How to Diagnose Plant Problems
Yellowing leaves, soft stems, smelly soil: these are all symptoms that our plants are going through something. Just like when you get a stuffy nose and sinus pressure from a head cold, plants will display symptoms of disease or improper care sometimes weeks before the problem becomes critical. While it can be alarming to see your beloved plants behaving in ways less than ideal, try not to fret or jump to conclusions. In this blog, we will go through the questions and steps that plant experts take to diagnose and treat plant problems!
Step One: Ask Questions
When working with plants for a while, it is not uncommon for friends, family, and even coworkers to send you a picture of their plant and ask, “What is wrong with my plant?” Rarely is one picture enough to, well, give the full picture of what is happening. Yellowing leaves, for example, can be a symptom of overwatering, underwatering, too much light, not enough light, too much fertilizer, not enough fertilizer, disease, and so on. How do we get the full picture then? Lots and lots of questions. The first step to determining what is wrong with your plant is to ask yourself questions.
To get a better idea on how this process might go, we will create an example.
Plant Age
You have a Monstera deliciosa, or Swiss Cheese plant, that has leaves that are drooping and yellowing. The first question you can ask yourself is: How long have you had this plant? You answer two years. Okay, that is a decent amount of time to keep a plant happy, so congratulations! Don’t get too worried about yellowing leaves just yet; growing plants will often drop their lower leaves with age as they put energy into new leaves. However, in this example, the yellowing seems to be spreading quickly and affecting newer leaves higher up on the stems, too.
Watering
Next, let’s talk about watering. How often do you water your Monstera? You have been watering your Monstera every other week on a schedule. When you water, how much are you adding into the pot? When you do water, you add water until it comes out the bottom of the pot and drains into a plastic dish. This actually answers another important question: Does your pot have drainage holes? One of the most common issues when watering plants is related to drainage. There are many pots out there that are purely decorative and without drainage holes, kind of like our plants at Wild Interiors. For this reason, our plants are kept in inner plastic grow pots that can be easily lifted out of their decorative ceramic pots. This is called a cachepot and allows you to place your plants in any decorative pot or basket without needing to be completely repotted! When watering plants like this, it is best to either remove them from the outer decorative pot to water them, or to regularly dump out any excess water that may be collecting at the bottom. Many houseplants do not like to be sitting in water, giving them “wet feet”. Even when drainage holes are present, they can sometimes be blocked by compacted soil or debris, so it is a good idea to regularly check that your pots are draining completely.
Lighting
Okay, back to your Monstera! The next set of questions are related to where your plant is located. To ask “How much light is your plant getting?” is very broad and often does not give enough information. Instead, let’s break down the importance of lighting. How close to a window is your plant? Your Monstera is sitting right in front of a south-facing window. In theory, this means that throughout the year, the plant is in a window that receives sun all day long (if you are in the Northern Hemisphere, that is). This may answer the next question: Does the sun directly touch your plant? In the wintertime, even though the sun is less intense because it is farther away, your Monstera may be getting more direct sunlight than it does in the summer, when the sun is overhead and coming in that south window at a steeper angle. Is the direct sunlight blocked by anything? This can include blinds or curtains that you close to keep the hot summer sun out of the house or a tree that blocks the sun in the summer when it is leafy. In this case, you have a large tree outside of your south-facing window. This means that in the summer, your Monstera is actually getting less bright light than it does in the winter. In fact, you notice that your Monstera tends to put out more new leaves in the winter than it does the summer!
Other questions that involve lighting include “What time of day and for how many hours does the sunlight come into the window?” Early morning sun, like that that comes in an east-facing window, is less intense than afternoon sun. In the summer, that period of time that your plant is getting direct light may be enough for a plant requiring bright, indirect light. A north-facing window will likely never receive any direct sunlight, depending on where in the world you are living. For this reason, a north-facing window is often considered a good spot for plants needing medium to low light, or for some of those bright light plants that do not do well with direct sunlight. West-facing windows received very intense direct sunlight in the summer. Just like south-facing windows, care should be taken on what plants can be placed in these windows to avoid burning their leaves.
The more light your plant receives, the more they will grow. In turn, the more they grow, the more water and nutrients they use up. In addition, lighting changes throughout the year. With that, your care may have to adjust too…
Fertilizing
Next up, let’s talk about fertilizing. Have you fertilized your plant recently? Indoor plants typically grow the most in the spring, summer, and early fall. Plants need plenty of light and warmer temperatures to grow, and will often go dormant in the winter. For this reason, it is recommended that fertilizer only be used in the spring and summer, while the plant is actively growing and needing additional fertilizers. In this case, you have been giving your Monstera fertilizer every other time you water. What kind of fertilizer do you use? You use a water-soluble organic fertilizer like Espoma Indoor Plant Food. What is the concentration of the fertilizer used? You followed the instructions and added the recommended amount of fertilizer to water.
There are many different types of fertilizers on the market, and it can be difficult to sort through them all. More harm than good can be done when fertilizing your indoor plants if instructions are not followed. Houseplants that are kept indoors are not receiving the same amount of light and water than they would be in their natural environment. This means that they are typically needing a lower concentration of nutrients, provided to them by their plant parents! By adding too much fertilizer to your plants, you can actually burn their roots, causing further damage in other parts of the plant.
Repotting
Finally, you can ask yourself: Have you repotted your plant recently? In this case, no you have not repotted your plant. In fact, the Monstera is in the same pot that it was when you purchased it two years ago. Aha! Perhaps this is related to the yellowing leaves that first drew your attention to your plant. Now that you think of it, when you have been watering your Monstera recently, the water seems to flow through the pot quickly. This may be due to the fact that the roots have grown so much that there are more of them in the pot than there is soil. Your Monstera’s leaves were yellowing starting from the bottom up because the soil was not retaining enough water to keep the plant watered for the full two weeks. This is one reason why feeling your soil can be more beneficial than watering on a schedule!
When plants are underwatered, they will often sacrifice their oldest leaves to focus on new growth. When chronically underwatered, their lowest leaves will start yellowing first, gradually moving up the plant. A word of caution: overwatering sometimes has the same symptoms as underwatering, which is why it is important to look at other parts of the plant like the roots before taking action and adding more water to the pot.
Step Two: Take Action
Your next step is to remove the plant from its pot and take a look at the roots. What color are the roots? Healthy roots will be yellowish-white in color. Are they firm or soft? It is normal for some roots to be on the softer side while others are plump and firm. As long as the majority of the roots are firm, they are likely healthy. If the majority of the roots are soft, this is an indication that they are rotting, possibly from being overwatered. Before placing in a new pot, you will want to trim away soft, hollow roots to prevent further damage if there are pathogens like bacteria or fungi present. Are there patches of overly wet or dry spots? Watering with only small amounts of water or allowing the roots to sit in water for too long can lead to inconsistent moisture, causing some parts of the root ball to rot while others are too dry.
Ideally, you can repot your houseplants in the spring or summer, giving the roots plenty of time to grow into their new soil before the growing season ends. You will want to choose a pot with adequate drainage that is only an inch or two larger than the pot it is currently in. Remember that all that excess soil around your plant’s roots will stay damp for longer because there are no roots in it yet to absorb that water. With a new pot comes a new care and watering routine.
While houseplants can often stay in the same pot for years at a time, there are certain factors that can impact how frequently a plant will need to be repotted. Fast growing plants will run out of room in their pots quicker than slow growers. Indications that your plant is ready for a new pot include roots growing out the top or bottom of the pot, increased watering needs, yellowing leaves, and stunted growth. Keep in mind that some plants, like cacti, succulents, ZZs, and Snake Plants, prefer smaller pots that allow their roots to dry out quickly and entirely before being watered again. These plants tend to be just fine if kept in the same pot for years at a time.
Pests and Disease
Being able to accurately identify and treat plant pests takes detailed observation, experience, and patience. It is good practice to quarantine any new plants you bring into your house, as pests can be present in grocery stores and garden centers alike. Accurately identifying plant pests is important so that you know how to appropriately treat them. Not all insecticides are created equal, and always follow the instructions indicated on the bottle to avoid damaging your plants!
Because diseases need to spread from one plant to the next, indoor plant diseases are less common than you might think. It is much more likely that environmental factors and improper care are leading to plant problems. If you have gone through the question-asking process and have ruled out every single environmental- or care-related issue, you can then look towards plant diseases as the possible cause for plant stress.
Step Three: Adjust
When you have identified and treated any plant problems, it is an opportunity to reflect on your care practices. If one plant has been improperly watered for a while, you may want to take a look at the other plants in your life. If you are a chronic overwaterer, uproot some of your more water-sensitive plants and check their roots for watering damage. If one plant is pot-bound and you have moved it to a larger pot, maybe another plant can be placed into the pot you've just freed up (as long as you wash it first!). One of the beautiful joys of being a plant parent is that, like our plants, we are constantly growing. Even those with the most plant knowledge make mistakes - and we learn from them! In fact, some of us spend so much time around plants at our jobs that those at home can be quite neglected! It is all a process, and the Wild Interiors Plant Care Team is here to support you as needed.
Do you have any plant care related questions or need a plant problem diagnosed? Feel free to reach out to us on Facebook and Instagram - and be prepared to answer a few questions!