I have had a number of requests for information on saving carrot seed. In this post I’m going to cover the basics around seed production of bi-annual crops, and specifically carrots.
Bi-annual crops are typically crops that need two growing seasons with a winter dormant period in the middle. Crops like these are Carrots, Beetroot, Salsify, Turnips and Scozonera. But can also include other plants like Brassicas.
These plants are either insect or wind pollinated and different management styles need to be used when trying to keep seed pure.
If you are only saving one seed variety of each crop then most of your problems are solved as they will not cross pollinate except for beets and spinach where the two are very easily crossed. (This discussion excludes Brassicas, which is a multiple post a topic all on its own)
Basically what needs to be done is plant your crops for seed production in the first summer, allow the plants to grow to full maturity and then they need to experience a period of vernalization over winter. This dormant period is generally essential in most root crops, however there are some varieties or individual plants ain a population that will produce seed just before winter if planted really early in summer. I believe though that the seed would not be of a superior quality and should not be saved for any reason as you will be perpetuating an early seeding variety or ‘sport’ of a variety.
Early in spring the following year you will notice that the carrot plants start to throw a flower spike, depending on the variety that you are growing this flower spike can be anything from 50cm to over 200 cm tall. Once the flowers open, you will notice that the flowers are predominantly visited by flies, but many other bugs and insects will visit the flowers to pollinate.
The individual flowers in the umbels open in successively, with male and female portions ripening in different orders to ensure that the flowers are not self pollinated.
The most important flower on a plant is the “King Flower” this is the largest flower on the plant and produces the best seed. This seed should be saved for propagation from year to year. The balance of the flowers also produce good quality viable seed.
Now the problem comes in when you are growing more than one variety of carrot and you would like to keep the seed pure. The easiest way to do this is with caging the plants. Very simply an insect proof net is erected over the cages and flies are caught in a regular fly-trap, the flies are released into the cages where they perform their duties admirably.
From there it’s a simple case of waiting for the seed to dry on the plant, picking the seed and then processing. They can be sown again within a few weeks, as long as they have had a chance to dry out properly.