When to plant carrots – to get the best harvest

Know when to plant carrots and you’ll be able to grow them almost all year round with ease. 

Full of fibre, Vitamin A and beta-carotene, carrots are a delicious and nutritious vegetable. They can be grown really successfully in containers, greenhouses and directly outside, all providing you get the timing right. 

With so many varieties to choose from, it’s no wonder carrots are such popular vegetables to grow and to eat. With a little know-how, you could be enjoying these fresh, crunchy homegrown veg for most of the year, regardless of the amount of space you may have for growing them. 

If you're interested in knowing how to grow carrots, then when to plant them is key to ensure a good crop. Here’s everything you need to know.

When to plant carrots

Carrots are a cool weather-loving crop and do best in full sunshine. With this in mind, knowing when to plant carrots will ensure you get a really excellent crop every time as part of your kitchen garden ideas. 

The general rule of thumb is to plant carrots in the springtime, about three weeks before the last frost is due, which will vary depending on the zone or area where you live.

As carrots are a long crop, Nick Welsh, owner of Seed Craft, recommends sowing 'rows of radishes between the rows of carrot. This not only helps mark where your carrots are, but also the radish loosen the soil allowing the carrots to grow better, while maximizing your growing space.'

There are also other choices for carrot companion planting to help boost the crops' health  and harvest.

What is the best month to plant carrots?

When thinking about the best month for when to plant carrots, there are a few variables to consider. You must take into account your specific climate, as well as the location you plan on planting the carrots – for instance whether part of your vegetable garden container ideas or directly into the ground.  

As a general rule, carrots should be sown in early spring and again in early fall. Carrots need warmth to germinate and, as such, a temperature of about 50°F– 80°F (10°C–26°C) is perfect. However, they will germinate at temperatures as low as 40°F (4°C).

'Carrots can be started from 1 April in the Midwest,' explains Mike Davison, greenhouse manager at Platt Hill Nursery in Illinois. 'They need plenty of sun to grow well, so the longer spring days are perfect.'

Be aware that some varieties will bolt if temperatures are too low, so choosing a variety that is hardy is key if you want to start sowing even earlier in the year. 

When to harvest carrots? You can force an earlier crop by using a cloche to protect your seedlings from frost. Varieties such as the Amsterdam and Nantes are good, fast maturing varieties, making them excellent for growing under cloches in the colder winter months. 

When can I plant carrots outside?

'Plant carrots any time from early spring once the threat of ground frosts have gone, right through until early fall, advises John Stolarczyk, curator of the World Carrot Museum. 

'Make additional plantings every three weeks through midsummer for continuous supply and a fall harvest,' he adds.

There are a couple of things to consider when planting carrots directly outside: 

• Dry carrot seeds will not germinate, so keep them well watered until you start to see shoots.
• Soil that is too rich will result in excessive leaf growth and forked, rough roots, so don’t work any additional fertilizer or soil improver into the ground before sowing.

Carrots are a cool season loving root vegetable and grow best in these conditions. For this reason they make an excellent addition to your vegetable garden almost all year round.

Can I sow carrots in containers? 

You can grow carrots in containers when you only have a small space. John suggests you should choose pots that are at least 12 inches deep and have good drainage. 'Choosing smaller varieties such as Thumbelina, Orbit, Parmex, Oxheart or Little Finger for container crops,' he recommends.

As carrots are quite a long crop, taking 10 to 16 weeks before they are ready to harvest, Mike Davison advises 'a fun thing to do is plant some leaf lettuce or grow spinach in with the carrots to have more in the planter boxes or containers.' This will give you something delicious to harvest while you are waiting for your carrots to develop. 

Can I plant carrots in a greenhouse?

If you don't manage to plant any carrot seeds in the ground during early fall, you could think about planting some in your greenhouse over the winter months for an early spring crop. 

Make sure you choose a sunny spot in the greenhouse and sow directly into well-drained compost. 

'Carrots like loose rich soil, preferably a little sandy, and soil that’s been worked quite deeply. Having loose sandy soil, will allow you to grow long slender straight carrots,' explains John. 

How to avoid carrot fly

Carrot flies are your carrots biggest enemy and will devastate an entire crop very quickly. 'Thin seedlings after you have watered, this will reduce the risk of breaking the roots and releasing the scent that attracts the fly,' advises Nick Welsh of Seed Craft.

As carrots flies can only fly about 60cm off the ground, Nick also suggests, 'erecting a a barrier of fine mesh or horticultural fleece higher than this around your bed, to stop them from reaching your crop.' 

Now that you know when to plant carrots you’ll be able to grow your own delicious crop at home or in your vegetable garden.