Lemon cultivation.

» Lemon plantation

·When are lemon trees planted?

Lemon trees are trees that demand warm temperatures, so the best time to plant them is in spring or autumn. Their ideal temperature is around 15-21^oC and they do not tolerate frost.

However, it should be noted that if the crop is to be planted without irrigation, it should be grown in the rainy season and in the cooler hours of the day.

·How are lemon trees planted?

Lemon trees are planted with two objectives in mind:

• Absorb as much incident light on the trees as possible.
• Facilitating the operation of machinery inside

Therefore, several planting frames are usually used depending on variety, planting or crop conditions: 6.5 x 5; 6.5 x 6; 7 x 5.

Edaphoclimatic requirements

·Soil

Lemon trees require permeable, deep, low salinity, low limestone and well-drained soils. These trees are sensitive to root asphyxia.

In addition, lemon trees prefer slightly acidic soils rich in organic matter.

·Climate

Lemon trees do not tolerate low temperatures. It is the most sensitive citrus species to cold, so it is recommended to be planted outdoors in areas where the climate is temperate. The ideal climate for its correct development is the Mediterranean climate.

• Orientation on the plot

As we have already mentioned, lemon trees are planted with the aim of getting the maximum amount of light and easy access for agricultural machinery.

» Care requirements for the lemon tree

-Soil preparation for growing lemons

Soil preparation for lemon trees consists of:

• Eliminating weeds and control their growth
• Leveling the ground
• Aerating topsoil
• Incorporating fertilisers or organic matter
• Achieving a well-drained soil
• Decreasing soil salinity
• Preparing irrigation systems

·Lemon tree irrigation

Lemon trees require frequent and abundant watering, keeping the roots constantly moist, but without waterlogging. In summer, daily watering is recommended, while in winter they should be watered 2-3 times a week.

The best option for these trees is to implement a drip irrigation system. Generally, for an adult lemon tree, 4 drippers are placed all over the wet bulb and at about 50 cm from the trunk, with a recommended flow rate of 4 L/h.

·Pruning the lemon tree

During the first 6 months, it is recommended to prune young lemon trees every 15-20 days, in order to eliminate “suckers”. After that, during the first year, it is advisable to prune every 3 months to give the trees the desired shape and to avoid crossing branches.

Mature trees are pruned in spring, after harvesting. Dead, weak or diseased branches are removed, leaving the centre open to allow light to reach the interior of the tree.

The types of pruning practised on lemons are:

• Formative pruning

This type of pruning is carried out when the tree is one year old. This is done at the end of the dry season, before growth starts again with the first rains.

In this pruning, the main branch is separated and once the side shoots emerge, only three to five main branches are left.

• Fruiting pruning

During fruiting pruning, the branches are thinned and trimmed to encourage flowering and fruiting. In addition, it also serves to improve aeration and light penetration, thus preventing diseases.

• Sanitation pruning

It is often carried out with the aim of removing diseased or broken branches.

• Rejuvenation pruning

This type of pruning consists of removing almost all the branches of the tree, keeping only the main branches. This provides new and vigorous growth and is therefore recommended for old trees or trees that have suffered from disease.

» Nutrients needed for growing lemons

The main nutrients needed by lemon trees are:

Macronutrients

• Nitrogen: It’s an essential element for growth, flowering, productivity and fruit quality.

• Phosphorus: It’s involved in the metabolism of carbohydrates, fats, proteins; essential in the production and transport of energy and in the processes of respiration and photosynthesis.

• Potassium: the most important element in lemon fertilisation. It is essential as a coenzyme and in protein synthesis, photosynthesis and carbohydrate metabolism.

• Magnesium: It’s constituent of the central atom of the chlorophyll molecule.

• Calcium: most of its activity is due to its coordination capacity, as it is able to establish stable and at the same time reversible bonds between molecules.

Micronutrients

• Iron: It’s essential for photosynthesis and respiration.
• Zinc: It’s involved in various enzymes.
• Manganese: It’s involved in the activation of numerous enzymes.
• Copper: It enables enzyme bonds in redox reactions.
• Molybdenum: It’s involved in atmospheric nitrogen fixation and nitrate reduction.

Deficiency or insufficiency of any of these mineral elements can negatively affect development and productivity.

Fertiliser for lemon trees

• What fertilisers does the lemon tree need for its cultivation?

As we have already seen in the previous section, the main components that the fertiliser for lemon trees should contain are nitrogen, phosphorus and potassium.

For organic cultivation of lemon trees, organic fertilisers, such as manure, compost or worm hummus, as well as those formulated with algae, minerals or other natural elements, shall be applied.

Some of Fervalle’s recommended fertilisers for growing lemons are Algavalle Plus, Missvalle and Engorplus..

Algavalle Plus: liquid formulation of algae extract with amino acids and enriched with molybdenum. Its functions include:

• Regulates plant growth
• It provides the nitrogen needed for plant development
• It promotes nitrogen absorption
• Increasing flowering

Missvalle is a blend of essential microelements (magnesium, manganese, molybdenum and zinc). Its benefits include:

• It supports nitrogen uptake and chlorophyll synthesis
• Synthesis of phytohormones
• It provides necessary nutrients
• It promotes sprouting
• It improves flowering, fruit set and fruit development

Engorplus is a fertiliser composed of free amino acids, organic acids and vitamins (A, B1, B2, B12, C and D6). Some of its benefits are:

• It increases cell division and fruit set.
• It induces the synthesis of proteins involved in plant growth and development.
• It guarantees a homogenization in the size of the fruit.

» Lemon harvesting

Lemons are preferably harvested by hand with the help of pliers. If they are harvested when they are still green, their post-harvest life will be longer than if they are harvested completely yellow.