Leaf sampling instructions from the Institute of Ecology of Thessaloniki
http://www.ssi.gov.gr/plantanalysis.php

During sampling, leaves are collected in perforated plastic bags, which are left open for better ventilation, immediately placed in a cool place (refrigerator) and transported as soon as possible to the laboratory for chemical analysis. For the identification of the sample, the origin of the sample shall be labelled: Name of the producer, municipality, municipality district, location, parcel number or code number of the estate (if available), variety, age of the rootstock, number of acres and total number of trees.
Sampling of apple leaves

Sampling shall be carried out in the period around mid-July in lowland areas, late July in semi-mountainous areas, and early August in mountainous areas. For this purpose, 80-100 healthy leaves (with stalk) are taken from the middle of annual shoots of average vigour (not glabrous or very weak) located at the periphery of the crown of the trees and at a height of 1,5-2 m from the ground. Sampling is carried out on a proportional number of trees in the orchard following the diagonals of the plot (from every 50th to 10th tree) and in fact four leaves are taken from each tree in the four directions of the horizon. The figure below shows the locations within the field from which the leaves can be sampled for representativeness.

Olive leaf sampling

Sampling shall be carried out in the period November-December. For this purpose, 120-150 healthy leaves (with stalk) are taken from the middle of annual shoots of average vigour, 30-50 cm long (not glabrous or very weak), located at the periphery of the crown of the trees and at a height of 1,5-2 m from the ground. Sampling shall be carried out on a proportional number of trees in the orchard following the diagonals of the plot and in fact leaves shall be taken from each tree in the four directions of the horizon.

Sampling of peach leaves

Sampling is carried out at the beginning of July in lowland areas and in mid-July in semi-mountainous areas.
For this purpose, 60-80 healthy leaves (with stalk) are taken from the middle of annual shoots of average vigour (not glabrous or very weak) located at the periphery of the crown of the trees and at a height of 1,5-2 m from the ground. Sampling is carried out on a proportional number of trees in the orchard following the diagonals of the plot and in fact four leaves are taken from each tree in the four directions of the horizon.

Sampling of cherry leaves

Sampling is carried out at the beginning of July in lowland areas, mid-July in semi-mountainous areas and at the end of July in mountainous areas; for this purpose, 60-80 healthy leaves (with stems) are taken from the middle of annual shoots of average vigour (not glabrous or very weak) located at the periphery of the crown of the trees and at a height of 1,5-2 m from the ground. Sampling is carried out on a proportional number of trees in the orchard following the diagonals of the plot (from every 50th to 10th tree) and in fact four leaves are taken from each tree in the four directions of the horizon.

Sampling of pear leaves

Sampling is carried out in the period around mid-July in lowland areas, late July in semi-mountainous areas and early August in mountainous areas.
For this purpose, 80-100 healthy leaves (with stalk) are taken from the middle of annual shoots of average vigour (not glabrous or very weak) located at the periphery of the crown of the trees and at a height of 1,5-2 m from the ground. Sampling is carried out on a proportional number of trees in the orchard following the diagonals of the plot (from every 50th to 10th tree) and in fact four leaves are taken from each tree in the four directions of the horizon.

Sampling of plum leaves

Sampling is carried out in the period around mid-July in lowland areas, late July in semi-mountainous areas and early August in mountainous areas.
For this purpose, 80-100 healthy leaves (with stalk) are taken from the middle of annual shoots of average vigour (not glabrous or very weak) located at the periphery of the crown of the trees and at a height of 1,5-2 metres from the ground. Sampling is carried out on a proportional number of trees in the orchard following the diagonals of the plot (from every 50th to 10th tree) and in fact four leaves are taken from each tree in the four directions of the horizon.

Apricot leaf sampling

Sampling shall be carried out in early July in lowland areas and in mid-July in semi-mountainous areas.
For this purpose, 60-80 healthy leaves (with stems) are taken from the middle of annual shoots of average vigour (not glabrous or very weak) located at the periphery of the crown of the trees and at a height of 1,5-2 m from the ground. Sampling is carried out on a proportional number of trees in the orchard following the diagonals of the plot and in fact four leaves are taken from each tree in the four directions of the horizon.

Sampling of kiwi leaves

Sampling is carried out in mid-July in lowland areas and at the end of July in semi-mountainous areas. For this purpose, 60-80 healthy leaves (with stalk) are taken from the middle of annual shoots of average vigour (not glabrous or very weak) located at the periphery of the crown of the trees and at a height of 1,5-2 m from the ground. Sampling is carried out on a proportional number of trees in the orchard following the diagonals of the plot and in fact four leaves are taken from each tree in the four directions of the horizon.

Sampling of vine leaves

Sampling can be carried out at two different stages of the growing season: at flowering and at the time of blossoming. In general, it is preferable to sample at flowering, when about 50-80% of the siliques have fallen. At this stage the stumps show signs of any deficiencies and the leaves are sufficiently mature. This period is also a good time to determine the fertilisation programme and correct any nutrient deficiencies before the grapes start to ripen. It is preferable to collect the sample by 10:00 am, before water stress occurs and before nutrient transfer takes place. To take a sample at the flowering stage, select fertile shoots that are sufficiently exposed to sunlight and have normal vigour. Then remove the leaf opposite the lower grape, cut off the shoot and keep the stem. We collect about 100 stems, which form the sample.

On the other hand, the perking period is considered to be the most suitable for obtaining information on the potassium-magnesium balance. To take a sample at the perking stage, 60-80 healthy leaves (with stems) are taken. Sampling is carried out on a proportional number of stumps following the diagonals of the plot. The most recently fully mature leaf of the main stem is selected, i.e. the last leaf of the stem that has reached full size in the sampling phase and is usually the 6th or 7th leaf from the growing tip of an actively growing stem.