Dashain or Bijaya Dashami, the main festival in the Hindu calendar, is fast approaching. On this occasion, elders give blessings to their younger relatives by putting a ‘tika’ on their forehead. Tika is a paste made of rice grains, yoghurt and vermilion. Apart from rice, another plant is central to the festival—barley. Sowing barley seeds marks the start of the 15-day long Dashain festival. The barley seeds sowed on Ghatasthapana (day one) produces barley grass or ‘jamara’. Unfortunately, things don’t always go to plan. Here are some scientific reasons why you may not be getting healthy, long and pale jamara without which Dashain is simply incomplete.

Jamara is the grass that emerges after barley seeds germinate. The Dashain jamara is yellowish while barley sprouts in the field are green. The field sprouts get their colour from a chemical called chlorophyll. But why is jamara yellowish? Is it because jamara is missing chlorophyll? The answer is yes. It depends on how much light the plant is getting. Chlorophyll is present in a plant cell compartment known as plastid. However, plastids need light to activate chlorophyll. The plastid that contains chlorophyll is known as chloroplast, and these are green in colour. As Dashain jamara is grown in darkness, these plastids don’t have chlorophyll. Therefore, the jamara is yellowish instead of green.

Light affects every single stage of a plant’s lifecycle, including early stages and germination. If the lighting isn’t right, the seeds may not sprout at all. In barley and wheat, white and blue light makes the seed go to sleep instead of promoting germination. Dormant seeds remain metabolically active, but dormancy suppresses the growth processes of barley. Therefore, dormancy is defined by the failure of viable seeds to germinate under favourable conditions. As white light promotes dormancy, growing jamara under white light reduces barley sprouting and growth.

Red light, however, doesn’t affect the germination of barley seeds. If it doesn’t affect germination, should we be growing jamara under red light rather than in total darkness? No, because red light decreases the length of young barley grass in comparison to the plants grown in total darkness. Therefore, to grow long, yellowish jamara for Dashain, keep growing them in the dark, as you’ve always been doing.

Barley seeds germinate within a couple of days of sowing. This is excellent news for Dashain because we need to grow jamara in a short period. However, things weren’t always this rosy at the onset of agriculture. The wild relatives of modern barley remain dormant for months after the grains mature in the plant. Due to the seeds remaining dormant, barley’s wild relatives may not germinate even when temperature and conditions are perfect. In contrast, modern barley seeds have low dormancy and can be subject to pre-harvest sprouting under certain conditions.

Pre-harvest sprouting poses a big problem for the agricultural industry causing significant losses. However, the long dormancy period in barley’s wild relatives has never been ideal. The ability to control germination is highly desirable for farmers and beer brewers because it eliminates the need to store the seeds for an extended period. Farmers have been breeding barley against dormancy for centuries, but it seems that most extensive breedings took place in the early stages of barley domestication.

Scientists found that 6,000- year-old barley seeds—recovered from the Judean Desert in present-day Israel—are similar to modern barley. This means that early farmers bred barley to obtain the desired traits more than six millennia ago. One of the characteristics is low dormancy in dry, mature modern barley grains, which allows modern barley to germinate quickly and uniformly. This isn’t only good for agriculture and the alcohol industry, it has also enabled jamara to sprout and grow rapidly for Dashain.

Most people save a stock of seeds and store them safely to grow jamara. Barley grains stored under cool, dry conditions remain healthy and can germinate even several decades after harvest. Only half of the barley seeds—with 20 percent moisture content—germinate after 10 days at 35 degrees Celsius and after 50 days at 25 degrees Celsius. So, high temperature and humidity significantly reduce seed viability, which means that grains fail to germinate under favourable conditions. If you too are storing barley grains to grow jamara, then avoid storing them in hot, humid rooms. Storing barley seeds in a cool and dry place helps to maintain grain health. More germination means jamara grows denser, so more jamara per pot. This is the science of jamara that we can use to improve jamara quality and growth to avoid any disappointments during Dashain.

Paudyal holds a PhD in Plant Sciences from the University of Leeds.