Carrots are one of the most popular and rewarding vegetables to grow in the UK. Sweet, crunchy and versatile, they are a staple of many home gardens and allotments. They may seem simple at first glance, but successful carrot growing requires careful attention to timing. Knowing when to plant carrots ensures a steady harvest, healthy roots and maximum flavour. Carrots thrive in cooler conditions and are relatively easy to cultivate once you understand their preferences. Whether you are a first time gardener or an experienced grower, getting the timing right will help you enjoy abundant crops throughout the season.
The growth cycle of carrots
Carrots are biennial plants, which means they complete their life cycle over two years. In the first year, they produce the edible taproot that we grow them for, along with leafy green foliage above the ground. In the second year, if left unharvested, they produce flowers and seeds. For gardening purposes, we focus on the first year, aiming to produce roots of good size and quality. Timing the sowing of carrot seeds is vital to ensure they have the right conditions to develop strong roots before bolting or becoming woody.
Ideal sowing seasons in the UK
In most regions of the UK, carrots can be sown from early spring through to mid summer. The main sowing season runs from March until July. The earliest sowings can be made under cloches or fleece from late March, depending on soil temperature. Carrots need soil temperatures of around 7 to 10 degrees Celsius to germinate successfully. Sowing into cold or wet soil can cause seeds to rot or fail to germinate, which is why waiting until the soil has warmed slightly is important. Later sowings in June and July can provide roots for autumn and winter harvests.
Early sowings for baby carrots
For those who want the first tender carrots of the season, early sowings can be made in March and April. These are often small, fast maturing varieties that produce sweet baby carrots ideal for eating fresh. Early sowings may need protection from frost using fleece or cloches, especially in northern regions. By providing some cover, you can start the season earlier and enjoy fresh carrots by early summer. Early sowings are best eaten young, as they do not store as well as maincrop carrots.
Maincrop carrot sowings
From May through July, conditions are ideal for sowing maincrop carrots. These are the larger, slower maturing varieties that produce robust roots suitable for storing. Maincrop carrots sown in early summer will mature in late summer and autumn, providing generous harvests. Because these varieties grow over a longer period, they need stable conditions with consistent watering and protection from pests. Maincrop carrots are often grown for their ability to keep well through the colder months, especially when stored correctly after harvest.
Successional sowing for a steady supply
Instead of sowing all your carrots at once, many gardeners prefer successional sowing. This means sowing small amounts every two to three weeks from March to July. By staggering the planting, you ensure a continuous supply of fresh carrots rather than one large glut. Successional sowing also reduces the risk of losing an entire crop to pests or weather, as different sowings may fare better under different conditions. Timing is therefore not just about when to start but also about maintaining a rhythm of planting throughout the season.
Soil preparation and timing
Carrots grow best in light, sandy soil that is free of stones. Heavy clay soils can cause roots to fork or split, so improving the soil before sowing is important. Soil should be prepared in late winter or early spring, ensuring it is loose and fine by the time seeds are sown. Adding well rotted compost can improve structure, but fresh manure should be avoided, as it encourages forking. Preparing the soil in advance ensures that when the time is right, seeds can be sown straight away into favourable conditions.
Why sowing too early causes problems
While the temptation may be to sow as early as possible, carrots sown into cold, wet soil are likely to fail. Germination rates are low in these conditions, and seedlings that do emerge may grow slowly and attract pests such as carrot fly. By waiting until late March or April, when the soil has warmed, you give the seeds the best chance to thrive. Early sowings that struggle often result in disappointment, while patience ensures a stronger, healthier crop.
Late sowings for winter harvests
Carrots sown in late June or early July can be harvested well into autumn and even winter, depending on the variety. These late sowings are especially useful for gardeners who want fresh roots after summer has ended. Some hardy varieties are bred for overwintering and can remain in the ground through mild winters, although protection with fleece or mulch may be needed in colder regions. By timing sowings carefully, it is possible to enjoy carrots almost year round.
Regional differences in sowing time
The timing of carrot planting varies slightly across the UK. In southern regions with warmer climates, sowing can begin earlier in spring and continue later into summer. In northern or higher altitude areas, the season is shorter, and sowing may not begin until April. Gardeners should always consider local conditions rather than relying solely on general guidelines. Observing soil temperature and weather patterns provides the most reliable indicator of when to start planting.
The importance of thinning seedlings
After sowing, carrots often germinate thickly, and thinning is necessary to allow roots to develop properly. Timing is critical here too. Thinning should be done when seedlings are a few centimetres tall, ideally in the evening when carrot flies are less active. Removing excess seedlings at the right stage prevents overcrowding and ensures carrots have enough space to grow. Although thinning may seem wasteful, it is vital for achieving strong, straight roots.
Conclusion
So, when should you plant carrots? The answer depends on what you want from your crop. For early baby carrots, sow in March and April under protection. For maincrop varieties, sow from May to July for larger roots and good storage potential. Successional sowing every few weeks ensures a steady supply throughout the season, while late sowings provide crops into winter. Timing is guided by soil temperature and local climate, with patience proving more successful than rushing. By planting carrots at the right time and preparing the soil well, you can enjoy one of the most rewarding homegrown vegetables throughout much of the year.
