How to Grow Carrot Companion Crops

Did you know that gardeners purposely grow some plants together to help produce the healthiest crops? Find out how companion gardening can help your carrots grow.


Leeks, onions or garlic are useful companions to carrots, since their strong smells keep away flies that attack carrots. For this example, we will use salad leek seeds. Grow carrots and leeks in a sunny or partly shaded place and use well-drained, light soil. Sow the carrot seeds in late spring to miss the first invasion of carrot flies. The seeds will germinate in three weeks, and they will be ready to harvest in 12 weeks.

Materials Needed:

  • deep crate
  • garbage bag
  • kid-safe scissors
  • gravel
  • bucket
  • sand
  • potting soil
  • ruler or stick
  • baby carrot seeds
  • salad leek seeds
  • sticks
  • polyethylene bag cover
  • horticultural fleece
  • fine netting
  • specific fly-resistant carrot varieties, such as Flyaway, Maestro, Sytan or Resistafly seeds

1. Line a deep crate with a garbage bag.

Cut to fit, and make a few small holes through the crate and the bag with scissors. Spread out a layer of gravel in the bottom for drainage.

2. Mix a bucketful of potting soil with sand.

Next, fill up the crate. Moisten the soil before sowing the seed.

Bucket of Sand and Vegetable Seeds

Bucket of Sand and Vegetable Seeds

Photo By: DK - Ready Set Grow! ©© 2010 Dorling Kindersley Limited

DK - Ready Set Grow!, © 2010 Dorling Kindersley Limited

3. Create room for seeds.

Make three trenches that are ½ inch (1 cm) deep along the length of crate using a ruler or a stick.

4. Plant baby carrot seeds.

Sprinkle seeds along the outer trenches and cover them with a little soil. If you space out the seeds, then there will be no need for thinning later, which releases a carrot smell.

5. Sow salad leek seeds.

Place into soil individually, 6 inches (15 cm) apart into the middle trench.

6. Put in sticks along the edges of crate.

This will hold up a polyethylene bag cover and encourage germination. The cover should be removed once the seedlings appear.

Allow Seeds to Gerninate

Allow Seeds to Gerninate

Photo By: DK - Ready Set Grow! ©© 2010 Dorling Kindersley Limited

DK - Ready Set Grow!, © 2010 Dorling Kindersley Limited

7. Use extra protection during summer months.

Low-flying female carrot flies are attracted to the smell of carrots and lay their eggs at the base of them. In addition to companion crops, gardeners protect their carrots by covering them under a horticultural fleece; surrounding them with a fine netting 2-feet high or growing them in tall pots; or using carrot varieties that have some resistance to carrot fly, such as Flyaway, Maestro, Sytan and Resistafly.

8. Tend to carrot seedlings.

If needed, thin them to 1/2 inch (1 cm) between the plants. This will allow the carrots to form larger roots. Water well during dry weather.

Thinning Carrot Seedlings

Thinning Carrot Seedlings

Photo By: DK - Ready Set Grow! ©© 2010 Dorling Kindersley Limited

DK - Ready Set Grow!, © 2010 Dorling Kindersley Limited

9. Harvest the carrots and leeks when they reach a good size.

If the leeks need longer, then leave them in the container until the winter when they have thickened up.

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