Who should read this chapter

Growing carrots can be one of the most complex of tasks, or the easiest, depending on your pest pressure, soil type and sowing time. This guide is most applicable if you have sandy soil, carrot fly problems and want to grow a lot of carrots all year round.

Growing year round carrots

Carrots are one of our favourite crops, we eat them fresh as snacks, in salads, steamed and in all manner of soups, curries, stir-fry's etc. Getting them all year round involves some planning though.

Brief introduction to the topics covered in this chapter

Brief introduction to the topics covered in this chapter

Carrot fly

Carrot fly is a devastating pest for carrot lovers and there's more confusion about it than most pests. Over the years I've believed all sorts of garden lore that's proven to be false in my own experience and independent research.

Carrots badly damaged by fly larvae need extensive clean-up to be edible

Carrots badly damaged by fly larvae need extensive clean-up to be edible

Here's a few of the myths:

  1. Plant after June, to avoid carrot fly. As you can see in the chart below carrot fly have two main activity periods (May and August) but continue to be quite active in autumn and even April if you over-winter your carrots like I do.
  2. A 60cm or 2' carrier will protect from carrot fly, which are very low flyers. This has proven in-effective in research and my own experience, the wind blows carrot fly over the barrier. I keep my containers 1.5m above the ground and even then I get some minor damage!
  3. Interplant with onions, or use spring onions as a barrier because the scent will confuse the carrot fly. Research shows that the spring onions are just acting as a physical barrier, it's nothing to do with the scent.
  4. Plant carrot fly resistant varieties like Flyaway or Resistafly. In my experience these varieties still get problems, but they might be worthwhile if you have low pest pressure and/or in combination with mesh/fleece

I've concluded that the best way to deal with carrot fly if you sow in the ground is to:

  1. Always use a fine net/fleece without holes and well secured to the ground
  2. Put the net on when you sow, otherwise if you are like me you will forget
  3. Weed well before sowing and cover the ground with a weed free compost, to minimise the need for subsequent weeding
  4. Use a garlic spray when you weed, thin or harvest
  5. Don't remove the net unless you really need to, in my case around December