Cultivation of the Carrot

 

Navigation of this page:

Growing at Home

Easy Guide

Common Problems

Harvesting

Storage

Annual Calendar

Seed Suppliers

Carrot Fly

Seeds

Dealing with carrot fly. HERE   How do Carrots produce seeds? HERE Download your own Growing Card here.

Why do carrots flower rather than form a usable root? Carrots require cold weather (chilling) to form flowers. If planted too early, this can occur.

Why do some of my carrots form many roots rather than one long root? Carrots form multiple roots (fork) when damage to the primary root occurs. Forking is associated with rocky, stony, or heavy soils. Carrot fly damage can also cause this problem. Deep digging, the addition of compost, and pest control will help reduce this disorder.

I regularly have very pale yellow coloured roots. Why does this happen? Hot weather and hot soil temperatures are responsible for poor colour formation in the roots. When temperatures go above 85°F, keep the plants well watered and mulch around the roots to cool the soil.  More answers here.
 

Watch some simple instructional videos from the Gardeners World Net - click on photo to learn more.

The carrot is a cool climate crop and can be sown early in the Spring in temperate climates, or in the autumn or winter in sub-tropical areas. The carrot plant is biennial, that is one which completes its life cycle in two years.  It stores in the first year what it is going to use in its second to produce seed. We interrupt its life cycle by gobbling it up in the first year before it has time to reach maturity. In the first year the plant produces the fleshy orange tap root which is eaten. If left in the ground the plant will flower the following spring.  Read more about how carrots flower and produce seed here. Read more about hybrid seeds here.

Watch the very informative video from Heritage Seed Library (part of Garden Organic) on how to collect carrot seeds. Here. (YouTube video)

The carrot's fruit is an akene, (a dry indehiscent, one-seeded fruit, formed from a single carpel and with the seed distinct from the fruit wall.) and holds thorns that allows it to remain on the plant during ripening. So called seeds derived from plants in the carrot family are not actually seeds at all, but rather complete fruits that are dried. These include anise, caraway, coriander, dill and fennel.

Not all of the chemical constituents of carrots are for our health; some appear to be there for the health of the carrot itself. One reason that the carrot can be stored for long periods of time, such as over winter in a root cellar, is that the carrot has a mechanism to guard against microbial decomposition (rot).

There are three enemies of carrot storage: wilt, re-growth and rot. The first of these is no problem if the carrot is stored where the humidity is high. The second is of little consequence if the carrot is stored at 0 to 5°C.

The carrot itself contributes much toward conquering the last enemy, rot. At the present time, scientists are busy determining how the disease response mechanism of the carrot operates. There appear to be three lines of resistance which the carrot uses, based on the chemicals contained within the carrot and its skin.  Read more about the Carrot Disease Response Mechanism and the contributory elements.

Growing carrots is still not an exact science and is considered by many home gardeners as a bit of a gamble. Visit new bingo sites here.

 Carrots fall naturally into groups according to their use, to see photos of some of these varieties click here.   For the A to Z of common varieties click here.

Fast maturing varieties: bred for forcing in cold frames or under cloches. The Amsterdam and Nantes types are shorter than main crop carrot and cylindrical rather than tapered, try Bolero and Ingot.

Stump Root Varieties: such as Early French Frame, these together with the fast maturing varieties often possess good flavour and can be frozen whole.

For tiny gardens and window boxes: try a round sort such as Rondo or Suko. Carrots do well in containers. Choose pots that are at least 12 inches deep and have good drainage. Use potting soil enriched with compost and keep the soil moist. For best results, look for small or "baby" varieties such as Thumbelina, Orbit, Parmex, Oxheart or Little Finger.

Traditional Summer Carrots: these have the prefix Chantenay which are short and squat with a pronounced taper.

For eating over Winter: one of the best in Autumn King, with a good flavour and long tapered roots, Long Red Surrey, first introduced in 1834, has to be one of tastiest varieties as it has a distinctive yellow core, it is out of favour with commercial growers but well worth growing.
James Scarlet Intermediate is another older main crop (1870) and well worth the try.

The healthiest Carrot? It's got to be Juwarot containing almost twice the carotene of any other carrot. High carotene carrots you can grow are 'Ingot' (particularly sweet flavour), 'Beta Champ' (great for juicing) and 'Healthmaster' (slow to grow but again quite sweet). Some high carotene carrots also tend to be high in turpenoids which can make some carrots strong tasting and bitter.

If you are allergic to carotene sow White Fodder and you will not be disappointed.

Companion Planting - Carrots do well alongside most plants, especially chives, Rosemary and Sage (which deter Carrot Fly). Dill, Coriander and other members of the Umbelliferae family should not be planted near carrots as they tend to cross pollinate which can be important if you are subsequently trying to save your own seed.

To see an explanation of the various parts of the carrot root, including diagram click here.

Examples of typical carrot root shapes here.

How do carrots produce seeds ?

Carrots are biennial plants and only flower every two years. In the first year the plant produces the edible root and a leafy top. If a carrot plant is left in the ground for another year, it flowers and seeds are produced. If the original carrot was sown using F1 hybrid seeds it may not reproduce properly, or not at all.

Sexual reproduction in carrots is therefore not different from other flowering plants. Pollen is produced and transferred to the female part of the flower, the stigma. The pollen grain then delivers the sperm cells within it to the ovary via a long tube where fertilisation takes place.

The seeds are tiny - a teaspoon can hold almost 2000!
The birds-nest-shaped fruit cluster of carrot has a remarkable mechanism for seed dispersal. The stalks are hygroscopic, so that when conditions are dry and suitable for seed dispersal they bend outward, exposing the fruits to wind and animals; when conditions are wet, they bend inwards, forming the familiar bird’s nest structure, which protects the seeds.

 Read more about how carrots flower and produce seed here.

Factors Affecting the Colour of Carrots

1. Temperatures above and below the optimum (above 70° and below 60°F) reduce the colour of carrots.

2. Spring and summer carrots are often of better colour than autumn and winter.

3. Carrots grown on sandy soils and soils high in organic matter produce a higher colour than did carrots on silt loams.

4. Excessive water decreases the colour.

5. Reducing the number of daylight hours has reduced the colour.

Colour is more intense in the older portions of the root. It decreases from the epidermis and center toward the cambium, and from the top to the bottom.

Carrots can taste soapy or bitter - Two ingredients determine a carrot's flavour: sugars and terpenoids (volatile compounds that impart the carrot flavour). Some varieties are naturally high in terpenoids, which make the carrots taste bitter or soapy. Because terpenoids develop earlier than sugars, a carrot that is harvested too young might taste bitter.

The taste in carrots is based on the right balance of sugars and terpenoids. Terpenoids produce a soapy turpentine-like taste that will mask sweetness. Differences in flavour components have been found to be attributable more to genetics than to climatic conditions; however, the controversy continues. Volatiles can also increase during cold storage (around -1C) which is a common practice (even for organics!)

Many different terpenes in carrot can cause a turpentine-like taste. Usually terpenes give a desirable taste to carrots, but in high concentrations can give undesirable taste. Factors influencing undesirable taste include genetics, growing conditions, diseases and insects, post-harvest handling and storage atmosphere.

Storing carrots near apples or other fruits that manufacture ethylene gas as they ripen, encourages the development of terpenoids in the vegetable and causing them to become bitter when exposed to ethylene. Read more here (pdf)
Raw carrots will taste more soapy than cooked ones, as cooking breaks down the terpenoids allowing the sweetness to come through.
The Nantes variety produces roots which have higher sugar content, lower in terpenoids and less suitable for long-term storage.

A lot depends on the growing conditions ( if you grow your own) - the flavour is best if they mature when days are warm and sunny and nights are cool and still. The plant is photosynthesizing like crazy in the daytime and putting a lot of sugars down into the root, then a cool night comes and the carrot 'rests' instead of burning up that sugar. Where the night time temps stay in the 60s or warmer, the plants respire more at night and use up the accumulated sugars. So for the sweetest roots, time your carrot crop to mature at a time of year with warm days and chilly nights. and no matter what the conditions, harvest late in the day rather than in the early morning.

One old wives tale I have heard, but not proven - take 2 pounds of carrots and boil them with three whole cloves and a bit of salt, is supposed to make them sweeter. (if you try this do tell me what you observe).

Carrots prefer light sandy soils so if your garden earth is on the light side you will have no problem. If you garden on clay or stony land then your carrots will always struggle. You will not fail so long as you are careful which varieties you choose - round or stumpy rooted types will succeed practically anywhere, whereas long rooted, tapering types will faulter. Carrots do well in containers. Choose pots which are at least 12 inches deep and give them good drainage. Use potting compost and keep them moist at all times. For best results try small varieties such as Parmex, Oxheart of Little Finger.

If soil or space is a big issue for you please note that Carrots and other root vegetables will grow well in containers as long as the pot is deep enough.  Be sure to choose a container that is twice as deep as the length of the carrot at maturity.

Maintenance  

The first few weeks after sowing determine the size of your crop. Carrots do not tolerate a deep planting in a dry bed, so the trick is to offer them a shallow sowing with even moisture. The seedlings grow slowly and can't compete with weeds. As they develop top dress with old manure or compost, avoid "hot" nitrogen sources like fresh manure and fish fertilizer as they cause new roots to "burn off" and fork.

Hand weeding is recommended until the carrots are 5cm tall. Thin the carrots to 8cm apart, then mulch with clean straw and compost to keep the weeds at bay.

Mulching also helps the soil retain moisture and prevents "green shoulder," which is caused by exposing the crowns of the carrots to the sun, making the roots bitter. If the tops of your carrot roots start to turn green, pull the soil up around them. Over watering your carrots can cause the roots to crack.

Harvesting - Most carrots can be harvested in less than three months. they can be picked anytime they reach a usable size. The largest carrots will have the darkest, greenest tops, but don't leave the roots in the ground too long or they will be tough. Most are at their prime when about 2.5cm in diameter at the crown.

Do not be fooled by the tops which can be quite bushy but in fact the carrots themselves are quite small. When harvesting, drench the bed with water first, making the carrots easier to pull.

When you find a carrot large enough, grasp the greens at the crown and tug gently with a twisting motion. If the greens snap off, carefully lift the roots with a small fork. Use damaged roots right away and store unblemished ones.

Lifted carrot should not be left on the ground surface for too long as they will attract the attention of carrot fly. Cut the leaves off as soon as they are out of the ground; as long as they are attached they continue to keep growing and draw moisture and nourishment from the roots.

During the first five months of storage, carrots will actually increase their vitamin A content; and, if protected from heat or light, can hold their nutrient content for another two or three months. Since carrots are rich in beta carotene, steaming them makes this nutrient more readily availability to the body as heat breaks down the tough cellular walls that encase the nutrient. The crisp texture of carrots is the result of the cell walls being stiffened with the indigestible food fibers cellulose, hemicellulose, and lignin.

Annual Calendar for Carrots

Spring: Sow seeds in February for a forced crop under cloches of cold frame. March April Sow your next crop of  Amsterdam Forcing seed outside protected by garden fleece in colder areas. These will be well on the way to maturity as your first crop finishes. recommended varieties Thumbelina, Suko and Baby Sweet.

Summer: June/July Harvest forced types sow late main crops in lighter soil. Crop varieties like Chantenay Red Cored which were sown in March mature in August/September. Recommended varieties King Midas (Imperator type), Kurodo (chantenay), and Nelson nantes type).

Autumn: August/September harvest early unprotected crops. October/November lift and store main crop types on heavier soil. Dig seed beds, remove any stones sow a crop of a forcing variety and protect under a cloche over winter. Recommended varieties: Juwarot and Fly away (nantes types) and Imperial Chantenay and Red Cored which are chantenay types.

Winter: December/January on lighter soil later main crop types can be left in the ground and lifted as needed throughout the period. If the weather is really cold or wet, protect with a covering of straw in early December.

Recommended varieties: Artist and Merida (nantes types) and Camberley and Scarlet Keeper (danvers types).

Easy Guide

Here is a guide to common problems: (Useful photos and information here (pdf)

Carrots often have forked or branches roots or develop thin secondary roots - why?

Damage to the growing tip of a young carrot. Common causes include soil insects and nematodes which feed on the growing tip resulting in branching of the carrot root. Carrots need a loose, friable soil to develop a good shape. Forking is caused by anything that impedes root growth. This includes nematodes, stones, or heavy, compacted soil. Causes include soil insects and nematodes which feed on the growing tip resulting in branching of the carrot root.

Gardeners are often dismayed when they harvest hairy or misshapen carrots. Imperfect carrots, or carrots with multiple roots – many of them twisted around each other – may come from several causes, including spacing, soil type, fertility, pests and disease.

Your carrots could be overcrowded. Next time, try thinning them to an inch apart after the leaves reach about three inches high.

Did you plant them in clay soil? If you have heavy clay soil, the clay sometimes forces the roots to grow crooked. Amend clay soil in next year’s carrot patch with well-broken down leaves, well-rotted compost. Carrots do well in light (sandy), fluffy soil that is not too full of amendments. Root-knot nematodes may cause deformed carrots. You can either verify this with a soil test and then you might have to solarize (treat soil with the sun’s heat using plastic sheeting in the summer), or rotate your carrots to another area next time.

Did you fertilize right before you planted your carrots? Excess nitrogen (over fertilization) can cause carrots to form multiple roots or get “hairy.” If you add manure-laden compost to your soil, do so in the fall, then let it overwinter before planting carrots in the spring.

Carrot roots will also become hairy in waterlogged ground.

Did you leave your carrots in the ground too long? Carrots are biennials. The first growing season, they grow a taproot. Next they put out secondary roots off the taproot, and then put up the flowering stem the second year. If you planted your carrots last fall, then overwintered them in the ground, they might be sending out whitish secondary roots by now and maybe a stem. Some varieties are more prone to bolting than others.

Cornel University, New York, has a useful  list of fact sheets on common carrot diseases - click here.

The University of California has some photos and further detail of common problems. - click here.

More photos and information here (pdf)

BUY YOUR SEEDS HERE:    Any seeds bought via these links makes a small a contribution to the upkeep of the World Carrot Museum.
 

Thompson & Morgan have a tremendous variety of carrot seeds for you to try, click on the link or banner to buy some.    See photos of common varieties supplied by Thompson and Morgan the leading seed suppliers in the US and UK. Click here.

Plant Me Now has a good range of carrot seeds and other carroty items.

Garden BargainsGarden Bargains has exactly that, and carrots!

 

B & Q for all your gardening needs.

Gardening Direct offer a fantastic range of great value, top quality plants, grown under greenhouse conditions and delivered direct to your door. Choose from a fantastic product range including Vegetable seeds and plants and the gardening hardware range.

Some Other Sources of Carrot Varieties for United States Home Gardeners

William Rubel gives a detailed commentary on the main online catalogues.

 

Evengreener is the UK's leading manufacturer of water butts and home compost bins. A genuinely 'green' company dedicated to providing useful products to help re-use, recycle and conserve resources.

The next page gives an in depth guide into carrot cultivation. This includes details on the best types of soil, cropping information. There is analysis of the number one pest - the carrot fly, categories of pests and diseases and the detailed classification of carrot types.

Check out articles of an anecdotal, humorous and gardening kind at this splendid web site - Garden Blethers from the Scottish Highlands. A serious look at the 'not so serious' aspects of gardening life (with the occasional serious 'bit' thrown in!) Click here to go there.

Need advice? try Organic Vegetable Gardening (uk), one of the best vegetable advisory websites in the UK. Their aim is to help gardeners grow their own fresh, tasty vegetables and fruit using dedicated growing guides,  and to give advice from fellow gardeners in a friendly forum.

Next Page - Cultivation - In depth guide