There are lots of reasons why some seeds do not have the "plant in garden option -- also know as sow outdoors". It could be that the plant has a really HIGH germination temp -- so by the time the soil and air temperature was reached and sustained, there would not be much time left in the growing season: examples of high germination temps: : Rosemary (Rosmarinus officinalis) 80-90 °F (27-32 °C) , Eggplant or Aubergine (Solanum melongena) 75-90 °F (24-32 °C) and watermelon -- which in the low temps requires more days to germinate (temp needs to be sustained longer) than it does at high temps: Watermelon (Citrullus lanatus) 70-95 °F (21-35 °C). It could also be that the plant has a high number of "days to harvest" -- that is the time it takes to grow from seedling to full grown -- so giving the plant a head start by sowing in doors in trays allows you to grow a plant that might not otherwise grow in your area . Maybe Leeks. or sweet potatoes. Also, sowing in trays makes better use of space -- for things like succession planting --- so if you are planning on harvesting a spring crop then using the space for a summer crop - you can start the summer crop indoors, giving it a jump start. So plants are also very susceptible to bug damage, wind damage, trampling, seedlings being eaten by birds etc. Also if the plant has a really low germination rate, sowing in trays is a good idea. So, WHY a particular seed does not have a sow outdoor option for your area will depend on the plant and the particulars of your area.

- Celeste Archer