Seeds to sow in January: 8 fabulous flowers and veggies to start now

The idea that there are seeds to sow in January might seem surprising – it’s the depths of winter, after all. But, as long as you have somewhere frost-free to keep them before the weather warms up, it’s totally possible to get growing now.

Raising flowers and veggies from seeds requires a little more patience and skill than buying plug plants from a nursery, but this only makes it more rewarding when your efforts pay off. What’s more, there tends to be a larger range to choose from. And it’s generally cheaper, too, making it easier to try out the latest garden trends.

Below, you’ll find eight options to include in your essential January gardening jobs to plant this month, to get a head start on your gardening plans. There are fragrant flowers, tasty herbs, and more – plus plenty of pro tips.

8 seeds to sow in January to get ahead this year

If your green fingers are itching to get stuck into some soil, consider sowing these top options this month. Apart from the seeds themselves, you’ll need a few small pots or trays, some seed-starting compost, and a greenhouse or sunny windowsill (remembering to keep them safely out of reach from curious pets and little ones).

If you’re opting for greenhouse growing, Sian Napier, plant expert and Gabriel Ash spokesperson says, “Make sure to keep the greenhouse warm – windows shut to avoid frost creeping in – and provide light as needed, especially as days are still short this time of year.”

Note that some seeds will need a bit of extra help to germinate, by means of a heated propagator. At just under £50, this compact electric propagator from Suttons is a good price, and comes with seven mini trays for seeds.

Sian Napier

Sian studied horticulture in 2010, based at Hestercombe House and Garden in Somerset. After successfully completing her diploma, she embarked on a varied career that encapsulates her true passion. This consists of gardening, designing gardens and writing as a spokesperson for luxury greenhouse brand, Gabriel Ash. Sian firmly believes that spending time outside in nature contributes to our health and wellbeing and is always happiest pottering about in her greenhouse.

1. Sweet peas

If you didn’t sow your sweet peas in the autumn, you can start these fragrant garden plants this month instead. Using root trainers, such as these Haxnicks ones from Amazon, is ideal for accommodating sweet peas’ long tap roots.

Jamie Shipley of Hedges Direct says, “Get these hardy annuals started in an unheated greenhouse or a warm windowsill now, and by spring they will be raring to go." Planting in January gives them time for their root systems to establish, he adds.

“I recommend lightly covering your seeds with a moist, peat-free compost – and don’t firm it down so that the plants can easily break through the surface to find the sunlight they need."

“If you’re leaving them in the greenhouse, cover the pots with mesh to keep hungry mice at bay,” adds Andrew White of Rhino Greenhouses. He shares another gardening tip, too: “When your seedlings have their first few pairs of leaves, pinch out the tops to stop them from getting leggy.”

Jamie Shipley

Jamie is currently a Managing Director at Hedges Direct Ltd, a position he has held since 2018. He has a robust skill and extensive knowledge of the horticulture and landscaping industries.

Andrew White

Andrew has nine years of experience in gardening-related topics and specialises in greenhouse growing and seed sowing. Andrew is head of sales and marketing manager at Rhino Greenhouses, so when he's not in his garden sowing the seeds for all manner of fruits, vegetables and plants, he is helping garden enthusiasts find the right products that fit their garden space.

2. Broad beans

Fresh broad beans are a delicious treat and growing them is a perfect option for beginner vegetable gardening. According to Sian, they are one of the hardiest crops you can grow in a greenhouse, and sowing the seeds now will give you an early crop.

“These beans can be planted in pots or trays and later transplanted into the ground, in early spring,” she says. “Choose a variety that is specifically suited for overwintering, like 'Aquadulce Claudia.'” You can buy "Aquadulce Claudia" broad bean seeds from Suttons.

Sowing "Aquadulce Claudia" now, rather than in the spring, means they are much less likely to be affected by blackflies, points out Chi Chi Dunford, head kitchen gardener at Sculpture by the Lakes. "And, you’re likely to see a better and earlier crop, too.

"Sow them in 7cm pots, two seeds for each pot, and thin out the weaker one once germinated," Chi Chi continues. "Keep them in an unheated greenhouse or cold frame as they don't need extra heat for germination. Plant out when they are 5cm tall."

3. Chillies

Andrew recommends sowing chillies in January if you have a heated propagator or greenhouse. “There are hundreds of varieties to choose from, varying in colour, heat and size. Chillies are easy to grow from seed and perfect for pots; keep them in your greenhouse or move them to a sunny balcony or patio once the plants are established.”

Andrew says to fill individual pots with seed compost and sow two to three seeds in each. “Cover them up with a little more compost or a sprinkling of vermiculite. Keep your chillies at 20-25°C and they should germinate within 10 days.”

He recommends potting them on as they grow larger, and feeding them with a high potash fertiliser once a week when they begin flowering.

4. Herbs

Home-grown herbs are one of the best ways to elevate dishes, and according to Sian, many grow well in a greenhouse – and are easy to start from seed. She particularly recommends sowing parsley and chives in January, which can handle cooler temperatures.

“Keep herbs on a windowsill or near the greenhouse’s light source to ensure they get plenty of sunlight,” she says. “Make sure to not overwater them.”

Whether growing herbs indoors or out, avoid harvesting them too zealously, as this will stress the plants. That way, you can enjoy a continuous crop.

5. Pelargoniums

Often known as geraniums, these tender, vibrant bloomers are cheerful patio container plants in summer and are drought-tolerant once established, too.

“Some varieties such as ‘Moulin Rouge’ and ‘Border Supreme’ can be sown in January in a heated propagator,” says Andrew. “Fill trays or pots with moist seed compost, sow seeds on top and cover them with a light sprinkle of compost or vermiculite. Keep them warm and ensure the compost stays moist. Your seedlings will germinate within two to three weeks.”

Once the seedlings are robust enough to handle, Andrew recommends transplanting them into three-inch pots. “After the last frost, harden them off (in a cold frame, if you have one) for a couple of weeks before planting out,” he adds.

6. Radishes

Radishes are a crunchy, spicy addition to a salad, and offer a splash of jewel-like colour, too.

Sian recommends these as seeds to sow in January, noting how they’re “one of the quickest vegetables to grow, making them perfect for beginners.

“Make sure they have plenty of space to grow, and sow them in succession every couple of weeks for a continuous harvest,” she adds. Thin them out as they grow if necessary, and be sure to harvest before they turn woody.

Suttons has a range of radish seed varieties available to buy.

7. Laurentia

Laurentia, or isotoma, is a pretty rockery plant and, as Jamie highlights, giving it a head start in a heated propagator now will mean sizeable plants by spring. Use a moist compost and plant in a propagator between 15-21ºC, he says.

He advises planting it out when risks of frosts have passed. "I recommend leaving it as late as the end of April or beginning of May."

These starry-bloomed beauties are also good plants for patio pots. Try “Blue Stars” from Thompson & Morgan.

8. Onions

“For large onions that are ready to harvest in late summer, sow exhibition varieties like ‘Ailsa Craig’ under glass now,” advises Andrew. “This traditional favourite is easy to grow and ideal for adding to autumnal dishes in the kitchen.

“The only downside to larger onions is that they don’t store well, so put them to use before the end of the year,” he continues. “If you’d prefer smaller onions, wait to sow your seeds until March or April.”

To grow, Andrew recommends filling a tray with compost and sowing the seeds thinly on the top, covering them up with 5mm of seed compost. “Keep them in a heated propagator or on a warm windowsill.

“When your onion seedlings are large enough to transplant, move them into 3-inch pots. In spring, plant them outside into finely raked soil, around 15cm apart.” They can be harvested from July onwards, he adds – “Let them dry in the sunshine and hang them in a cool, airy place to store.”

You can buy organic "Ailsa Craig" onion seeds from Suttons.

FAQs

What should you avoid when sowing seeds in January?

A lack of light can lead to leggy seedlings. If January’s darker days are likely to affect your indoor seed-sowing efforts, consider buying grow lights, such as these well-rated ones from Amazon.

Proper watering is important, too. Andy Tudbury, head gardener at Lincolnshire’s Belvoir Castle, highlights how your pots or trays should remain slightly damp and not wet. “'Damping off', caused by overwatering, is one of the main reasons seeds refuse to germinate,” he warns.

Another key tip to remember is to always harden seedlings off before moving them outdoors, to acclimatise them to their new surroundings. Be sure to wait until inclement weather has passed before doing so.

Can you sow any seeds outdoors in January?

It's generally a bit too early to sow seeds outdoors. However, there are some lovely winter bedding plants to add to pots, if you want to get out in the fresh air.

While it's fun to grow new plants indoors at the start of the year, ones that are out in inclement winter weather shouldn't be overlooked. Our guide on how to protect plants from frost will help them make it through to spring.