Using seeds is a cheap way to start new plants, and many times you can get them for free by collecting them yourself. You can start seeds indoors, and you can also plant seeds in an outdoor garden. Planting seeds in an outdoor garden is only natural---as long as you go about it the right way.
Many seeds fall off of plants in the fall, but they do not grow right away. Instead, they lay dormant in the ground until the winter is over and spring returns. These seeds need stratification, a period of time in which they are exposed to cold. Most seeds of this type need two to four months of stratification to germinate properly. Other seeds grow right away and do not need a cooling period to germinate.
Therefore, if you plant the seeds when they would fall naturally, nature should do the rest of the work for you.
Although plants need to be planted at levels relative to their roots, most seeds need to be planted relative to their size, about twice as deep as they are large. One inch deep is usually fine for planting larger, coin-sized seeds, while smaller seeds can be tossed on the ground with only a layer of soil sprinkled on top of them.
Seeds need moist soil in which to germinate and grow, but they do not need soaking wet soil. Although it isn't always easy to control how much water an outdoor garden gets, you can keep the soil from drying out. Sprinkle the soil with water to keep it moist, and the seeds will grow well to thank you.
After planting so many seeds in an outdoor garden, you are bound to forget what is planted where. To avoid this, label each section of seeds as you plant them. This way you won't wonder what that strange plant is and pull it up as a weed.