When planting containers...
1. use a coffee filter to cover drain hole in pot before filling with soil. This will allow water to drain but prevent soil from coming out.
2. Allways leave 1 to 2 " of room from the top of soil to top of pot soil watering will not flood dirt and fertilizers away.
3. Buy simple rubber furniture squares from the hardware store and use three to four under pot to keep deck clean from a ring mark and not block drain hole.