Why is lettuce revenue counted in heads rather than kilograms?

Lettuce is sold by the head, so revenue follows the number of saleable heads a house produces in a year. A house producing heavy heads slowly can earn less than one producing lighter heads on a shorter turn, which is the opposite of how a fruiting crop is judged.

Why is a lettuce project planned around a named cultivar?

Head mass, density tolerance and tipburn risk are cultivar properties rather than type properties. The type sets head form and leaf shape; the cultivar sets what the house is dimensioned for, so the choice belongs in the brief before the design.

Crops · Leafy green

Lettuce.

Q: What decides how many cycles a year a lettuce greenhouse delivers?

The system layout more than the climate. The movement of plants through the house, the spacing changes as heads expand and the harvest and replant turnaround set the cycle count; the climate envelope itself is narrow rather than demanding.

A short cycle repeated all year, where the head is the unit sold.

Grow lettuce under glass The varieties

Days, not weeks

Lettuce is mostly water, and what it carries beyond that is eaten exactly as it left the plant. Vitamin C, potassium and folate sit in the leaf, and a salad is never cooked, so nothing is boiled out and nothing is added back. The leaf is both the crop and the meal.

Water is also why the head is fragile. A cut lettuce goes on living and goes on losing moisture, and it spends its own condition doing it. A fruit can finish ripening on the way; a leaf only gets older. Turgor, colour and shelf life all start running down at the hour of cutting.

That puts distance at the centre of the argument. A house near its market can cut in the morning and deliver the same day, and the head reaches the plate with most of its life still ahead of it. It can also do that in every month of the year, which is the part an open field in a hard climate cannot promise.

Nutrition facts

Lettuce, green leaf, raw

Per 100 g

Energy: 15 kcal
Fat: 0.15 g
Carbohydrate: 2.87 g
Sugars: 0.78 g
Fiber: 1.3 g
Protein: 1.36 g
Sodium: 28 mg
Potassium: 194 mg
Vitamin C: 9.2 mg

Source: USDA FoodData Central, FDC 169249

Which lettuce?
The commercial classes.

Repeat harvests. Consistent head quality and size. The class you sell decides the plant load, the harvest rhythm and the house.

Butterhead Lettuce

Butterhead is the soft-leaved wholehead lettuce sold with its outer leaves intact, and the type most European buyers picture when they specify lettuce.

Green Crispy Lettuce

Green crispy is the dense, crunchy-leaved lettuce sold both as a wholehead and into processing, where the leaf holds its texture after cutting.

Green Oakleaf Lettuce

Green oakleaf lettuce is a lobed, soft-leaved head grown for leaf shape rather than for weight.

Lollo Bionda Lettuce

Lollo Bionda is the green Lolla lettuce, with a tightly curled leaf margin and bought for appearance rather than for weight.

Lollo Rosso Lettuce

Lollo Rosso is the red Lolla lettuce, where the tightly curled leaf margin and the red pigmentation are both the product.

Red Crispy Lettuce

Red crispy is the red-pigmented counterpart of the green crispy head, sold wholehead and into mixed-leaf packs where colour intensity is part of the specification.

Red Oakleaf Lettuce

Red oakleaf lettuce carries the lobed leaf of the oakleaf types with red pigmentation, and most often reaches the consumer inside a multi-type pack.

Lettuce is sold by the head, not by the kilogram, and that single fact reorganises the economics. Revenue follows the number of saleable heads a house produces in a year, so the design questions are cycle length, planting density and the share of heads that reach grade. A house that produces heavy heads slowly can earn less than one producing lighter heads on a shorter turn, which is the opposite of how a fruiting crop is judged.

What the crop needs

The crop is short-cycle and hydroponic, and it is planted and cleared many times a year. That rhythm makes the system layout as important as the climate: the movement of plants through the house, the spacing changes as heads expand and the harvest and replant turnaround all set how many cycles a year the building can actually deliver. The climate envelope itself is narrow rather than demanding.

What separates the varieties

The commercial types divide by head form and leaf shape — butterhead, Batavia, crispy, oakleaf, incised, Lolla and romaine — and increasingly by cultivar within each type. A lettuce project is planned around a named cultivar because head mass, density tolerance and tipburn risk are cultivar properties rather than type properties. Romaine carries the highest tipburn risk of the family, because its upright head encloses the fastest-growing leaf margins where air moves least.

DutchGreenhouses® designs the structure, climate, screening and irrigation around the lettuce type, its system and the local climate, so the house turns cycles at the head quality the market grades on. Get in touch to plan a lettuce greenhouse.

The greenhouse behind lettuce