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Green Valley Supply's Gardening Encyclopedia


Sulfur does not fluctuate as much as other elements, hence is 
not absorbed in excess. A deficiency of this element does not 
evidence itself as early as do others. Deficiency shows late in 
the growth period when the plants fail to develop to normal 
size. Many species of annual plants can reproduce from the 
amount contained in their seed. 
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In most plants, lack of magnesium does not show up until 
considerable growth has been made. So much of this element 
is contained in the seeds that the seedlings are independent 
of outside supplies for quite a long period of time. Some crops 
can reproduce from the original magnesium content of their 
seed if the seedlings are not allowed to make too much vegeta- 
tive growth. The chief deficiency symptom of this element is 
found in a high ratio of roots to leaves and stalks. The root 
system is of more than normal size. A moderate excess of magnesium produces foliage a little 
greener and larger than is normal. When the excess becomes 
great, however, the leaves become smaller than average, though 
they retain their green color. The tips of the leaves may wilt 
and die if they are exposed to hot weather.
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Symptoms of calcium deficiency are more pronounced and 
appear earlier in most plants than do those of other elements. 
Unlike the other nutrients whose deficiency symptoms first be- 
come clearly defined on stalks and leaves, the first signs of 
calcium deficiency are mirrored in lack of root growth. The 
small roots growing from the seed disintegrate. The seedling 
makes a tuft of leaves which at first appear greener than nor- 
mal. Eventually, they lose their color and the plant dies pre- 
maturely. Small additions of calcium to the nutrient solution 
have marked corrective effects. 

Because lack of calcium curtails root development, a higher 
ratio of leaves and stalk to total weight of plant is obtained. It 
is with lack of calcium and nitrogen that the greatest extremes 
in the ratio of roots to tops are obtained. The former produces 
the least and the latter the largest amount of roots in relation 
to leaves and stalks. 

Lack of calcium does not have such a pronounced harmful 
effect upon rice as it does on other crops. Rice requires little 
calcium for growth and contains only a small amount of it at 
maturity. The element seems to play some special part in the 
synthesis of proteins, for crops high in proteins are also high 
in calcium. 

Absorption of excess calcium, is possible under unfavorable 
cultural conditions. When these happen, the plants usually find 
it hard to avail themselves of iron but absorb nitrogen in larger 
quantities than are needed. For this reason a calcium excess may be found associated with conditions which cause the foliage 
to be either a lighter or a darker green than is normal. 

No species have yet been found which can reproduce from 
the amount of calcium contained in their seed alone, though 
there is a possibility that certain species of rice might. 
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Lack of phosphorus also causes diminutive plants. The 
symptoms in young plants are a dark green to purplish color 
of the leaves, abnormal stiffness of stalks and leaves, poor root 
development, and some discoloration. The roots are longer 
than usual but produce few laterals. 

Plants absorb an excess of phosphorus under special condi- 
tions, such as when nitrogen is lacking in the nutrient solution. 
It is difficult to tell the symptoms of phosphorus excess from 
those of nitrogen deficiency. In such a case plants are characterized by large root systems, sparse foliage, stiff leaves and 

Species having sizable seed, such as many cereals, can repro- 
duce without receiving phosphorus from outside sources, that 
contained in the seed being enough to produce diminutive 
plants. However, plants like lettuce, radish, and turnip, which 
have small, seed, must be provided with an additional supply 
of this element to reproduce. 
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Lack of potassium produces a greater range of symptoms 
among different species than does lack of nitrogen. Plants like 
the cereal grains, which produce central stalks or shoots, die 
prematurely unless provided with this element from the very 
beginning. In crops such as lettuce, beets, and carrots, how- 
ever, the effects of potassium deficiency are less severe, and are  quickly remedied by addition of small amounts of the element 
to the nutrient solution. 

Unlike nitrogen, potassium does not enter into fixed chemical compounds inside the plant. However, crops like potatoes, 
which are predominantly starch, absorb large amounts of it 
and produce better-quality crops if an ample supply is avail- 
able. It is assumed that the element plays an important role 
in photosynthesis of crops rich in starch and sugar. 

The deficiency symptoms of potassium can be described as a 
premature breakdown of the younger foliage. The leaves 
droop and, as deficiency continues, may change in color (be- 
coming either lighter or darker according to species) and die. 
The first symptoms to be noticed are brown spots on the older 
portion of the leaves. 

An excess of potassium makes straw and leaves of plants stiffer 
than normal. Sometimes the tips of the youngest leaves wilt 
and those of the older leaves turn brown. There is no charac- 
teristic off-color of the foliage unless growth is slowed down 

Very few species can reproduce themselves from the small 
amount of potassium contained in their seed. The tuber crops, 
such as potato, are a notable exception. They contain fairly 
large amounts of this element, can make considerable growth 
from that contained in the tuber, and reproduce small tubers 
without additional supplies from outside sources. 
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Nitrogen (N)

Nitrogen is usually absorbed in greater amounts than any 
other element. Lack of it from the beginning causes diminu- 
tive plants with comparatively larger root systems, smaller and 
lighter colored leaves, and drier leaf tips than the normal plant. 
It does not in general interfere with the processes essential for 
growth in plants like wheat, whose seed contains enough nitro- 
gen to produce another seed in a small plant. When nitrogen 
is deficient, growth proceeds normally but on a diminutive 
scale. But plants with small seed, like lettuce, cannot repro- 
duce unless they are provided with this element. 

Many species can reproduce from the original fund of nitro- 
gen contained in their seed or seedlings without additional sup- 
plies from outside sources. Seed from such plants will germi- 
nate but cannot itself produce viable seed. Many cereal grains 
are in this class. They show increases in growth directly pro- 

Symptoms of Change 

Proportional to additions of nitrogen to the solution until an ex- 
cess of nitrogen becomes available. Then the ratio is no longer 
consistent. The excess produces very lush vegetation with a 
corresponding decrease in the firmness of stems and leaves. 
Foliage is produced rapidly at the expense of root growth, the 
ratio of fruit or seed to vegetation is subnormal, and the con- 
formation of plant parts is off-type. 

In an experiment with wheat reacting to lack and excess of 
nitrogen, the ratio of grain to total weight of plant when ni- 
trogen was deficient was 15 per cent (i, 2, 3) . When the 
element was in excess, the same ratio was 20 per cent (6, 7) . 
In a culture from which nitrogen was removed when the plants 
were three months old, the ratio was 30 per cent (4, 5) . When 
nitrogen was lacking, the plants did not produce enough foliage 
and were unable to manufacture the starch needed for the 
kernels. When an excess of the element was present, too much 
foliage was produced; that is, vegetative growth continued too 

Symptoms of Change 

This also cut down the production of grain. Starch for 
the kernels is not produced from new leaves but only from 
those which have attained some size. If a high production of 
grain is to be obtained, it is necessary for the plants to stop 
forming new leaves after they have attained size. Thus, by 
prolonging vegetative growth the nitrogen excess inhibits the 
formation of the kernels. 

This tendency of nitrogen to cut down the storage of starch 
and sugar is not so important for some flowers and crops grown 
chiefly for their leafy tissue. However, they may also absorb 
an excess. 
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Echinacea (Coneflower)

Echinacea (Coneflower)

(From the Greek eckinos, a hedgehog, alluding to the spiny backs of the receptacle)


Echinacea purpurea (Rudbeckia purpurea)

English Names: Purple cone flower, Black Sampson.

Large daisylike flowers sometimes five inches across, varying from rosy-purple to light rose, with high-pointed purple central cone; freely borne on a compact, bushy, rather coarse plant from two to three and a half feet high.

Excellent for the herbaceous border and good for cutting. A perfectly hardy perennial of easiest culture in any garden soil. May be used to cover dry and waste spots but responds well to rich soil, especially sandy loam. Prefers full sun. Propagate by seed or not too frequently by division. Var. serotina (E. inter media), a later-flowering variety, with brighter colored, broader, and flatter petals; possibly better than the type.

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Dicentra (Bleeding Heart)

Dicentra (Bleeding Heart)

(From the Greek du, double, and kentron, spurred, originally misspelled Dielytra and supposed to be Dielytra)

Dicentra spectabilis (Dielytra spectdbilis)

English Names: Bleeding heart, Seal flower, Lady's reticule.

Deep rosy-red, flat, heart-shaped flowers with protruding white inner petals, hanging delicately along graceful arching stems one to two feet high. Foliage deeply cut and handsome, but not persistent. The plant must be cut down or hidden after the flowering season.

A very dainty and charming flower, and a great favorite in oldfashioned gardens. Excellent for the herbaceous border or for naturalizing in the wild garden. A perfectly hardy perennial of easiest culture in moderately rich, light loam. Will grow in sun or shade, but thrives best in partial shade. Propagate by division of crown or roots. Var. alba. Has white flowers, but a weak and sickly habit.

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Dianthus (Carnation, Pink, Sweet William)

Dianthus (Carnation, Pink, Sweet William)

(From the Greek dios, divine, and anthos, z flower)

Dianthus barbatus, vars.

English Names: Sweet William, Bunch pink, Blooming down, London pride,

London tuft, Snowflake, Sweet John.

Single and double round flat flowers, an inch to an inch and a half in diameter, very variously colored and marked, in shades of white, pink, and crimson, borne in dense rounded terminal heads of twenty to thirty flowers and often four inches across, on leafy erect stems from ten to eighteen inches high. The foliage is simple, rather broadly pointed, and clean looking when young, but after blooming the plant becomes decidedly shabby.

An old garden favorite, and popular at the present day, perhaps more for its association than for its qualities. The single whites, true pinks, and dark crimsons make fine spots of color in the herbaceous border, but the magentas must be carefully avoided, and many of the parti-colored varieties are ugly. The double flowers last longer but are rather clumsy in form.

Excellent for cutting. Theoretically, the plant will last several years, but the second year is by far its best blooming season, so that it is usually treated as a biennial, seeds being sown in July for bloom the following year. One or two plants of the best colors should be allowed to seed (a paper bag tied over the head marks the plant and protects and collects the seed) and the rest should be cut down or pulled up immediately after blooming.

The bare spot left before the new seedlings have made their first year's growth is rather difficult to conceal, as Dianthus is necessarily planted in the front of the border. Of easiest culture, thriving in any soil, even clay or sand, and in full exposure to the sun; is little the worse for drought. Propagate by seed.

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Delphinium (Larkspur)

Delphinium (Larkspur)

(From the Greek name for the plant, ddphinion derived from delphin, a dolphin, from a supposed resemblance in the flower) Delphinium "Belladonna" English Names: Hybrid larkspur, Belladonna larkspur.

Curiously shaped, vivid sky-blue flowers, an inch and a half wide, with pure white centres, borne in graceful stalky spikes about twelve inches long on leafy stems from two to four feet high. Foliage finely cut and decorative. One of the best of the hybrid Delphiniums (though rather low-growing), on account of the sturdiness of the plant, its early and long blos soming season, and the very beautiful color of the flower. Invaluable for the herbaceous border or for massing againstshrubbery.

Excellent for cutting. A perfectly hardy perennial of easy culture, will thrive in any good garden soil in sun or partial shade, but does best in a deep, rich, sandy loam, exposed to the sun. Propagate by seed, cuttings, or by division; will Moom the first year from seed sown indoors in February or March, or following year from seed sown outdoors in August.

All members of the genus Delphinium are toxic to humans and livestock.

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