Germination
- Water does two things to a seed.
- First, it activates enzymes that stimulate the release of food energy stored during dormancy.
- Second, it splits the tough seed coat open so that oxygen gets in.
- Energy stored in the cotyledon ‘burns and is used only in the presence of oxygen, powering the seedlings cells as they begin to divide and grow.
- This process is called respiration.
- Soil holds the water and air that a seed needs to respirate.
- Too much water drives out air pockets in soil.
- Don’t over-water.
- Without air, seeds can't use their stored energy through respiration.
- Never let seeded soil dry out. Without water, seeds can't use their stored energy.
- This stored energy only lasts so long.
- That's why a sprouting seed works so hard to break the soil and unfold into the light quickly.
- Its also the reason that germination of many seeds is triggered by light.
- If a small seed germinated in a moist but dark environment, it might run out of energy before ever reaching the soil surface.
- But if a seed needs light, it won't germinate until it's close to the soil surface.
- That way, it has a chance to survive.
- But before a seed begins to grow up, it grows down, anchoring itself with a root, the first life to emerge from the seed coat.
- The root allows the spout to begin to absorb water and food from the soil.
- A seed can only store so much energy.
- That's why smaller seeds must be planted shallower, larger seeds deeper.
- Little seeds planted too deep will exhaust themselves and die underground.
- Large seeds can easily dry up if planted too shallow.
- Really small seeds should just be pressed onto the soil surface.
page revision: 0, last edited: 13 Mar 2009 20:08