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 bulb^2
	01	000	Beginning of seed imbibition^1
	03	003	Seed imbibition complete^1
	05	005	Radicle emerged from seed.^1 Roots appearing^2
	07	007	Cotyledon breaking through seed coat^1
	09	009	Emergence: cotyledon breaks through soil surface.^1 Green shoot visible^2
		010	Cotyledon visible as hook^1
		011	Hook stage: hooked cotyledon green^1
		012	Whip stage: cotyledon has whip-like form^1
1: Leaf development (Main shoot)	10	100	Advanced whip stage: whip begins to die off^1
	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 over^3 70% of the expected shaft length and diameter reached^4
	48	408	Leaves bent over in 50% of plants^3
	49	409	Leaves dead, bulb top dry; dormancy^3 Growth complete; length and stem diameter typical for variety reached^4
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.