The BBCH-scale for citrus is a classification system used in biology to describe the phenological development of citrus plants using the BBCH-scale.
The phenological growth stages and BBCH-identification keys of citrus plants are: Growth stageCodeDescription0: Sprouting/Bud development00 Dormancy: leaf and inflorescence buds undifferentiated, closed and covered by green scales01 Beginning of bud swelling03 End of bud swelling: green scales slightly separated07 Beginning of bud burst09 Green leaf tips visible1: Leaf development10 First leaves separating: green scales slightly open, leaves emerging11 First leaves visibleIn Citrus the term "visible" replaces "unfolded" used for other fruit species. Leaf unfolding takes place precociously in citrus.15 More leaves visible, not yet at full size19 First leaves fully expanded3: Shoot development31 Beginning of shoot growth: axes of developing shoots visible32 Shoots about 20% of final length39 Shoots about 90% of final length5: Inflorescence emergence51 Inflorescence buds swelling: buds closed, light green scales visible53 Bud burst: scales separated, floral tips visible55 Flowers visible, still closed (green bud), borne on single or multiflowered leafy or leafless inflorescences56 Flower petals elongating; sepals covering half corolla (white bud)57 Sepals open: petal tips visible; flowers with white or purplish petals, still closed59 Most flowers with petals forming a hollow ball6: Flowering60 First flowers open61 Beginning of flowering: about 10% of flowers open65 Full flowering: 50% of flowers open; first petals falling67 Flowers fading: majority of petals fallen69 End of flowering: all petals fallen7: Development of fruit71 Fruit set; beginning of ovary growth; beginning of fruitlets abscission72 Green fruit surrounded by sepal crown73 Some fruits slightly yellow: beginning of physiological fruit drop74 Fruits about 40% of final size. Dark green fruit: end of physiological fruit drop79 Fruits about 90% of final size 8: Maturity of fruit81 Beginning of fruit colouring (colour-break)83 Fruit ripe for picking; fruit has not yet developed variety-specific colour85 Advanced ripening; increase in intensity of variety-specific colour89 Fruit ripe for consumption; fruit has typical taste and firmness; beginning of senescence and fruit abscission 9: Senescence, beginning of dormancy91 Shoot growth complete; foliage fully green93 Beginning of senescence and abscission of old leaves97 Winter dormancy period
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