When diagnosing indoor plant problems don't start with leaf symptoms. Yellow and other discolored leaves are generic symptoms with many possible causes. You can go online and find a match, but the chances are high that you will get a misdiagnosis.
If your plant is languishing and getting more discolored leaves than you think it should and you don't know why, then follow the steps below. They are guidelines listed in order of probability. Start at the top and work your way down the list. Don't move down the list until you have ruled out all the ones above it.
First: Check the pot size. Have you recently moved your plant into a larger pot or added new soil? If so, this is the most likely cause of your plant's problems. Unnecessary repotting and over potting are the most common cause of plant problems, yet the most overlooked.
Second: Consider the available light. Every plant has a range of acceptable light intensity. If the available light is outside that range (either too little or too much), then your plant will gradually decline. Fertilizer, humidity and changing the watering frequency will not correct light deficiencies. You must match your plants with their light requirements.
Third: If the pot size is OK and the light intensity is acceptable, then improper watering is the next most likely cause of plant problems. Most potted plants do best when the top inch or two of soil is allowed to dry before watering thoroughly. However, some plants (succulents) must dry out more than that between waterings others while (peace lilies, ferns) must be watered as soon as the surface of the soil feels dry.
Fourth: If leaf tips and edges are discolored, evaluate your water quality and fertilizing routine. Excess mineral salts cause leaf tip damage. These excess mineral salts come from using hard local tap water for your plants and from using too much fertilizer. The solution is to use distilled or filtered water and to stop fertilizing.
Fifth: Examine your plant for signs of insect pests. Spider mites appear as dust-like particles on the undersides of leaves and make tiny webs. Mealybugs appear as tiny specks of white, cotton-like material where leaf stems join trunks or branches. Scale insects look like small raised freckles along leaf stems and on leaf surfaces. They also leave a trail of sticky "honeydew" under the infested plant. Fungus gnats show up as tiny flying gnats. Aphids are oval, slightly raised bumps on tender newly emerged growth. Whiteflies are aptly named and swarm about when a plant is disturbed. Make a habit of checking your plants regularly (at least monthly) for early signs of plant pests. They are much easier to eradicate when you treat them before they infest the entire plant.
Sixth: Check the pH of your soil. Soil that is too acid (below 6.0 pH) or too alkaline (above 6.8 pH) prevents soil nutrients from being absorbed by plant roots.
Seventh: Consider temperature extremes. Most houseplants are from tropical regions where temperatures are in the 55 to 90-degree F. range. Temperatures outside this range can cause damage to plant leaves and stems and to plant roots if the exposure is for an extended period of time.
Next to last: Very dry air can be a problem for a very limited number of exotic houseplants. Contrary to popular belief, most houseplants can do just fine in low humidity, as long as the soil is watered properly. Plant symptoms are often attributed to but are rarely the result of low humidity. Misting helps keep plants clean, but does not effectively raise humidity levels. If you have a humidity-sensitive plant such as some ferns, some Orchids, and terrarium plants, then increase the humidity by using a humidifier or a pebble tray.
Last: Nutrient deficiencies are often assumed to be the cause of plant ailments and fertilizer is assumed to be the cure. Nutrient deficiencies are, in fact, the least common cause of all plant problems. Indoor plants use very little nutrients and they cannot be force-fed. Most potting soils have several years' worth of nutrients. If your plant has been in the same pot and soil for several years or more and is growing well, then it may benefit from dilute fertilizer. Ailing plants are poor candidates for increased nutrient supply.
Cosmetics for plants is not something you hear much about, but it can make a huge difference in how plants look. We all know how good grooming and cosmetics can greatly enhance the appearance of people, but we often fail to make that connection to our plants.
What does that mean? Cosmetic plant work includes, trimming and removing dead and discolored leaves; pruning back overgrown and leggy stems; repositioning or straightening main stems and trunks; rotating plants to prevent uneven growth; removing unnecessary and unsightly stakes, string and other support devices; dusting and/or shining leaves; and keeping pots and potting soil looking neat and clean.
On many occasions, I have been called upon to rejuvenate plants with the owners expecting repotting and fertilizer. However, after about 10 or 15 minutes of cosmetic work, the plant owner has been surprised at how much better that plant looks as a result of some cosmetic work.
Because PRUNING is the most neglected of all plant care tasks, that is often the single most important cosmetic technique. Older plants that have never been pruned are often tall, leggy and leaning. Sometimes they are held in place by various artificial devices such as stakes, broom handles, string, wire, and colorful ribbons. All of these help support the plant but also make it look unsightly. The simpler and more elegant solution is pruning back overgrown stems. Pruning will eliminate the leaning and allow for the removal of the support devices.
Some LEANING STEMS don't need pruning or propping; they simply need to be repositioned in their pots. In some instances that means pushing the leaning stem to a vertical position and tamping the soil around its base to hold it in place. In other cases, the main stem or trunk resists this so that repositioning the entire rootball is necessary. This, too, is quite simple. Just pull the entire rootball up a few inches from the pot, then tilt the rootball slightly so that the main stem is vertical and push the rootball back into the pot. The surface of the soil will now be at a slight angle and that can be remedied by adding a small amount of potting mix to the surface to level it out.
ROTATE your plants in place regularly so they grow evenly. Most plants tend to grow toward the window or other light source. Over time they will lean precariously or become lopsided.
The most obvious and easiest cosmetic technique that most folks do already is the removal of dead and DISCOLORED LEAVES. This can be done with your fingers or with sharp scissors. Discolored leaves never regain their color so remove them as soon as they discolor.
BROWN LEAF TIPS can be trimmed off with scissors. When trimming a single leaf, make the cuts so that the original contour of the leaf is maintained. A blunt cut may be easier, but it will be obvious what you have done. Trim leaf tips and edges as you would fingernails and no one will be the wiser!
Heavy DUST can block out sunlight for the leaves. Light dust is unsightly. In either case, the plant's appearance will improve if you remove dust accumulation as soon as it is noticeable. A feather duster, Swiffer, sponge or damp cloth are effective dust removers. Some plants may have a white film residue of insecticide or fertilizer applied in the nursery. You may need a little dish soap or vinegar to remove this residue. Finally, there are leaf shine products available to give a nice shine to hard-leafed plants. Some folks like shiny leaves while others prefer the more natural look. If you want to use LEAF SHINE, try to avoid those that leave the leaf surface oily as that will then attract dust. Try some mineral oil diluted with lots of water. Never use vegetable oils, milk or animal fats as these food substances may attract pests.
Finally, remove all dead plant tissue from the soil surface. Outside, this leaf debris may break down and provide compost, but that does not happen with your indoor plants, so discard it so it doesn't attract pests. You can spread a light TOP DRESSING over the soil surface if you prefer. Spanish moss is light and airy and easy to pull apart and spread over the surface without interfering with air penetrating into the root zone. It also maintains its natural silvery gray color. Green moss locks great initially, but soon turns brown and has to be replaced regularly. Stones and pebbles can be used, but they make it harder to use your finger to determine soil moisture. Never use fine-grained sand or pebbles as they prevent the soil from drying out properly. Bark chips are sometimes used, but they will gradually decay over time and may become a source for fungus gnats. There are commercial products such as ground cork and coir that can also be used.
Finally, CLEAN POTS can greatly enhance the overall appearance of your plants. Terracotta pots often develop white crusts on their outside rims and sides. These are mineral deposits that have leached out of the soil and through the porous terra cotta. These deposits are harmless but unsightly. A solution of vinegar and water and a little elbow grease will remove these deposits. Plastic and metal pots can be cleaned up with soap and water or any household cleaner. Just be sure not to get these solutions in the soil itself. If your plant is potted in an unattractive plastic pot, you can cover it up by placing it inside of a more attractive planter of your choice. Spread some Spanish moss over the surface to disguise the hidden pot inside. The French call this CACHEPOT or hidden pot.
It can be said that cosmetics is the art of deception. But if it enhances the appearance of your plants and makes them more pleasurable to see, then, by all means, go ahead and practice these cosmetic techniques. You may be surprised to see how much better and healthier your plants can look without doing anything else!
I care for hundreds of plants in the homes and offices of other people - environments over which I have little control. Consequently, I am often challenged to keep plants alive and healthy where the conventional plant care wisdom simply does not apply or can not be used.
For example, most homes and offices have very low humidity here during NYC winters. Installing humidifiers and pebble trays are not options. As it turns out, if I compensate for the low humidity by increasing the soil moisture, the so-called high humidity plants seem to do quite well in low humidity.
Likewise, repotting plants in other people's spaces is difficult if not impossible. It is messy, time-consuming and expensive. (I charge for my professional services based on time spent.) That means I look for other solutions to plant problems that others might solve by repotting. Surprisingly often, plants seem to do quite well when left in their pots even though they are quite potbound. Crowded roots may deter growth a bit, but it does not seem to have an adverse effect on a plant's health. In some instances where a plant will not last a full week between my weekly service visits, I may install a sub-irrigation system or just leave the plant sitting in a couple of days worth of water, something that is ordinarily a no-no!
Replacing soil is another problem in other people's homes and offices, so I rarely do it. I care for plants that have been in the same pot and soil for over 25 years and they are doing just fine. So, maybe that conventional wisdom about repotting or replacing soil periodically is not so essential after all.
Available light in homes and offices is often challenging. I cannot relocate a plant in someone's home just to improve its light. That means I have to be able to properly assess the light and make recommendations for specific low light plants. I have learned from experience what plant species will manage to survive in the very low light. Along with that, I have learned that the usual watering regimen is not appropriate because plants in very low light use very little water or nutrients and also grow very slowly.
Treating plant pests in the spaces of other people is another challenge. Personally, I don't like using chemical pesticides and I would never use them in someone else's space. So I have been forced to rely on safe products that are also effective. Those include dish soap, alcohol and water. More importantly, I know how to spot pest infestations very early so that spot treatment is often all that is necessary. I also understand that plants that are under stress due to improper light or water are more prone to pest infestations. As I have improved my own skills in assessing light and understanding watering, I have discovered that I have far fewer plant pest issues that I did before.
I am often called upon to repot a plant that looks too big and/or is leaning. When I see the plant, all I may need to do is physically reposition the plant in its pot and then prune back the overgrown branches that have created an unwieldy appearance. Many times a little pruning, a little dusting and the removal of some discolored leaves improves a plant's appearance so much that the client is thrilled and amazed that major replanting wasn't necessary, as they had assumed.
There are many other examples, but my profession dictates that I seek the simplest, neatest and cleanest solutions to various plant problems. That means I have to discard the conventional methods of plant care and find creative, less intrusive ways to treat plants. Not all my experiments with simplicity have succeeded, but most have and that has opened my eyes to the way most people go about caring for their plants and how those ways could easily be improved.
My book, "Don't Repot That Plant and Other Indoor Plant Care Mistakes," is a result of my many years of experimentation with the most effective plant care techniques in the less than ideal home and office environments in which most of us live and work.
For folks who are new to indoor plant care, getting a plant to grow bigger and faster is understandably the most tangible measure of success. However, at a certain point having a very large plant may not be the best outcome. Moving a large plant into ever larger pots is also not always practical. Large plants can take up too much indoor space or may start hitting the ceiling or may lead to complaints from others who have to share the same space. If that happens to you, then it is probably time to understand how to prune.
Not all plants are pruned in the same way. However, most plants that tend to get very large can be pruned back fairly simply. Pruning will not affect the health of your plant, but it will affect its appearance - much like getting a haircut. You get to decide just how big and what shape that plant will take and you prune accordingly. In general, any stem can be cut back to any height that you prefer. The pruned stem will not die but will produce new foliage on that stem starting just below where you make the pruning cut. Use a sharp knife or pruners and make a clean cut at any angle. It is that easy!
Keeping a plant at an appropriate size and shape for its space is an individual choice and one that raises your level of plant care expertise.
On a personal note, I am often called upon to repot a plant that has grown too large. Instead, I simply prune the overgrown plant and the owner is amazed at how much better it looks. Besides, pruning is much easier and less risky than repotting! Give it a try.
A leggy plant is one that has long lower stems that are mostly bare, but have healthy growth and foliage only at their tops. This happens with may plants as they get older. It does not mean they are unhealthy, need fertilizer or a bigger pot.
We all know that plants require light to survive. Indoor plants often get less than the ideal amount of light required for vigorous growth. Any plant can support only a finite number of leaves The more light a plant receives, the more leaves it can support. In reduced light, a plant may max out and no longer be able to support more leaves. But it doesn't stop growing. Rather, it continues to put out new foliage at the growing tips while shedding older leaves on the lower parts of the stems. Hence, you end up with tall, bare stems with all the growth at the top ends of those stems.
There is another reason a plant may lose lower stem leaves. Under watering will often cause lower leaves to die prematurely. If you have been watering a plant properly and it still gets leggy, it is most likely because it is getting less than optimum light. You then have two choices; one is to move it to a sunnier location; the other is to prune back the leggy stems.
For a leggy plant, any stem can be pruned back to almost any height. New foliage will then emerge on that stem just below the pruning cut and grow upward from there. Pruning is usually the only way to eliminate long, bare stems and to get your plant back to being shorter, but fuller and more compact.