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How do Carrots Produce Seeds?  

Carrot (Daucus carota L.) develops 'umbels' which are groups of flowers which produce seeds. Carrot seeds are not true seeds in a botanical sense but are dry fruits called 'schizocarps'. The Carrot is not a fruit in the common understanding, so there are no seeds inside or on the carrot. The part of the carrot that you eat grows in the ground, usually with the wide end of the carrot just at the surface of the soil. The round mark you can see on that end of the carrot is where the leaves used to be - a big soft bunch of deep green leaves that look a bit like a fern.

Then the carrot is ready, it sends up a tall stem, which produces flowers, and eventually seeds. The seeds are very small, on average between 1 and mm in length and brownish is colour. Depending on the variety there are approximately 8000 seeds in half an ounce of seeds, so there are approximately 250,000 in a pound, roughly 2500 would fill a teaspoon.

Now for the bad news - If you are planning to grow carrots, letting one go to seed may not be the best solution. Carrots are biennial - that means they take two years to reach maturity when they can produce seeds. Secondly, the vast majority of carrots that you buy from the supermarket are F1 hybrids. That means the seed comes from TWO parents who are different. (One may be big and fat, while the other is fast growing and a nice colour.)

By using pollen from one to fertilise the flowers of the other, the plant breeder and seed specialist aims to produce carrots with distinctive characteristics which are appropriate to the market.  For example long and thin, deeper colour and consistency, or resistance to carrot fly, drought etc. The resultant carrot aims to be just what the farmer wants, but there are usually two problems for the consumer - The carrot may not have taste (low on the farmers list of priorities, because you can't cook and taste before you buy!!) and in the vast majority of cases, F1 hybrids are sterile.

If you grow an F1 carrot and harvest the seed ( after two years!!) they may very well not grow.  In some cases you just get no flowers or seeds at all, or a sterile plant or a plant totally unlike its original.  (read more below) 

Heirloom versus hybrid seeds

The big difference in vegetable seeds is whether they are heirlooms or hybrids. Heirloom seeds are those that are open-pollinated, and passed down from generation to generation. Seeds from heirloom vegetables are true to type, meaning that you can save the seed from a certain plant and expect to get the same thing when you go ahead and plant those seeds again next season.

Hybrid vegetable seeds are created by artificially crossing two or more varieties of a certain plant. Hybrid vegetables are what one typically sees being sold in the your local garden store, those rows of bright, uniform carrots are probably grown from hybrid seeds.

One big disadvantage with hybrids is that you cannot save the seed: resulting seeds may be either sterile or produce a plant totally unlike its original. Although hybrid plants produce fruit that ripens at the same time and may be more resistant to pests or diseases, they’re not selected for their taste. They are typically selected for appearance and shelf life. Hybrid seeds are typically more expensive than heirlooms, too.

Home gardeners will likely be more satisfied with heirloom vegetable varsities for the flavour they deliver, and the sheer variety of vegetable types that are available. Blue potatoes, purple carrots, and orange tomatoes are not unusual among heirloom varieties. And perhaps best of all is that gardeners can save the seed from their heirloom vegetable plants, and continue to grow them year after year, and pass them on the family and friends well into the future. The same simply cannot be said for hybrids.

To learn more about saving seed and heirloom vegetables, visit Seed Savers Exchange.

Read more about the difference between hybrid and non hybrid seeds here.  Read more about carrot seed dormancy here.


Carrot seeds do not mature uniformly within a single plant. Seed maturation depends on the positions of flowers on the maternal plant, from which seeds are originated. Flowers and seeds in different orders (primary, secondary and tertiary) of umbels exhibit various levels of maturity.

Each umbel consists of multiple 'rays', groups of flowers. Maturity of rays depends on their positions (outer, middle and inner) in an umbel, with the outer maturing first.  The birds-nest-shaped fruit cluster (umbel) of the carrot has a remarkable mechanism for seed dispersal. 'lThe 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. More about carrot seed research here.

Carrot Sead Head

Carrots are biennial, flowering in their second year of growth. In areas with mild winters, leave your carrots in the ground, mulching them heavily. The foliage will die back in autumn, but will then re-sprout and start to flower in the spring. In colder areas, dig up your carrots in the autumn, and select the best coloured and shaped roots. Twist off the foliage, and store the roots in a box of dry sand in a frost free place, making sure that they don't touch. In spring, replant the roots, and they will re-sprout and flower.

If you want to maintain a carrot variety effectively, you really need to save seed from at least 40 good roots to maintain good genetic diversity. If you have too small a genetic pool, you will end up with small, poor quality roots in a very few generations.

Carrots grow into big plants waist high or taller, producing successive branches with large flat umbels of flowers. They are insect pollinated, and need to be isolated from other flowering carrot varieties by at least 500m in an open field situation. This is not normally a big problem, since few people let their carrots go to seed. However, they will cross with wild carrot (Queen Anne's Lace), giving thin white useless roots.

As with all insect pollinated crops, barriers such as houses, tall hedges and other high crops can affect insect flight paths drastically, so you don't necessarily need to eliminate all Queen Anne's Lace within a 1/2 km radius; but do watch out for any white roots in subsequent generations and get rid of them.

Watch the very informative video from Heritage Seed Library (part of Garden Organic) on how to collect carrot seeds. Here. (YouTube video) or download the seed saving guide here (pdf)

Carrot Seed under the microscope

To harvest your carrot seed, keep an eye on the umbels of flowers, and cut them off with secateurs as they start to turn brown and dry. If you have plenty of plants, just save seed from the first and second umbels of flowers to appear on each plant, as these will give the biggest and best seed. Dry the seed heads further inside, and then rub them between your hands or in a sieve to separate them. You will notice that the seeds have a 'beard' which is removed in commercial seed to make them easier to pack.

You can sieve the seeds further to remove more of the chaff, but there is no need to get the seed completely clean - just sow slightly more thickly to allow for the chaff mixed in.

Dried carrot seed is relatively short lived, but if it is stored somewhere cool and dry, it should give good germination for 3 years. Seeds can be safely stored for at least three years. Place seeds in jars, manila envelopes, cloth or mesh bags, plastic containers, or foil envelopes. The best containers are air-tight, such as a sealed glass jar, metal can, or foil envelope. Protect seed from sunlight.Store seeds in a cool (below 15 °C is ideal), dry location. Place the seeds in a refrigerator for long term storage.

For short-term storage, keep the seeds in a cool, shady and dry place.


What do seeds contain and how do they work?

A seed is the product of a fertilised ovule (egg). It is the means by which the progeny of a plant can be spread. The seed contains the embryo from which a new plant will grow. The seed contains a supply of food called the endosperm that is used by the new plant to develop. The whole seed is covered in a seed coat known as the testa. Seeds are found in a great variety of types.

The testa protects the contents of the seed. For the seed to grow the testa needs to split. The seed imbibes water which causes it to swell and split open the testa. The seed coat varies between different types of seed, which in turn affects, the uptake of water. Some seed coats are very thick and need to go through a process of scarification to allow absorption of water. In the wild this would occur by the gnawing actions of animals, passing through an animal's digestive tract or abrasion by a rocky surface. In the artificial environment of gardening this process is imitated by nicking the seed coat with a sharp knife or rubbing with sandpaper.

If a seed has a thin coat the presence of light can either encourage or inhibit seed growth. Smaller seeds tend to require light for germination.

Read more about the difference between hybrid and non hybrid seeds here.  Read more about carrot seed dormancy here.


BUY YOUR SEEDS HERE:
Thompson & Morgan have a tremendous variety of carrot seeds for you to try, click on the link or banner to buy some. 

Any seeds bought via this link makes a small a contribution to the upkeep of the World Carrot Museum.
See photos of common varieties supplied by Thompson and Morgan the leading seed suppliers in the US and UK. Click here.

Some Sources of Carrot Seed Varieties for United States Home Gardeners - here

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

Salt Spring Seeds (Heritage and Heirloom seeds) - here

Black Carrots - see Carrot Museum Black Carrot page.


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