Timing

• Sunroots require 125 days of frost-free weather to bloom. Although in warmer regions the tubers can be planted in late fall, early spring is ideal. Wait for the soil to warm to at least 50 degrees Fahrenheit to plant the tubers. If the soil is cooler than 45 degrees, the tubers will sit and not sprout. The largest sunroot plant yield is realized when the air temperature is between 65 and 80 degrees.
  
  

Preparation

• Self-seeding experts, sunroots have a tendency to take over the garden, so find a place in the garden for them to spread out. Till the soil so that it is loose and fluffy to a depth of 10 inches. Mix 2 inches of compost and 2 inches of manure into the top 8 inches of soil. If you have clay soil, mix in some additional, chunky compost to help with drainage.
  
  

Planting

• Plant the sunroot tubers 4 inches deep and 1 foot apart. If planting more than one row, space the rows 3 feet apart. Water the bed to a depth of 6 inches and cover it with a 2-inch layer of straw. The sunroot tubers sprout within two to three weeks after planting. The young leaves and stems have fine hairs and look a bit like weeds so be careful cultivating the sunroot bed.
  
  

Harvest

• Harvest the sunroot tubers after the foliage dies back in fall. The tubers are generally packed together and intertwined with the plant's roots so it may take some work to separate them. Take what you need and leave the rest where they can overwinter and be harvested in spring. Allow the foliage to remain on the stored plants to remind you where the remaining tubers are located.