BBCH-scale (bulb vegetable)

In biology, the BBCH-scale for bulb vegetables describes the phenological development of bulb vegetable plants, such as onion, leek, garlic and shallot, using the BBCH-scale.

The phenological growth stages and BBCH-identification keys of bulb vegetables are:

Growth stage	Code (2-digit)	Code (3-digit)	Description
0: Germination	00	000	Dry seed,1 dormant bulb2
	01	000	Beginning of seed imbibition1
	03	003	Seed imbibition complete1
	05	005	Radicle emerged from seed.1 Roots appearing2
	07	007	Cotyledon breaking through seed coat1
	09	009	Emergence: cotyledon breaks through soil surface.1 Green shoot visible2
		010	Cotyledon visible as hook1
		011	Hook stage: hooked cotyledon green1
		012	Whip stage: cotyledon has whip-like form1
1: Leaf development (Main shoot)	10	100	Advanced whip stage: whip begins to die off1
	11	101	First leaf (> 3 cm) clearly visible
	12	102	2nd leaf (> 3 cm) clearly visible
	13	103	3rd leaf (> 3 cm)
	1 .	10 .	Stages continuous till . . .
	19	109	9 or more leaves clearly visible
4: Development of harvestable vegetative plant parts	41	401	Leaf bases begin to thicken or extend
	43	403	30% of the expected bulb or shaft diameter reached
	45	405	50% of the expected bulb or shaft diameter reached
	47	407	Bolting begins; in 10% of the plants leaves bent over3 70% of the expected shaft length and diameter reached4
	48	408	Leaves bent over in 50% of plants3
	49	409	Leaves dead, bulb top dry; dormancy3 Growth complete; length and stem diameter typical for variety reached4
5: Inflorescence emergence	51	501	Onion bulb begins to elongate
	53	503	30% of the expected length of flower stem reached
	55	505	Flower stem at full length; sheath closed
	57	507	Sheath burst open
	59	509	First flower petals visible; flowers still closed
6: Flowering	60	600	First flowers open (sporadically)
	61	601	Beginning of flowering: 10% of flowers open
	62	602	20% of flowers open
	63	603	30% of flowers open
	64	604	40% of flowers open
	65	605	Full flowering: 50% of flowers open
	67	607	Flowering finishing: 70% of petals fallen or dry
	69	609	End of flowering
7: Development of fruit	71	701	First capsules formed
	72	702	20% of capsules formed
	73	703	30% of capsules formed
	74	704	40% of capsules formed
	75	705	50% of capsules formed
	76	706	60% of capsules formed
	77	707	70% of capsules formed
	78	708	80% of capsules formed
	79	709	Capsule development complete; seeds pale
8: Ripening of fruit and seed	81	801	Beginning of ripening: 10% of capsules ripe
	85	805	First capsules bursting
	89	809	Fully ripe: seeds black and hard
9: Senescence	92	902	Leaves and shoots beginning to discolour
	95	905	50% of leaves yellow or dead
	97	907	Plants or above ground parts dead
	99	909	Harvested product (seeds)

1 Seed sown
2 Onion sets, shallot and garlic
3 For onions, garlic
4 For leek

References

• Feller, C.; H. Bleiholder; L. Buhr; H. Hack; M. Hess; R. Klose; U. Meier; R. Stauss; T. van den Boom; E. Weber (1995). "Phänologische Entwicklungsstadien von Gemüsepflanzen: I. Zwiebel-, Wurzel-, Knollen- und Blattgemüse. Nachrichtenbl. Deut". Pflanzenschutzd. 47: 193–206.