Lettuce
Lettuce is one of the great ingredient in salad.
There are many variants of this vegetable like Iceberg
lettuce, Romaine lettuce/Cos lettuce (include little gem), Butterhead lettuce, Batavia lettuce, Oak leaf lettuce/Salad bowl lettuce, Indian lettuce etc.
There are some special varieties of lettuce like Freckle, Red iceberg etc.
Freckle is a special romaine lettuce which full of red splash and spot, which
is rare in Hong Kong. Red iceberg is a rare red leaf iceberg lettuce, which
cannot be found in Hong Kong. Chinese lettuce (aka Tang lettuce) is the most
common lettuce in restaurant within Hong Kong. Autumn is the best time to grow
lettuce due to cool weather, which encourages seeds to spout. The Chinese lettuce
and iceberg lettuce are pretty affordable, only 5 HKD for one lettuce. Nowerdays, the Chinese lettuce is slowly replaced by Italian lettuce. The term "Italian" is actually a misnomer; Italian lettuce is a new variant Chinese lettuce with better storage for transportation and better ability to adapt harsh environment, thus Chinese give a western name to give a better image of this lettuce like Chanel, Dior etc those famous brand. Some people asked Italian seed company about pricing of this lettuce and the company replied that they never seen this lettuce before. While
uncommon one like Butterhead lettuce, Oak leaf lettuce etc import from overseas such as Australia are 45 – 60 HK
dollar per vegetable, which is too much for family expenditure.
While most of the lettuce are intend for harvest mature head, some of them are harvest as baby leaf. Baby leaf are lettuce seedlings that harvest in the size of credit card. Those young seedlings taste more crispy than the mature head lettuce. They yield a higher price due to the uncommon status in Hong Kong. Baby leaf lettuce are more easy to grow when compare to whole head lettuce as baby leaf seeds are intended for direct sown, seeds are sown directly in fertile field rather than punnets, and they are ready for harvest around 35-40 days depends on the climate. They skip lots of growing time when compare to whole head lettuce (60-90 days from seeds) and provde more yield when they sow intensively.
For whole head lettuce, the seeds need to take a month for forming suitable size seedling in punnets before they are suit for transplanting. So, most holiday farmers in our farm get those AFCD (Agriculture, Fisheries and Conservation Department) seedlings directly and plant them. Only few holiday farmers like me enjoy the fun of trialling new seeds. The most interesting part is watching the seeds germinate and form cotyledon, true leafs, until the young plants can be transferred to the land. Another advantage of starting from seeds is choosing a wide variant of species like butterhead lettuce etc. The important thing in buying seeds to sure they are not treated with pesticide and genetically modified to fulfill the rules that no chemicals is allowed from AFCD.
Most of the holiday farmer will try to grow different lettuce together, so they could pick up different variant according to the types of cuisine. According to my experience, they grow Romaine lettuce, Coral Lettuce etc. These lettuces are expensive within the supermarket, which are the most suitable type for Caesar salad.
I had the best harvest of Iceberg lettuce in January of 2009. I used three months to grow them from seedlings. These Iceberg lettuces were as large as volley ball and I were happy with that!
For the worst time of growing lettuce, it was the Romaine lettuce in August of 2009, those young plants died due to the high temperature in summer.
Finally, I introduced some Australian lettuce to my home as I studied in Western Australia. The Australian yellow lettuce grew well in the farm under Hong Kong’s climate, which is very cold in December, 2015 to March, 2016.
I grew some baby leaf red cos lettuce in my place near the end of 2016. I sourced those seeds from EE Muir and Sons in Perth, then sowed them in December, 2016. They grew rapidly and I started to harvest them in January, 2017 for salad with pasta as dinner. In the meanwhile, I started Australian red oak lettuce seeds in punnets for forming seedlings, they did well in there and waiting for transplantation after radish harvest for Chinese New year. At April 2017, those red oak leaf lettuce reach mature size and generate a great harvest, it was very crispy and fresh as well when compare to the baby leaf red cos lettuce.
More Australian lettuce seeds are trialed in Ma On Shan during my holiday in Hong Kong. Those pelleted little gem and butterhead lettuce seeds were sowed in late December, 2017. They formed seedlings quickly and ready to transplant near the end of January, but suffered from bird damage. The lost seedlings are replaced and net cover are added to set up a barrier for refuge. On the other hand, another Australian baby leaf green cos lettuce was given to the neighbour city farmer for direct sowing and formed massive seedlings, harvest time will be coming soon.
Lettuce is watery, crispy. Our family loves to eat lettuce and they said the taste was very interesting. Lettuce can be good salad ingredient and Chinese meal ingredient depends on the way to prepare.
While most of the lettuce are intend for harvest mature head, some of them are harvest as baby leaf. Baby leaf are lettuce seedlings that harvest in the size of credit card. Those young seedlings taste more crispy than the mature head lettuce. They yield a higher price due to the uncommon status in Hong Kong. Baby leaf lettuce are more easy to grow when compare to whole head lettuce as baby leaf seeds are intended for direct sown, seeds are sown directly in fertile field rather than punnets, and they are ready for harvest around 35-40 days depends on the climate. They skip lots of growing time when compare to whole head lettuce (60-90 days from seeds) and provde more yield when they sow intensively.
For whole head lettuce, the seeds need to take a month for forming suitable size seedling in punnets before they are suit for transplanting. So, most holiday farmers in our farm get those AFCD (Agriculture, Fisheries and Conservation Department) seedlings directly and plant them. Only few holiday farmers like me enjoy the fun of trialling new seeds. The most interesting part is watching the seeds germinate and form cotyledon, true leafs, until the young plants can be transferred to the land. Another advantage of starting from seeds is choosing a wide variant of species like butterhead lettuce etc. The important thing in buying seeds to sure they are not treated with pesticide and genetically modified to fulfill the rules that no chemicals is allowed from AFCD.
Most of the holiday farmer will try to grow different lettuce together, so they could pick up different variant according to the types of cuisine. According to my experience, they grow Romaine lettuce, Coral Lettuce etc. These lettuces are expensive within the supermarket, which are the most suitable type for Caesar salad.
I had the best harvest of Iceberg lettuce in January of 2009. I used three months to grow them from seedlings. These Iceberg lettuces were as large as volley ball and I were happy with that!
In April of 2011, I got some Indian lettuce (aka Yau Mak vegetable, Celtuce) seedlings from Mr. Wong, he
sowed those seeds intensively in a small land, then wait for seedling. Later,
he dug up some seedling and young plants for me and I transferred them to the
farmland immediately. They adapted the environment rapidly and grew very fast,
I harvested them by picking the external leaf, stir fried with garlic. The vegetable is very
tasty! I ate them with crispy sound within the mouth.
In the January of 2012, I got different kinds of lettuce seeds from many shop, and sowed them in the tray, as well as mount the table lamp, in order to compensate lesser sunlight. Unfortunately, those seedlings wilted due to microorganism infection, I had to sow the seeds again, until the formation of new seedling, because of that, the incubation of seedling prolonged to two months. Finally, due to shorten time to grow, I had to harvest them early.
In the January of 2012, I got different kinds of lettuce seeds from many shop, and sowed them in the tray, as well as mount the table lamp, in order to compensate lesser sunlight. Unfortunately, those seedlings wilted due to microorganism infection, I had to sow the seeds again, until the formation of new seedling, because of that, the incubation of seedling prolonged to two months. Finally, due to shorten time to grow, I had to harvest them early.
For the worst time of growing lettuce, it was the Romaine lettuce in August of 2009, those young plants died due to the high temperature in summer.
Finally, I introduced some Australian lettuce to my home as I studied in Western Australia. The Australian yellow lettuce grew well in the farm under Hong Kong’s climate, which is very cold in December, 2015 to March, 2016.
I grew some baby leaf red cos lettuce in my place near the end of 2016. I sourced those seeds from EE Muir and Sons in Perth, then sowed them in December, 2016. They grew rapidly and I started to harvest them in January, 2017 for salad with pasta as dinner. In the meanwhile, I started Australian red oak lettuce seeds in punnets for forming seedlings, they did well in there and waiting for transplantation after radish harvest for Chinese New year. At April 2017, those red oak leaf lettuce reach mature size and generate a great harvest, it was very crispy and fresh as well when compare to the baby leaf red cos lettuce.
More Australian lettuce seeds are trialed in Ma On Shan during my holiday in Hong Kong. Those pelleted little gem and butterhead lettuce seeds were sowed in late December, 2017. They formed seedlings quickly and ready to transplant near the end of January, but suffered from bird damage. The lost seedlings are replaced and net cover are added to set up a barrier for refuge. On the other hand, another Australian baby leaf green cos lettuce was given to the neighbour city farmer for direct sowing and formed massive seedlings, harvest time will be coming soon.
Lettuce is watery, crispy. Our family loves to eat lettuce and they said the taste was very interesting. Lettuce can be good salad ingredient and Chinese meal ingredient depends on the way to prepare.
For the food chemistry of lettuce, phenol compound can be found, which is
an effective antioxidant.(1)
Different lettuce under different growth conditions contain different level of antioxidant. Different varieties of lettuce contain different concentration of antioxidant, for example, “Red Sails” showing a higher response than “Baronet”. (1) Especially when transplanted to open field, it shows higher phenol compound when compare to growth in high tunnel.(1) So, the research also find out that Greenhouse-grown lettuce was rather poor in total phenolic concentration and antioxidant capacity.(1)
Free radical are produced with endogenous process and damage our body. In our body respiration, radical will be produced, which damage the cell by forming unsaturated bonds in membrane lipids.(2) Persistent peroxidation induces in the loss of membrane fluidity, receptor alignment, which will have potential in cellular lysis.(2) Free radical also damaged sulfur containing enzymes, which also induce inactivation of protein function, denature of the protein structure by forming cross link.(2) Sometimes, DNA also affected and damaged, which cause mutation and carcinogen properties.(2) Even neurotransmitter and hormone can be affected, neurotransmitter is important in regulation of sympathetic nervous system and parasympathetic nervous system; it will cause many symptoms like hypertension, stomach pain, nausea etc if the function are altered.(2) Hormone disruption which indicate there are endocrine problems within body like precocious puberty or Gynecomastia in male.(2)
Cleaning of the free radical is the main effect for those phenol compounds. The Mechanism of action of antioxidants are done by scavenging of reactive oxygen and nitrogen species, chelation of redox-active metals, inhibition of radical-generating enzymes and induction of endogenous antioxidant gene expression. (3) These reactions will induce anti-inflammatory, chemopreventive, antidiabetic and antiatherogenic efficacy, which reduce the levels of cell damage.(3)
Flavonids is a good example of phenol compounds to maintain body health. Using flavonoids as example, it also maintains the health by the adjustment of adhesion in monocytes, which reduce the inflammation effect in the atherosclerosis. (4) Especially those metabolites like (+) catechin and quercertin of flavonoids show greater effect to reduce the risk of cardiovascular disease.(4)
Different lettuce under different growth conditions contain different level of antioxidant. Different varieties of lettuce contain different concentration of antioxidant, for example, “Red Sails” showing a higher response than “Baronet”. (1) Especially when transplanted to open field, it shows higher phenol compound when compare to growth in high tunnel.(1) So, the research also find out that Greenhouse-grown lettuce was rather poor in total phenolic concentration and antioxidant capacity.(1)
Free radical are produced with endogenous process and damage our body. In our body respiration, radical will be produced, which damage the cell by forming unsaturated bonds in membrane lipids.(2) Persistent peroxidation induces in the loss of membrane fluidity, receptor alignment, which will have potential in cellular lysis.(2) Free radical also damaged sulfur containing enzymes, which also induce inactivation of protein function, denature of the protein structure by forming cross link.(2) Sometimes, DNA also affected and damaged, which cause mutation and carcinogen properties.(2) Even neurotransmitter and hormone can be affected, neurotransmitter is important in regulation of sympathetic nervous system and parasympathetic nervous system; it will cause many symptoms like hypertension, stomach pain, nausea etc if the function are altered.(2) Hormone disruption which indicate there are endocrine problems within body like precocious puberty or Gynecomastia in male.(2)
Cleaning of the free radical is the main effect for those phenol compounds. The Mechanism of action of antioxidants are done by scavenging of reactive oxygen and nitrogen species, chelation of redox-active metals, inhibition of radical-generating enzymes and induction of endogenous antioxidant gene expression. (3) These reactions will induce anti-inflammatory, chemopreventive, antidiabetic and antiatherogenic efficacy, which reduce the levels of cell damage.(3)
Flavonids is a good example of phenol compounds to maintain body health. Using flavonoids as example, it also maintains the health by the adjustment of adhesion in monocytes, which reduce the inflammation effect in the atherosclerosis. (4) Especially those metabolites like (+) catechin and quercertin of flavonoids show greater effect to reduce the risk of cardiovascular disease.(4)
1. Oh M-M, Carey EE, Rajashekar CB.
Antioxidant phytochemicals in lettuce grown in high tunnels and open field.
Horticulture, Environment, and Biotechnology. 2011;52(2):133.
2. Machlin LJ, Bendich A. Free radical tissue damage: protective
role of antioxidant nutrients. The FASEB Journal. 1987;1(6):441-5.
3. Vermerris W, Nicholson R. Phenolic Compound Biochemistry.
Dordrecht, NETHERLANDS: Springer Netherlands; 2006.
4. Heim KC. Natural Polyphenol and Flavonoid Polymers. Antioxidant Polymers: John Wiley & Sons,
Inc.; 2012. p. 23-53.
 |
Figure 1: Indian lettuce reach mature stage and ready to harvest
|
 |
Figure 2: Indian lettuce seedlings that ready to transplant to ground
|
 |
Figure 3: Iceberg lettuce reach maturity and ready to harvest in 2009
|
 |
Figure 4: Iceberg lettuce harvest in basket
|
 |
Figure 5: Iceberg lettuce forming a head which suitable for both fresh and processing markets
|
 |
Figure 6: The size of iceberg lettuce is like a small volleyball
|
 |
Figure 7: Australian Yellow lettuce also make a good contrast when compare to other lettuce. Most of the other lettuce are deep green while this lettuce made a bright green color, which is easily distinguish.
|
 |
Figure 8: Australian yellow lettuce is sucessfully grow in Hong Kong, yield some harvest
|
 |
Figure 9: Australian yellow lettuce is a great companion for salad
|
 |
Figure 10: Baby leaf is a good choice for those who got limited space to grow lettuce
|
 |
Figure 11: This baby leaf red cos lettuce can be harvested after a month from sowing
|
 |
Figure 12: Baby leaf lettuce are harvested and ready to make salad
|
 |
Figure 13: Baby leaf lettuce salad and pasta create a delicious dinner
|
 |
Figure 14: Waitrose French dressing are added in the lettuce, which create a great contrast of taste combine with the freshless from the baby leaf lettuce, which cannot easily found in western restaurant
|
 |
Figure 15: Red oak leaf lettuce also a major player in salad. They are not common in Hong Kong, purchase one wholehead oak leaf lettuce need HKD 30-40 as it is import from overseas or growing in local organic farm
|
 |
Figure 16: Red oak lettuce harvest from the farm (side view)
|
 |
Figure 17: Red oak lettuce harvest (top view)
|
 | ||
Figure 18: Red oak lettuce create a good salad
|
 |
Figure 20: Net are used to protect those Little Gem Cos and butterhead lettuce seedlings from bird
|
 |
Figure 21: Little gem lettuce and butterhead lettuce grow more quickly after protection from birds
|
 |
Figure 22: Australian baby leaf green cos lettuce seeds were given to neighbour farmer and grew well in the field. They are ready for harvest when the leaves reach the size of credit card/payment card like oyster, octopus, opal, smartrider etc
|
 |
Figure 23: Australian baby leaf green cos lettuce seeds were given to neighbour farmer and grew well in the field. They are ready for harvest as those leaves reach 8 cm already (the size of credit card/payment card like oyster, octopus, opal, smartrider etc). Supermarkets in Hong Kong have baby leaf green cos from USA for sale, but quite expensive.
|
 |
Figure 24: Australian little gem lettuce are ready for harvest. They are ready for harvest when the leaves wrap together and from a heart/core around the plant.
|
Comments
Post a Comment