Corpus Christi Caller Times Caller.com - Fertilize lawn before long winter's nap

Marketplace \| Services \| Contact Us \| Community \| Arts & Entertainment \| Local Guides

Saturday, October 9, 1999

Fertilize lawn before long winter's nap
Properly applied, it helps root system grow

   Too often, people think that lawn care is approaching an end as autumn nears. Although it is true that mowing and irrigation frequency will substantially decrease along with the temperatures, you still need to take steps to prepare your lawn for its long winter's rest.
   With the change of season, comes the reminder to fertilize your lawn. Cold fronts and the subsequent increase in rainfall make October and early November the perfect time to fertilize your lawn. Lawn care in the fall is particularly important to ensure a thick healthy lawn in the spring.
   Most of our lawns are warm season grass varieties which grow little above ground during the winter, but the root system continues to develop even with reduced top growth. It is important to fertilize in late fall for good root growth and overwintering of your grass.
   Before you buy fertilizer, it is important to read the label and understand what you are purchasing. Every bag of fertilizer has three numbers clearly displayed on it. These numbers are percentages by weight of nitrogen (N), phosphorus (P2O5) and potassium (K2O), commonly called potash. For example, a 15-5-10 fertilizer contains 15 percent nitrogen, 5 percent phosphorus and 10 percent potash. A 20-10-20 fertilizer (20+10+20=50 percent fertilizer) has the same nutrient ratios as a 30-15-30 fertilizer (30+15+30=75 percent fertilizer); however, the latter formula has less filler in the mix.
   Besides the "big three" elements, or macronutrients, fertilizers also may include sulfur, calcium or magnesium. Micronutrients such as iron, zinc, manganese or molybdenum may also be in the fertilizer. Don't assume that you are getting any of these micronutrients even if the fertilizer is labeled as a 'complete' fertilizer. 'Complete' only refers to the presence of nitrogen, phosphorus and potassium, not any micronutrients.
   It is important to remember that a late application of a high-nitrogen fertilizer can produce a flush of growth which may weaken your lawn or shrubs in the event of an early freeze. That is why it is important to fertilize your lawn with a "winterizer" type of fertilizer. Be careful: just because the name is on the bag, it may or may not be what you need. The key to success is buying a fertilizer with slow-release nitrogen. A winterizer should have approximately 60-70 percent slow-release nitrogen.
   What does this mean? For example, if you fertilize with a 70-percent slow-release nitrogen, 30 percent of the nitrogen is available at the time of application. The remaining 70 percent is released over a 3-to-5 month period depending on temperature and rainfall. Make sure you read the label since there are no regulations regarding the use of the term "winterizer".
   Soil samples in our area often show an abundance of phosphorus, especially in the heavy clay soils in the Corpus Christi area. Much of the area was previously farmland which received phosphorus-rich fertilizers in the past. Since phosphorus is not readily mobile in the soil, many of our lawns do not need much if any phosphorus. It is important not to keep adding additional phosphorus in these cases because excessive phosphorus can tie up micronutrients such as iron and zinc in the soil, making them unavailable to your grass.
   Remember that after you fertilize, you need to water it in. It is important to wash the fertilizer off of the grass blades to prevent burning. Application of approximately 1/2 to 3/4 of an inch of water will wash the fertilizer into the soil where the root system will take up the nutrients. Overwatering, especially in sandy soils will leech out the nutrients.
   In the event of torrential rains like we've experienced for the last two years during October, with 20-plus inches of rain, you may need to reapply. Much of the fertilizer may be washed away, especially if a slow-release formulation wasn't used.
   One final note about fertilizers is "you get what you pay for". Don't be afraid to pay a few extra dollars for a quality fertilizer. The extra money covers the cost of slow-release forms of fertilizers and micronutrients. You will see the value in your healthy lawn next spring.



1999 Caller-Times Publishing Company, a Scripps Howard newspaper. All rights reserved.