Seed preparation before sowing
Some seeds requires specific preparation for a successful and rapid germination. Those are mostly hard seeds (with hard outer peel), where germination period would be unnecessarily stretched without such a treatment, as in the wild, where it germinates gradually and sometimes after many years. Here is an overview of several suitable methods.
- Soaking in the water: Basic and easiest option, for some species, is to soak the seeds for a while in the water. The time is usually 12-24, sometimes up to 48 hours. Occasionally it is necessary to change the water regularly during soaking. Even without this preparation, you get good results, but soaked seeds are germinating faster and more evenly.
- Manual seed disruption – Scarification: Should be done with very hard seeds, for easier access of water and gas into the seed. Actual essence is the disruption of the hard shell of the seed. It is done with a sharp object (scalpel, knife, needle), or abrading by the sandpaper or sand. These methods require some practice to avoid damage of the seed. In nature, soil microorganisms are responsible for the disturbance of the seed packaging.
- Chemical seal disruption: An attempt is to break the hard shell of the seed, this time by etching of the surface. It is accomplished by use of different acids. Most commonly by gibberelic (GA3) or sulfuric acid. This method also requires some practice. In nature, similar proces is achieved by animals (passed through the digestive tract).
- Cold stratification: Commonly used and a natural way, when temperature fluctuations cause disruption of the seed shell. It is simply done when sown seeds are well affected by the winter season, by several freezing and defrosting of the soil. Sufficient temperatures are just around the freezing point. If all fresh or well-stocked seeds are sown, for most of these species will suffice one winter period. If autumn sowing is done, those seeds should germinate in the spring after the first winter. If seeds are dry, late sown or incorectely stored it takes time to germinate, even till next spring. Therefore after two winter periods (year and half after sowing). In rare cases, even later.
- Stimulation of the seeds by heat: This is used for species, which seeds in nature germinate by cause of natural fire. Several methods can be used. It is necessary to keep sown seeds well moist for a few days, so the seeds swell slightly. Then the sown flower pot needs to be well watered by boiling water. Another option is to simulate a natural fire, when paper or grass is lit on the top of the pot. Produced ash, left in the pot, contributes for better seed germination.