Varieties

• Mustard plants come in yellow, brown and Oriental varieties. Yellow mustard plants mature earlier and remain shorter than the other two types, according to Purdue University.
  
  

Leaves

• Leaves reach approximately 6 to 8 inches at harvesting time. Smaller leaves 4 to 5 inches in length taste best for eating raw. Larger leaves work better prepared as cooked greens, suggests University of Illinois Extension. Leaves that develop flowers or seeds should be avoided, as they taste bad.
  
  

Time Frame

• Mustard plants take 50 to 75 days to mature to their full size. Some fast-growing varieties, such as Florida Broadleaf and Green Wave, mature in only 45 days.