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Lettuce can be grown in water in a hydroponic system or as a demonstration of a plant’s resilience to recover from trauma by regrowing a harvested head stub.
Of all the commercially hydroponic-grown crops, lettuce is the most cost-efficient, primarily because its lighting requirements are lower. Regrowing lettuce from a stub demonstrates nature’s ability to recover from stressors, but lettuce grown this way is often bitter.
Table of Contents
- Table of Contents
- Two Ways to Grow Lettuce in Water
- Regrowing Lettuce from Stem Stubs
- Growing Lettuce In a Small Hydropic System
- FAQs on 5 Easy Lettuce Varieties You Can Grow in Water
- In Closing
Two Ways to Grow Lettuce in Water
Lettuce grows in water as a new plant or as lettuce scraps are rejuvenated.
You can regrow several vegetables, including carrots, spring onions, celery, and lettuce, in water on your kitchen window sill. Ith carrots, you can only stimulate the regrowth of the greens, but with lettuce, you can regrow living lettuce.
Growing Lettuce in Water (Hydroponics)
Hydroponic lettuce growing is attracting massive funding as it allows growers to reduce transport and develop a head of lettuce closer to the market.
I predict this market will continue to grow as we realize the unsustainability of shipping heads of lettuce grown in the Salinas Valley of California nearly 3,000 miles to Washington, D.C.
Not all crops are as effective as leaf lettuce in vertical hydroponics. Prof Bruce Bugbee argues that the energy exchange for growing most crops is too high, mainly the light cost. But leaf lettuce can use less light to produce more biomass (compared to corn or wheat, for instance).
Regrowing Lettuce from Stem Stubs
Let’s first get the regrowing of plants out of the way.
While it’s unlikely that growing lettuce plants from kitchen scraps is a practical way to save money, it’s a fun experiment for children – regrowing leaves from a lettuce stump. You can use regular lettuce from your local store or your homegrown variety to regrow lettuce.
There is no waste involved, as the lettuce stem is all you need, harvest the leaves for your salad and keep the remaining limb. Just be aware beforehand that the regrown lettuce leaves may turn bitter, but the stub ought to produce leaves.
I have never been able to grow a head of lettuce from a lettuce stump, but don’t take my word for it, try anyhow. I have regenerated a new life cycle from one celery plant, some green onions (green onions are easy), and romaine lettuce.
Growing romaine lettuce from a root end is more effective (food-wise) than increasing an iceberg so bitter it was almost inedible (I munched it anyway, for the children’s sake). “Look, guys, you grew more food from the lettuce scraps. Yum!” Say no more to the things we do for our children.
Green or spring onions are more manageable than lettuce, and lettuce is easier to grow a few leaves than celery. Carrots are the easiest, but you can’t produce the carrot.
I share step-by-step instructions below. Remember that although lettuce prefers shade, the stem will do well in sunlight – place it on a bright window sill and soon, the salad-making remnants will be new living lettuce.
Step-by-Step Guide to Regrow Lettuce
I will make these step-by-step instructions simple enough for you to print and get your children growing lettuce from the remaining stems after making them a caesar salad.
If you haven’t got lettuce in the garden, purchased lettuce will do fine. If you want to grow lettuce, I have several guides, including winter, summer and spring lettuce crops.
Step 1 – Get Everything You’ll Need Ready
- A shallow dish about 3 inches (75mm) deep and 4 inches (10 cm) wide.
- Lettuce scrap from a Romaine lettuce
- Dechlorinated water. If you take water fresh from the tap, let it stand for a while for fluorine and chloride to evaporate. Alternatively, use some spring water.
- Three to four toothpicks to stabilize the lettuce stump.
Step 2 – Regrowing Lettuce – What Happens?
- We will grow food from kitchen waste, creating new growth from what we usually discard.
- Water is vital to regrowing lettuce, and growth will be initiated when the lettuce scrap is placed in water. The lettuce growth point (meristem) is just above the ground, and the meristem is where cells reproduce to grow (or regrow) lettuce.
- Three factors are essential to growing lettuce (or other veggies); water, light, and carbon dioxide (CO2). CO2 is the air we exhale after breathing oxygen, and plants use this to grow new cells. Using sunlight, they use CO2 and water to produce the sugars, their growing food.
Step 3 – Natural Sunlight, Water, Carbon Dioxide and a Meristem
- Take lettuce, cut the outer leaves off, and keep the core stem. You will need only about two inches.
- Press the tree toothpicks into the kitchen waste lettuce stem, creating a tripod to keep the stem upright in the sallow dish.
- The old lettuce cut should face downwards and the meristem (where the leaves were and new growth will emerge) upwards.
- Fill the dish about an inch (25mm) deep with dechlorinated water. Place the lettuce in water enough the cover the bottom tip (about half an inch), leaving the meristem open to natural sunlight.
Step 4 – Watch Your Lettuce Regrow
- Don’t be disappointed if your regrowing lettuce doesn’t produce a whole head.
- The regrown lettuce will start by producing small leaves to harvest sunlight better for plant food production.
- They will need a sunny windowsill or a similar place with much indirect light.
- If the window sill gets direct sunlight for more than three hours a day, move your regrown lettuce to a spot with less direct sun.
- It will take about a week for your regrowing lettuce to grow enough leaves for you to make your small salad.
- Watch out for high temperatures that may make your plant produce seeds rather than leaves.
- Lettuce is a biennial plant, meaning that in the first year, they produce leaves, and in the second year, they produce seeds, but if temperatures go too high, they skip leaf-growing and go straight to seed production (it’s called bolting).
Well done on your regrown lettuce!! What was the salad like?
Growing Lettuce In a Small Hydropic System
One of the most significant advantages of growing lettuce hydroponically is that water is in a closed system. We reuse water repeatedly, topping up what’s lost through transpiration and respiration.
Vertical gardens allow us to produce more lettuce using only water and light – no soil. Growing lettuce this way is highly productive – but not organic. Because there is no potting soil, there are no microorganisms.
A single plant is anchored in a small pot using a porous growing medium that exposes the root end to water containing hydroponic fertilizer and oxygen. The roots anchored in the small pot can support growing lettuce by allowing the water to run intermittently.
Growing lettuce using hydroponics allows growers to optimize space and water usage and produce more per square foot without using soil.
It is an alternative to growing lettuce organically, and several court cases later, the advocates for food safety won the chance to classify hydroponic food as non-organic.
Consumers and sustainability advocates are split. The cost of transporting lettuce across the U.S. is unhealthy for greenhouse gas emissions. The argument is that if plants get enough nutrients, growing lettuce closer to the market, more lettuce for less input, makes perfect sense.
You can read the counterarguments here, and the N.Y. Times also ran an article in July 2021 covering the arguments for and against.
I covered the topic in a previous article What is hydroponic gardening? Grow Much Faster
Five Lettuce to Grow in Water
A list of 5 cultivars popular in controlled environments, the emerging name for hydroponics, is listed below.
1. Romaine Lettuce – Green Forest
Romaine lettuce has long, crisp leaves and a slightly bitter flavor. As a low calory option, Romaine lettuce can be enjoyed as part of a healthy diet.
Green Forest Romaine lettuce is characterized by its dark green, crinkly leaves. It is a highly nutritious variety of lettuce packed with antioxidants, vitamins, and minerals such as vitamins A, C, and magnesium.
It is also high in dietary fiber, which can help to promote healthy digestion. This variety of lettuce has a sweet and mildly bitter flavor, and its crunchy texture makes it a popular choice for salads and burgers.
2. Leaf Lettuce – Starfighter
Starfighter leaf lettuce is a variety developed by Johnny’s Selected Seeds. It is a fast-growing, heat-resistant variety ready to harvest in as little as 45 days.
Its leaves are a deep green color and are tender and crisp, making them ideal for salads. Starfighter leaf lettuce has a mild flavor and is a good source of vitamins A, C, and folate, and it is also high in fiber and low in calories.
Looseleaf lettuce is a famous salad green, generally more tender than other types, and it has a mild flavor and is often used in salads and sandwiches.
Because of its tenderness, it is essential to keep looseleaf lettuce refrigerated and to use it within a few days of harvesting. Having lettuce plants indoors, especially looseleaf lettuces, will give you a constant supply throughout the growing season.
Staggered, succession planting keeps a constant supply up to a fall harvest.
3. Butter Lettuce – Rex
Butter lettuce, or Boston or Bibb lettuce, is a type of leaf lettuce. It is closely related to iceberg lettuce but has a much softer, almost velvety texture and a milder flavor.
The butter lettuce leaves are large, smooth, and have a buttery texture, and they also have a mild, sweet flavor that is slightly nutty. It is ideal for salads, sandwiches, wraps, and even burgers and is also perfect for burritos and other Mexican dishes.
Rex lettuce is a fast-growing variety known for its mild flavor and excellent texture. It is a great addition to salads and sandwiches, adding a nice crunch. It is also famous for garnishes and can be used for top soups or other dishes.
The leaves are often frilled and have an almost buttery texture. Bibb lettuce is popular in sandwiches, salads, and wraps and is an excellent source of vitamins A and C, calcium, iron, and fiber.
4. Crisp Lettuce – Megenta
Butterhead, or Boston or Bibb, is the best type of lettuce for hydroponics. This type of lettuce is known for its sweet flavor, crisp texture and ability to hold well in hydroponic systems. It is also relatively easy to grow and has a fast growth rate.
Crisp lettuce has a crunchy texture and a mild, slightly sweet flavor. It is often used in salads or as a garnish, and it can also be used in sandwiches, wraps, and tacos.
Crisp lettuce is famous for its crunchy texture and mild flavor, making it an excellent choice for salads and other dishes. It is usually light green and has a slightly sweet taste.
5. Iceberg Lettuce – Crispino
The best iceberg lettuce for hydroponics is a variety called “Crispino,” which is a long-standing choice among hydroponic gardeners and has a reputation for being easy to grow, highly resistant to disease, and producing a high-quality crop.
Other varieties to consider include “Eden’s Gem,” “Gem Heart,” and “Summertime.”
The leaves are a deep green color and are crunchy and sweet. It is slow to bolt, making it an excellent choice for home gardeners who want to enjoy a long harvest season.
It is also tolerant of high temperatures and humidity, making it an excellent choice for warmer climates. Its large leaves make it ideal for wraps, tacos, and sandwiches.
FAQs on 5 Easy Lettuce Varieties You Can Grow in Water
Growing in water is an excellent option for increasing or regrowing lettuce. It’s vital that lettuce plants growing in water need to start as seedlings grown in inert soil.
I cover starting lettuce seedlings in my How to Grow Lettuce in Summer article. If you think growing lettuce in water is unusual, growing a cool-season crop in summer is something else.
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