People often say you have to feed your plants, but in reality plants make their own food through the process of photosynthesis, which yields oxygen and glucose. Glucose is the food that plants use for energy and growth, they don’t need us to actually feed them. Since plants can make their own food, they are called autotrophs. The green pigments in plants, called chlorophyll, capture light energy from the sun. The process isn’t nearly as simple as I’ve described it.
Plants can further be divided into two classifications, C3 or C4, which is determined based on how efficiently the plant can photosynthesize and whether the plant has to go through the process of photorespiration, which is required for C3 plants. This makes C4 plants, like corn, sorghum and sugarcane more drought resistant because of the complex processes that occur within the plant at molecular levels. The majority of plants are C3 plants. For more information on this topic check out the article from University of Illinois, The difference between C3 and C4 plants.
So why do plants need a soil that is sufficient in macronutrients and micronutrients if that is not their food? Well, the short answer is that nutrients help plants grow and keep them healthy so that they can photosynthesize efficiently. As the plant mass increases, the plant leaf size/surface area increases, which allows the plant to capture more sunlight and turn it into more food.
You can check out the Home and Garden Information Center’s webpage about fertilizer to learn more about macronutrients and micronutrients. Macronutrients are those elements that the plant needs the most of to be healthy. Water provides hydrogen and oxygen. Carbon dioxide provides oxygen and carbon which are part of the required macronutrients for all plants. The remaining macronutrients are provided by soil (unless the plant is being grown hydroponically, of course). Plants can only take up or use nutrients that are dissolved in soil water. This is why it is so important to make sure that your soil gets sufficient water. Some plants are called heavy feeders and this is generally in relation to their need for larger amounts of the macronutrients, especially nitrogen. Some examples are tomatoes, everything in the cabbage family, and beets. The University of Maryland provides more information on fertilizing vegetables.
By providing an optimum growing environment, through correct amounts of light, moisture, and nutrients, the plant will have the best chance at reaching its full potential. As I eagerly wait for the first produce from my vegetable garden this season, I want to be sure that all my plants reach their full potential and produce a large amount of food for me and my family to enjoy this growing season.
Please comment below with what you are doing this year to ensure that your plants are healthy and happy and growing well. Do you test your soil every 3 years or whenever you are planting a garden in a new area? Do you research the plant needs (full sun, part sun, or shade) before planting? What questions do you have about managing soil fertility and nutrients?
This year, the University of Maryland Extension Master Gardener Grow It Eat It Program celebrates the resource that supports all life on earth – soil! Look for soil education programs offered by your local Master Gardener program, and visit the Home & Garden Information Center website for more information about soil health.