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.

Lettuce — DutchGreenhouses

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.

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.

Lettuce

The varieties

Butterhead lettuce

Soft, loosely wrapped leaves, and the type least tolerant of handling.

Greenleaf / Batavia lettuce

A firmer, more robust head than butterhead, and it travels better.

Green crispy lettuce

A dense, crunchy head that suits both wholehead sale and high density.

Red crispy lettuce

The crispy head in red, where colour development is part of the grade.

Green oakleaf lettuce

A lobed, soft leaf grown for shape rather than for weight.

Red oakleaf lettuce

Lobed leaf and red pigment, usually sold as part of a set.

Green incised lettuce

A deeply cut leaf aimed at density and automated harvest.

Lollo Bionda lettuce

Tightly curled green leaf, sold on appearance.

Lollo Rosso lettuce

The red Lolla, where curl and colour are both the product.

Romaine lettuce

The upright head, and the tipburn risk that comes with it.

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.