Determining the correct growth stage of a canola crop can help farmers with management decisions for several production
practices, including herbicide timing, fungicide timing and harvest timing. Canola growth stages can be described by the
BBCH scale. This scale was developed to describe the ten principal growth stages (8 of which apply to canola in Western
Canada) which are further sectioned into secondary stages. Growth stages may overlap when the crop is completing one
growth stage at the same time the next growth stage begins. The growth stages described below are for individual plant
assessments. Field scale growth stages across a field can be extremely variable for canola. Growth stages can overlap so
the principal growth stage is determined when over 50% of the plants reach a growth stage.1
Table 1. BBCH growth stages and description.
Figure 1. Canola growth stages.
Germination - Growth Stage 0
Canola can emerge four to 15 days after seeding depending on heat, moisture, seedbed and seed condition. Canola can
germinate at 2oC, but 10oC is ideal. The root emerges from the seed followed by the shoot and seed leaves (cotyledons).2
The growing point is now above the soil and vulnerable to early season hardships such as frost.
Figure 2. Hypocotyl with cotyledons emerged from seed (BBCH 07).
Leaf Development - Growth Stage 1
This stage begins with the unfolding of the cotyledons (BBCH 10, Figure 3). Leaf stages are then identified by the
number of leaves unfolded on the plant (Figure 4).1 The first true leaf may appear four to eight days after emergence.2
Growth can be slowed by cool temperatures, dry or saturated soil conditions, insect feeding, or disease. The crop should
be kept weed free at this stage. Crop loss due to weeds is most substantial when weeds are present from emergence to the
two-leaf stage of canola.2 Leaves continue to emerge forming a rosette (Figure 5). Uptake of nitrogen and potassium
rapidly increase at the five-leaf stage and remain high through 50% flowering.2 The next growth stage, stem elongation,
may begin by the six-leaf stage.
Figure 3. Cotyledon canola (BBCH 10).
Figure 4. Canola with the first leaf unfolded (BBCH 11).
Figure 5. Leaves form a rosette prior to stem elongation.
Stem Elongation - Growth Stage 3
The stem begins to emerge from the rosette. Each secondary stage is identified by the number of visible internodes.
Budding often overlaps with stem elongation and can begin when the first internode is visible.
Inflorescence Emergence (Budding) - Growth Stage 5
This is the beginning of the reproductive growth stages. The bud can be present in the rosette as the first internode
appears on the stem. At BBCH 50, flower buds are present though they may not be visible.1 Flower buds become visible at
BBCH 51 and first petals become visible, enclosed in a yellow bud, at BBCH 59. Flowering is soon to follow.
Figure 6. Individual flower buds visible but closed (BBCH 55).
Flowering - Growth Stage 6
Flowering begins when the first flowers open (Figure 7). The secondary stages of flowering are based on the percentage
of flowers open on the main raceme.1 Flowering can advance by three to five flowers opening per day. Canola typically
flowers for two to three weeks but if conditions are favorable this can vary dramatically.2 If fungicide is planned,
recommendations for application are typically between 20 and 50% flowering before petals fall. Full flowering is when
50% of the flowers on the main raceme are open with older petals falling. This is when the maximum plant height is also
achieved.2 After this stage, flowering begins to decline and the field appears less yellow. Most petals have fallen by
the 70% flowering stage.1
Figure 7. Canola at first flower (BBCH 60).
Development of Seeds and Pods - Growth Stage 7
Pods begin to develop while the plant is still flowering. Typically, 10% of pods have reached their final size when the
plants are at the 70% flowering stage. (BBCH 67 & BBCH 71).2
Figure 8. Flowering declining. Majority of petals fallen while many pods have reached final size.
Ripening - Growth Stage 8
This stage overlaps with the previous stage with seed fill beginning when approximately 60% of pods have reached their
final size. The ripening stage begins when seed is green and filling the pod cavity and ends when the pod is ripe with
dark and hard seed.1 When seeds reach physiological maturity, they stop pod fill and begin losing moisture and changing
colour from green to brown.2 The seed colour change percentage can be determined by assessing the main raceme in
portions. If the seeds on the bottom 30% of the main raceme have changed colour then the stage is 30% seed colour change
(BBCH 83). If seeds in 60% of the main raceme have changed colour then the stage is 60% seed colour change (BBCH 86).
Seed colour change occurs at an average rate of 10% change every two to three days. Some canola plants may have very
small main racemes and many branches. If this is the case, assess the branches and ensure the seeds in these branches
are firm prior to swathing.2
Figure 9. Seeds are mature and changing colour.
Senescence - Growth Stage 9
This is the final growth stage where the plant dies naturally if not desiccated or swathed.
1Meier, Uwe. 2018. Growth stages of mono- and dicotyledonous plants. BBCH Monograph. Quedlinburg
2018. Open Agrar Repositorium. 10.5073/20180906-074619 https://www.julius-kuehn.de/en/jki-publication-series/bbch-scale/.
2Canola Council of Canada. Canola Encyclopedia. https://www.canolacouncil.org/canola-encyclopedia/.
ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. Performance may vary from location to location and from year to year, as local growing, soil and weather conditions may
vary. Growers should evaluate data from multiple locations and years whenever possible and should consider the impacts
of these conditions on the grower’s fields.
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