Editing Cabbage (section)

=== Modern cultivation ===
[[File:Dojranski zelki.jpg|thumb|A cabbage field in [[North Macedonia]]]]
Cabbage is generally grown for its densely leaved heads, produced during the first year of its biennial cycle. Plants perform best when grown in well-drained soil in a location that receives full sun. Different varieties prefer different soil types, ranging from lighter sand to heavier clay, but all prefer fertile ground with a [[Soil pH|pH]] between 6.0 and 6.8.<ref name=Brad56/> For optimal growth, there must be adequate levels of [[nitrogen]] in the soil, especially during the early head formation stage, and sufficient [[phosphorus]] and [[potassium]] during the early stages of expansion of the outer leaves.<ref name="Wien and Wurr 533">[[#Wurr|Wien and Wurr]], p. 533</ref> 

Temperatures between {{convert|4|and|24|C|F}} prompt the best growth, and extended periods of higher or lower temperatures may result in premature [[bolting (horticulture)|bolting]] (flowering).<ref name=Brad56>[[#Bradley|Bradley et al.]], pp. 56–57</ref> Flowering induced by periods of low temperatures (a process called [[vernalization]]) only occurs if the plant is past the juvenile period. The transition from a juvenile to adult state happens when the stem diameter is about {{convert|6|mm|in|frac=16|abbr=on}}. Vernalization allows the plant to grow to an adequate size before flowering. In certain climates, cabbage can be planted at the beginning of the cold period and survive until a later warm period without being induced to flower, a practice that was common in the eastern US.<ref>[[#Wurr|Wien and Wurr]], pp. 512–515</ref>

[[File:Cabbages Green and Purple 2120px.jpg|thumb|right|upright|Green and purple cabbages]]
Plants are generally started in protected locations early in the growing season before being [[transplanting|transplanted]] outside, although some are seeded directly into the ground from which they will be harvested.<ref name=UI/> Seedlings typically emerge in about 4–6 days from seeds planted {{convert|1/2|in|mm|abbr=on|order=flip}} deep at a soil temperature between {{convert|20|and|30|C|F}}.<ref>[[#Maynard|Maynard and Hochmuth]], p. 111</ref> Growers normally place plants {{convert|12|to|24|in|cm|order=flip|abbr=on}} apart.<ref name=UI/> Closer spacing reduces the resources available to each plant (especially the amount of light) and increases the time taken to reach maturity.<ref>[[#Wurr|Wien and Wurr]], p. 534</ref> 

Some varieties of cabbage have been developed for ornamental use; these are generally called "flowering cabbage". They do not produce heads and feature purple or green outer leaves surrounding an inner grouping of smaller leaves in white, red, or pink.<ref name=UI/> Early varieties of cabbage take about 70 days from planting to reach maturity, while late varieties take about 120 days.<ref>[[#Maynard|Maynard and Hochmuth]], p. 415</ref> 

Cabbages are mature when they are firm and solid to the touch. They are harvested by cutting the stalk just below the bottom leaves with a blade. The outer leaves are trimmed, and any diseased, damaged, or necrotic leaves are removed.<ref>{{cite book |author=Thompson, A. Keith |title=Fruit and Vegetables: Harvesting, Handling and Storage |year=2003 |edition=2nd |publisher=Blackwell Publishing |page=178 |isbn=978-1-4051-0619-1}}</ref> Delays in harvest can result in the head splitting as a result of expansion of the inner leaves and continued stem growth.<ref>[[#Wurr|Wien and Wurr]], p. 524</ref>

When being grown for seed, cabbages must be isolated from other ''B.&nbsp;oleracea'' subspecies, including the wild varieties, by {{convert|1/2|to|1|mi|km|1|order=flip|abbr=on}} to prevent cross-pollination. Other ''Brassica'' [[species]], such as ''[[Brassica rapa|B.&nbsp;rapa]]'', ''[[Brassica juncea|B.&nbsp;juncea]]'', ''[[Brassica nigra|B.&nbsp;nigra]]'', ''[[Brassica napus|B.&nbsp;napus]]'' and ''[[Raphanus sativus]]'', do not readily cross-pollinate.<ref>[[#Katz|Katz and Weaver]], p. 282</ref>