It’s a common tale. A bed of carrots is seeded, they sprout and start to grow, and a harvest of crisp roots beckons in a few short months. Yet, when it comes time to dig the crop, it’s discovered that some of the carrots have forked, developing multiple roots. The multi-rooted carrots may look a little funny and are harder to clean, but forking doesn’t affect the flavour. So, what causes carrots to fork?
Carrots fork because the growing tip of the root has been impeded or damaged by someone or something. The someone may be a soil insect or nematode that has nibbled on the tip of the root. The somethings are likely obstacles in the soil like small pebbles or stones. Gardeners who battle heavy clay soil may also notice a larger percentage of forked carrots.
Sometimes the reason for forked carrots can be traced back to the gardener. For example, a few years ago, every single carrot in my neighbour’s raised garden bed forked. The soil was excellent – light, fluffy and relatively stone free with no visible insect issues. As it turns out, that entire bed had not been direct seeded, which is recommended for most root crops, but rather transplanted. My neighbour had thinned her main crop of carrots earlier in the season and re-planted all those young thinned plants into a new bed, damaging the growing tips of the roots and resulting in 100% forked carrots.
Dense soils can be lightened with generous amounts of compost or shredded leaves. You may also wish to grow shorter types of carrots, like Chatenay and Danvers, instead of the long, slender Imperator varieties that need deep, light soils to grow straight.
To combat insect issues, rotate your carrot crop annually, allowing a three to four year rotation cycle. If nematodes are a persistent problem, consider solarizing your soil by covering the bed with black plastic for 4 to 6 weeks.
Finally, as my neighbour learned, carrots should be direct seeded, not transplanted to ensure long, straight roots.