Can a Seed Be Exposed to Too Much Water?

Inhibition

• When a dry seed takes in water, it is known as inhibition. As a seed soaks up water, it expands, hydrating the enzymes and food within. Hydrated enzymes activate, increasing the metabolic activity needed for growth. Water in the seed also causes the pressure needed for cells to expand and enlarge. When the soil temperature, moisture and light requirements are just right, the seed develops an embryonic root that grows downward into the soil.

Effects of Wet Soil

• Seeds exposed to too much water can drown, causing the inhibition process to progress too rapidly, damaging the seeds. Too much water can also cause seeds to rot due to a lack of oxygen. To prevent seeds from getting too much moisture, start seeds in a light, soilless potting mix that contains 1 part vermiculite, or perlite, and 1 part peat moss. Mix the two and water until damp, but not wet. If you squeeze the soil and water runs out, it is too wet.

Damping Off

• Damping off is a fungal disease that can affect all types of plant seedlings. Symptoms include seeds rotting before they can sprout and seedling collapse near the soil surface. Causes include placing seeds in cold, wet soil or sowing seeds in poor-draining soil and planting them too deeply. To prevent damping off, avoid overcrowding seeds, provide good air circulation and avoid overwatering; water seedlings using a bottom tray. Sterilizing growing medium and containers also helps reduce the risk of damping off.

Scarification

• Some seeds have a hard seed coat that does not allow water to penetrate the seed; these seeds need to be scarified to allow water to enter. Scarification is any method of scratching, breaking or otherwise altering the seed coat to allow the water and gases to enter for germination. In nature, seeds are scarified as they pass through an animals' digestive tract or when exposed to freezing temperatures that modify the seed coat. You can scarify seeds by using a knife or sandpaper to scratch through the hard seed coat.