Significance

• When they're grown from seed, zinnias begin to bloom between 8 and 12 weeks following sowing. Seed sowing is not recommended until the final spring frost has passed, to prevent damage to your flowers. Additionally, night temperatures should be 50 degrees Fahrenheit or higher to promote healthier growth.
  
  

Time Frame

• Final spring frost dates vary across the different USDA zones in northern Texas. On average, the final spring frost occurs in Dalhart, Texas by the second week of May, while Amarillo's final spring frost date falls in the final week of April.
  
  

Considerations

• To enjoy zinnia blooms earlier in the year, North Texas gardeners may start growing zinnias indoors four to six weeks before the final frost date. Zinnias should be started in peat or other biodegradable pots to prevent damage to their roots when removing the plants during transplanting.