warmth to get going.

I had loads of aubergines last year, they turned out great!

Chillies

If you want proper spicy chillies by summer, January is the perfect time to sow them. Chilli seeds can be slow to germinate, and the plants take ages to mature, so starting early is crucial.

Pop your chilli seeds in small pots in a heated propagator. They love warmth and will sulk without it. I usually sow a few different varieties – some mild ones for everyday cooking and a couple of properly hot ones for when I’m feeling brave.

The great thing about growing chillies from seed is you get access to so many more varieties than you’d ever find in the shops. You can grow anything from sweet, mild peppers to absolutely ferocious superhots.

Sweet Peppers

Sweet peppers are basically chillies without the heat, and they need the same treatment. Long growing season, lots of warmth, early start – you know the drill by now.

I sow pepper seeds the same way as chillies, in a heated propagator with seed compost in small pots. Keep them warm and give them good light once they germinate, and you’ll have strong plants ready to go into your greenhouse by spring.

‘California Wonder’ is a brilliant variety that produces large, blocky peppers that ripen to red. Perfect for stuffing or roasting.

Tomatoes (for Greenhouse Growing)

Now, some people say don’t sow tomatoes until February or even early March, and they’ve got a point. Tomatoes can get leggy if they don’t have enough light, and January is pretty dark. But if you’ve got a grow light or a really bright spot, and you’re growing them in a greenhouse, you can absolutely start tomatoes in January.

The benefit of early sowing is you get earlier fruit. I usually start a few plants in late January in my heated propagator, then do another sowing in March as a backup.

There are hundreds of tomato varieties to choose from. For greenhouse growing, I like ‘Sungold’ for cherry tomatoes (they’re ridiculously sweet) and ‘Shirley’ for standard-sized fruit.

Celeriac

Celeriac is one of those vegetables that needs ample time to develop. It’s basically a turnip-shaped root that tastes like celery, and it’s brilliant roasted or mashed.

Sow celeriac seeds in a heated propagator in late January. The seeds are tiny, so sprinkle them thinly on the surface of seed compost and don’t cover them – they need light to germinate. Once they’re big enough to handle, prick them out into individual pots.

Onions (Exhibition Varieties)

If you want massive onions like the ones you see at garden shows, you need to start them from seed in January. Varieties like ‘Ailsa Craig’ and ‘Globo’ are bred to grow enormously if you give them a long enough growing season.

Sow onion seeds in seed trays or small pots in a heated propagator. They’ll germinate within a couple of weeks, and you can plant them out in early spring once they’ve grown a bit. Starting exhibition onions in January gives them the extra time they need to develop those impressive bulbs.

Even if you’re not bothered about winning prizes, starting onions from seed gives you loads more choice than buying sets, and it’s much cheaper too.

Vegetables to Sow in Greenhouses or Cold Frames

These are hardier vegetables that don’t need quite as much warmth, but they still benefit from a bit of protection from the worst of the weather.

Broad Beans

Broad beans are tough as old boots and can handle cold weather brilliantly. ‘Aquadulce Claudia’ is the classic variety for autumn or January sowing because it’s the hardiest.

You can sow broad bean seeds directly outside if your soil isn’t waterlogged, but I prefer starting them in large pots in my cold frame. This way, you avoid problems with mice eating the seeds, and you can give the plants a head start.

Sow one seed per pot about 5cm deep. They’ll germinate even in quite cold conditions and can go outside in early spring.

‘The Sutton’ is another brilliant variety if you’re short on space, as it’s a dwarf type that doesn’t need staking.

Early Peas

Early pea varieties like ‘Douce Provence’ can be sown in pots in January for an early crop. They’re not quite as hardy as broad beans, so I keep mine in the cold frame or unheated greenhouse until the worst of the winter weather is over.

Sow pea seeds about 5cm apart in deep pots or trays. They’ll need something to climb up eventually, but for now, just focus on getting them germinated and growing.

Starting peas early means you get fresh pea shoots and tender pods weeks before outdoor-sown peas are ready.

Lettuce

Lettuce is brilliant for winter sowing because it germinates quickly and grows fast. You can sow lettuce seeds on a bright windowsill or in a cold frame and have fresh salad leaves in just a few weeks.

I like to sow a few seeds every couple of weeks through winter so I’ve got a constant supply. ‘Little Gem’ is a reliable variety that stays compact, or try ‘Winter Density’ for cold weather.

Just scatter the seeds thinly on seed compost, cover lightly, and keep them moist. They’ll be up in no time.

Spinach

Spinach is another quick-growing leafy green that’s perfect for January sowing. It’s much happier in cool conditions than hot weather, so winter is actually ideal for it.

Sow spinach seeds in pots or seed trays and keep them on a bright windowsill or in a cold frame. You can start harvesting the outer leaves once the plants are big enough, and they’ll keep producing for weeks.

Spring Onions

Spring onions grow quickly and don’t take up much space, making them perfect for windowsill growing. Sow seeds thinly in small pots or trays and they’ll germinate within a week or so.

You can harvest them as baby salad onions within about 8 weeks, or let them grow a bit bigger if you prefer more substantial spring onions.

Quick-Growing Vegetables for Windowsills

These are the speedy crops that’ll give you fresh greens in just days or weeks. Perfect if you’re impatient like me.

Mustard

Mustard is ridiculously quick – you can harvest it as microgreens in about 7-10 days. Just scatter the seeds on moist compost or even damp kitchen paper, keep them on a bright windowsill, and watch them grow.

The leaves have a lovely peppery flavour that’s brilliant in salads or sandwiches.

Cress

Cress is just as quick as mustard and even easier to grow. Most of us grew it on cotton wool in primary school, and it’s still just as simple now.

Scatter cress seeds on damp kitchen paper or compost, keep them moist, and they’ll be ready to harvest in about a week. The classic combination is egg and cress sandwiches, but it’s also lovely in salads.

Rocket

Rocket seeds germinate quickly, and the leaves have that distinctive peppery flavour that you either love or hate. I’m firmly in the love camp.

Sow rocket seeds in pots on a sunny windowsill and you’ll have fresh leaves ready to pick in about 3-4 weeks. It’s much nicer than shop-bought rocket, and so much cheaper too.

Flowers to Sow Indoors in January

Don’t forget the flowers! Getting flower seeds started in January means you’ll have strong plants ready to fill your garden with colour come spring and summer.

Sweet Peas

Sweet peas are one of the best things to sow in January. These fragrant climbers need a good root system before they go outside, and starting them early gives them time to develop strong plants.

I sow sweet peas in deep pots (they have long roots) or old toilet roll tubes, then keep them somewhere cool once they’ve germinated. They don’t need heat – in fact, they prefer cooler conditions. An unheated greenhouse or cold frame is perfect.

If you’re in a mild area, you can put them outside in a sheltered spot once they’re growing. In colder areas, keep them under cover until early spring.

‘Cupani’ is a gorgeous variety with deep purple flowers and an incredible scent.

Begonias

Begonias are tender bedding plants that flower all summer long if you give them a good start. The seeds are absolutely tiny – like dust – so handle them carefully.

Sprinkle begonia seeds on the surface of seed compost (don’t cover them as they need light to germinate) and keep them in a heated propagator or on a warm windowsill. They’ll take a couple of weeks to germinate, but once they get going, they’re brilliant.

Geraniums (Pelargoniums)

Geraniums from seed take a while to get going, which is why January is the best time to start them. They need warmth to germinate, so use a heated propagator.

Once established, geraniums are tough as nails and flower their heads off all summer. They’re perfect for pots, hanging baskets, or borders.

Petunias

Petunias are another tender annual that needs an early start. The seeds are tiny and need light to germinate, so scatter them on the surface of seed compost and keep them in a heated propagator.

They’ll take 7-14 days to germinate, and once they’re big enough to handle, prick them out into individual pots. By late spring, you’ll have strong plants covered in flowers.

Dahlias

You can start dahlia tubers off in pots in late January if you’ve got space. Plant them in compost with the crown just below the surface and keep them frost-free.

By the time it’s warm enough to plant them outside, they’ll already have shoots growing and you’ll get flowers earlier than if you planted the tubers directly outside.

Herbs to Sow in January

Fresh herbs in winter are an absolute game-changer. These are all happy growing on a sunny windowsill.

Basil

Basil is usually thought of as a summer herb, but you can grow it indoors all year round on a warm windowsill. It needs quite a bit of warmth to germinate and grow well, so keep it somewhere toasty.

Sow basil seeds on the surface of seed compost and keep the pot somewhere warm and bright. Once the seedlings are big enough to handle, pot them on into slightly larger pots.

Having fresh basil in January is absolutely brilliant for perking up winter meals.

Parsley

Parsley takes ages to germinate – sometimes up to three weeks – so starting it in January means you’ll have useable plants by early spring.

Sow parsley seeds in small pots and keep them on a bright windowsill. Once they germinate, they grow steadily and you can keep harvesting the outer leaves for months.

Thyme

Thyme is a hardy herb that’s brilliant to have fresh year-round. It’s quite slow-growing from seed, so starting it in January gives you a head start.

Sow thyme seeds thinly on the surface of seed compost and keep them somewhere bright. They’ll germinate within a couple of weeks and can eventually live on your windowsill permanently.

Oregano

Oregano is similar to thyme – hardy, aromatic, and slow-growing from seed. Start it in January, and you’ll have decent-sized plants by summer.

Sow oregano seeds on a sunny windowsill and keep the compost moist but not waterlogged. Once established, oregano is pretty much indestructible.

Fruits to Sow or Plant in January

January is brilliant for planting bare-root fruit trees and bushes whilst they’re dormant. You can also start some fruits from seed.

Strawberries

Growing strawberries from seed is definitely the long route, but it’s doable and gives you access to loads more varieties. Alpine strawberries work particularly well from seed.

Sow strawberry seeds on the surface of seed compost in a heated propagator or on a warm windowsill. They’ll take 2-3 weeks to germinate, and the plants can go outside after the last frost.

I planted strawberries from bare roots last year, and I was able to harvest new plants when they grew offshoots, so I’ve got even more this year!

Bare-Root Fruit

January is the best time to plant bare-root raspberries, loganberries, gooseberries, blackcurrants and fruit trees like apples. They’re dormant now, which means they’re easier to handle and establish better than pot-grown plants.

Choose a sunny spot with well-drained soil, dig a hole twice as wide as the roots, and plant them at the same depth they were growing before. Water them in well, even in winter, to settle the soil around the roots.

Preparing Seed Potatoes

Late January is the perfect time to start chitting seed potatoes ready for planting in spring.

Chitting Early Varieties

Chitting just means letting your seed potatoes develop short, sturdy shoots before you plant them. This gives them a head start and leads to earlier harvests.

Pop your seed potatoes in egg boxes or seed trays with the end that has the most eyes facing upward. Put them somewhere cool, bright and frost-free – a spare bedroom windowsill or porch is ideal.

‘Charlotte’ is a brilliant early variety that chits well. By the time March arrives, your potatoes should have short, dark green shoots about 2cm long and be ready for planting.

Top Tips for January Seed Sowing

Here’s what I’ve learned over the years about sowing seeds in January:

Don’t sow too early – I know it’s tempting when you’re desperate to get growing, but seeds sown in late January often do better than those sown in early January because there’s more daylight.

Keep it warm – Most seeds need warmth to germinate. A heated propagator is worth every penny if you’re serious about growing from seed.

Give them light – Once seeds germinate, they need good light or they’ll get leggy and weak. A sunny windowsill is essential, or consider getting a grow light.

Don’t overwater – More seedlings die from overwatering than anything else. Keep the compost moist but not soggy.

Be patient – Some seeds, like parsley, take ages to germinate. Don’t give up on them too soon.

Label everything – Seriously, label everything. You will not remember what you’ve sown.

What to Do With Your Seedlings

Once your seeds have germinated and grown their first true leaves (the ones that appear after the seed leaves), you’ll need to prick them out into individual pots if they’re crowded.

Handle seedlings by their leaves, never the stem, which is easily damaged. Use a dibber or pencil to gently lift them out, then replant them in small pots filled with potting compost.

Keep them somewhere bright and warm, and gradually move them somewhere cooler as they grow stronger. This process is called hardening off and helps prevent shock when they eventually go outside.

When to Plant Out

Most of the things you sow in January won’t go outside until after the last frost, which is usually sometime in May in most of the UK (though it varies depending on where you are).

Keep an eye on weather forecasts and don’t rush to plant things out too early. One late frost can kill tender plants like tomatoes, chillies and peppers.

Hardy things like broad beans, peas and sweet peas can go out earlier – usually from early March onwards if the weather’s reasonable.

Is January Too Early?

Some people reckon January’s too early for seed sowing, and for some things, they’re probably right. Tomatoes, for example, can struggle with a lack of light in January and end up leggy.

But for long-season crops like chillies, peppers and aubergines, January is actually ideal. And for quick things like microgreens and salad leaves, it doesn’t matter what time of year it is – they’ll grow anywhere warm and bright.

My advice is to start with the things that definitely need an early start (chillies, peppers, aubergines, onions) and then add in other things if you’ve got space and enthusiasm.

What I’m Sowing This January

Right, so what am I actually sowing this year? I’ve got:

• Chillies (about five different varieties because I got carried away)
• Sweet peppers
• Aubergines
• ‘Ailsa Craig’ onions
• Sweet peas
• Broad beans in pots
• Various salad leaves on the kitchen windowsill
• Herbs (basil, parsley, thyme)

I’ll probably add more as the month goes on because I always get overexcited and end up with far too many plants. But that’s half the fun, isn’t it?

Final Thoughts

January doesn’t have to be a boring month in the garden. There are loads you can be doing indoors that’ll set you up for a brilliant growing season.

Even if you’ve never grown anything from seed before, have a go with something simple like cress or lettuce. Once you see those first green shoots appearing, you’ll be hooked.

And if you’re already an experienced gardener, January is your chance to try new varieties and experiment with things you’ve not grown before.

Either way, get your seed packets out, get your compost ready, and let’s make this the best growing year yet.

Happy sowing!