Radish
Raphanus sativus
One of the fastest vegetables from seed to harvest, ready in 3-4 weeks. Excellent as a row marker between slow-germinating crops.
Overview
Companion Planting
Carrot
Lettuce
Pea
Spinach
Nasturtium
Cress
ParsnipToxicity
Radishes are non-toxic to humans, dogs, and cats; large quantities may cause mild digestive upset in pets due to isothiocyanates and high fiber content.
Planting Tips
1 cm of water per m² equals 10 liters. Use the Watering Calculator for exact amounts.
Care Tip: Thin seedlings to 5-8 cm apart soon after emergence and harvest promptly when mature to prevent woody texture.
Common Pests
Flea Beetles
Symptoms: Tiny shot-holes in leaves of seedlings, giving foliage a lace-like appearance; heavy infestations stunt growth.
Treatment: Apply neem oil or pyrethrin-based sprays; use sticky traps to reduce adult populations.
Prevention: Cover seedlings with floating row covers immediately after sowing; remove crop debris that shelters overwintering adults.
Cabbage Root Maggot
Symptoms: Wilting plants despite adequate water; brown tunnels and slimy channels bored through roots.
Treatment: Remove and destroy infested plants; apply beneficial nematodes to the soil to target larvae.
Prevention: Place root collars or row covers at planting to block egg-laying flies; practice crop rotation away from brassicas.
Aphids
Symptoms: Clusters of small green or gray insects on undersides of leaves; curling, yellowing foliage and sticky honeydew residue.
Treatment: Spray with a strong water jet or apply insecticidal soap; introduce beneficial insects like ladybugs or lacewings.
Prevention: Encourage natural predators, use reflective mulches, and avoid over-fertilizing with nitrogen.
Common Diseases
Clubroot
Symptoms: Swollen, gnarled, and lumpy roots; yellowing and wilting of above-ground foliage due to impaired nutrient uptake.
Treatment: No chemical cure; remove and destroy infected plants and raise soil pH to 7.2 or above with lime.
Prevention: Rotate crops on a 4-year cycle away from all brassicas; ensure good drainage and use certified disease-free seed.
Downy Mildew
Symptoms: Yellow patches on upper leaf surfaces with grayish-purple fuzzy growth on undersides; leaves may curl and die.
Treatment: Remove affected leaves promptly; apply copper-based fungicide if infection is severe.
Prevention: Provide good air circulation by proper spacing, avoid overhead watering, and use resistant varieties when available.
Damping Off
Symptoms: Seeds fail to germinate or seedlings collapse at the soil line with thin, pinched stems; often appears in cool, wet conditions.
Treatment: No cure for affected seedlings; remove and discard them to prevent spread.
Prevention: Use sterile seed-starting mix, avoid overwatering, ensure good drainage, and sow in warm-enough soil above 10 C.