Kohlrabi
Brassica oleracea var. gongylodes
Unique brassica with a swollen stem that tastes like a mild, sweet turnip. Quick to mature and easy to grow.
Overview
Companion Planting
Beetroot
Onion
LettuceBad Companions
Tomato
Bell Pepper
Chili PepperToxicity
Non-toxic to humans, dogs, and cats; safe to eat raw or cooked. Feed to pets only in moderation, as excessive amounts may cause digestive upset due to high fiber and oxalate content.
Planting Tips
1 cm of water per m² equals 10 liters. Use the Watering Calculator for exact amounts.
Care Tip: Space plants 15-20 cm apart, mulch with 5-8 cm of organic material to retain moisture, and harvest when bulbs reach 5-8 cm diameter to avoid toughness.
Common Pests
Aphids
Symptoms: Curling or distorted leaves, sticky honeydew residue, and clusters of small green or black insects on undersides of leaves.
Treatment: Spray with a strong water jet or apply insecticidal soap; release beneficial insects such as ladybugs or lacewings.
Prevention: Inspect plants regularly, encourage natural predators, and avoid over-fertilizing with nitrogen.
Cabbage Worms
Symptoms: Irregularly shaped holes chewed through leaves, visible green caterpillars, and dark frass (droppings) on foliage.
Treatment: Handpick caterpillars or apply Bacillus thuringiensis (Bt) spray to affected plants.
Prevention: Use lightweight floating row covers to exclude adult butterflies and moths from laying eggs.
Flea Beetles
Symptoms: Numerous small, round shot-holes in leaves giving a sieve-like appearance, especially on young seedlings.
Treatment: Apply neem oil or kaolin clay spray; use yellow sticky traps to reduce adult populations.
Prevention: Cover seedlings with row covers immediately after transplanting and remove plant debris at season's end.
Common Diseases
Clubroot
Symptoms: Wilting during the day despite adequate watering; swollen, distorted roots and stunted growth.
Treatment: No chemical cure; remove and destroy infected plants and raise soil pH to 7.2 or above with lime.
Prevention: Practice 4+ year crop rotation for brassicas, use resistant varieties, and ensure good soil drainage.
Black Rot
Symptoms: V-shaped yellow-to-brown lesions starting at leaf margins, with darkened veins turning black.
Treatment: Remove and destroy infected plant tissue immediately; no effective chemical treatment once established.
Prevention: Use certified disease-free seed, rotate crops on a 2-3 year cycle, and avoid overhead irrigation.
Downy Mildew
Symptoms: Yellow patches on upper leaf surfaces with a grayish-white fuzzy growth on the underside.
Treatment: Apply copper-based fungicide at first sign of infection; remove severely affected leaves.
Prevention: Ensure adequate plant spacing for air circulation, water at soil level, and avoid working among wet plants.