What is wrong with my carrots?
Terry Ellaco , by email
You say your carrots have been grown in the same raised bed for two years. They’re surrounded by a 60cm (2ft) high wall of polycarbonate and are covered by a top of Enviromesh. The soil is light and well drained and you leave them in the ground over winter. There were some cabbages in the same bed in the spring. I can understand your concern, not least because you tell me that last summer you had your first introduction to leek moth and are still traumatised!
This time, the problem isn’t a moth, but a much smaller and, unfortunately, more insidious problem. These are the symptoms of root knot eelworm attack.
Eelworms, also called nematodes, are minute, soil-inhabiting creatures of which there are many different kinds, most of which live harmlessly in the soil. A few, however, can cause the gardener some problems.
Root knot eelworms are generally more common in greenhouses but they can become serious on outdoor plants, including vegetables, especially during warm weather and on light soils. These, of course, are just the conditions in your raised bed during last summer. I suspect they were almost certainly present in the soil already and it was the favourable weather conditions that caused them to become apparent. There will be many thousands of the eelworms in the soil and, sadly, there’s no chemical control for them.
So what are you to do? In an ideal world, I’d advise you not to grow carrots in the same plot again, or to introduce a long rotation, but clearly, neither is possible in a raised bed
and with limited space. And, of course, other root vegetables, such as parsnips, beetroot and so on, may also be affected. Unusually, therefore, my advice in this case is to do nothing, except to choose fast-growing early varieties, which should mature and give you a satisfactory crop before the eelworms have had chance to do much damage. I should add that, if you cut away the damaged parts, any decently sized roots will still be perfectly safe to eat.