Open a pack of heirloom seeds and potential life comes spilling out. If you are in the habit of collecting your own seeds, then you know just how abundant these things are and at what little cost they come. However, even for the standard punter, a pack of seeds offers the best value and knowing how to use those seeds is an essential skill.
Select seeds based on what is in season, type of light the plants will receive, and what you like to eat. For example, I like to eat lots of leafy greens and they seem to do pretty well in my dark and boggy yard. If you don't know what to grow, have a look over the neighbors fence or even ask them what they recommend. If you prefer a less invasive approach, seed packaging will generally describe the ideal environment for the plant in question.
Once you've settled on what to plant, it then becomes a question of where and how. Again, a little research and experimentation will help to determine which seeds to sew directly into the patch and which to propogate in trays. The same goes for planting location. We do, however, have some rules of thumb:
Soak seeds with a hard coating (beans, peas, nasturtium, etc...) overnight. This accelerates germination and improves the probability that your seed will, in fact, yield a plant. Drain the water into your garden and plant the seeds to their prescribed depth. This method works so well that drained seeds left in a jar will sprout all by themselves!
Plant seeds to a depth twice the diameter of the seed in question. This is a rule that generally applies to larger seeds, such as the ones pictured above (that would be a broad bean, peas, and beetroot). For example, a broad bean is about 2cm in diameter, therefore you should plant it 4cm deep. Check the package for spacing information and plant away.
The gardening world is full of short-cuts and gadgets, but the best tool ever invented is a hand with fingers. Use those fingers to borrow little holes in the soil. To be extra sure that the seeds will grow, plant two in each hole. We call this, "the buddy system."
Not all seeds are created equally and some are simply too small to measure and plant individually. For these seeds, tomato and radish come to mind, the broadcast method is a better option. Create a shallow furrow with your index finger and lightly sprinkle the seeds down the line. Dust with soil to cover and prevent bird/wind theft, but not so much as to inhibit growth. Very little coverage is required for small seeds.
Last but not least, don't forget to water the newly planted seeds. Ideally, get to them first thing in the morning and continue daily watering until plants mature. Take a cup of coffee with you and make it part of the morning routine. Watering is a nice way to be seen and look like a responsible citizen. Admire your work and wait for the compliments to start rolling in...