Description of sunflower growth stages

The total time required for development of a sunflower plant and the time between the various stages of development depends on the genetic background of the plant and the growing environment. When determining the growth stage of a sunflower field, the average development of a large number of plants should be considered. This staging method also can be used for individual plants. The same system can be used for classifying a single head or branched sunflower. In the case of branched sunflower, make determinations using only the main branch or head. In stages R7 through R9, use healthy, disease-free heads to determine plant development if possible because some diseases can cause head discoloration.

V-E

V-2

V-4

V-12

True leaf — 4 cm

R-1

R-2

R-2   Less than 2 cm

R-3

R-3    More than 2 cm

R-3 Top View

R-4 Top View

R-5.1

R-5.5

R-5.9

R-6

R-7

R-8

R-9

Reviewed and reprinted May 2013