BBCH growth stages explained: a practical guide for crop records

Product labels, advisers and research trials often say things like “apply at BBCH 30–39”. If the code means little to you, you are not alone. The BBCH scale is simple once you see how it is built, and recording it with each treatment makes your records far more useful.

What is the BBCH scale?

The BBCH scale is a standard way to describe the development stage of a plant with a number. The name comes from the German organizations that developed it: the Federal Biological Research Centre, the Federal Plant Variety Office and the chemical industry (Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie).

Its big advantage is that it uses one system for many crops. Wheat, oilseed rape, potatoes, maize and grapes all have their own BBCH scales, but the logic is the same.

How the codes work

A BBCH code has two digits:

• the first digit is the principal growth stage, from 0 to 9,
• the second digit is the secondary stage, a step within that principal stage.

The principal stages are:

Code	Principal stage
0	Germination, sprouting, bud development
1	Leaf development
2	Formation of side shoots, tillering
3	Stem elongation or rosette growth
4	Development of harvestable vegetative parts, booting
5	Inflorescence emergence, heading
6	Flowering
7	Development of fruit
8	Ripening
9	Senescence

Not every crop passes through every principal stage, and stages can overlap. In cereals, for example, leaf development continues while tillering starts.

Key stages in cereals

Cereals are where BBCH codes appear most often on labels. Some stages worth knowing:

• BBCH 13: three leaves unfolded.
• BBCH 21: beginning of tillering, first tiller visible.
• BBCH 30: beginning of stem elongation.
• BBCH 31: first node detectable.
• BBCH 32: second node detectable.
• BBCH 37: flag leaf just visible.
• BBCH 39: flag leaf fully emerged, ligule just visible.
• BBCH 51 to 59: heading, from the first spikelets visible to the ear fully emerged.
• BBCH 61 to 69: flowering; BBCH 65 is full flowering.
• BBCH 71 to 89: grain development and ripening, from watery ripe to fully ripe.

If you have used the Zadoks scale for cereals, the numbers will look familiar: the two systems are closely aligned.

Why record the growth stage?

• Labels depend on it. Many products may only be used up to a certain stage, and the timing of fungicides and growth regulators is usually set by stage.
• It explains results. A herbicide applied at BBCH 13 behaves differently from the same product at BBCH 25. Without the stage, your records cannot tell you why one field responded better than another.
• Rules increasingly expect it. Detailed record-keeping rules, such as those in the EU, use standard codes for crops and stages so that records can be compared and processed electronically.

Recording BBCH in practice

Walk the field before you spray and note the stage most plants have reached, not the most advanced plant you can find. In Agro Notes you choose the BBCH stage from a list for the crop when you record a treatment, so it ends up in your spray records and in the PDF or CSV export without extra typing.