Lesson 2 - Barley

Planting times differ across the globe. Some varieties are sown during autumn (winter barley), and harvested the following summer. Others are sown during spring (spring barley) and harvested that same summer. A third type, known as facultative varieties, can be sown at any time. This is because they withstand cold temperatures. Some differences between winter and spring barley are listed below.

Winter barley:

• Requires low temperatures (vernalisation) for good flowering, whereas facultative barley does not have this requirement.
• Does not flower, or flowers too late, if planted during spring.
• Produces leaves and some tillers rapidly in autumn. The process is slowed over winter and then accelerates in the spring.
• Is usually sown in September in the northern hemisphere.

Spring barley:

• Does not survive the cold if planted in the autumn.
• Is ready to harvest, on average, 60-70 days after planting.

So why do we worry about the times at which we plant different varieties? Depending on the part of the world, the quality of the barley grown at different times of the year can be different and yields also vary with when the barley is sown and harvested. Farmers and grain merchants benefit from producing winter and spring barley as it spreads the work of harvesting and processing. For example, if you grow 20,000 t of spring barley you would need to harvest 20,000 t over a few days. If you grow 10,000 t of spring and 10,000 t of winter you double the amount of time you have to do the work.

The crop’s flowering stage is critical for the development of the grain on the spike. If it is interrupted, or the plant becomes stressed (drought, frost or other abnormal weather), it negatively affects the yield and/or the quality of the grain.

The yield of a barley crop is the mass of grain produced per unit area and is usually quoted in tonnes per hectare (t/ha). Yield is affected by the availability of water and nutrients, the amount of sunlight and the temperature.

We cannot plant barley at the same time in all parts of the world, so when are barley crops planted in the main barley growing regions? Let's find out next.