The time of day does matter when it comes to fertilizing outdoor plants. It is generally recommended to fertilize in the coolest part of the day, such as early morning or late evening, especially in hot summer weather.
There are a few reasons why the time of day is important for fertilizing. Firstly, fertilizing in the early morning or late evening helps to minimize stress on the plants. During these times, the temperature is usually cooler, which reduces the risk of overheating and potential damage to the plants. Fertilizing during the heat of the day can cause the water in the fertilizer solution to evaporate quickly, leaving the plants without the nutrients they need.
Additionally, fertilizing in the early morning or late evening allows the plants to absorb the nutrients more effectively. During these times, the stomata (pores) on the leaves are typically open, which allows for better nutrient uptake. In contrast, during the hottest part of the day, the stomata tend to close to prevent water loss through transpiration. Fertilizing during this time may result in less efficient nutrient absorption.
Another reason to fertilize in the cooler parts of the day is to prevent the risk of burning the plants. Fertilizers contain concentrated nutrients, and if applied in direct sunlight or during hot temperatures, they can potentially burn the leaves or roots of the plants. By fertilizing in the early morning or late evening, when the sun is not as intense, you reduce the risk of burning the plants.
When applying fertilizer, it is important to water it in well. This helps to distribute the nutrients throughout the soil profile and ensures that they reach the roots of the plants. Watering also helps to prevent burning by diluting the fertilizer and preventing it from sitting on the leaves or roots.
In my personal experience, I have found that fertilizing in the early morning works best for my outdoor plants. I live in a hot climate, and by fertilizing early in the day, I can avoid the intense heat and ensure that the plants have ample time to absorb the nutrients before the stomata start to close. I always make sure to water the fertilizer in thoroughly to avoid any potential burning.
To summarize, the time of day does matter when it comes to fertilizing outdoor plants. Fertilizing in the coolest part of the day, such as early morning or late evening, helps to minimize stress on the plants, allows for better nutrient absorption, and reduces the risk of burning. It is also important to water in the fertilizer well to distribute the nutrients and prevent burning.