Plant of the Month: Lettuce

HISTORICAL INFORMATION

The plant we now call lettuce was once thought to have been bred from a ‘weed’ growing in the countries close to the Mediterranean Sea. Wild varieties (Lactuca serriola) can still be found growing there, and in parts of Asia. The wild species were cultivated and eaten by the Ancient Egyptians and Ancient Romans, so the plant has been part of the diet of human beings for a very long time!  Selective breeding, plus hybridisation with the original ‘weed’ species is believed to have resulted in the species we know today, Lactuca sativa. ¹ The plant we now recognise as ‘lettuce’ is believed to have been eaten by the Chinese as early as the 5th Century C.E. In addition, a variety of ‘stem lettuce’ (“celtuce” originates from China. ²

Recent research indicates that lettuces originated in the Caucasus area, between the Black Sea and the Caspian Sea – north east of the Mediterranean, in countries that some call the Middle East, some call Eastern Europe and yet others, Western Asia! Selective breeding and hybridisation removed the prickles from the original ‘weed’ species, enlarged the leaves and created plants that formed heads.³

Lettuce, together with its near relative chicory, is among the ten most popular vegetables grown in the world.⁴

In the 19th century, there were more than 1000 varieties of open-pollinated lettuce known throughout the world. Many of these were last in the 20th century.

DESCRIPTION

Lettuces are annual, fast-growing, comparatively soft-leafed plants, which are members of the daisy family (which includes sunflowers and dandelions). Most types are low-growing, although some Cos varieties may reach 60cm.

Lettuces can be grouped into four main types:

1. loose-leaf, like the hydroponic varieties sold in the supermarket: salad bowl, oakleaf
2. butterhead
3. cos, also known as Romaine
4. crisp-head, like iceberg lettuce

CULINARY USES

Lettuce is a rich source of Vitamin A and Vitamin K.  The darker the leaves of green varieties, the richer the nutrients. Many people find red-leafed varieties more bitter than green-leaf lettuces. Bitterness in food is very good for gut health.

Lettuces are most often used fresh in salads, sandwiches, wraps or smoothies; For those following a low-carb or low-calorie lifestyle, large lettuce leaves make excellent wraps – we fill ours with grated cheese, grated carrot, thinly sliced cucumber, small segments of capsicum, halves of tiny wild tomatoes and, sometimes, some ham. If you are using cos leaves, you may need to remove the central vein in order to roll it around the filling.

Some varieties can be cooked, particularly those with thicker leaves, or those that form hearts. Leaves wilt quickly, so add them to stir fry at the last moment. Grill or barbecue whole hearts of baby cos lettuce (or endive, a close relation).

MEDICINAL USES

In ancient times, the white sap exuded by lettuce was believed to aid sleep. This effect has been lost in most modern lettuces as they are not as “sappy”.

In traditional medicine, lettuce has been used to:

• fight inflammation
• relief from constipation (providing both fibre and water)
• treat asthma, coughs and bronchitis
• soothe painful skin ulcers (used in the form of a poultice)
• treat rheumatism (used in the form of a poultice)

HOW TO GROW LETTUCE

The easiest to grow are the loose-leaf types, which are often called ‘cut and come again’ varieties. They don’t form a “heart”, they have loose leaves around a central growing point. You can remove the leaves as needed and, as long as you never touch the leaves right in the centre, the plant will keep on growing more leaves for several weeks.

Butterhead lettuces are also relatively easy to grow. These varieties form a loose heart. The leaves are soft and tender and easily bruised. In their early weeks of their life, they can also be grown as ‘cut and come again’ lettuces but, if you want a heart, at some point, you have to stop picking!

Cos or Romaine lettuces grow very easily in the cooler months, in our garden that was late autumn through to late winter. Once the warmth of Spring hit, they bolted to seed.

In our experience, crisp-head lettuces are the most difficult to grow in wester Sydney. The need a long cool period, one that we often don’t get. If Spring comes early, as it did in 2021, then Iceberg type lettuces will generally fail. To bypass the short length of the cool growing season, you could try starting them in autumn in a cool environment and plant them out in late autumn when the risk of unseasonable heatwaves has passed.

Lettuce seeds generally germinate easily but can just as easily be killed by too much water! It is good to add vermiculite or perlite to your seed-raising mix to increase drainage, and to cover the soil surface around your baby seedlings with cinnamon as this discourages the fungus which causes ‘damping off’ – a disease which can kill your seedlings overnight!

Keep your lettuce plants well-watered, but not saturated! Allow the soil to dry out a little before you water again.

If you are growing lettuces only for “cut an come again” use, it doesn’t matter if the plants are very close together. If you are growing lettuce is for their heads, you will need to space them according to the directions on the seed packet. Heads will not form if the plants have to compete for space, light, water, and nutrients.

Sow lettuce seeds every two or three weeks during the growing season for a continual harvest. This is called “succession sowing”.

Lettuce don’t do well in the heat of summer in western Sydney, anything above 25°C will cause stress and bolting. However, they can be grown for summer salads as long as you keep them sufficiently moist and give them shade from the afternoon sun – for example, on the eastern side of the house or trellis.

LETTUCE IN THE PSW SEEDBANK (your seedbank)

• Lettuce ‘Australian Yellow’ – Australian bred, loose-leaf variety, wavy, yellow-green leaves; good in hot weather
• Lettuce ‘Barba dei Frati’ (“Monk’s Beard” or “Friar’s Beard”) unusual shaped, loose-leaf variety – cooking variety
• Lettuce ‘Biscia Rossa’ (“Red Snake”) – open Italian variety, crisp green leaves, red margins
• Lettuce ‘Black Seeded Simpson’ – loose-leaf variety, 1700s heirloom, crinkled leaves, matures quickly
• Lettuce ‘Bronze Mignonette’ – butterhead-type with bronze tinged leaves
• Lettuce ‘Buttercrunch’ – popular variety, lime-green, buttery leaves
• Lettuce ‘Cimmaron’ – Cos-style, bronze leaves
• Lettuce ‘Cos Verdi’ (“Green Cos”) – green, upright variety with sweet leaves
• Lettuce ‘Croatian’ – hearting variety, green to bronze leaves
• Lettuce ‘Drunken Woman’ – loose-leaf variety, green leaves with bronze tip
• Lettuce ‘Forellenschuse’ (“Flashy Trout Back” or “Speckled Trout”) – Cos-style, green leaves splashed with deep red
• Lettuce ‘Freckles’ – Cos type, lime green leaves with red speckles (easy to grow)
• Lettuce ‘Frilly Pink’ – loose-leaf variety, frilly pink edges on green leaves
• Lettuce ‘Grand Rapids’ – loose-leaf style; green, crinkled leaves
• Lettuce ‘Green Mignonette’ – butterhead variety, small head, green leaves
• Lettuce ‘Little Gem’ – small, Cos variety, sweet
• Lettuce ‘Marvel of Four Seasons’ – French heirloom, butterhead variety, wavy burgundy and green leaves
• Lettuce ‘Michelle’ – loose-leaf variety, mid-green leaves
• Lettuce ‘Oakleaf Green’ – loose-leaf variety, oak-leaf shape, green leaves
• Lettuce ‘Oakleaf Red’ – loose-leaf variety, oak-leaf shape, deep-red leaves
• Lettuce ‘Parris Island’ – Cos variety large, slightly crinkled leaves
• Lettuce ‘Rabbit Ear’ – open-hearted variety; small, dark green, pointed leaves
• Lettuce ‘Red Coral’ – open-hearted variety; red leaves, frilled edges
• Lettuce ‘Red Cos’ – brilliant, red-burgundy leaves
• Lettuce ‘Red Cross’ – butterhead type, sweet, buttery, red leaves
• Lettuce ‘Regina della Ghiacciole” – Italian iceberg variety, crisp leaves, good flavour
• Lettuce ‘Ricciolina da Tagelio’ (“Old Man’s Beard”) – red leaves, loose leaf variety
• Lettuce ‘Romano Bionda’ – Cos-style, light coloured leaves with white stem; classic Caesar salad lettuce
• Lettuce ‘Salad Bowl Green’ – loose-leaf variety; light green, wavy leaves
• Lettuce ‘Salad Bowl Red’ – loose-leaf variety; bronze-red leaves, slightly bitter
• Lettuce ‘Webb’s Wonderful’ – iceberg type, does not like hot weather
• Lettuce ‘White Boston’ – butterhead variety; light green, tender leaves

Links above are to the PSW 2023 catalogue, where you can find information about, and (sometimes) photos of, the varieties available.
The catalogue is now open for mail order and “click and collect” sales. Please note that mail orders incur a $5 postage and handling fee; “click and collect” orders incur a $2 handling fee.

Seeds for all seasons are available while in stock.
Please note: seeds are for sale to PSW and PSN members only.
Thank you.

JOIN PSW NOW

Until next month
Lynne (PSW Seed Savers Team Coordinator and Custodian of the Seed Bank)

DISCLAIMER
This article is for gardening information and general interest only. Being neither a herbalist nor a qualified medical practitioner, I cannot give any medical advice on the use of any plant, internally or externally. Readers of this article must do their own research before using cabbages for any purpose other than as a garden plant.

REFERENCES

1. 1. McGill University, California: Lettuce
   2. Texas A&M University, Universal Boon to the Salad Bowl
   3. Wageningen University & Research, Tracing the Origin of Lettuce
   4. World Atlas, The Most Popular Vegetables In The World