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PH Soil Meters

Soil Meter Technical

The EL-SM-METER3IN1 is an electronic soil measuring instrument but which requires no batteries or external power. So let’s explain that apparent contradiction first... It is well known that electricity can be obtained from batteries, and more recently using solar power. This Monitor incorporates a light sensor in order to give a measurement of sunlight, and this sensor works by generating a voltage that depends on the strength of the light. Although it is small for a solar cell, there is enough power to operate the Monitor. But that is not the only power source available because this Monitor actually makes a battery every time the probes are inserted into moist soil. The probes are made of different metals (there are 4 separate contacts on it’s 2 probes, using 3 types of metal) and when placed in an electrically conducting environment like moist soil, all the components of an electric cell (battery) are in place. So the Monitor will still work even in the dark.

Basically, the light meter displays the voltage generated by the light sensor, the pH meter displays the voltage generated by its probe/soil ‘battery’, and the moisture meter displays the current passing through the soil which depends on its moisture level.

The indicating meter is basically a spring-loaded electric motor that manages to rotate the indicating ‘needle’ further if more electrical voltage is generated.

To select the meter function, a clearly labelled 3-position switch gives the choice.

The pH function measures acidity/alkalinity, where a lower value below 7 is increasing acidity, whereas a higher number above 7 is increasing alkalinity. A pH measurement of 7 is the perfect balance being neither acidic not alkaline. Note that different plants prefer different pH, and not necessarily 7.

Vegetables             Ideal pH Reading                                     Ideal pH Reading
Bean                        6.0 - 7.5                         Lettuce                   6.0 - 7.0
Broccoli                     6.0 - 7.5                         Onion                     6.0 - 7.0
Brussels                    6.0 - 7.5                         Pea                        6.0 - 7.5
Cabbage                   6.0 - 7.5                         Pepper                    5.5 - 7.0
Carrot                       5.5 - 7.0                         Potato                     4.5 - 6.0
Cauliflower                 5.5 - 7.5                        Radish                     6.0 - 7.0
Cress                        6.0 - 7.0                        Spinach                    6.0 - 7.5
Cucumber                  5.5 - 7.5                        Swede                      5.5 - 7.0
Leek                         6.0 - 8.0                         Tomato                    5.5 - 7.5
Fruit                        Ideal pH Reading                                       Ideal pH Reading
Blackberry                 5.0 - 6.0                           Melon                      5.5 - 6.5
Cherry                      6.0 - 7.5                           Peach                      6.0 - 7.5
Currant Black             6.0 - 8.0                           Raspberry                5.0 - 6.5
Currant Red               5.5 - 7.0                           Rhubarb                  5.5 - 7.0
Gooseberry                5.0 - 6.5                           Strawberry               5.0 - 7.5
Grapevine                  6.0 - 7.0                           Lawns                     6.0 - 7.5
Flowers/Shrubs          Ideal pH Reading                                     Ideal pH Reading
Alyssum                    6.0 - 7.5                          Gladiolus                  6.0 - 7.0
Azalea                      4.5 - 6.0                          Hydrangea Blue         4.0 - 5.0
Carnation                  6.0 - 7.5                          Hydrangea Pink         6.0 - 7.0
Chrysanthemum        6.0 - 7.0                           Hydrangea White       6.5 - 8.0
Clematis                   5.5 - 7.0                           Marigold                   5.5 - 7.0
Daffodil                     6.0 - 6.5                           Rhododendron          4.5 - 6.0
Dahlia                       6.0 - 7.5                           Rose                        6.0 - 7.0
Fuchsia                      5.5 - 6.5   

Red Zone
             Green Zone         Green Zone          Green Zone           Green Zone
Plants 1-3            Plants 4 - 5         Plants 5 - 6          Plants 6-7             Plants 6-7
Aloe                       Parachute Plant     Action Plant           Amazon Lily            Moon Flower
Anchor Plant           Pen Wiper             African Violet         Angel Wings            Mosaic Plant
Asparagus Fern       Pink Buttons          Angle Tears           Apostle Plant     Mother-In-Law Plant
Baby Jane              Pocket Book          Plant Aralia            False Azalea           Mouse Plant
Baby pine of China  Poinsetta               Bachelor Button     Brazilian Firecracker  Nut Orchid
Baby’s Breath         Queens Tears         Boxwood               Bridal Wreath          Oleander
Beaver Tail             Roman Candle       Burn Plant              Burrowtail               Peacock Plant
Bishops Cap            Sand Dollar           Cape/Crape Myrtle Butterfly Gardenia   Peperomia
Bloodleaf                Sedom                  Chile Bells             Caladium               Periwinkle
Cactus                    Shrimp Plant         Cloth of God          Calla Lily                Petticote Palm
Chicken Gizzard      Tiger Jaws             Corn Plant             Camellia                  Pitcher Plant
Christ Plant             Umbrella Tree       Crimson Flag          Chenille Plant      Polynesian Ti Plant
Crassula                 Wall Fern               Devils Ivy             Cobra Plant           Pothos
Crown of Thorns     White Jewel            Dieffenbachia         Coleus                   Prayer Plant
Dumbcane              Green Zone          Euonymus             Columnea             Quaker Ladies
Easter Orchid          Plants 4-5            Finger of God         Copper Leaf          Sansevieria
Euphorbia               Airplane Plant         Firethorn                Croton                  Saxifraga
Fig, Fiddle Leaf        Begonia                 Flarningo plant        Darlingtonia         Scindapsus
Firecracker Plant     Bird of Paradise      Fleur D’Amour         Dawn Flower        Sea Grape
Flaming Sword        Blushing Bride         Flower of Heaven    Dracaena Palm     Spider Plant
Floral Firecracker     Bonsai Tree           Glory Lily                Easter Lily            Temple Bells
Foolproof Plant        Bromelaid              Goldust Plant          Echeveria             Turk’s Cap
Gas Plant                Candle Plant          Hoya                      Egyptian Star Cluster  Velvet Plant
Geranium               Century Plant         Impatiens               Explosion Plant      Verbena
Ghost Plant             Ceropegia              Kashmir Bouquet     False Holly            Violet Flame
Glory of Texas        Chain Cactus          Kiss-Me-Today        Fan Iris                 Wandering Jew
Golden Dew Drop    Daphne                  Lady of the Night     Fan Ivy                 Wax Plant
Good Luck Plant      Earth Star               Lantern Plant          Farewell to Spring   Zebra Plant
Hibiscus                  Echeveria               Medicine Plant         Ferns 
Honey-Bunny          Hairy Toad Plant      Naked Lady Lily      Fiery Love Flower   Blue Zone          
Ice Plant                 Hearts on a String   Pussy Foot              Fig, Creeping         Plants 8-10 
Ivy                         Hen and Chicken    Queens Jewels         Finger Aralia         Watering is not
Jade Plant               Inch Plant               Rouge Plant            Fingernail Plant       necessary 
Jasmine Star           Little Stars              Rubber Plant           Fire Fragon 
Jelly Beans              Mock Orange          Shooting Star          Five Fingers 
Lantana                   Norfolk Island Blue Solomons seal         Fuchsia 
Little Candles           Patience Plant        Star of Bethlehem    Gardenia 
Little Owl Eyes         Pearl Plant              Victoria Aralia         Honey Bells 
Living Vase              Philodendron          Water Melon            Jasmine 
Lobster Plant            Ponytail                                               Jungle Flame 
Marguerite Blue        Radiator Plant                                      Kalachoe 
Mimicry Plant           Sea Urchin                                           Ladies Tresses 
Moonstones              Stoneface                                            Leopard Plant 
Mother of Pearl         String of Pearls                                    Magic Flower 
Musk Plant                Vitamin C Plant                                   Man in a Boat 
Panda Plant               Youth and Old Age                              Match me if you Can