Conditions

• Collard green plants need full sun -- about eight to 10 hours a day. A partial shade location also works for collard greens but yields plants that have a milder flavor. In addition, your collard greens' planting soil should be well-drained. Do not plant collard greens in areas where vegetables such as broccoli, cabbage or Brussels sprouts have been grown in the past year or more because this can lead to stem and root diseases.
  
  

Planting

• Apply a 10-10-10 fertilizer to your collard green planting soil, following the manufacturer's guidelines, and rototill the soil. Sow your collard green seeds 1/4 to 1/2 inch deep. Thin the seedlings so that they are six inches apart, and as the plants continue to grow, remove entire plants so that your collard green plants have 18 inches between them. You can put these excess seedlings in other rows if you do not want to dispose of them. In addition, keep rows of collard green plants three feet apart.
  
  

Fertilizer and Insecticide

• When caring for transplanted collar green plants, apply a transplant starter fertilizer such as a 10-30-10 fertilizer or a 10-52-17 fertilizer according to the label directions. If root maggots have been a problem in your collard green planting site in the past, put a garden insecticide mixed with water on the area, following the manufacturer's instructions. Also, apply a biological worm spray or dust to the planting site to control leaf-eating caterpillars.
  
  

Watering and Other Care

• Give your collard green plants an inch of water per week if rainfall does not occur during the week, especially in hot weather. In addition, handpick weeds that appear or apply a chemical weed killer to the area following the label instructions. This is critical because weeds compete for the water and nutrients your collard green plants need to thrive.