Clubroot
📖 Overview
Clubroot is a soil-borne disease caused by a water mould that attacks the roots of brassicas—cabbage, broccoli, cauliflower, kohlrabi, radish, and turnip. Once established in your garden, it can persist for years and severely stunt or kill your crops. The disease thrives in wet, acidic soils and is particularly problematic in temperate regions with heavy spring rains or poorly drained garden beds.
You'll first notice the problem in mid to late summer when plants that should be thriving suddenly wilt during warm days, even though the soil is moist. When you dig up an affected plant, the roots won't look normal—instead of smooth, healthy root systems, you'll see grotesque lumps, swellings, and finger-like growths that feel soft and white inside, like a sponge. This distinctive clubbing of the roots is where the disease gets its name and is the unmistakable sign of clubroot infection.
Clubroot is often confused with root-knot nematodes, but nematode galls are much smaller (pinhead to pea-sized), numerous, and scattered along the root. Clubroot swellings are larger, more irregular, and concentrated at the root base and main lateral roots. Additionally, roots infested with nematodes remain firm inside, whereas clubroot produces that characteristic soft, white interior.
Once your soil is infected, the spores can survive 15 to 20 years, making long-term management essential. There is no chemical fungicide effective at hobby scale, and no cure for an infected plant. Prevention through soil pH management, crop rotation, and resistant varieties is your best defence.
🔍 How to identify
A növény hervad meleg-időben, de a talaj nedves. Kiásás után a GYÖKEREK megduzzadnak, golyva-szerű kinövések, "ujj"-ként vagy "csomó"-ként. Belül fehér-szivacsos.
🌿 Common host plants
💊 Treatment
NINCS gyógyszer. A fertőzött növény + gyökér környéke (kb 30 cm) eltávolítása. Mész szórása (pH 7.2-fölé emelés blokkolja).
Nincs hatékony fungicid hobbi-szinten.
🛡️ Prevention
Mész-trágya (kalcium-karbonát) a talajba — pH 7.0+. Vetésforgás MIN. 6 év! Ellenálló fajták (Kilatron F1 káposzta). Jó vízelvezetés. NE használj fertőzött palántát.
Frequently asked questions
How long does clubroot persist in soil once it's there?
Clubroot spores can survive 15 to 20 years in infected soil, which is why infected gardens remain a problem for decades. This makes prevention and strict crop rotation of at least 6 years essential, even after you remove all infected plants.
Can I save a plant once I see wilting and clubbing symptoms?
No—there is no cure for clubroot once it infects the root system. Remove the entire plant immediately, including roots, and dig out the soil in a 30 cm radius around the planting hole to reduce spore load in your garden.
What soil pH stops clubroot from thriving?
Raising your soil pH to 7.2 or above significantly suppresses the disease, since the pathogen prefers acidic conditions. Applying lime (calcium carbonate) as a soil amendment before planting brassicas is the single most effective prevention method available to home gardeners.
Does wet spring weather make clubroot worse?
Yes—clubroot is a water mould that thrives in wet, poorly drained soils, especially during cool, moist springs. Improve drainage in affected beds, avoid overhead watering, and ensure good air circulation to reduce the risk of infection.
Are resistant brassica varieties really worth planting in infected soil?
Yes, resistant varieties like Kilatron F1 cabbage offer genuine protection and are worth seeking out if your garden has a clubroot history. However, even resistant plants cannot thrive in heavily infested soil, so combine resistance with pH management and strict 6-year crop rotation for best results.
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