Turnip
Brassica rapa
Fast-growing root vegetable with edible greens. Spring and autumn sowings avoid the pest pressure of summer months.
Overview
Companion Planting
Good Companions
Pea
Onion
NasturtiumBad Companions
None
Toxicity
Non-toxic to humans, dogs, and cats; however, feed only in moderation to pets as glucosinolates can suppress thyroid function and cause digestive upset in large amounts.
Planting Tips
1 cm of water per m² equals 10 liters. Use the Watering Calculator for exact amounts.
Care Tip: Thin seedlings to 10-15 cm apart once true leaves appear, and use mulch to retain moisture and suppress weeds.
Common Pests
Cabbage Root Maggot (Delia radicum)
Symptoms: Wilting unresponsive to watering, stunted growth, and tunneling damage inside roots.
Treatment: Apply beneficial nematodes to the soil or use an approved soil drench insecticide at planting time.
Prevention: Use floating row covers over seedbeds and practice crop rotation; avoid planting brassicas in the same spot for at least 3 years.
Flea Beetles
Symptoms: Numerous small round holes (shot-holes) in leaves, especially on young seedlings.
Treatment: Spray with neem oil or spinosad-based insecticide when populations are high.
Prevention: Cover transplants with row covers immediately after planting and keep beds free of brassica crop debris.
Aphids
Symptoms: Curled, yellowing leaves with sticky honeydew residue and possible sooty mold.
Treatment: Knock off with a strong water spray or apply insecticidal soap; introduce ladybugs as biological control.
Prevention: Encourage natural predators, avoid excessive nitrogen fertilization, and inspect plants regularly.
Common Diseases
Clubroot (Plasmodiophora brassicae)
Symptoms: Swollen, distorted roots forming club-shaped galls; above-ground wilting, yellowing, and stunted growth.
Treatment: No effective cure once established; remove and destroy infected plants and do not compost them.
Prevention: Maintain soil pH around 7.0-7.2 with lime, rotate brassica crops on a 4+ year cycle, and ensure good soil drainage.
Alternaria Leaf Spot (Alternaria spp.)
Symptoms: Small, dark brown to black circular spots with concentric rings on older leaves, spreading in cool wet weather.
Treatment: Apply a copper-based fungicide at first sign of infection and remove severely affected foliage.
Prevention: Use disease-free seed, practice crop rotation, and avoid overhead watering to keep foliage dry.
Downy Mildew (Peronospora parasitica)
Symptoms: Yellow patches on upper leaf surfaces with grayish-white fuzzy growth on the undersides.
Treatment: Apply a copper or mancozeb-based fungicide; remove and destroy heavily infected leaves.
Prevention: Ensure good air circulation by proper spacing, avoid overhead irrigation, and plant resistant varieties when available.