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Lettuce: From Ancient Pyramids to the Stars
Last month’s sweltering sun has given way to heavy rain and cooler breezes. For a while, shorts and t-shirts replaced jeans and fleeces. The heatwave also brought about a seasonal change in my diet. No more hearty soups; salads and sandwiches became the order of the day. Aestivation over, now I feel able to move and work faster, but I retain my taste for fresh green food.
Just outside my backdoor, a pot stands as a quiet reminder of the heatwave. And in it are three lofty, yellowing plants. Each leafy pagoda is crowned with clusters of small yellow daisy-like blooms. These aren’t your average summer bedding plants; they are lettuce flowers. The trio have bolted in the scorching sun. However, the flowers have a tale to tell. Lettuce is a member of the daisy family (Asteraceae). Hands up if you knew the eye-opening fact that your salad leaves share a common ancestor with sunflowers and pretty marguerites. You did? Perhaps you read last week’s Capital Gardens blog article by my fellow garden writer, Andy Williams, on the fascinating daisy family.
At first glance, lettuce might seem like just another ordinary salad ingredient. Yet its odyssey from wild weed to salad staple is nothing short of extraordinary. In 2021 researchers at Wageningen University and the Chinese BGI examined the DNA of 445 different types of lettuce. Their results published in the prestigious periodical Nature Genetics showed that the first wild lettuce to be modified by cultivation happened 6,000 years ago in the Caucasus.
The study showed that domestication happened once from a single wild ancestor (Lactuca serriola). Early farmers valued this species for the medicinal oil harvested from its seeds and its bitter, latex-rich sap. Through careful selection, those ancient cultivators transformed the wild plant by selecting against characteristics such as leaf prickles, bitterness, and early flowering.
Lettuce was eaten by Persian Kings and Egyptian Pharaohs. In Ancient Egypt lettuce was linked to the god Osiris and regarded as a symbol of fertility. Lettuce was also valued by the Ancient Greeks and Romans, who favoured it as a salad crop, and further bred the plants. Over millennia, a new plant species (Lactuca sativa) diverged into two main, morphologically distinct types: leafy lettuce and stem lettuce. Fast forward to the Byzantine era, and the Greek Island of Kos became a major production area for lettuces, giving rise to the Cos lettuce types we enjoy today.
Moving on, when Catherine of Aragon married King Henry VIII of England, she brought with her not only a royal bloodline but also a love for leafy greens. To her dismay, fresh salads were non-existent in English courtly dining at that time. Such was her insatiable craving for salad that hunger won out over tradition, and imported greens soon appeared at her table. To ensure a steady supply, Queen Catherine enlisted Dutch gardeners to cultivate lettuce in her private gardens, and she became widely credited with introducing the lettuce and the concept of eating fresh salads to England.
Seeds of lettuce even hitched a ride across the Atlantic with Christopher Columbus during his second voyage to the Americas in 1493. And later European settlers spread diverse lettuce varieties to North and South America.
Over centuries of cultivation and experimentation, we arrived at the five main types we enjoy today: Butterhead – quick maturing, with soft leaves and a loose heart. Cos/Romaine – tall, upright heads. Crisphead/Iceberg – solid hearts, large crisp heads. Loose leaf – loosely bunched salad leaf types. Summer crisp/Batavian – somewhere between crisphead and loose leaf types.
Lettuce hasn’t just been lauded for its taste—it’s prized for its surprising medicinal benefits as well. The ancient Greeks served it after a meal to help their guests digestion and get a good night’s sleep. The dictatorial Roman Emperor Domitian served it as an entrée for his feasts, aware of its sleep inducing properties, and then gleefully watched as his terrified guests struggled to keep their eyes open.
Is lettuce the Mogadon of the salad bowl? The soporific principle found in lettuce is concentrated in the milky sap you can see dribbling out from the cut base of the stems. The genus name for lettuce and its wild relatives, ‘Lactuca’ derives from the Latin word lac meaning ‘milk’. And the white fluid is known as lactucarium, or lettuce opium, because of its sedative and analgesic properties. It’s no wonder Beatrix Potter, an enthusiastic botanist, wrote about how the Flopsy Bunnies fall fast asleep and get captured after gorging themselves on overgrown lettuce in Mr. McGregor’s rubbish heap. Spoiler alert – they are freed by a wood mouse who fills the sack with rubbish instead.
Lettuce is no longer just a terrestrial treat – it has successfully been grown in space! As part of NASA’s research, lettuce was experimentally cultivated in microgravity aboard the International Space Station (ISS). This humble leafy green may hold the key to promoting both physical health and mental well-being for astronauts embarking on longer missions to destinations like the Moon and Mars.
From its ancient roots to its journey into space, lettuce has proved it is more than just another green leaf. If these crisp facts have tickled your taste buds for some fresh salad, then now is a good time to grow your own. Quick growing, home grown lettuce tastes much better than the tired leaves found in shop bought salad bags. Lettuces can be cultivated in large pots or grow bags where space is an issue. I recommend starting with cut-and-come-again varieties. With these types, you simply harvest the outer leaves as they grow, allowing the inner crown to keep producing fresh salads for summer long harvests. Give it a go – Cos you’re worth it!
Further Reading:
Learn about the daisy family.
How to grow lettuce.
