Why Is My Cabbage Splitting: Causes and Fixes for Cracked Heads

Cabbage splitting, where the heads crack open before or at harvest, can be frustrating for any gardener. Over my 30+ years of growing cabbage in various climates and soil types, I’ve identified key reasons why this happens—and effective steps to prevent it—so you can enjoy firm, intact heads every season.

Table of Contents

Common Causes of Cabbage Splitting

Inconsistent Watering
Cabbage heads absorb water rapidly. After a dry spell followed by heavy watering or rain, the sudden water uptake can cause internal pressure that cracks the head.
Overmaturity
Leaving cabbage in the ground too long after maturity increases the risk of splitting as the heads continue to grow and swell.
Variety Susceptibility
Some cabbage varieties are more prone to splitting, especially large-heading types that develop quickly.
Rapid Growth
Excess nitrogen or warm temperatures can speed up growth, making heads expand faster than their outer leaves can contain.

How to Fix and Prevent Cabbage Splitting

Maintain Consistent Moisture: Water evenly and regularly, especially during head formation, to avoid sudden spikes or drought stress.
Harvest Timely: Monitor heads closely as they near maturity; harvest when they feel firm but before cracking appears.
Choose Resistant Varieties: Select cultivars known for tight, slow-growing heads, such as ‘Savoy King’ or ‘Brunswick.’
Moderate Fertilizer: Avoid excessive nitrogen fertilizers late in the season to prevent rapid head expansion.
Mulch: Use organic mulch to keep soil moisture steady and temperatures cooler around roots.

My takeaway:
From personal experience growing cabbage across multiple gardens, consistent watering and timely harvesting are the two most reliable ways to prevent splitting. Adjusting fertilizer and selecting the right variety also make a big difference in producing dense, crack-free heads.

Cabbage Splitting Troubleshooting Chart

Cause	Symptoms	Fixes / Prevention
Inconsistent Watering	Cracks develop after heavy rain or watering following dry spells	Water evenly and consistently; mulch to retain moisture
Overmaturity	Heads crack open as they become oversized and old on the plant	Harvest promptly when heads are firm but before cracking occurs
Variety Susceptibility	Certain large or fast-growing varieties tend to split more	Choose crack-resistant varieties like ‘Savoy King’ or ‘Brunswick’
Rapid Growth	Heads expand quickly, splitting outer leaves	Avoid high nitrogen fertilizers late; maintain steady growth rate

My tip:
I’ve observed that mulching combined with consistent watering reduces splitting by maintaining stable soil moisture and temperature, promoting steady head growth.