Calendar vs. Truth
People often ask us at PCS “When will I be able to graze this?” “What is the best day to plant?” “How many days until this will be ready to harvest?” We can give estimates and date ranges to answer these questions, but the answer is often “It depends on the conditions and the plant.”
It would be great if we had set dates to plant each different crop. If we knew that on those exact dates for each it would not rain heavily after, go dry, turn cold, or get blazing hot too soon. But, unfortunately, that is not the case. Advisable windows to plant can be given, but the weather is too big of a factor to ignore on the actual day you get in the field. Always try to have fields fit when you get into them, even though that may seem impossible sometimes.
Aside from rain and dry conditions at planting, temperature requirements need to be met as well, especially for warm season annuals. No one can say the exact day soil temperatures will reach 65 degrees and rising, but that is the requirement that we have to be patient enough to meet for successful warm season annual establishment.
When should I chop or bale my forage? For cool season annuals like cereal rye, the timing is based off of maximizing tonnage as well as quality. The same goes for warm season annuals such as sorghum sudan, sudangrass, and multi-species blends. For many of the grasses, including warm season and cool season, where high quality baleage or silage is the goal, you often want to harvest at boot stage. This is when valuable nutrients and sugars are still throughout the whole plant before they are all sent directly to seed production. In the case of silage where you are wanting higher starch, then it would be advised to wait for the heads to fill out and reach soft-dough stage (when the kernals pop and feel like dough when squeezed). The timing of when those stages occur can vary largely based on weather. Specifically, for the warm seasons, the warmer the temperatures (with moisture available) the quicker their growth will be.
The decision of when to graze is going to be similar to the mechanical harvest, when grasses are at boot stage. Another factor that comes into grazing, and sometimes to the mechanical harvest, is planning to get multiple passes of grazing off a crop. Sudangrass, for example, can be planted early summer and be grazed 2-3 times when managed properly. This is another time where it is important to monitor plant stage and height when beginning grazing, as well as when to stop to allow for adequate regrowth. Setting up your grazing rotation does have to fit your operation, but plant height must also be monitored closely. Go off of the plant, not the calendar.
The moral of the story here is do not rely solely on calendar dates or number of days when making various decision like planting, harvesting and grazing forages. The truth is that weather conditions, plant stage of development, and grazing needs have to be taken into account for these decisions.