Plants usually absorb most nutrients from the soil. A foliar spray was invented to supplement nutrients in the soil by spraying the nutrients directly on the leaves of the plant. A small opening in the leaves allows the nutrients to enter the plant.
Question: Why was this process invented?
Answer: To enable a precise way to add nutrients to plants. Also, plants may have difficulty absorbing nutrients from the soil.
Question: When can’t plants absorb nutrients from the soil?
Answer: Not all soil is the same. The amount of organic material, the pH, temperature, amount of water, and presence of pest and disease can all affect how a plant absorbs nutrients.
Did you know that the Amazon rainforest has nutrient-poor soils? But it has the most biodiversity on the planet. This occurs because the nutrients are being used in living tissue, or are locked up in the dead organic material. Dead tissue such as leaves, bark, roots all needs to be broken down by organisms or burned before nutrients are available for new plants. In soil, the nutrients may be present but are locked up in the dead organic material.
Plants absorb nutrients with a positive or negative charge. The pH or power of Hydronium is the concentration of positive hydrogen ions. These hydrogen ions interact with nutrients in the soil. Low pH soils prevent many nutrients from being absorbed while high pH soils reduce the absorption of iron, manganese, copper, and zinc. (See more in our nutrient deficiency article)
Temperature affects plant’s ability to absorb nutrients from the soil. Some nutrients that temperature effects include: phosphorus and iron.
Not having enough water in the soil prevents plants from absorbing nutrients in the soil. However, if there is too much water, flooding this damages to roots and the plant can’t absorb nutrients. Too much water can also cause leaching when water carries nutrients away. Having the right amount of water in the soil is necessary for plant nutrition.
Pests and Disease
Insects that feed off of roots and pathogens that infect roots affect plant’s ability to get nutrients. A plant that has a nutrient deficiency is also easier for an insect to eat.
Many factors in the soil that affect how a plant can take up nutrients: organic material, pH, temperature, water, pests, and diseases. How can we overcome these issues?
Foliar Feeding Another Way for Plants
Foliar feeding was proven effective in the 1950’s using radioactive phosphorus and watching the radioactive nutrient move inside the plant.
A foliar spray gets around these issues of the soil by applying the nutrient directly onto the plant. When nutrients are applied to the soil growers can’t be sure how much is absorbed, and when it is absorbed. With a foliar spray, you can accurately apply an exact amount of nutrients for the plant. In soil, much of fertilizers can be wasted with runoff and leaching of soil and nutrients. Because foliar feeding is exact and reduces waste less fertilizer is needed for plants. This saves money and helps the environment. More great info in our article on How to Increase Yields While Doing Your Part to Protect the Environment.
Soil presents many challenges for plants to absorb nutrients including: pH, temperature, water, pests, and diseases. To make sure plants get nutrients, we can use foliar feeding to apply an exact amount of nutrients directly to the plant.