By Luke “not-a-botanist” Langlois

Editor Makena asked all to consider Plants & Opinions for her theme. Luke takes a look at what plants need.

We all know that plants cannot just live on their own. Plants need water, sunlight, and carbon dioxide so they can carry out their autotrophic genius in the form of photosynthesis. Water, sunlight, and CO₂  are all critical for a plant’s survival, but the average citizen often overlooks the specificities of another important element of a plant’s survival: the soil. One who is not well-versed in botany (or AP Biology) might simply say that soil contains “nutrients.” While this is true, knowing that soil has nutrients is not enough to keep a plant in good health. The goal of this post is to inform you of what exactly the term “nutrients” entails. Additionally, I will run through some brief symptoms of plant nutrient shortages, so you can recognize specific nutrient shortages in your own houseplants and how to fix them.

Before I dive into the nitty gritty, you should know that plants have two categories of nutrients: macronutrients and micronutrients. Plants require macronutrients in large numbers, hence the name macronutrients. Since these elements are needed in relatively large numbers, it is recommended that a plant caretaker regularly refreshes the plant’s base with these elements. On the contrary, micronutrients are elements that plants only need in small numbers, hence the name micronutrients. It is only necessary to replace micronutrients if the plant has a visible deficiency. It is important to remember that it is entirely possible to overdo it on the nutrients. Imagine a person taking a whole bottle of nutrient supplements in a day. It’s the same concept. Anyways, the main types of macronutrients are calcium, nitrogen, magnesium, phosphorus, potassium, and sulfur. The main types of micronutrients are boron, copper, iron, manganese, molybdenum, and zinc. Now, let us dive into a few signs of these nutrient deficiencies.

Macronutrient Deficiency Symptoms

Calcium (Ca) – New leaves (leaves at the top of the plant) have noticeably irregular or distorted shapes. Just because one leaf is strangely shaped does not mean there is a calcium deficiency, but if your plant seems to emerge with a brand new shape of leaf often, it may be time to replenish the calcium.

Nitrogen (N) – Older leaves (leaves found near the bottom of the plant) begin to display a yellow shade while the newer leaves display a normal, light green shade.

Phosphorus (P) – The tips of the leaves look like they have been burnt and may have that “crunchy” feel. The rest of the leaf will usually maintain its original color, unless there are other shortages.

Sulfur (S) – A sulfur shortage will result in the younger leaves turning into the unhealthy yellow color first. Sometimes, older leaves will follow suit. This is not to be confused with a nitrogen shortage. If it’s a nitrogen shortage, the OLDER leaves are going to display signs of yellowing first.

Magnesium (Mg) – Older leaves begin turning yellow at their edges, which causes the leaf to display somewhat of an arrowhead shape in its center.

Micronutrient Deficiency Symptoms

Copper (Cu) – A plant with a copper shortage is going to have an unusual deep green color. This shortage may also cause a plant to become stunted.

Iron (Fe) – Just like that protein-fueled BEAST on the streets, your plants are capable of pumping iron, too. An iron deficiency is going to cause a yellowing between the veins of younger leaves. More severe iron deficiencies, like the one depicted below, can cause a yellowing around almost every vein in the leaf.

Zinc (Zn) – The terminal leaf of your plant may display a unique, rosette pattern. But, the plant is not just trying to impress its caretaker; it has a zinc shortage!

Here’s a disclaimer before I say a bit more: I am by no stretch of the imagination an expert on plants or a botanist. The physical traits that plants display vary from species to species, and some of these shortage signs may not apply to every species of plant. If it’s fall, and your plant is known to begin yellowing during the fall, do not go on a mad dash for magnesium. Use your botanical judgement to determine whether or not your plant needs some love. Before I depart, I would like to briefly explain how you solve these shortages. You are going to want to find soils or fertilizers that contain the missing nutrients and give them to your plants. Note: bags are not going to outwardly say “MAGNESIUM!” You may have to do a bit of research if you notice an unhealthy plant. The amount of nutrients that a plant needs varies based on whether the missing nutrient is a macronutrient or micronutrient, the size of the plant, and the severity of the shortage. To sum it up, gardening is a therapeutic and healthy hobby that many humans enjoy. It is only right that plants get to feel the same way.

Source: University of Arizona

Plant Editor: Makena Behnke