Daucus carota subsp. sativus
Carrots are descendants of Queen Anne’s Lace (Daucus carota), a wild plant. We see a lot of it here in spring hedgerows. Daucus carota is itself probably descended from Daucus maritima, the seaside wild carrot. It’s impressive how many of our vegetables originate on the sea shore! (See the footnote at the end of the lesson.)
It has fibrous, white and thin roots with a woody core. This plant has been valued for its leaves and flowers, and the leaves of carrots are indeed edible.
- Unless otherwise labelled, all carrots in these photographs are grown in no dig soil. I never loosen soil in any way for growing carrots, nor for any other vegetable.
Selective breeding started in Afghanistan thousands of years ago and resulted in larger white and purple roots. A new wave of selections in 16th century Holland created the orange carrot, perhaps for the House of Orange royal family.
Carrots are in the Apiaceae family along with parsnips. In mediaeval Britain, the carrot was white and similar to parsnip, and they share many traits including pests. Other relatives are celery, celeriac, parsley, coriander, dill and fennel. All have flowers that hang in umbels, hence the family’s common name of umbellifer.
One more family member is cumin (Cuminum cyminum). I have grown and harvested cumin seeds, in the second summer after sowing the previous April. This illustrates both how umbellifers are biennial, and the extraordinary culinary value of this wonderful plant family.
- Days from seed to first harvest: 70–90. The lower number represents summer harvests and also smaller carrots.
- Two sowings in a year can cover most of your needs.
Carrot seeds sownCarrots ready to harvestEarly springThrough early summer, last few in late summerEarly summerThrough autumn
From a single sowing, you can see the quality of carrots changing every week. They start small and very tender, then become denser and larger.
- Best climate is temperate but many are possible. In cool climates, make one sowing in mid to late spring. In hot climates, give plenty of water.
With healthy no dig soil there should be no problem of larger roots becoming woody. However, there still is the possibility of splitting, and there may be damage from pests.
Why grow them
The flavour of homegrown carrots is just so different!
A man on one of my courses said it was carrots that got him keen to grow vegetables, after he had sown a few seeds in a pot of compost outside the kitchen door. He had never grown any vegetables before, and when he pulled the first carrot to eat he was simply amazed at how it tasted. He had never known such flavours in bought carrots, and I suspect that a majority of the population no longer has any inkling about the true taste and sweetness of carrots. They are missing it, and sadly do not know they are missing it!
- Baby carrots when freshly pulled give you this experience very strongly.
- Larger carrots continue to taste way better than most of what you can buy, plus they hold their texture and flavour when cooked (in a stew for example).
- When grown in healthy soil, carrots store exceptionally well. From the two sowing dates I recommend, you can enjoy homegrown carrots to eat for three quarters of the year.
Suitable for containers/shade?
Carrots can grow in shade, just for smaller harvests.
They are very suitable for container growing. The amount of harvest will be in proportion to the container used, and you can be creative.
I was contacted by a gardener in Tasmania, who grows many carrots every year in an old bath. He fills it mostly with compost, also some soil and perlite.
- Fill small to medium-sized containers with compost only, for maximum fertility. Just ensure that water is able to drain out freely.
- Weed control is easy, but you may need to protect containers from scratching blackbirds. You could cover with a wire netting cover, stapled to a wooden surround which sits on top. Alternatively, you could use netting draped over such a structure, or fleece or mesh!
- Compost used for growing two years of carrots (four to five plantings) is good to scatter as mulch in the garden, including on beds for vegetables. It has fewer nutrients but will be appreciated by soil organisms. Then use new compost in the container.
There are two classifications of carrots, although this is not strictly defined, and is more about being clear how different varieties perform.
- The first gives rapid growth in the spring and does not always grow big carrots, although they can grow large. Varieties include Amsterdam, Nantes, Chantenay and Paris Market – interestingly, all of French origin. Perhaps bred for the lucrative early market, in a country with an ideal climate for early carrots, before the use of polythene.
- The second is for later sowings, to grow large roots which store well through winter. They are denser and with a lower water content, hence they store in good condition.
My list of varieties just scratches the surface of what you may be able to buy and is to give you an idea of what to look for. In terms of flavour, I notice that the main improvements are from carrots being grown in good soil. Between varieties, I rarely notice huge differences.
Having said that, a tasting by Raymond Blanc and his chefs (as told to me) concluded that their Nantes carrots had the best flavour. That was in the gardens at Le Manor aux Quatres Saisons in Oxfordshire, UK.
- Amsterdam Forcing grows thin, pointed carrots very quickly, and is mainly suitable for early harvest.
- Chantenay carrots are half-length with broad shoulders and are quite quick to mature, so are useful for sowing at any time up to midsummer.
- Nantes varieties have round ends and grow quickly, so are suitable for early carrots. They can also grow quite large and store reasonably well. There are many different varieties of these, and I favour Nantes 2 Milan.
- Berlicum is like a larger version of Nantes. It can yield a huge harvest and the carrots store well, so I find it good to sow in early summer.
- Autumn King grows pointed carrots which store well, as long as the variety has been well maintained.
- There are many carrot varieties of different colours, and I find their flavour is often less rich. However that is a subjective observation, and they are rewarding to grow, at least for the amazing colours.
- Heritage varieties can be fun to grow. However, my recent harvest of St Valery carrots illustrates how they are not necessarily being well maintained by seed companies. See what I mean in the photos below! Heritage is heritage for a reason: something better came along.
- Bingenheimer in Europe produce good carrot seed and I find their Nantes Milan especially strong and reliable. I compared it to Nantes 2 Milan from Kings Seeds, and the latter grew larger leaves but smaller carrots, of a pale colour and more pointed – they were poor.
- Hybrid varieties give decent results and I like Nairobi F1, a Nantes which reaches harvest size about two weeks before open-pollinated Nantes. The flavour and texture are good.
- Sugarsnax F1 claims to be extra sweet but, for me, it had average sweetness, though it is pleasingly long and has good colour – see the photo below.
- Round varieties, such as Atlas and Paris Market, grow quickly and are suitable for small containers, for small to medium amounts of carrot.
- Some varieties claim resistance to root fly, but I have not found this to be the case here!
- Seeds germinate in ten days, on average.
I recommend sowing direct rather than in modules. However, a difficulty is that carrot seeds are tiny, and early growth can quickly disappear after night-time grazing by slugs or rabbits, even woodlice. Success comes from sowing in beds with no slug habitat nearby, and perhaps with a cover against rabbits. Fleece, for example, can protect early spring sowings from rabbits as well as increasing their speed of growth.
- You can multisow carrots for transplanting. However, this usually causes a break to forked and fanged roots from the all-important taproot. The taproot is your carrot, so it grows shorter and smaller. Multisowing is nonetheless possible for achieving a harvest: sow in deep modules or toilet rolls. Carrots will probably be forked and smaller as a result.
Temperature for first sowings
Soil temperature needs to be above a certain level, around 10 °C/50 °F, but there is no need to measure it. Instead, watch for new weeds appearing in your garden – a good sign for your first carrot sowing is when you first notice more than a very few.
- If you know that your carrot bed has many weed seeds waiting to germinate, best delay sowing while you wait for this to happen. Then lightly rake or hoe the surface on a dry afternoon. The delay to your sowing is probably compensated by much easier weeding of carrots.
The date of first sowing will not be in winter. Carrots were actually the first seeds I ever sowed, in January 1981! The seed packet said you could sow from January, outside, and who was I to disbelieve the experts? I now realise that it is rarely expert gardeners who write this advice.
I didn’t harvest a carrot from that sowing in 1981, in fact I never saw any leaves either. Make your first sowing no earlier than the beginning of spring, which here is sometime in March.
Minimise pest habitat
Unless your climate is dry enough that there are very few slugs and snails (or perhaps the soil is sandy, which also means few molluscs), it’s vital that you sow in open ground. There must be no decomposing wooden sides or vegetation nearby, no mulch of hay or straw, not too much long grass along edges, and no nearby containers or dry stone walls. All of these may be habitat for slugs and snails.
I often hear the comment ‘my carrots never came up’. Usually, they would have done, but were eaten rapidly and therefore never seen!
Giving seeds what they need
The soil/compost surface needs to be reasonably fine, but not perfectly so. For example, I never sieve compost for beds, and sow into a surface with many lumps the size of marbles.
This is better than a fine soil surface which can easily be compacted by rain, a process called ‘capping’. The result is a hard layer at the surface, which prevents the emergence of germinating leaves.
- Best spread the compost just before winter, then rake it smooth in early spring. Two separate and quick sessions of raking is good, on dry afternoons – the surface movement serves to kill germinating weed seeds. Here I aim to do it first in late February and then again in mid-March, across all empty beds in fact.
Seeds need to be about 1 cm/0.5 in below the surface level, to keep them moist while germinating. However, if sown too deeply, the tiny carrot seeds may not be able to grow their leaves enough to reach daylight.
- To make lines in the compost for sowing into, use any of a wooden dibber, a ridging hoe, the corner of a rake, or your fingers. The hollow line is called a drill.
- Drills can either be along a bed or across it. The advantage of across is that, for beds 1.2 m/4 ft or wider, they make it possible to put your feet between rows to reach the middle.
- Hold a decent number of seeds in the palm of your hand and then hold the hand downwards, so that seeds trickle into a curved shape made by your four fingers.
- As seeds descend, rub them between your thumb and fingers so that they fall into the drill, all the while keeping your hand moving along the length of the drill.
- Rehearse this with some dry sand, before using precious seed.
With some practice, it’s possible to sow quickly and evenly, almost at a walking pace when drills run along the bed.
For sowing larger areas, I would invest in a seed drilling tool. This is economical with seed and gives precise results.
- Nonetheless, you can see that I am growing quite a large number of carrots, just using my fingers. And one of many advantages of handwork is the ease of intersowing between other vegetables.
Once seeds are in place, use a rake or your fingers to level the surface, which results in the drills being filled with sometimes quite dry compost. This is fine, and in dry weather it’s good to walk on the drills, to firm them and conserve moisture.
The width between rows for spring sowings can be as little as 15–22 cm/6–9 in. Sow seeds at two per centimetre/five per inch and you can expect about three-quarters of them to germinate. This close spacing gives early harvests from a second thinning after about two months – see below.
Carrots for autumn and winter, which you want to be large, can have 30 cm/12 in between rows. Sow three seeds per two centimetres/seven per inch, and after two to three months thin to about 2.5 cm/1 in between each carrot.
- Once carrots are growing strongly, say after about three or four weeks, you may see that you sowed too thickly, a common experience! It’s worth doing a quick first thin of seedlings wherever you see them in thick clumps.
- The best stage for this first thinning is when you see one or two true leaves – don’t worry to do it too precisely, or you may reduce harvests from the second thin.
A huge advantage of this is the gain in season length. Carrot seeds spend six weeks germinating plus growing into small seedlings. During all this time they need very little light and moisture. They also probably benefit from nearby companions.
The intersowing method is the same for all vegetables, apart from adjusting spacings a little so that they can fit between existing plants. My examples below cover the two main seasons of sowing.
If you like eating radish, sow them with early carrots in the same drills for a ‘free harvest’.
- Because the radish emerge quickly, revealing the lines you sowed, this makes early weeding easier between the rows when carrot leaves are barely visible.
It’s important not to sow too many radish seeds because they risk smothering the little leaves of carrots. About one radish seed per 5 cm/2 in is the maximum.
Harvest radishes five to seven weeks later, with a gentle pull to ease them out – this does not damage the more deeply rooted carrot seedlings.
Carrot sowings in early summer can be between a few different vegetables. Examples are garlic, lettuce which you are picking for outer leaves, and spring onions, depending on how you spaced them.
You can discover more options of different vegetables to sow between. Also of other seeds to sow with your carrots, such as spring onions perhaps.
Best results come from ensuring that the newly made drills are moist before you sow. In early spring this is not usually an issue, but in summer it’s often worthwhile to walk alongside the newly made drills with a watering can, dropping a decent amount of water into them. Then sow seeds on the moist soil at the bottom of each drill.
After sowing, rake the bed level, often with drier soil or compost above the new carrot seeds. Following that, it’s rare that you need to water for about the first six weeks, as long as the drills were moist.
- Check for the emergence of carrot seedlings within 10 to 14 days – if you do not see many and it is dry, there may not have been enough moisture for seeds to germinate. In this case, give the whole bed a good soaking.
- After that you should not need to water too often. Not before carrots are more than medium size, then perhaps twice a week in dry weather.
Carrots do not need a huge amount of water, and they taste sweeter when soil is a little dry. The amount is about half what you might give to strongly growing cabbage.
Extra mulch to retain moisture?
I do not recommend this for two reasons:
- Any undecomposed mulch before sowing will harbour slugs and woodlice, causing loss of seedlings. However, a compost mulch is fine in this regard.
- Carrot leaves make a dense canopy that retains moisture.
See above for a first thin of very small seedlings within the first month. The next thin is about one month later – this is the joyful moment of your first harvest!
Look along each row to spot carrots that are grouped more closely to each other than about 5 mm/0.2 in. From any such clumps, choose the larger carrots for harvest. Ease each one upwards, while firmly holding the main stalk, close to the carrot’s shoulder. Sometimes it’s easier to pull two or three together when they are very close and perhaps even intertwined.
With no dig and compost mulch, even on clay soil, it should be possible to pull carrots without using a tool. However, if the soil is hard from being dry, you need to water before each harvest.
- If for any reason a stalk snaps before the carrot pulls out, use any hand tool with a pointed end (trowel/hori hori) and insert it close to the carrot row, vertically downwards.
- With slight leverage, and while pulling the carrot, you can loosen it enough to harvest. Be careful not to lever too much, otherwise you may break the taproots of neighbouring carrots.
How to judge readiness
One sign is when you see the shoulders of a few carrots above the surface level. They are large enough to be pushing upwards a little, as well as growing downwards. This is the moment to do a first thin for harvest.
- When carrots are nicely spaced, without being overcrowded, you have the lovely choice of harvesting now or leaving carrots to grow larger.
- If new plantings are establishing among carrots, as with Brussels in the photos below, keep pulling the carrots nearest to them, as the Brussels/new vegetables grow and need more moisture.
When to pick and how often
Aim to maximise the use of both bed space and sunlight. Therefore, during the first month of harvests from any one sowing, keep pulling just the largest carrots while leaving their smaller neighbours to grow.
- This maintains a full cover of leaves.
- The effect is enhanced by interplanting of new vegetables, such as Brussels sprouts. For three weeks after transplanting them in the carrot bed, we keep pulling carrots that are close to them, to make more space and still have good leaf cover.
At some point after that, you may want to clear ground or take a large harvest, and then it’s quick to pull carrots from a whole area. Soon afterwards, in this case, the Brussels sprout leaves cover all the surface.
Even in the warmth of summer, homegrown carrots can store for up to a month. Just leave any soil or compost on them after pulling, and keep in a paper sack somewhere cool.
Storing carrots for winter is exactly the same process. They do not need to be packed in sand, although you can if you want to. Possibly this keeps them a little moister.
- Grade carrots at harvest, to wash and use the small ones first while leaving the large carrots unwashed for storing long term.
- Any stored root vegetable loses moisture over time, becoming softer and slightly shrivelled after three to four months. However, even at this stage, the flavour is excellent, just with a dense texture.
- During or towards the end of winter, wizened roots still have leaves growing out of them, showing that they are alive and good to eat. A similar process to sprouts on potatoes.
From an autumn harvest, you need to select about ten carrots of best size, shape and quality. These are worth storing in sand over winter. Plant them out in March/early spring, 30 cm/12 in apart.
The flower stems are beautiful, and by midsummer their white flowers will have converted to seeds. At this point there’s a risk of seeds falling out, during a heavy rainstorm for example. Watch for that, and do not grow carrots for seed within about 20 m/65 ft of wild carrots.
It’s a skilled process – do find out more before undertaking it.
Which pests are likely, and when
There are many, and here are some common ones:
- Slugs cause damage to new sowings, as mentioned above. They eat into carrot roots making round holes, particularly when carrots are in the ground for more than four months from sowing.
- Rabbits and deer are voracious for carrot leaves. The tell-tale sign is a carrot stalk with no foliage on it!
- Rats and mice chew on the shoulders of carrots. You notice small teeth marks, and it’s difficult to say exactly which pest made them.
- Carrot root flies are so small you rarely see them. They lay eggs on soil near to carrots they have found by smelling. The eggs hatch into maggots which tunnel into carrots and keep going around them while eating. This results in a dark circle of rotting carrot. In bad cases, you can lose almost a whole crop – see details below.
Covers solve most of these problems, whether fleece in the spring or mesh in summer. As long as there are no holes, you have protection against carrot root fly. Nonetheless, it seems a few always manage to crawl under the edges of any cover.
Covers such as bird netting also protect against rabbits and deer.
For rodents, you may need to set traps.
For slugs, it’s as I describe above: keep their habitat very, very minimal.
Carrot root fly (Psila rosae)
The flies are rarely seen – shiny, black and 6–8mm/0.2–0.3in long. The most spectacular damage happens to carrots, but all umbellifer roots suffer some eating by the maggots.
Carrots suffer the most because they have a higher surface area, and their flesh is more tender. Parsnip and celeriac, in contrast, have more fibrous bulbs or roots.
There are two hatchings every year, the first one in May and the second one in August to September. The second hatching is often the most numerous, and it’s vexing because carrots for storing over winter may then not store well. If present at harvest time, maggots continue to eat the carrots, even when stored in boxes, socks, or sand.
Ways to reduce damage:
- None are 100% effective, in my experience.
- Cover the whole sowing with mesh. This includes securing the sides more than one needs to for butterfly protection. The cover needs to go on in April and stay on until, say, mid-June. Then, for summer sowings, the cover needs to go on by the second week of August.
- The root flies stay low to surface level, and some gardeners have success with creating a polythene ‘wall’ around their carrots, rather like a windbreak. It needs to be at least 60 cm/2 ft high, and this can be difficult in windy situations.
- It is claimed that interplanting helps to confuse the flies, so they struggle to find the umbellifer plants and lay fewer eggs. For example, the smell of onions is supposed to deter them, and one year I experimented with a mix of carrot and many onions in the same bed. Damage to the carrots was actually worse than normal, so I reckon this is not a foolproof way to protect carrots from pest damage.
- Timing is perhaps our best way to achieve a healthy harvest, if not 100% perfect. Carrot sowings in early spring can give quite big harvests, before the flies arrive in late spring. Then sow in June rather than May for winter carrots, so that you have just the second hatching to contend with.
Some years the flies are less common and you may see no damage. Or you may be on a windy hillside and the flies just keep blowing away before they can lay many eggs.
Other likely difficulties
Splitting roots is perhaps the main issue and usually happens with older carrots, which are more than four months old. It should only happen to a few, and may be encouraged by overwatering.
Carrot shoulders turn a red colour when exposed to light. This is not edible and can simply be cut off, or pull compost over the shoulders of large carrots to keep them orange.
Every so often, during my 40 years of growing carrots, I have noticed a few with discoloured, purple skin, perhaps rotting at the bottom. However, this has never been bad enough that I have needed to find out more. If you are troubled by anything like this, I suggest searching on the internet. Here I don’t want to frighten readers into thinking that diseases can be a major problem. In healthy soil, they are not.
After the final harvest of a carrot bed, all you need to do is remove any small weeds and rake it level. After the last autumn carrots, and before winter, we spread 2.5/1 in of compost.
Your options depend on when the carrots are finishing, or which interplants you want to grow. In my example with Brussels sprouts, you could instead interplant with cabbage, kale, swedes, dwarf beans, or multisown leeks and beetroot.
Follow summer harvests with any of the above, also lettuce or chicory.
In 1860 we gathered some seed of the Daucus maritima (sea-side carrot) at Bognor, which, on being sown in a prepared plot the following spring, certainly resulted in fairly succulent roots, which on being cooked were pronounced by our party of four to be excellent. While on this subject, it may be mentioned as not a little remarkable, that so many of our garden esculents should be derived from sea-side plants. Thus, probably carrot, but certainly celery, sea-kale, asparagus, and cabbage. This would seem to point to the fact that cultivation requires a complete change of the circumstances necessary to maintain a wild condition; and hence cultivated plants can only be kept up by the labours of a cultivator.Now, as regards the sea-side carrot, we are after all inclined to the belief that it is the parent of the cultivated varieties, whilst, on the other hand, we view the Daucus Carota (the wild inland carrot) as a probable descendant from the cultivated or garden stock; and if this be so, the Daucus maritima is the original species from which both the wild and cultivated races have descended.
Science and Practice in Farm Cultivation, by James Buckman, F.L.S., F.G.S. late Professor of Geology and Rural Economy at the Royal Agricultural College (London: Robert Hardwicke, 192, Piccadilly. 1865.)