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Nutrient Deficiency in Plants: How to Tell What They Need 

Nutrient Deficiency in Plants: How to Tell What They Need 

While growing houseplants can be a lot of fun, it can also be quite challenging. Many of us have experienced the same scenario with houseplants. You get a new plant and proudly display it in the window of your home. However, in time the plant starts to exhibit signs of stress, such as yellowing leaves and stunted growth. While many issues with houseplants can be solved by changing their exposure to sunlight, others are related to imbalances with soil nutrients. To help you care for your houseplants, Soltech Solutions put together this brief guide on identifying nutrient deficiency symptoms. Nutrient Deficiency

Macronutrients and Micronutrients Explained

Just like the human body, plants require very specific nutrients to grow and flourish. Plant scientists have developed specific categories for explaining the value of different nutrients to overall plant health. Of these categorizations, macronutrients and micronutrients are the most important to know in caring for your houseplants. According to Cornell University, there are a total of 18 essential elements in plant nutrition. Each of these elements plays a critical role in the growth of any plant species. Of the 18 essential elements, 9 are considered macronutrients, and 9 are considered micronutrients. While imbalances with any nutrient can hinder plant growth, macronutrients are far more important than micronutrients. Within the macronutrient category, there are also primary macronutrients.

What is the N-P-K Ratio?

The most important soil nutrients for sustaining plant growth are nitrogen (N), phosphorus (P), and potassium (K). If you have ever looked at the label on a container of fertilizer, you have likely seen these elements represented in an N-P-K ratio. The N-P-K ratio is used to compare relative amounts of the primary macronutrients nitrogen, phosphorus, and potassium in fertilizer products. Because it is a fraction, an N-P-K ratio of 50-30-30 is the same as an N-P-K ratio of 5-3-3. Fertilizer manufacturers make products with different levels of nitrogen, phosphorus, and potassium for different phases of growth. For example, early phases of growth require higher levels of nitrogen. Yet, when plants are ready to grow flowers, they need more phosphorus and potassium than they did earlier. If you are looking for a good all-around fertilizer for basic houseplant cultivation, we recommend a balanced N-P-K ratio such as 6-4-5.

Nitrogen (N) Deficiency

Nitrogen is critical to the early phases of plant growth. It is generally mixed into fertilizer products from ammonium or nitrate. Nitrogen is the nutrient responsible for helping plants retain their green coloration. Nitrogen deficiency is one of the most common nutrient issues with houseplants and home gardens. With these nutrient deficiency symptoms, older leaves close to the bottom of the plant turn yellow. Another indicator of nitrogen deficiency is the light green coloration of the entire plant. Nutrient Deficiency Please note, nitrogen deficiency can often be easily confused for other problems.

Phosphorus (P) Deficiency

Phosphorus is another of the macronutrients found in fertilizers. Fertilizers used specifically for flowering and fruiting will generally have a noticeably higher potassium level than those for standard growth. Nonetheless, plants use at least some amount of phosphorus during all phases of growth. Phosphorus is commonly mixed into fertilizers with bone or phosphate. Phosphorus deficiency is most commonly indicated by “abnormally dark green or reddish purple color along the edge of the lower plant leaves.” As this is quite different than how other nutrient deficiencies are expressed, phosphorus deficiency is relatively easy to identify.

Potassium (K) Deficiency

Potassium is 3rd macronutrient in the N-P-K ratio. While potassium is particularly important during the flowering stage, it is utilized at some level during all phases of plant growth. Nutrient mixes generally get their potassium from potash. Potassium deficiencies are indicated by a yellowing of leaf margins that begins at the tips and works inwards. With severe cases of potassium deficiency, the leaf edges may become brown and overall growth will be stunted. To correctly diagnose potassium deficiency, you have to not only identify that leaves are yellowing and browning, but also the pattern through which it is happening.


While growing houseplants is a relaxing and therapeutic hobby, it does take some effort to get your processes right. Learning to identify nutrient deficiency symptoms can be a great way to troubleshoot current issues, while also expanding your capabilities. Please contact Soltech Solutions if you have additional questions about your houseplants.