In biology, the BBCH-scale for bulb vegetables describes the

phenological Phenology is the study of periodic events in biological life cycles and how these are influenced by seasonal and interannual variations in climate, as well as habitat factors (such as elevation). Examples include the date of emergence of leav ...

development of bulb vegetable plants, such as

onion An onion (''Allium cepa'' L., from Latin ''cepa'' meaning "onion"), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus ''Allium''. The shallot is a botanical variety of the oni ...

leek The leek is a vegetable, a cultivar of '' Allium ampeloprasum'', the broadleaf wild leek (syn. ''Allium porrum''). The edible part of the plant is a bundle of leaf sheaths that is sometimes erroneously called a stem or stalk. The genus ''All ...

garlic Garlic (''Allium sativum'') is a species of bulbous flowering plant in the genus ''Allium''. Its close relatives include the onion, shallot, leek, chive, Welsh onion and Chinese onion. It is native to South Asia, Central Asia and northe ...

and

shallot The shallot is a botanical variety (a cultivar) of the onion. Until 2010, the (French red) shallot was classified as a separate species, ''Allium ascalonicum''. The taxon was synonymized with '' Allium cepa'' (the common onion) in 2010, as the ...

, using the

BBCH-scale The BBCH-scale is used to identify the phenological development stages of plants. BBCH-scales have been developed for a range of crop species where similar growth stages of each plant are given the same code. Phenological development stages of plan ...

. The phenological growth stages and BBCH-identification keys of bulb vegetables are: 1 Seed sown
2 Onion sets, shallot and garlic
3 For onions, garlic
4 For leek

References

* {{cite journal , last = Feller , first = C. , author2=H. Bleiholder , author3=L. Buhr , author4=H. Hack , author5=M. Hess , author6=R. Klose , author7=U. Meier , author8=R. Stauss , author9=T. van den Boom , author10=E. Weber , title = Phänologische Entwicklungsstadien von Gemüsepflanzen: I. Zwiebel-, Wurzel-, Knollen- und Blattgemüse. Nachrichtenbl. Deut. , journal = Pflanzenschutzd. , volume = 47 , pages = 193–206 , date = 1995 BBCH-scale