What Your Peace Lily Needs in October – 5 Quick Checks to Keep It Lush and Encourage More Blooms

A peace lily parked in the same corner it occupied all summer is probably getting less light than it did in August. October is the month to adjust for that, along with a few other small things.

Houseplant trouble in winter often gets blamed on the furnace. But in October, the bigger culprit is usually the light. Days are shorter now, and the sun sits lower, so a corner that seemed plenty bright in July can dim without anyone noticing. Growth slows down, and the potting mix stays wet longer after each watering.

Good peace lily care this month is mostly about adjusting where the plant sits, plus a bit of cleanup below the soil line. September was all about easing off the water and giving the last feeding of the year. October picks up from there. The jobs are small, and one of them is really just paying attention. You can do them in any order – though flushing the pot is better done earlier in the month.

1. Move It Closer to the Light

Peace lilies (Spathiphyllum spp.) are often chosen for their ability to tolerate low light, and that part of their reputation holds up fine. But low light is something they survive – it is not a desirable growing situation. A plant kept too dark over winter tends to put out smaller leaves on long, floppy stems. An east-facing window that worked all summer might need trading for a south-facing one now.

Scorch is much less of a risk under October sun than in midsummer. Even so, 3 feet (1 m) back from a bright south-facing window is the safer spot. Turn the pot a quarter every week or two. Otherwise, it leans.

A peace lily without flowers this month isn't a problem, either. Most tend to bloom sometime between winter and late summer.

2. Keep the Leaves off Cold Glass

Black leaf tips after a cold snap? That's often a chilling injury, not a disease. It usually starts at the tips and edges of older leaves and creeps inward from there. Growth can slow at 50°F (10°C) or below, before anything shows at all. A leaf pressed to a windowpane on a 40°F (4°C) night could get much colder than the room.

Pull the pot a few inches back from the glass and keep it away from exterior doors that let in a blast every time someone walks through. Heating vents are no better. I like to check the temperature of my windowsills using the TempPro TP50 digital thermometer, available on Amazon. It records highs and lows, so if you place it next to the pot for a night, it will show just how cold that windowsill gets.

3. Flush the Pot, Then Put the Fertilizer Away

That crusty white ring on the soil, or along the pot rim, is usually mineral salt. Fertilizer leaves it behind. Hard tap water does too, once the moisture evaporates. Peace lilies aren't salt-tolerant, so brown, crispy leaf tips are often the first sign of buildup.

Scrape off the crust first, taking no more than about ¼ inch (6 mm) of potting mix with it. Then set the pot in a sink or tub and pour water through slowly until roughly twice the pot's volume has drained out the bottom. For a 6-inch (15 cm) pot, that's about 10 cups (2.4L).

Flush your peace lily pot early in the fall – or at least before the heat comes on for good – so the mix has time to dry. After that, don't feed again until new growth shows up in spring. Water only when the potting mix feels dry.

If you're not sure when to water peace lilies or plants in general, then I recommend getting a moisture meter like the Yamron 4-in-1 Soil Moisture Meter from Amazon, which also checks temperature, light levels, and soil pH.

4. Keep an Eye Out for Fungus Gnats

Tiny dark flies drifting up off the pot are most likely fungus gnats (Bradysia spp.), not fruit flies. Adults are mostly a nuisance. Their larvae live in the top inch or two (2.5–5 cm) of damp potting mix and feed on organic matter, sometimes on fine roots as well. Cooler rooms keep the mix wetter for longer. Gnats like that.

A dry top inch (2.5cm) between waterings goes a long way toward breaking the cycle. Pick up a pack of Expert Gardener Plant Insect Sticky Traps from Walmart, and tuck one in at the edge of every plant pot. This helps control them and gives a rough count of the adults.

Drier soil and bottom watering are the best long-term cure for fungus gnats. You can use any plastic tray, but I like this Ebristar bottom watering tray from Amazon as you can adjust the height easily.

To check for fungus gnat larvae, a little trick is to press a ¼-inch (6 mm) slice of raw potato into the potting mix and look underneath after a day or two.

5. Add a Grow Light for Darker Rooms

Not every home has a south-facing window to spare. Supplemental light can make up the difference, and foliage plants often do well with 12 to 16 hours of light a day through the darker months. It's pretty easy to set up these days.

A grow light, like this Sansi pot-clip LED grow light on Amazon, clips onto the rim and has a timer that shuts it off after 12 hours. Start it a little farther from the leaves than seems necessary. If new growth stays small after a few weeks, ease it closer. Pale, washed-out leaves usually mean it's gone too far the other way.

October Peace Lily Esssentials

By November, a peace lily set up this way mostly just needs a glance now and then. The next real push tends to come in late winter – fresh leaves first, and with some luck, a white spathe or two not long after.