It is necessary to preserve your Begonias prior to the winter months.
For the Begonia novice, following are a few tips for preserving your Begonia tubers for the next season: Preserving Your Begonias

• Stop watering the plants as soon as the lower leaves on the plants begin to yellow.
  
• Pull them as soon as they begin to show signs of dormancy.
  
• Dig (do not pull) the entire plant from the soil.
  Shake off any loose soil and lay the plants in a single layer in a dry location (away from the sun).
  
• Turn nursery flats upside down and place the plants on the flats to allow for maximum air circulation.
  
• Break the foliage gently away when it becomes dry and brown (this will generally occur in about one month).
  
• Shake off any excess soil and rinse the tubers in fresh water to remove the remaining soil.
  
• Place the prepared tubers in a nursery flat lined with dry newspaper.
  
• Place them back in a dry location away from the sun until they are dry to the touch.
  
• Discard any damaged tubers or those showing signs of rot.
  
• Dust the tubers with sulfur powder to discourage mold and fungus disease during storage.
  
• Place the prepared tubers in a single layer between pads of newspaper and store in a cool, dry place (such as a lower level shelf in the garage) until it's time to plant them again in April or May.
  
• Make sure the Begonias are stored in paper.
  Never store Begonias in plastic since plastic retains moisture and will cause the tubers to rot.
  

Planting Your Begonias

• Check your stored tubers in the spring for signs of life.
  Small pink numbs will be evident on the concave side.
  
• Prepare the soil in the planting bed with organic matter, such as oak leaf compost or any fast-draining rich potting soil, after the soil has warmed.
  
• Plant the begonias right side up.
  Lay the tuber with the pink nubs and concave side facing up.
  
• Push it gently into the soft soil to settle it in place.
  
• Water immediately after planting, then only when the top two inches of soil feels dry to the touch.
  Water in the morning hours.
  
• Set the containers in a warm shady location.
  
• Fertilize with a high nitrogen fertilizer every two weeks.
  Switch to a 0-10-10 fertilizer and continue to fertilize every two weeks when the plants begin to set flower buds.
  

Since Begonia tubers get larger and larger over the years, the resulting plants from those large tubers are going to be magnificent.
Single tubers can eventually reach 5 to 7 inches across.
Use these preserving and planting tips to enjoy your begonias for years.