by Bonnah Boyd, Somervell County Master Gardener
Fall lawn fertilization is equally as important as spring fertilization. It prolongs fall color, increases winter hardiness, promotes earlier spring green-up and helps maintain a dense turf that resists winter weeds.
The best way to pinpoint the time to fertilize is by monitoring your mowing frequency. When you don’t need to mow for 2 weeks, the time to fertilize is at hand. In general, fall fertilization of warm-season grasses should occur between October 1 and 15 in this area.
Fertilizers used in the fall should be high in nitrogen and potassium and low in phosphorus (or no phosphorus). A 2-1-2 or 1-0-1 ratio of nutrients is preferred. The fertilizer should be a combination of quick-and slow-release nitrogen portion of the forms to encourage production of carbohydrates. These carbohydrates are then stored in the roots for use in earlier spring greening of the lawn and as an energy source for the grass during winter stress.
The amount of fertilizer to apply is 1 pound of actual nitrogen per 1,000 square feet. Look on the fertilizer bag for guidance on how much area the bag will cover. (Some organic fertilizers contain less than half the nitrogen of “conventional” or chemical fertilizers. Be sure to apply enough organic fertilizer to gain the results you expect.)
The easiest way to broadcast lawn fertilizer is by using a walk-behind spreader on wheels. To spread the calculated amount of fertilizer evenly across the entire lawn, follow these guidelines:
- Determine how many sections you have in the lawn that you can easily walk the spreader around without stopping, going across driveways, or through gates.
- Divide the amount of fertilizer proportionally based on the number and size of sections.
- Divide each section’s fertilizer amount in half, and pour half into the spreader.
- Cut back the spreader setting to the smallest opening that still lets the fertilizer pellets flow out of the hopper easily. Be careful not to apply too much fertilizer too fast.
- Turn the spreader on, and walk it north to south across the lawn and keep going back and forth until the spreader is empty.
- Fill the spreader with the other half of the section’s fertilizer, and walk the spreader east to west, back and forth, until the spreader is empty.
- Water the lawn thoroughly to activate the fertilizer and prevent fertilizer burn on the grass.
Try not to fertilize prior to a predicted heavy rain. Nitrogen, and other fertilizer nutrients, can easily run off in heavy rains into the storm sewers and into creeks and streams. Nitrogen can cause an “algae bloom” that consumes oxygen in the water to the point of killing fish.
Reference: Doug Welch’s TEXAS GARDEN ALMANAC