In 2008, scientists in Israel found a seed of a date palm that was 2,000 years old. When the seed germinated, it became the oldest known seed to grow. What conditions did this require?
Germination of seeds occurs in five stages. They are: Water (Imbibition), Oxygen (respiration), light or darkness, temperature, and development into a seedling.
Imbibition is where a seed starts to absorb water. As the seed begins to absorb the water, it swells and rehydrates the cells of the seed. Then the seed is activated and starts to release energy from its food stores. This swelling results in the seed coat bursting.
The seed needs oxygen to produce energy to break down its food stores. This is called respiration. If a seed is planted too deep, it will not receive enough oxygen to start the germination process.
Some seeds require a certain amount of light to germinate, but some require darkness. It varies widely, so it is best to refer to the specifications on your seed. Most seeds will germinate at room temperature. Higher temperatures increase germination to a point. Once that has been reached, germination rates decline. Once the proper conditions have been met, the seed will start to develop a radicle, which is the plant's first root. Depending on the group of plants, the development will differ between monocots and dicots.
When a monocot seed germinates, it produces a single leaf. It is usually long and narrow. Even when it is quite a round shape, there is only one seed leaf. Monocots tend to have fibrous root structure like grass. When a dicot germinates, it produces two seed leaves. They contain the food for the new plant, so they are usually fatter than the actual leaves. The first true leaves are often a different shape. Dicots tend to have a taproot as part of their root structure, like a dandelion.
Plants require sixteen different elements to be able to thrive and grow, and if it lacks one or more of these nutrients, it may not be able to complete its life cycle. The first of these are carbon, oxygen, and hydrogen. These promote photosynthesis. Plants receive these elements from air and from water.
Next are the primary macronutrients. They are nitrogen, phosphorus, and potassium. In most commercial fertilizers, they list the ratio of these three elements or the NPK ratio. They are the three numbers listed on the front of the label. They indicate the percentage of each component in the fertilizer - the rest are fillers. So if you know your plants are nitrogen deficient, you are looking for a fertilizer where the first number is the largest.