Around two decades ago, when a newly launched burger joint opened in Karachi, I remember it took a lot of convincing to persuade my mother to buy a dozen burgers from that fast food chain.

Her argument was that she could easily prepare the exact same burger at home for one fourth of the expenditure. “But the greens you use are plain, soft lettuce, and the ones in their massive burgers is of different, crispier variety,” was, to her dismay, my customary retort.

Incidentally, those greens were historically known as crisphead lettuce and are now more commonly called iceberg lettuce. Iceberg lettuce, back then, was scarcely available here in Karachi. It was only available, that too at highly inflated prices, at the iconic Empress Market and a few local marts. With increased demand and availability, you are now highly likely to procure iceberg lettuce easily from any regular street vegetable seller in the city.

Since this lettuce was shaped like a head and was crispier than the other lettuce varieties, it was traditionally known as crisphead lettuce. However, back in the early 20th century, when this lettuce variety was being transported across America, it needed to be covered with lots of crushed ice in order to ensure its freshness and crispness for a longer period of time. Hence it was given the name iceberg lettuce.

If you wish to add some much-needed crunch and texture to your everyday meals, iceberg lettuce is the green for you

You can also easily grow iceberg lettuce at your home. Iceberg lettuce is a winter crop which ideally requires temperatures to be as low as 10 to 20 degrees Celsius for optimal growth. To sow the seeds, a well-drained potting mix and moist soil is needed. It should be devoid of any stones, since that may inhibit the comparatively weaker seedling to germinate easily.

Simply sprinkle the seeds on the soil surface of a seedling pot or tray and cover it with a fine layer of compost. To avoid seeds from getting dispersed due to watering, there are two ways to provide water to the seeds. The more practised one is to put the seed pot in a tray filled with water. The soil will imbibe water from the drainage hole at the bottom of the pot. This process is known as the bottom-up watering technique. Another technique is to simply water the pot before sowing the seeds. Depending upon the seed quality, climate and soil medium, seeds are likely to germinate within a week to 15 days.

Once the sapling produces four to five true leaves, it is time to transplant it into a bigger space. If a container is being used to do this then it should be at least 10 inches in size. If the plant is being shifted into the ground, the distance between each plant should be at least a foot on either side. The permanent position of the plant should ensure sunlight exposure from morning till noon.

Like all leafy plants, the iceberg lettuce also requires generous watering. It should be ensured that the soil medium is well-drained with a proper water drainage mechanism in place. Since iceberg lettuce is a leafy plant, its nutritional requirement throughout its life cycle remains constant. The plant should be provided with any of the nitrogen-based fertilisers every 15 days, starting from the very beginning till the eventual harvest. Depending upon multiple factors, including weather and seed variety, it will take around eight to 12 weeks to harvest the iceberg lettuce head.

Iceberg lettuce is harvested when the head forming in the centre of the plant is firm to touch. There is also a probability that heads do not form completely and the leaves remain on the plant in an open manner. This is usually an occurrence in those hotter regions which have a comparatively shorter winter season. In this case, the leaves are also harvested along with whatever head is formed, to be used for meals.

Keep in mind that, with an increase in mercury levels, the iceberg lettuce leaves start tasting bitter. To minimise the chances of bitterness, the plant should be provided with a semi-shaded environment, such as the overhead installation of a green net. This will result in filtered sunlight reaching the plant.

It is recommended to sow the seeds after every 20 days. This will ensure an ample and continuous iceberg lettuce supply throughout the season for you and your family.

Please send your queries and emails to doctree101@hotmail.com. The writer is a physician and a host for the YouTube channel ‘DocTree Gardening’ promoting organic kitchen gardening

Published in Dawn, EOS, March 12th, 2023