Seed germination is the process in which seeds or spores sprout and begin to grow after being dormant for a period of time. The length of dormancy varies depending environmental conditions in which the seed is surrounded by. The environmental conditions that determine when a seed will begin to germinate are the temperature, oxygen, the amount of light, and the supply of water (Germination, accessed 23 February 2010, http://www.answers. com/topic/germination).
For a seed to begin germinating the temperature should be between 25 to 30 degrees Celsius. Radish seeds however prefer to grow in cooler temperatures from10 to 18 degrees Celsius. The seed also requires large quantities of oxygen to start germination which is obtained from the air and soil moisture. If the seed is sown deeply in the soil, the seed will fail to germinate due to the lack of oxygen. Light is needed for germination to begin however some seeds germination is hindered by light (Factors affecting seed germination, accessed 23 February 2010, http://www.tutorvista.com/content/biology/biology-iv/plant-growth-movements/affecting-seed-germination.php).
The supply of water is the prime requirement for germination as there is no water in a mature seeds embryo. The seed therefore needs to absorb water in order to become active and begin germinating. (Yahya,H, 2010, The Miracle in the seed, accessed 13 march 2010, http://www.harunyahya.com/books/science/seed/seed6.php). If a plant is watered with a small amount of water they weaken, which happens when they loose water faster than they gain it from the soil. Before the plant begins to loose strength the stomata pores close up which helps keep the water inside but allows less carbon dioxide to enter the plant. Plants require carbon dioxide to grow, so the growth of the plants will be slowed down because of the lack of water. However if plants get too much water the can not get any air from the soil which is used in respiration. The soil becomes so damp that it encourages disease, causing organisms, which may affect the plant as well as rotting the roots. Lack of nitrogen in the may also cause the leaves to turn yellow and fall off. (http://wiki.answers.com/Q/How_does_the_amount_of_water_ affect _plant_ growth)
The type of soil also affects germination and the growth of the plant. The soil is important as is provides nutrients such as potassium, nitrogen and phosphorus which is essential for their growth and survival. There are many different soils and mixtures that can be used for example (potting mix, garden soil, Mulch and manure) which all contain different ingredients (Plant Nutrients, accessed 10 March 2010,http://www.ncagr.gov/cyber/kidswrld/plant/ nutrient.htm). A general potting mix contains horticulture sand, composted pine bark, living micro organisms (bacteria, fungi, protozoa), base fertilizer and compost. Potting is a blend of composted organic material suitable for all indoor and outdoor plants. Some...