Hanna Instruments HI 3896 - Manual (Page 8)

8
PLANTS pH
ORCHARD
Apple 5-6.5
Apricot 6-7
Cherry 6-7.5
Grapefruit 6-7.5
Grapevine 6-7
Lemon 6-7
Nectarine 6-7.5
Orange 5-7
Peach 6-7.5
Pear 6-7.5
Plum 6-7.5
Pomegranate 5.5-6.5
Walnut 6-8
VEGETABLES AND HERBACEOUS
CULTIVATIONS
Artichoke 6.5-7.5
Asparagus 6-8
Barley 6-7
Bean 6-7.5
Brussels Sprout 6-7.5
Early carrot 5.5-7
Late carrot 5.5-7
Cucumber 5.5-7.5
Egg Plant 5.5-7
Lettuce 6-7
Maize 6-7.5
Melon 5.5-6.5
Oat 6-7
Onion 6-7
Pea 6-7.5
Pepper 6-7
Early Potato 4.5-6
Late Potato 4.5-6
Sweet Potato 5.5-6
Pumpkin 5.5-7.5
Rice 5-6.5
Soybean 5.5-6.5
Spinach 6-7.5
Strawberry 5-7.5
String 6-7.5
Sugar beet 6-7
Sunflower 6-7.5
Tomato 5.5-6.5
Watermelon 5.5-6.5
Wheat 6-7
LAWN
Lawn 6-7.5
Tab.4. Range of preferred
pH
PLANTS pH
GARDEN PLANTS AND FLOWERS
Acacia 6-8
Acanthus 6-7
Amaranth 6-6.5
Bougainvillea 5.5-7.5
Dahlia 6-7.5
Erica 4.5-6
Euphorbia 6-7
Fuchsia 5.5-7.5
Gentian 5-7.5
Gladiolus 6-7
Hellebore 6-7.5
Hyacinth 6.5-7.5
Iris 5-6.5
Juniper 5-6.5
Ligustrum 5-7.5
Magnolia 5-6
Narcissus 6-8,5
Oleander 6-7.5
Peony 6-7.5
Paulownia 6-8
Portulaca 5.5-7.5
Primula 6-7.5
Rhododendron 4.5-6
Roses 5.5-7
Sedum 6-7.5
Sunflower 6-7.5
Tulip 6-7
Viola 5.5-6.5
HOUSEPLANTS
Abutilon 5.5-6.5
African violet 6-7
Anthurium 5-6
Araucaria 5-6
Azalea 4.5-6
Begonia 5.5-7.5
Camellia 4.5-5.5
Croton 5-6
Cyclamen 6-7
Dieffenbachia 5-6
Dracaena 5-6
Freesia 6-7.5
Gardenia 5-6
Geranium 6-8
Hibiscus 6-8
Jasmine 5.5-7
Kalanchoe 6-7.5
Mimosa 5-7
Orchid 4.5-5.5
Palms 6-7.5
Peperomia 5-6
Philodendron 5-6
Yucca 6-7.5
9
The three elements that are most needed by plants are nitrogen (N), phosphorus (P) and
potassium (K). This is the reason why they are called macronutrients and should be given
to the plants. Other elements, the so-called microelements are generally present in
sufficient quantities in the soil and the plants need them in smaller doses.
Nitrogen is an indispensable element for the plant’s life and is a key factor in fertilization.
It is present in proteins, vitamins, hormones, chlorophyll, etc. Nitrogen allows the devel-
opment of the vegetative activity of the plant, in particular, causes a lengthening of trunks
and sprouts and increases the production of foliage and fruits (even though the quality
depends by other elements). An excess of Nitrogen weakens the plants’ structure creating
an unbalanced relationship between the green parts and the wooden parts. In addition, the
plant becomes less resistant to diseases.
The nitrogen adsorbed by the plants derives from the mineralization of organic matter and
the application of fertilizers, but legumes (soybean, pea, clover, alfalfa, etc.) are able to
take nitrogen by a symbiotic association with Rhizobium bacteria.
The fact that nitrate (the nitrogen chemical compound that the plants absorb mostly) is not
durable in the soil and the large amount required for crop production, make it necessary to
add this element, avoiding excesses.
Phosphorus is an important element in the composition of DNA and RNA, the regulators
of the energetic exchange (ATP, ADP), as well as the reserve substances in seeds and bulbs.
It contributes to the formation of buds, roots and blooming as well as lignification. A lack
of phosphorus results in: stifling of plant, slow growth, a reduction of production, smaller
fruits and a lower expansion of the roots.
Most of the Phosphorus present in the soil is not available for plants and its release in the
soil solution from which it is taken, is very slow.
Therefore, in order to avoid an impoverishment of the soil, and to give to the plants the
appropriate quantity, a rational fertilization is needed.
Even if potassium is not a constituent of important compounds, it plays a remarkable role
in many physiological activities like the control of the cellular turgor and the accumulation
of carbohydrates. In addition, it increases the size of fruits, their flavor as well as yielding
a positive effect on the color and fragrance of flowers. Potassium also makes plants more
resistant to diseases.
Generally speaking, potassium is normally retained by the soil and the losses are caused
by plant absorption or erosion. In sandy soils however the level may be inadequate.
The quantity of substances to add to the soil, depends not only on the chemical state of the
soil but also on factors such as local climate, the physical structure, previous and present
cultivation, microbiological activities etc. Hence, only after a technical and economical
evaluation, it is possible choose the proper quantity of fertilizer to add.
Nutrients
Nitrogen
Phosphorus
Potassium
Fertilization