Tony O’Neill, gardener and author of the popular “Composting Masterclass” and “Your First Vegetable Garden,” combines lifelong passion and expert knowledge to simplify the art of gardening. His mission? Helping you cultivate a thriving garden.
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Peace lilies (Spathiphyllum species) are attractive indoor foliage plants that produce showy white arum-like spathes. They aren’t true lilies but aroid (members of the Araceae family).
The peace lily is a low-maintenance plant that blooms unusually in medium light and has lovely glossy green foliage. According to the NASA Clean Air Study, spathiphyllum purifies indoor air of some environmental pollutants, including formaldehyde and benzene.
Peace Lilly Natural Habitat
Peace lilies are tropical evergreen plants that grow on the forest floor and enjoy dappled light and consistent moisture. They originate from Mexico, Tropical America, Malesia, and the Western Pacific.
Success in growing any plant indoors largely depends on our ability to replicate its natural habitat. I stress the plant’s lineage and origin for this reason. Knowing where it came from and its natural habitat, we can more easily create a space that will allow our plant to feel at home.
The essential elements that ensure sustainable life for every indoor plant are:
- Soil characteristics – water management, aeration, consistency, constitution, pH, and nutritional content.
- Water needs – availability, need for dry periods, and quantity.
- Preferred light levels.
- Preferred temperatures.
- Preferred humidity levels.
- Nutritional needs – macronutrients and micronutrients – in total, 17 essential nutrients.
- Propagation means – sexual (pollination means) and asexual propagation.
- Potting and repotting requirements.
- Managing blooms.
- Potential diseases.
- Potential pests.
These essential elements vary according to plant species and their evolutionary adaptation to the specific conditions of their natural habitat. While we can acclimatize plants through hardening off, we cannot change their biological requirements.
What The Peace Lily Needs to Thrive
| Soil: | Compost, coconut coir, pumice, and expanded shale. See details below. |
| Watering: | Keep soil moist, but do not overwater |
| Light: | Commercial cultivation is under a 50% shade cloth – 2.8 to 3.25 Ft.c (30 to 35 LUX) |
| Temperature: | Night: 54 to 68⁰ F (12 to 20⁰ C) Day: 68 to 85 ⁰F (20 to 30 ⁰C) |
| Humidity: | Generally above 60% |
| Propagation: | Propagation by stem cuttings at temperatures above 74⁰ F (23⁰ C) |
| Pruning: | Prune from the top down and remove the dead or discolored leaves regularly. The plant will survive aggressive pruning. |
| Fertilizer: | Use organic, slow-release fertilizer in early spring. |
| Repotting: | Re-pot, if necessary, in February or March. |
| Growth and Size: | While it can grow up to 6 ft tall, it more typically grows to 3 ft in an indoor setting |
| Pests: | The most common insect pests infesting in homes are mealybugs and scales. Occasionally spider mites. |
| Toxicity: | It can cause contact dermatitis. Contains calcium oxalate crystals – will cause |
Making Peace Lily Potting Soil
Essentially what you’re looking for in a healthy soil mix is a balance between retaining water while ensuring good drainage, providing adequate aeration (avoiding anaerobic conditions), maintaining the right pH, and ensuring the soil has sufficient cation exchange capacity (CEC).
If you’ve had the opportunity to read my Composting Masterclass book, you’d understand why I’m so passionate about using compost, even in potting soil. A good potting mix for your Peace Lily should include the following ingredients in the given proportions:
- One part compost
- Two parts coconut coir
- Half a part of the pumice (or perlite)
- Half a part expanded shale, or LECA (lightweight expanded clay aggregate)
Each of the above serves a specific purpose in emulating the Spathiphyllum‘snatural habitat.
Compost
Adding compost to potting soil has several benefits; an essential one is the soil’s increased ability to keep nutrients available for plant access. Cation exchange capacity (CEC) can be seen as magnetizing the soil to save water and some cation-charged nutrients in the ground. Soils with low CEC (like sand) cannot retain moisture and nutrients; they simply flow through the soil.
Coconut Coir
While sphagnum peat moss is often given as the default potting mix, I have found that coconut coir is a better option. One of the main reasons I prefer coconut coir is its ready inclination to accept watering.
Coconut coir has outstanding water retention and drainage abilities, with most forms of coir holding up to nine times their weight in water. This natural air-to-water ratio helps nourish plant root systems without oversaturating them or putting them at risk of root rot.
Pumice
Unlike perlite, pumice manages water well while boosting aeration.
Expanded Shale
Expanded shale, like pumice, does not break down like organic materials, so the soil stays aerated for years. It helps make potting soils airy, light, and water-retentive.
The Truth About Peace Lily Light Needs?
While it’s true that most aroids need plenty of dappled light, especially to maintain variegation, this is not true for the Peace Lily. Firstly, the Spathiphyllum species does not variegate, and the plant is one of the few that flower in low light.
Peace Lily plants are classified as low-light plants, loosely described as a light level “bright enough to read a newspaper.” Most low-light plants are grown for their foliage, not flowers.
A north window or a shaded corner would be ideal locations for a low-light plant. These plants are “understory plants” in their natural habitats, which means they develop beneath the branches of bigger plants.
Foot-candle
A foot-candle is a unit of brightness or light intensity, and it is described as the amount of light that a surface of 1 square foot that is 1 foot from a light source received from a single candle.
Peace Lily Thrives in Low Light
Low light intensity plants typically need between 50 and 250 foot candles per square foot. A handful of the plants in this group can be kept alive with as few as ten-foot candles of artificial light.
Ten to fifteen watts of fluorescent light per square foot of growing space should be provided for low-light plants. Your Peace Lily needs a single fluorescent tube, such as a 2-foot 20-watt or 4-foot 40-watt tube.
Peace Lily Watering Needs
Overwatering is the main reason why potted plants die. When surrounded by water, roots can’t breathe – as crucial to roots as to humans.
The general rule is to only water when necessary. To decide when to water, one may utilize the following techniques:
- Touch-Test: The most accurate test for soil moisture is to feel how dry the potting soil feels. If the mixture is dry at your fingertip after inserting your finger up to the second digit, it needs water.
- Tap the Pot: When potting mix in a clay pot starts to dry up, it shrinks away from its sides. Use a stick or your knuckles to tap the pot’s side. Water is required if the sound is hollow; if the sound is dull, the soil is moist.
- Estimate weight: It’s easy to see a weight reduction as potting mixtures dry up.
- Assess soil color: As potting combinations dry, their color will shift from dark to lighter.
When watering is necessary, water deeply. Apply water until the bottom of the pot is completely submerged. This removes accumulated salts and ensures that most of the roots in the bottom two-thirds of the pot get enough water. Empty the tray, and don’t let the pot sit in the accumulated water.
Do Peace Lilieslike being misted?
My suggestion – give the misting thing a miss. It provides pathogens with transport and doesn’t improve humidity levels – unless it’s super-fine.
Instead, invest in a humidifier that effectively provides humidity to many plants at once.
Fertilizing Peace Lilies
Fertilize every other month at a quarter concentration, except during the winter when the plant is not actively growing and needs to hibernate. Select from one of the three below:
- Controlled release: These are synthetic fertilizers coated with materials to reduce their immediate solubility and availability to plants.
- Slow-release: Can be organic or synthetic. The release rate is a product of soil temperature, particle size, and the growing medium’s organic content and microbial life.
- Liquid fertilizer: This quickly replaces leached nutrients after extended rainfall. Best suited for established plants.
Using Epsom Salts
Epsom salt (magnesium sulfate) lowers the pH and provides magnesium and sulfur, two nutrients often deficient in alkaline soils. Benefits of magnesium for your Peace Lily include:
- Aids photosynthesis by helping your Spathiphyllum species create chlorophyll
- Promotes healthy cell division and protein formation
- Increases Peace Lily’s ability to access water
- Allows the Spathiphyllum to take in and use phosphorus
Magnesium has a poor cation exchange capacity (CEC), i.e., it binds poorly to soil particles. The only way your plant gets access is if it remains in situ near the roots.
Repotting Your Peace Lily
Only repot if you notice roots emerging from the pot’s drain holes.
You can turn the plant on its side and partially remove it from the pot to inspect the roots to determine if it is rootbound. It is time to repot if they are all coiled up tightly around the outside of the soil, which is a clear indicator of them being rootbound.
Maintaining Your Peace Lily
Older leaves will ultimately turn yellow and drop off naturally, leaving the majority of the leaves at the vine’s end. Selective pruning is advised to maintain vines at a manageable length and encourage new growth.
Plants can be pruned back to 2 inches from the soil line for a new start. Always leave a node near the cut for future growth, and you can use the pruned parts as cuttings for further propagation.
How to Propagate Peace Lily
Cuttings or air-layering are both simple methods for growing the Peace Lily. In 3–4 weeks, cuttings take root in water or vermiculite; in 1-2 weeks, buds will begin to grow under warm conditions. The best practice is to group many rooted cuttings into a single container.
Propagate Peace Lily in water
Find a section of your Peace Lily vine with a few leaves and a few nodes, then propagate it in water (where the leaves and roots grow out of the stem). Cut at a 45-degree angle, about a quarter-inch below a node, with a clean set of shears.
If you cut below a node, the node will be part of the cutting. Because that is where new roots will grow, it is crucial to add.
Place the cutting in a jar with room-temperature water, ensuring that at least one node—preferably more—is submerged. If there are any leaves below the surface, remove them gently because they have a propensity to decay.
Within the first week or two, you should notice little roots forming, but at least a few weeks before the roots are sufficiently long to allow you to pot the cutting. Give the roots room to grow to a few inches.
You can treat your cutting like a typical plant after you’ve placed it in potting soil and given it a good watering!
Propagate Peace Lily in Vermiculite
To propagate your Peace Lily in vermiculite (or perlite, or pumice), start with the same first step to cut.
Place the base of your cutting into a small container with moistened vermiculite. Make sure at least one node, more, if possible, is buried. Don’t bury any of the leaves – instead, remove them.
Keep the vermiculite moist (but not wet), allowing the roots to develop. Regularly misting the vermiculite keeps it sufficiently moist for root growth.
Before a new root system forms, at least a few weeks will pass. You may check this by giving the cutting a very light tug after about a month. If there is resistance, a root system has developed, and you can plant it (them) in a potting mix (see above)
Air-Layering Peace Lily
The phenomenon of air layering propagation frequently happens in nature. An example is when a low branch or stem reaches the ground and establishes roots.
The newly rooted stem receives identical genetic material directly, which can then be severed from the parent plant to begin a new plant.
Air layering is relatively easy to do. Coconut coir that has just been wet is wrapped around a damaged stem. Peel the bark off a section of a branch in the middle, then wrap moss over the wound and fasten it with floral ties or plant twine. To keep the moisture in, cover everything with plastic wrap.
Roots will emerge in about three weeks, after which you can cut below the rooted section for Peace Lily plant duplication. I think that’s so clever.
Peace Lily Challenges
Spathiphyllum species generally have few pest problems but are occasionally affected by some insects or diseases. Root rots, with symptoms of brown or nonexistent roots, are commonly promoted by overwatering.
Blackening of the leaf margins or tips can be caused by overwatering, inadequate watering, or excess fertilizer (because of the buildup of salts in the soil). The discoloration of the soil is often accompanied by leaves becoming yellow.
The most common insect pests infesting Spathiphyllum species in homes are mealybugs and scales. Mealybugs appear as white, cottony masses, frequently in the leaf axils, on the lower surfaces of leaves, and even on the roots.
Scales look like bark-colored bumps on the stems and leaves and are sometimes difficult to distinguish from the plant material on which they feed. These pests may produce copious amounts of honeydew (many, but not all, do), so the leaves and nearby surfaces may be sticky and sooty mold may develop.
Infested plants become stunted, and with severe infestations, plant parts begin to die. Pesticides may be used to control these insects, but often it is better to discard the plant and start over with clean plants or cuttings.
Spider mites occasionally infest Spathiphyllum species but can easily be controlled with a thorough cleaning and frequent applications of insecticidal soap.
Low light can result in loss of variegation. Low temperatures or abrupt changes from very high to moderate temperatures can cause scattered brown patches, usually located in the center of the leaf, especially if plants are succulent and thriving.
Is Peace Lily toxic?
All aroids, including Peace Lily, Philodendron, and Monstera, are toxic to people and pets as they contain calcium oxalate crystals. These toxins can cause swelling, inflammation, and pain in contact with the skin or oral cavities. Keep your Philodendron away from cats, dogs, and small children who may accidentally ingest it.
Frequently Asked Questions
In Closing
The Peace Lily is a true gem in the houseplant collection, with its beautiful spathe flowers making it stand out. You’re in for a fantastic treat if you’re prepared for a wide range of growth and coloring. If you look after your Peace Lily, it will continue to produce beautiful leaves and flowers for many years.
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