Define seed-bed:

It is defined as  preparation of soil in which seedlings are germinated.

 A seedbed is the local soil environment in which seeds are buried (planted). Often it comprises not only the soil but also a specially prepared cold frame, hotbed or raised bed used to grow the seedlings in a controlled environment into larger young plants before transplanting them into a garden or field.

The preparation of a seedbed may include following  steps:

1. Levelling:

The site will have been levelled for even  irrigation and drainage purpose.

2.Breaking up the soil:

Breaking up the soil. Compacted soil will be broken up by digging. This allows air and water to enter, and helps the seedling penetrate the soil. Smaller seeds require a finer soil structure. The surface the soil can be broken down into a fine granular structure using a tool such as a rake.

3.Soil improvement.

The soil structure may be improved by the introduction of organic matter such as compost or peat.

4.Fertilizing

Fertilizing. The nitrate and phosphate levels of the soil can be adjusted with fertilizer. If the soil is deficient in any micro nutrients, these too can be added.

Seed Germination:

Germination of seed is natural process it also depends upon on some physical and chemical properties of soil.

Germination occurs when a spore or seed starts to grow. It is a term used in botany. When a spore or seed germinates, it produces a shoot or seedling, or (in the case of fungi) a hypha. The biology of spores is different from seeds.

A spore germinates if and when conditions are right. It has a very limited lifespan. The method of spore-bearers, which are lower plants such as mosses, ferns and also fungi, is to produce vast numbers of spores, of which only a small percentage germinate.

Seeds contain an embryo, a store of food (the endosperm), and a protective coat. Seed plants include Gymnosperms (such as conifers) and Angiosperms (such as flowering plants). Seeds can survive much longer than spores, sometimes for hundreds of years. The strategy of seed-bearing plants is to invest energy and material in the substance of seeds, and they have evolved more sophisticated methods of dispersal than just wind.

Seeds do not germinate until their requirements are met, and these needs differ from species to species.

1.      The dormancy period must be over. Dormancy is governed by changes inside the seed. Each species has its own dormancy period, and will not germinate until that period is over.

2.      Their hibernation must be over. The hibernation is ended when events in the environment trigger germination. Sometimes this is just temperature and water, sometimes fire, sometimes the seed must go through a long cold spell.

The requirements for fruits is the same as for seeds. A fruit is just a seed with one or more extra layers derived from parts of the flower.

Herbicides

Definition of Herbicides

 Herbicides are pesticides used to kill unwanted plants

Selective herbicides kill specific targets, while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic mimics of natural plant hormones.

Herbicides used to clear waste ground, industrial sites, railways and railway embankments are not selective and kill all plant material with which they come into contact. Smaller quantities are used in forestry, pasture systems, and management of areas set aside as wildlife habitat.

Some plants produce natural herbicides, such as the genus Juglans (walnuts), or the tree of heaven; such action of natural herbicides, and other related chemical interactions, is called allelopathy.

Herbicides are widely used in agriculture and landscape turf management. In the US, they account for about 70% of all agricultural pesticide use

Zinnia

Zinnia is a genus of 20 species of annual and perennial plants of the family Asteraceae. They are native to scrub and dry grassland in an area stretching from the Southwestern United States to South America, with a centre of diversity in Mexico.^[3] Members of the genus are notable for their solitary long-stemmed flowers that come in a variety of bright colors. The genus name honours German botanist Johann Gottfried Zinn  Sun exposure: Full Sun Soil type: Any, Sandy, Loamy Flower color: Red, Pink, Orange, Yellow, Purple, White,Multicolor Bloom time: Summer Get a zing from zinnias! Zinnias are one of the easiest annuals to grow, grow quickly, and bloom heavily. They make a massive burst of color in your garden. Zinnias have bright, solitary, daisy-like flowerheads on a single, erect stem. The most common zinnia is "dahlia-flowered" and grows up to three feet. Other types are "cactus-flowered." Use in an annual or mixed border. Smaller zinnias are suitable for edging, windowboxes or other containers. The narrow-leaf zinnia also works well in hanging baskets. Zinnias are very popular for cut flowers. Planting Zinnias are grown from seed; they grow very quickly in the right conditions. Zinnias do not like to be transplanted. Full sun is essential wiht a minimum daylight temperature of 60 degrees F. Zinnias are adaptable but prefer fertile, humus-rich, well drained soil at pH preference 5.5 - 7.5. If soil is amended with compost, the flowers will grow more quickly. Sow seeds 1/4-inch deep. Space plants 4 to 24 inches apart depending on variety. (Many common varieties are 6 inches within the row and 2 feet in between rows.) See back of seed package. Germination occurs at 74 to 80 degrees F in 5 to 76 days. Sow in succession for a longer flowering display. Care Deadhead to prolong flowering. Maintain moderate soil moisture and fertilize lightly. Zinnias will die with the first frost. Pests Bacterial and fungal spots, powdery mildew, bacterial wilt. Minimize wetting of foliage to avoid disease. Caterpillars, mealybugs, and spider mites also cause problems. Avoid spraying and tolerate some leaf damage unless the situation is uncontrolled. Harvest/Storage Zinnias generally take 60 to 70 days from seed to flower (though it depends on conditions). Recommended Varieties Get a full-size flower on a compact plant with cultivars of the 'Dreamland Series.' Dwarf and compact, these zinnias have fully double flowerheads, to 4 inches across in a wide color range; stems are 8–12 inches tall. The 'Thumbelinia Series' cultivars and dwarf and spreading, with single or semi-double, weather-resistant flowerheads in many colors. Their petals are 1-1/4 inch across and stems grow up to 6 inches long. The 'State Fair Series' are the biggest and tallest of them all with large, double flowerheads that are 3 inches across. Stems grow to 30 inches tall. Special Features Attracts Butterflies Wit & Wisdom The small narrow-leaf zinnias make nice dried flowers, too.

Uses

A number of species of zinnia are popular flowering plants. Their varied habits allow for uses in several parts of a garden, and their tendency to attract butterflies and hummingbirds is seen as desirable.

Biochemistry

Biochemistry, sometimes called biological chemistry, is the study of chemical processes within and relating to, living organisms