Radish Seeds & Different Types of Water

Germination

• Germination begins when radish seeds take up enough water to hydrate the seed. Seed coats allow water to enter and as it does the seed swells and the coat cracks. The water is essential for the chemical reactions that promote growth. Radish seeds are easy to germinate within a few days. The seedling plants live off food stored in the seed leaves (cotyledons) and begin to grow as soon hydration takes place.

Salinity

• Water flows from where there is lots of it to where there is less of it. This is called diffusion. Diffusion across the seed coat is called osmosis because seed coats are selective about chemicals they allow to pass through. Under the right conditions, radish seeds will allow water in like a sponge. If the water is very salty it will not flow into the seed. The amount of salt in water is called salinity.

Temperature

• Cold temperatures prevent seeds from germinating so that they do not germinate during the winter when the new plants might freeze. In the spring when the soil and soil water have warmed up most seeds begin to germinate. Radish seeds like to germinate between 45 degrees and 85 degrees Fahrenheit. Radish seeds do not germinate well above 95 degrees. Very hot summers are not a good time for most seeds to germinate.

Acids and Bases

• Rainwater, unless it is acid rain from pollution, can dilute the acid concentration of the soil and promote seed germination. The measurement of the amount of acid or base in soil and soil water is called pH. The pH range is 1 to 14: pH7 is neutral; below 7 acidic; above 7 basic or alkaline. Most seeds prefer a pH around neutral for germination. Radish seeds prefer a pH about 6.5, which is slightly acidic.