Lettuce was a crop known more than 2,500 years ago by Greeks and Romans. Since then, cultivation techniques have been perfected and evolving, adapting to the new times. And the watering was not going to be less. Currently, the irrigation system most chosen by farmers for this vegetable is drip irrigation.
Do you know the needs and requirements that irrigation should have in lettuce cultivation?
In this article we will explain it in detail. But first, let’s learn a little more about the cultivation of Lactuca sativa L.
Lettuce cultivation: edafoclimatic requirements.
Lettuce is a crop that is produced worldwide, being demanded by consumers for its high water content. In addition, it provides abundant amounts of vitamins (A, C, E, B1, B2, B3) and minerals (phosphorus, iron, calcium, potassium, etc.).
This vegetable is mainly consumed fresh, being very popular in its presentation format in salad bags type IV range. Therefore, it is necessary that our crop arrives in optimal conditions to harvest, and irrigation plays a fundamental role in it.
The world of lettuce varieties is very broad and I would give to write a complete article. As a summary, the best known are: Iceberg, Romana, Trocadero, Oak Leaf and Lollo Rossa, among others.
When establishing our irrigation system for this vegetable, it is important to know what are the optimum of the edafoclimatic variables (temperature, soil, humidity), since depending on these values we will have to establish our irrigation program.
Optimum conditions for lettuce cultivation: Mild temperatures (15-20ºC) with difference between day and night temperature.
Lettuce is a crop that grows optimally in a cool climate, having its optimum growth temperature between 15-20ºC. However, it is a crop that for its germination and coagulation requires a temperature variation between day and night (around 10 degrees of difference).
It is important to know that lettuce is a vegetable that is more resistant to low temperatures (it can withstand up to -6ºC) than at high temperatures (more than 30ºC have a serious impact on development and cause early spikes). In addition, it is interesting to know that with frequent rains they can suffer fungal attacks, something to consider when planning our installation. Fertirrigation becomes an important ally.
Optimum conditions for lettuce cultivation: Relative humidity between 60-80%, below 60% it stops development and above 80% we can have fungal attacks.
Regarding the humidity requirement, being a vegetable with a reduced root system and having a great development of the aerial part, we are faced with a crop very sensitive to the lack of moisture, withstanding badly the periods of drought.
However, high humidity can also cause performance drops due to botrytis attacks (also called rot). Therefore, it is necessary to establish the irrigation system and program so that our crop is in the optimum relative humidity, located between 60 and 80%.
What are the optimal conditions for lettuce cultivation? Alkaline, sandy-silty and light soils, which prevent waterlogging in order to avoid rot.
The ideal soil for lettuce cultivation is alkaline (optimum pH between 6.7 and 7.4), sandy-silty and rich in organic matter. It is very important that our crop is established on lightly textured soils to prevent waterlogging, which could cause problems from fungal attacks.
What are the optimal conditions for lettuce cultivation? Planting frames depending on the variety chosen, but taking care that the horses raise the plant enough so that it does not touch the surface and avoid fungal attacks.
As for the planting frames, they vary depending on the variety of lettuce to grow. In general, planting density can vary between 10 and 40 plants per m2. It is important to make a good plantation design to allow cultivation work and minimize contact between plants.
In general, an optimal planting frame would be 30×30 cm leaving corridors between lines of 80 to 120 cm. This is for large varieties, for “baby” type of lettuce the planting density will be larger and, therefore, smaller frames.
An important point is the design of the ridges, keys to avoid contact with moisture on the ground surface. With 25 cm tall ridges (taking care to leave the root ball at ground level to avoid drying the roots), we ensure this direct contact and reduce the fungal attack of the leaves.
What type of irrigation does the cultivation of lettuce need?
Irrigation is a fundamental factor in lettuce cultivation. It must be applied with precision and within values that cannot be exceeded by default or excess. With a water deficit lettuce can enter a vegetative stop, develop necrosis at the edges and increase the incidence of botritis. However, if we water excessively and get to soil the soil, we can cause root asphyxiation and decrease the weight of the bud.
Based on everything explained above, we can conclude that the irrigation that best suits the demands of lettuce cultivation is drip irrigation.
The drip allows the lettuce crop to be continuously and uniformly irrigated, avoiding waterlogging and keeping the soil surface dry enough to prevent the neck from rotting from fungal attacks.
It is highly recommended to complement drip irrigation with sprinkler irrigation in the first days after transplant, to ensure that plants take root properly.
Are you thinking of planting lettuce for the first time?
Are you still watering your crop by flooding? In GESTIRIEGO we advise and help you install the most suitable irrigation system for your crop, but also to convert or modernize your current irrigation system.
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