How to Bring Houseplants Indoors for Winter: The Complete Step-by-Step Guide
So every summer my houseplants live outside on the deck and honestly they look amazing out there. Way better than they ever look inside. More light, fresh air, rain, all that stuff plants love.
But then September comes and I gotta start thinking about bringing them back in before it gets too cold. And this is where things can go really wrong if you don’t know what you’re doing.
I definitely didn’t know what I was doing the first few years. One year I literally waited until the night before a frost and just hauled everything inside in a panic. The results were… not great. My fiddle leaf fig dropped like half its leaves. I brought spider mites into the house that spread everywhere. Some plants just never really recovered that winter.
So after screwing it up enough times, I figured out what actually matters. And I also started reading actual research on this stuff because some of the advice online is questionable at best.
Here’s what I do now that keeps my plants from looking sad and dropping all their leaves.
1. Start Way Earlier Than You Think You Need To
Biggest mistake I made for years – waiting until frost was in the forecast. When you’re scrambling to bring everything in the night before a freeze, you’ve already waited too long.
I start the whole process in early September now. Soon as nights are consistently hitting 50°F or below, that’s my cue to get moving. And I mean start the process, not finish it. This takes time.
There’s actually research showing plants need like 47 days to fully adapt their photosynthesis between really different light levels.[1] Which explains so much about why they freak out when you just suddenly move them.
What happens is outdoors your plant grows these “sun leaves” that are built for bright light. When you move that plant straight into your house with way less light, those leaves literally can’t photosynthesize right anymore. So the plant drops them because they’re useless in low light.[1] It’s not being dramatic, it’s just basic plant biology.
Different Plants Have Different Limits Though
The “bring plants in before frost” advice is way too vague because different species have totally different temperature tolerance.
Tropical plants should come inside when nights hit 45°F – way before actual frost.[2] But even that’s not specific enough. My fiddle leaf fig starts looking pathetic below 55°F so I bring it in first. My pothos doesn’t care until temps get into the 40s. And my Meyer lemon tree can handle brief dips to 35°F.[3]
So you gotta know your actual plants.
Timing also depends where you live. I’m in the Northeast so mid-September is when I start this whole thing. If you’re further south you can wait longer. General rule I follow is start the transition process 2-3 weeks before your area’s typical first frost date.[4] Not the night before.
2. Do the Gradual Acclimation Thing (Even Though It Feels Like Overkill)
I used to completely skip this step. Just bring plants straight inside, stick them by a window, done. Then wonder why they looked terrible.
The right way involves gradually transitioning them which honestly seems excessive until you see how much better it works.
First week – move plants from wherever they are outside to a shady spot. I use the covered part of my deck. They’re still outside but getting way less light. This starts them making shade-adapted leaves.
Second week – keep them in shade but start bringing them inside for increasing amounts of time each day. Two hours the first day, four hours the next, then eight, then overnight. By end of week they’re mostly inside.
One horticulturist from University of Illinois pointed out that indoor light is SO much lower than outside, even compared to shaded outdoor areas.[5] Like dramatically lower. Which is why even with gradual transition you still need your brightest windows.
I learned this trick of putting plants right outside the window where they’ll eventually live indoors. Makes the light more similar even though one’s outside and one’s inside.[6]
Some leaf drop will happen no matter what. Especially ficus species – they’re just sensitive. My fiddle leaf fig drops leaves if I move it two feet to the left. Don’t freak out about some leaf loss, just keep care consistent.[7]
3. Check Every Single Plant for Bugs (And I Mean Really Check)
This is where I get kinda obsessive but whatever, it’s worth it. Plants outside all summer definitely picked up pests. If you bring those inside you’ll be fighting bugs all winter.
I check plants every day for 1-2 weeks before they come in for good. Not just looking at them – actually inspecting.[8]
What I do:
- Use my phone magnifier to look at undersides of every leaf (where aphids, spider mites, whiteflies hide)
- Check where leaves meet stems (mealybugs love these spots)
- Look at all the stems for scale (little brown bumpy things)
- Check the soil surface
There’s this shake test that works great – hold white paper under the plant and tap leaves hard. Tiny moving dots mean spider mites. Thin shapes mean thrips. You won’t see these otherwise.[9]
Most people forget to check roots but you should. Pull the plant out and look at the root ball. Sometimes pillbugs or root aphids are hiding down there.[10]
For fungus gnats I do the potato test. Stick slices of raw potato in the soil, check after like 4-8 hours. If there’s tiny white worms with black heads, you got fungus gnat larvae.[11]
4. Actually Treat the Pests (Don’t Just Hope They Go Away)
If you find bugs, deal with them before bringing plants inside. I made the mistake once of bringing in a plant with spider mites thinking “it’s not that bad” and they spread to half my collection. Never again.
Penn State Extension recommends systemic insecticide granules applied 1-2 weeks before plants come in.[12] I use imidacloprid – about 2.5 tablespoons per gallon pot, work it into top inch of soil, water it in. Lasts 2-3 months.
For organic stuff the water submersion method works good. Cover soil with plastic so it doesn’t float, then dunk the whole plant in a bucket of water with dish soap for 15-20 minutes. Drowns and suffocates pests.[13]
What I use from least to most aggressive:
- Blast with hose for soft bugs like aphids
- Insecticidal soap (but has to hit bugs directly, no residual)
- Neem oil mixed with water (tablespoon or two per quart with some soap)
- Rubbing alcohol dabbed on mealybugs and scale
- Systemic granules for persistent stuff
Fungus gnats are annoying because you gotta get larvae AND adults together or they just keep reproducing. BTI (Mosquito Bits) for larvae – soak some in water, use that to water plants weekly. Yellow sticky traps for adults.[14]
Side note – if you have cats or dogs those essential oils everyone recommends can be toxic to pets.[15] The granules are actually safer which seems backwards.
5. Quarantine Everything (Yeah It Takes Forever But Do It Anyway)
Even after checking and treating, I still keep plants separate from my other houseplants for 3-4 weeks. Sounds excessive, it is excessive, but it works.
“Quarantine” comes from Italian for 40 days because that’s how long it takes to be sure.[16] Some pest life cycles are 2-3 weeks so if you only wait one week you might move plants before eggs hatch.
During quarantine:
- Check weekly with magnifier
- Spray with neem oil or insecticidal soap once a week preventatively
- Keep sticky traps near plants
- Watch for any problems
If I find ANY bugs during quarantine I treat them and restart the whole clock. Only after 3-4 weeks with zero issues do plants join the rest of my collection.
Missouri Botanical Garden and Iowa State both say 3-4 weeks minimum, not two weeks like most articles say.[17] Feels like forever but better than infestations.
6. Clean Plants and Check Pots Before They Come In
Before final move inside I clean everything. Summer outside means covered in dust and pollen that clogs up their pores.
I wipe each leaf with damp cloth. For plants with lots of tiny leaves I just shower them in the tub or spray with hose outside.
Check for sticky residue on leaves – that’s honeydew from bugs and can cause mold.[18] Wash with soapy water if you find any.
Trim off dead or yellow stuff. Summer can make plants look messy. Cutting just above where leaves meet stems encourages bushier growth.[19]
Check drainage holes aren’t clogged. Summer watering compacts soil.[20] If they’re really rootbound I’ll repot, but if borderline I wait til spring. Repotting before winter stresses them out.
One thing I learned with citrus – test soil pH if something seems off. Being outside can change pH and some plants are really sensitive to that.[21] I use cheap test strips.
7. Change How You Care for Them Indoors (Don’t Use Summer Schedule)
This is where most people screw up. They bring plants inside but water and fertilize like it’s still summer.
Indoor conditions are completely different:
- Way less light
- Cooler
- Lower humidity
- No wind
Everything slows down.
Overwatering is the number one problem with houseplants in winter according to University of Maryland Extension.[22] Soil doesn’t dry as fast indoors. I cut watering by at least 25-50% compared to summer. Always check soil first – finger an inch or two down. Still moist? Wait.
Stop Fertilizing
This seems weird but you should stop fertilizing about a month before bringing plants in.[23] Most go semi-dormant in winter and can’t process nutrients. Extra fertilizer just builds up and damages roots.
I don’t fertilize again til March/April when new growth starts. Until then, nothing.
The Humidity Problem
Winter heating drops humidity way down. Most tropical plants want 50%+ humidity and my house gets down to like 20% in winter.
What actually helps:
- Humidifier near plants (best option)
- Pebble trays with water below pot level
- Grouping plants together
- Moving to humid rooms like bathroom
What doesn’t really help:
- Misting (only raises humidity for like 30 seconds, can cause fungal issues)
Keep plants away from heating vents and drafty windows. If pot feels cold near a window, plant is getting cold stress even without frost.[24]
The Light Situation Is Worse Than You Think
Worth mentioning again because it’s such a big deal – indoor light is dramatically lower than outdoors. Not just a little less, like order of magnitude less.
Research shows insufficient light is one of the main reasons houseplants decline after coming inside.[25] They literally can’t make enough energy from photosynthesis.
Start with brightest windows (south or west facing usually). Most plants would benefit from grow lights in winter. I run mine 12-13 hours daily.
Signs of not enough light:
- Leggy stretched growth
- Pale yellowing leaves
- Continued leaf drop after initial adjustment
- No new growth for months
If you see this, move closer to window or add grow light.
What to Do When Things Go Wrong (Because They Will)
Some leaf drop first 2-3 weeks is normal. Plant is adjusting. Ficus species especially drop leaves with any change.
If leaves keep dropping after a month something else is wrong:
- Not enough light (most common)
- Watering issues
- Cold drafts
- Pests you missed
Don’t keep moving plant around trying to find the “right spot” – that stresses it more. Pick brightest location, keep care consistent, wait.[26]
If Pests Show Up Despite Quarantine
Sometimes you miss stuff. If bugs appear after bringing in:
- Isolate that plant immediately
- Check all nearby plants
- Treat aggressively (systemic granules time)
- Consider if plant is worth saving vs just tossing
Fungal Issues
White coating (powdery mildew) or fuzzy gray stuff (mold):
- Better air circulation (use fan)
- Stop misting
- Water soil only, not leaves
- Remove infected leaves immediately
- Spray with baking soda solution (tablespoon per gallon water with some soap)[27]
Cold Damage
If plant got cold before you brought it in, you’ll see blackened mushy foliage. Cut damaged parts off right away. Put in bright light, reduce water til you see recovery, don’t fertilize.[28]
What Actually Matters Most
After doing this for years here’s what I’ve figured out really matters:
- Timing – Start 2-3 weeks before frost, not when it’s imminent
- Gradual transition – Those 1-2 weeks of acclimation prevent so many problems
- Pest management – One infested plant can ruin your whole collection
- Quarantine – 3-4 weeks catches stuff before it spreads
- Adjust care – Less water, no fertilizer, more humidity, brightest light you can
Some plants just aren’t worth overwintering indoors. Basil is an annual, trying to keep it alive all winter is more trouble than it’s worth. Sometimes better to take cuttings or just buy new in spring.
The research backs up what experienced plant people figured out through trial and error – gradual transitions, pest management, adjusted care make the difference. Skip these steps and you’ll fight problems all winter.
Start early, take your time with the transition, be thorough about checking for bugs, don’t overthink it. Your plants will look actually good all winter instead of barely surviving til they can go back outside.
References
[1] Ochoa de Alda, J. A. G., et al. (2024). Indoor light environment limits photosynthetic efficiency and constrains plant species selection in buildings. Nature Scientific Reports. https://www.nature.com/articles/s41598-024-74607-4
[2] Chicago Botanic Garden. Bringing Houseplants Indoors. https://www.chicagobotanic.org/plantinfo/smartgardener/bringing_houseplants_indoors
[3] Fine Gardening. How to Grow Citrus All Year Long in Cold Climates. https://www.finegardening.com/article/how-to-grow-citrus-all-year-long-in-cold-climates
[4] Gardener’s Path. How to Acclimate Plants for Winter Indoors. https://gardenerspath.com/plants/houseplants/acclimate-plants-indoors/
[5] University of Illinois Extension. (2022). Tips for moving houseplants indoors and overwinter care. https://extension.illinois.edu/blogs/good-growing/2022-09-09-tips-moving-houseplants-indoors-and-overwinter-care
[6] Gardener’s Path. How to Acclimate Plants for Winter Indoors. https://gardenerspath.com/plants/houseplants/acclimate-plants-indoors/
[7] Pennington. Why Is My Plant Dropping Leaves. https://www.pennington.com/all-products/fertilizer/resources/why-is-my-plant-dropping-leaves
[8] Chicago Botanic Garden. Bringing Houseplants Indoors. https://www.chicagobotanic.org/plantinfo/smartgardener/bringing_houseplants_indoors
[9] Get Busy Gardening. How To Debug Plants Before Bringing Them Indoors. https://getbusygardening.com/debugging-and-cleaning-potted-plants/
[10] Clemson HGIC. Common Houseplant Insects & Related Pests. https://hgic.clemson.edu/factsheet/common-houseplant-insects-related-pests/
[11] Get Busy Gardening. How To Debug Plants Before Bringing Them Indoors. https://getbusygardening.com/debugging-and-cleaning-potted-plants/
[12] Penn State Extension. Bringing Houseplants Indoors. https://extension.psu.edu/bringing-houseplants-indoors
[13] Adams Fairacre Farms. How to Debug Plants. https://adamsfarms.com/gardentips/how-to-debug-plants/
[14] Get Busy Gardening. How To Debug Plants Before Bringing Them Indoors. https://getbusygardening.com/debugging-and-cleaning-potted-plants/
[15] Healthline. Essential Oils as Spider Repellent. https://www.healthline.com/health/essential-oils-spider-repellent
[16] Gardening Know How. When Should You Keep Houseplants Separate: Tips For Quarantining New Houseplants. https://www.gardeningknowhow.com/houseplants/hpgen/when-how-to-quarantine-houseplants.htm
[17] Potted Plants.org. Quarantine New Houseplants: Keeping Your Plant Collection Safe. https://pottedplants.org/blog/quarantine-new-houseplants-and-how-to-do-it/
[18] Gardening Know How. Sticky Plant Leaves. https://www.gardeningknowhow.com/houseplants/hpgen/sticky-plant-leaves.htm
[19] Gardening Know How. Houseplant Pruning Guide. https://www.gardeningknowhow.com/houseplants/hpgen/houseplant-pruning-guide.htm
[20] Gardening Know How. Do Pots Need Drain Holes. https://www.gardeningknowhow.com/special/containers/do-pots-need-drain-holes.htm
[21] Nature Hills. Move Citrus Trees Indoors for the Winter. https://naturehills.com/blogs/garden-blog/fall-citrus-tree-care
[22] University of Maryland Extension. Selection and Care of Indoor Plants. https://extension.umd.edu/resources/yard-garden/indoor-plants/selection-and-care-indoor-plants
[23] Iowa State Extension. Tips for moving houseplants indoors.
[24] Gardener’s Path. How to Acclimate Plants for Winter Indoors. https://gardenerspath.com/plants/houseplants/acclimate-plants-indoors/
[25] Ochoa de Alda, J. A. G., et al. (2024). Indoor light environment limits photosynthetic efficiency. Frontiers in Plant Science.
[26] Pennington. Why Is My Plant Dropping Leaves. https://www.pennington.com/all-products/fertilizer/resources/why-is-my-plant-dropping-leaves
[27] Gardening Know How. Powdery Mildew Treatment Indoors. https://www.gardeningknowhow.com/houseplants/hpgen/powdery-mildew-treatment.htm
[28] Penn State Extension. Bringing Houseplants Indoors. https://extension.psu.edu/bringing-houseplants-indoors
