Silks.

Forage maize is typically harvested 7-10 weeks after the tassel emerges, depending on the specific variety and growing conditions.

Tassel.

The tassel, the male flowering part of the maize plant.  This plant stage determines the number of cobs per plant which is highly sensitive to lack of water (and consequently nitrogen) at this growth stage, both of which effect final yield.

Silking.

Shortly after the tassel emerges, the silks (female flowers) appear from the tip of the cob sheath. This event is shortly followed by pollen release by the tassels.

The onset of silking may be used as a guide for when to harvest. When the corn plant reaches the half-milk line, approximately 42 to 47 days after silking, plants will normally have 40 percent moisture and 97 percent of their total dry weight.

Weather.

Weather conditions during pollination are important. Pollen is only released by individual plant over a period of 7 to 10 days. For pollination to occur, a grain of pollen must land on a receptive silk.

Very heavy rain or very high temperatures during this critical time can reduce the level of pollination which has a direct impact on the number of kernels which subsequently develop.

Grain abortion limit.

Once fertilisation is complete it becomes less and less possible for grain abortions to occur.  This point is reached at approximately 21 days post fertilisation.  With the final number of grains set marking the end of maximum sensitivity to water stress.