I took a bit of a break from blogging during the colder months, but I'm so ready for spring, and my blog is also ready to grow, too!
I was invited to speak to 2 garden clubs in the next month about the topic of Houseplants!
The general consensus is that people kill them and don't know why, so in this post I'll be addressing the following topics in regard to houseplants.
- General care, including:
- Lighting, water, fertilizer, soil, containers/drainage
- Common mistakes
- Common pests/diseases
- Plants to improve indoor air quality
- Easiest low-maintenance house plants
- Plants beginners should stay away from
There are specialty fertilizers available for some plants, like orchids and African violets, but in most cases those are not necessary. For most houseplants, an organic, all-purpose fertilizer with a balance of N-P-K (nitrogen, phosphate, potassium) is going to work fine.
I prefer organic liquid formulas -- I LOVED Ladybug brand products, produced here in central Texas, but unfortunately, these products are no longer produced, so I've been bouncing between products in order to find a new favorite. I'm currently testing out organic formulas from Agrothrive, Espoma, Medina, and Dr. Earth. If you are sensitive to smells, stay away from fish emulsion or liquid seaweed in the ingredients, or simply use them outside and allow your plants to dry before returning them to the indoors.
Organic fertilizers won't contain things like synthetic urea, which can "off-gas" into ammonia, an indoor air pollutant -- more on that later! They'll also help you avoid the salt accumulation that can happen with repeated use of fertilizers like that popular blue powdered synthetic fertilizer, which is detrimental to important soil microbes, and eventually can be damaging to your plant.
WaterMy general rule of thumb is simple. Let the soil dry out between waterings. How dry is where things can get confusing. Some plants, like Sansevieria (a.k.a. Snake Plant or Mother-in-law's Tongue) thrive when the soil is almost crispy before the next watering. Other plants, like Spathiphyllum (a.k.a. Peace Lily) prefer to dry out only slightly. Knowing how much to water your houseplants will come with experience, but some plants are more forgiving than others, so stick with those easy plants until you get the hang of it. (I've made you a list toward the end of the blog!) Overwatering kills more houseplants than underwatering. If you're unsure if it's time to water, it's safer to wait another day, rather than to cause the plant's soil to stay wet for too long. When there is too much water in the soil, there usually isn't enough oxygen around the roots, and that is where your problems start. When the soil is too wet, the roots begin to rot, and that can further add to the confusion because a plant with rotten roots often looks exactly like a thirsty plant. When the roots are damaged (rotten), they can't deliver water to the plant, therefore, it wilts, just like a plant without water. Rainwater is always better than tap water, if that's an option for you. And of course, remember to water the soil, not the leaves.
Poor drainage contributes to root rot, so it's important to choose a container with drainage holes. Use a saucer beneath the container to manage any water/soil that leaks from the drainage holes.
If your favorite container doesn't have a drainage hole, and drilling a hole isn't an option, you can opt for the pot-in-pot method.
Keep your plant in a container with drainage holes, and set it inside the pot that does not have drainage holes. The outer pot will act as the saucer.
|New Earth Top Shelf Potting Soil
*Steps up onto soapbox.*
Potting soil is a pet-peeve of mine. I cringe when I see someone purchase a beautiful plant and then reach for a $2 bag of potting soil (or even worse, a $1 bag of topsoil -- double cringe!).
Most people don't understand the difference, and I feel like it's my responsibility as the professional to educate people about this.
Have you ever heard the saying "you get what you pay for"? This seems to be especially true for soil.
A good quality potting soil will be made with a variety of ingredients, like peat moss, perlite, compost, bark,, etc., and when the bag of soil is dry it shouldn't weigh 40 lbs.
(If it's sold by weight, that's your first clue to avoid it!) My current favorite potting soil is New Earth's Organic Top Shelf Potting Soil. I usually buy mine at H-E-B, and I use it for all my indoor and outdoor potted plants.
(New Earth also makes some great products for the garden.
I also love that New Earth's Potting Soil comes enriched with Medina's Growing Green Fertilizer, another Texas product, and it's a great value at around $5 per bag.
- Don't overwater. Most houseplant deaths are water related.
- Don't leave plants in their original nursery container. They're almost always "root bound" and ready for a larger container.
- Don't forget to fertilize. Fertilize every 1-3 months, depending on the formulation. If you're using organics (and I hope you are!) usually that's once a month for liquid. Check the packaging if you aren't sure.
- Don't panic. Remember, when you bring a new plant home it's going to experience many changes -- temperature, light, soil, water, humidity, and damage to the roots (when you repot them), so it's understandable that a plant might shed a few leaves. Don't panic and make matters worse by relocating the plant every time it drops a leaf. Following the tips on lighting, watering, fertilizer, etc. will help you avoid most major problems.
Common pests and diseases
Disease and pest problems on houseplants, while not rare, are less common than they are for outdoor plants, and when they appear they are usually a symptom of a larger problem (water stress, root bound, etc.)
- Spider mites. These tiny critters suck the life juice from leaves, leaving them looking faded and decorated with fine strands of spider webbing. If you aren't sure if your plant has spider mites, tap the leaves onto a white piece of paper and then check it for tiny, moving dots (usually red). These seem to be more common on thirsty plants, especially if you frequently wait for the plant to wilt before watering it.
- Aphids. You'll usually see the bugs on leaves and stems. Their biggest giveaway is a sticky, shiny residue left on leaves.
- Gnats. Most common in soggy plants. Cut back on the watering and they'll often go away. You can also spray the soil with insecticidal soap to speed up the process.
- Scale insects. Usually hard, not moving, waxy bumps on plant stems (sometimes leaves, too). They pop off easily with a fingernail, or you can squish them or kill them with rubbing alcohol on a cotton swab.
- Fungus - More common in humid conditions, but generally less common in the home than bugs. Usually manifests as a white, black, or rusty powder on leaves, or as leaf spots.
Evaluate the plant for underlying problems that could be contributing to disease or pest issues. Does the plant need water more frequently? Are the roots running out of space? Is it sitting in soggy soil? Correct the issues instead of only treating the symptoms. When you do treat pests/diseases, choose the least toxic solution. For pests, sometimes more than 1 treatment is necessary, since the pest's eggs may hatch after the treatment. This doesn't mean the treatment didn't work.
- Insecticidal soap. This is my first choice for pests, because it is a low-toxicity product, but it still does a great job.
- Neem oil. This is my first choice for scale insects. If you have been unsuccessful in treating for other pests several times with insecticidal soap, try neem oil. Warning: Oils get hot when exposed to sunlight (think of people tanning on the beach with coconut oil), so don't use this on plants that are exposed to direct sunlight when temperatures are 90 degrees or higher.
Neem oil also works well as a fungicide.
- Pyrethrins. This is made from Chrysanthemums, but don't let that fool you. It's quite harmful to beneficial insects, like bees and ladybugs, so only use this as a last resort.
Plants to improve indoor air quality
In 1989 NASA tested common houseplants for their ability to remove common indoor air pollutants, like trichloroethylene, benzene, and formaldehyde. Wait, are these things actually in my home? Yes, they're there with other yucky chemicals, like xylene and ammonia, and they come from very common things like attic insulation, carpet adhesive, paint, wood varnish, paper products, foam in mattresses and furniture, laminate floors, cleaners, printing ink, leather....and fertilizers*. Ok, back to our topic! Indoor air pollution is a problem, especially because newer, energy efficient buildings are tightly sealed, therefore, the air pollutants are trapped inside with nowhere to go, resulting in indoor air quality that is often worse than outdoor air quality.
Major takeaways from the NASA study
- All the plants tested removed some air pollutants
- Some plants remove some chemicals better than others
- There is some link between the removal of toxins and the microbes in the soil* (Fun fact: Did you know soil microbes can adapt to use these air pollutants as food?!)
Top 10 houseplants for beginners
- ZZ plant
- Snake plant/mother-in-law's tongue - available in many colors
- Pothos ivy
- Spider/airplane plant
- Pilea peperomiodes
- Monstera deliciosa
ZZ plant from Wikipedia Snake plant via proflowers.com
|Pothos ivy from Wikipedia
|Spider plant from Wikipedia
|Split-leaf philodendron from Lowe's
15 houseplants for newbies to stay away from
- Ficus (F. benjamina, F. lyrata, etc.) - They tend to shed and it's difficult for less experienced plant lovers to decipher normal shedding from problem shedding.
- Orchids - Too many variables with potting medium, container type, species, etc.
- Palms - Not forgiving of over watering. Bugs.
- Ferns - Not forgiving and some are messy.
- African violets - Finicky about watering. Rot easily.
- Peace lily (Spathiphyllum)- Once they wilt, they look ugly forever.
- Cacti/succulents - Super easy outdoors, but they tend to stay too wet for too long indoors. This includes string of pearls, string of dolphins, string of hearts, or outdoor succulents.
- Begonias - Watering issues, rots easily.
- English ivy (Hedera) - Spider mites, root rot, easy to overwater.
- Crotons - Spider mites common and hard to see, watering issues, root rot.
- Nerve plant (Fittonia) - Watering issues, root rot.
- Polka dot plant (Hypoestes) - Watering issues, root rot.
- Creeping fig ivy (Ficus) - If it dries out once, the whole plant goes crispy.
- Flamingo flower (Anthurium) - Unpopular opinion, but they're picky about soil moisture and drainage.
- Air plants - Don't get me started. :)
Bonus: Mixed planters/dish gardens - Too hard to keep all plants happy together.