Seed wants to germinate, by its very nature there is nothing more important for a seed to do, and with your help, it can. Seeds, however, have built-in mechanisms to prevent them germinating at the wrong time, or in the wrong place, so it is up to you to convince the seed that everything ready to go and safe for it to germinate. For some seeds, like most annuals, this is as easy, but for others it may take some effort to trigger all the necessary mechanisms to begin successful germination.
Seed should be planted at a depth equal to the length of the seed. In the case of small seeds, a fine dusting of sand is best. Some seeds require light for germination and must not be covered -please refer to the specific notes for the seed variety, or consult with a good book on seed starting and germination.
Starting Seeds In Situ
Starting seeds in the garden - Many seeds are best started , that is planting them where you want them to grow in the garden. Prepare the soil by digging to at least 15cm deep (6in) and breaking-up any large clumps. This is the perfect time to add some organic material like compost, mushroom manure, or well-composted steer manure. Rake the soil lightly to smooth. Large seeds, such as Sunflower and Pot Marigolds, may be individually inserted into the soil - no deeper than twice the length of the seed. Smaller seeds may be lightly scattered, then lightly watered in - this process will allow them to find their own natural depth. Two more steps for really successful seed starting in the garden - Label your seedbeds well, and protect them from marauding birds by using very fine mesh netting or floating row covers such as Reemay.
If a viable seed does not germinate when provide with its correct temperature and moisture needs, then chances are that it is dormant. Seeds of trees, shrubs, and most wild or rarely cultivated plants have a number of mechanisms to protect their seed from germinating if conditions are not exactly right. Temperatures in mid spring are very similar to those in mid autumn, but if some species were to germinate in the fall, the delicate seedlings could be killed by the harsh temperatures of winter. To prevent this, many seeds require not only specific conditions, but also a specific series of events to occur before they germinate.
This technique requires the seed to be chilled for a set period of time to mimic the natural cold of winter. Many seeds will not germinate until certain that the winter has passed and it is safe to grow. Larger seeds, the size of a seasame seed and larger, should be soaked over night in clean pure water at room temperature. If the seed is very fine, you may sprinkle the seeds directly onto the starter pots that are filled with a good sterile seed starting medium. Refrigerate for a minimum of 3 weeks, but it is best to keep them cold for 6-8 weeks.
Some seeds have thick protective coats that protect the delicate embryonic plant inside, but this coat can sometimes inhibit germination by preventing necessary moisture from entering the seed. In this case it is important to break the seal of the seed coat without damaging the inner seed. Large seeds like those of peonies may be individually scored or filed, but smaller seed such as those of rhododendrons require a more subtle approach.
Rhododendron seeds, small and delicate as they may appear, require scarification to break through the tough seed coat, as this allows moisture in to enter the seed and begin the germination process. Since the seed is often quite small, this must be done using the following technique: First, take a 15cm (6in) clay pot, that has been washed and sterilized, and fill with sterilized seed starting mix. Firm the mixture in the pot and level it of about 2cm (1in) below the rim. Take a small amount of damp sterilized sand, just enough to comfortably fit inside your fist, and mix the Rhododendron seeds into it. Rub or crush the mixture between your hands once or twice - please do this over a large plate or other container to catch any that falls out. The mixture may then be spread on the surface of your carefully packed starter pot.
Some seeds may become extremely dry and may need to be rehydrated before sowing. While the traditional method was to simply plunge the seed, such as those of peas, beans an lupins, in water and soak overnight, this has proven to give the seeds a bit too much of a shock. It is better to gently introduce moisture, while still allowing the seeds to breath. By placing the seeds in damp sand at room temperature for a day, the right amount of moisture is able to enter the seed. Some of these seeds will also benefit from .