Fertilizers have the capacity to burn plants when applied incorrectly. Air temperature and weather greatly determine when gardeners should apply fertilizer to their lawns and plants. If gardeners apply fertilizer at a time during the day when the weather is rainy or air temperatures are too hot, both plant damage and environmental problems can occur.
Air temperatures factor in when planning to fertilize lawns, especially if you are using a quick-release fertilizer. Avoid applying a quick-release fertilizer when air temperatures are above 85 degrees Fahrenheit, according to the University of Minnesota. If you suspect that your afternoon is going to be above 85 degrees Fahrenheit, fertilize your lawn with quick-release fertilizer in the early morning to prevent burning up you plants. Quick-release fertilizers rapidly contribute nitrogen to plants; therefore, vegetation can burn when temperatures are hot.
Gardeners must water their lawns after applying either quick-release or slow-release granular fertilizers. When lawns are wet as they get in the cool temperatures of the night, they are more susceptible to contracting a fungal disease. The best time to apply water to your lawn is in the early morning. Applying fertilizer to soil that is still wet from dew will also reduce the risk of burning up your plants.
Applying fertilizer and water in the afternoon results in losing soil moisture from evaporation. As the sun beats down on your lawn, you can lose the moisture that is preventing your lawn or plants from becoming burned. It is important for grass to dry out slightly before the nighttime temperatures. Wet grass combined with cool temperatures results in fungal diseases. Fertilize your lawn at a time when you will not lose moisture from evaporation such as early in the day.
Avoid fertilizing before stormy weather washes the fertilizer off the soil. If you expect rain in the morning, fertilize in the midmorning. Also, turn off your sprinkler system after you apply enough water that your lawn needs for the fertilizer's nutrients to sink into the soil. Irrigating at the wrong time removes the nutrients from the top of the soil.