Growing a Healthy Lawn in Shady Areas

Growing healthy grass in shady areas of your yard can be a most challenging task even for veteran yard warriors. Despite claims by some it is possible to grow a healthy lawn in areas with a fair amount of daily shade. There are many factors which can affect the performance of grass in partial shade; In some instances it may be near impossible to grow grass but in most case there is enough partial daylight. Within our community we can see ample examples of homeowners successfully growing a St. Augustine lawn. This is not just because of luck but because the proper rules are being followed for success. The following tips may provide assistance to homeowners struggling to maintain their lawn in shady areas.
  1. Your lawn needs daylight for it to properly perform "photosynthesis"....PERIOD. Photosynthesis is a process used by plants such as grass to convert light energy, normally from the Sun, into chemical energy that can be later released to fuel the grass' activities. Some varieties of grass require more sunlight than others to properly perform photosynthesis. For areas affected by partial shade it is important to select a shade tolerant variety of St. Augustine grass.
  2. As previously mentioned, it is VERY IMPORTANT you select a shade tolerate variety of St. Augustine grass to lay in your shady areas. Some varieties of St. Augustine grass required full sun all day while other select cultivars perform better in partial shade or short periods of full sun. Some of the more popular shade tolerant cultivars are Seville, Delmar, Palmetto and Bitterblue. Refer to the University of Florida Agricultural Extension article on St. Augustine grass for more details.
  3. Because trees shed their leaves and oftentimes leaves are left to decay the soil acidity from the decaying leaf matter can become too high for St. Augustine to perform optimally. Improper soil pH can lead to lethargic growth, fungus problems or decline then eventual takeover by invasive weeds. Maintain proper soil pH. The Seminole County Extension office across from Flea World in Sanford can test your soil pH for $2 per soil sample and give recommendations on how to correct the soil pH.
  4. When possible, rake tree leaves up and dispose of properly. If you have a bagging lawn mower consider bagging both grass clipping and tree leaves.
  5. Trees consume a lot of water and have extensive root systems which can compete for soil moisture.  On the other hand, grass growing under trees and the shade canopy has the advantage of less moisture loss due to evaporation. Depending on many variables your shade tolerant St. Augustine grass may need supplemental watering in sandy soil when large water-loving trees are present. Adjust your watering pattern depending on your specific environment.
  6. Some types of lawn fungus thrive in areas where leaf moisture is present for long periods. It is common for grass under trees to maintain longer leaf moisture than grass growing directly under full sunlight. Regardless of whether your St. Augustine is growing in full sunlight or partial shade try to minimize the period of leaf moisture by watering early in the morning just prior to sunrise or just after (5-8am) and never just prior to sunset. 
  7. Newly sodded St. Augustine lawns will benefit from an immediate application of granular fungicide such as Bayer Advanced or Scott's lawn fungicides. Because new sod typically requires daily watering the leaf blades are wet for long periods which promotes fungus growth. Apply the fungicide on top of the new sod the same day as installation at the "curative rate" listed in the directions.
  8. Apply lawn fungicide 3-5 times per year as needed especially under conditions where long periods of tree shade promote fungus growth.
  9. It should be noted that trees tend to decrease wind across the surface of the ground where grass grows which can results moisture staying longer on grass leaf blades longer allowing for fungus to thrive.
  10. Irrigate lawn using the rules for watering. City watering restrictions are always in effect.
  11. Just as trees compete for soil moisture they also compete for nutrients. Consider fertilizing your grass under your trees more often to compensate for added loss of nutrients from your trees. However, consider that grass growing in partial shade typically does not require as much fertilizer as grass growing in full sun therefore you may or may not have to compensate.
  12. Refer to our other Lawn Maintenance Tips.