The BBCH is the growth stage of a plant. There´s plenty of information to be found but if you just want to play CnC, here´s the most important facts:


Every plant on your field is calculated individually. Differences in fertilizing can lead to different BBCH levels on your field (e.g. lack of nutrients leads to slower growth). Every 10 steps of BBCH the plant animations change to display growth.

On the F1 field map you are shown an average of the fields BBCH. The eye next to that BBCH level is showing you a growth stage map.

The most important info for you is: when can I harvest a field with the best output?

For all grains it´s easy: BBCH 90 (Rye, Barley and Wheat). The animation changes from 89 to 90 by becoming light brown instead of green. So there´s actually no way to get the timing wrong. If there´s patches of green in an otherwise brown field, you can either ignore it and harvest it (the green patches will not be harvested). Or you can wait for several days for the slow grown parts to become ripe. No worries, atm the BBCH 90 stage lasts very long and the ripe field won´t rot while you wait for the late arrivals.

For Maize it´s easy as well: BBCH 80 for threshing or chaffing it. The stage 80 is reached when the big juicy green plants shrink to something less juicy but far more harvestable from BBCH 79 to 80. The plant you want to hatvest is yellowish and considerably smaller than the green monster before.

The most complicated plant is Grass. It doesn´t matter what you want to do with it, the highest yield is in the stages BBCH 60-79. 60-69 is the last green stage wether 70-79 is the first brown/yellow stage. Here´s a link to a post with pics. The pic´s titles are the BBCH stages.

That´s something I can´t really answer Wouldn´t know nothing about neither.

What I know is the XML. Just open the Base Folder of the game and look for the fruits in the config folder. The field_grass xml is showing that the yield for chopping and the residueVolumePerSquareMeter (swath) is highest at stages 6 and 7. So there only seems to be grass swath or grass chaff to be harvested. The timing is setting the amount. From those two materials you can produce hay, silage or just use them in the form of field grass or chaff. Those "filltypes" got individual values for energyMJperKG, proteinConcentration or fibreConcentration which might become a factor when the feeding system is expanded.

Back to your question: The "age" of the grass influences the amount of stuff you can harvest and therefore indirectely the total of nutrients. But there´s no diffenrent types of grass like young and old grass.