These pellets are round and flat and a single seed is placed in each. Upon watering, the pellets will expand into a small cube-shaped structure where the germinated seed will grow. A good planting medium for seed starting should be porous and well drained, as well as being free of any insect, disease or weed pests. For this reason it is usually advisable to purchase or make a seed starting medium. Avoid the use of outdoor soil.
Many seed starting mixes are available at garden supply stores.
If you will be starting small, fine seeds there is an advantage to using one of the finely screened mixes. These mixes are in most cases considered sterile and will need no disinfecting. Fill your planting container with the growing medium and you are ready to start your seeds. For small amounts of containers or flats I find that the sprayer attachment on the kitchen sink works well. Use warm water and in a matter of minutes the mix will be adequately moist.