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March is the turning point of the houseplant calendar. The spring equinox arrives around March 20, days are now longer than nights, and over the course of the month monstera, pothos, and philodendrons start visibly moving again. The whole care routine shifts this month — more water, first fertilizer of the year, repotting season begins, and thrips show up with the new growth flushes.

What's happening to your plants in March

The spring equinox (on or around March 19–21 in the Northern hemisphere) is a biological trigger for many houseplants. Near-equal day and night length (per the National Weather Service, day and night are equal a few days before the equinox, and days then grow longer than nights), combined with the increasing sun angle of late March, produces the light intensity cues that signal plants to break dormancy and resume active growth.

Over the course of March, most tropical foliage plants begin to show new growth. Pothos and heartleaf philodendron are usually first, extending new nodes and leaves. Monstera follows with its tightly rolled new leaf emerging from the center. Even plants that appeared completely static through January and February start showing visible change in March.

What this means physiologically: the plant's photosynthetic rate increases with higher light intensity, which increases its demand for water, carbon dioxide, and nutrients. Root activity increases. The plant begins actively building new cells. This is a fundamentally different metabolic state than the dormancy you managed through winter, and it requires fundamentally different care.

The shift doesn't happen overnight. In early March, many plants are still in the transition zone — more active than January but not yet at full spring pace. By late March, the transition is largely complete for most tropical foliage plants, and spring care practices apply.

Southern hemisphere readers: your March is equivalent to the Northern hemisphere's September — the beginning of fall dormancy transition, time to taper watering and fertilizer, not increase them.

Light this month

March light improves meaningfully through the month. The sun angle is rising, day length is increasing, and in many Northern hemisphere regions the cloud cover that characterizes February starts to break.

South-facing windows remain strong performers, but the geometry is changing. The sun is now rising higher in the sky, which means it no longer penetrates as deeply into south-facing rooms as it did in December and January. Plants that sat in a broad band of direct winter sun near south windows may now be receiving indirect light as the sun angle rises. Check whether your south-facing plant positions are still optimal.

East and west windows are now delivering their best light of the season — the sun's angle and duration at east and west windows in late March produces genuinely useful morning and afternoon direct light. March is a good time to redistribute plants into east or west positions that couldn't support them in winter.

Supplemental grow lights can begin to be reduced in late March if your natural light is improving significantly. Don't rush this — many growers scale back too quickly and plants stall. Match the reduction to what you're actually observing.

Watch for heat through glass. As sun angle rises and intensity increases, south-facing glass can now transmit enough concentrated light and heat to scorch some tender leaves, particularly new growth. If you see whitened or papery patches on leaves touching or near south glass, move the plant back slightly.

Watering adjustments

March is when watering frequency starts to increase meaningfully. Do it gradually, following the plant's signals rather than a calendar.

The rule: when a plant has a fully unfurled new leaf — not a node swelling, not an emerging cataphyll, but an actually opened leaf — increase watering frequency for that plant. Before that point, hold at late-winter levels. After it, check soil moisture more frequently and water when the soil is dry to the touch down an inch or so (for most tropicals, per Iowa State Extension) rather than letting it dry as deeply as in winter.

For calathea and heartleaf philodendron, which prefer consistently moist (not soggy) soil per NC State Extension, shift toward more frequent checks in March and do not allow full drying. Pothos and ZZ plant tolerate drying, so they can still dry out more between waterings than they will at the summer peak.

Drainage remains important. March is also the time to check that all drainage holes are clear and that pots are not sitting in standing water in their saucers. Roots that survived winter dormancy in a relatively stable environment can be damaged by sudden waterlogging if drainage is compromised.

For help calibrating your specific plant and pot combination, the watering frequency calculator can walk you through the variables.

Humidity

As heating systems begin to run less frequently in March (assuming outdoor temperatures are rising), indoor humidity starts recovering on its own. This is a welcome change after the dry-air grind of November through February.

That said, heating systems in many Northern hemisphere climates still run regularly through March, and cold snaps are common. Don't dismantle your humidity setup — pebble trays, humidifiers, plant groupings — until you can see that your most sensitive plants (calathea, ferns, nerve plant) are no longer showing new crispy tip development.

NC State Extension recommends "a humidity level above 60%" for zebra plant (Calathea zebrina), so humidity support still pays off for tropical foliage plants during the transition period. March is not the time to declare victory and move on.

By late March in most climates, natural humidity is improving enough that strict humidifier management becomes less critical. But watch your plants rather than the calendar.

Pest pressure this month

March brings a new pest: thrips. Thrips (Frankliniella spp. and related genera, per UC IPM) are tiny, elongated insects that feed by puncturing the outer layer of plant tissue and sucking out the cell contents. They are attracted to new, tender growth — which is exactly what most of your plants are producing in March.

The early signs of thrips damage are subtle: silver-gray streaking or stippling on new leaves, distorted leaf edges, and small dark fecal spots on foliage. Thrips themselves are small enough (less than 1/20 inch long, per UC IPM) to be missed without close inspection — hold a white piece of paper under a leaf, tap the leaf, and look for small moving specks.

Thrips are particularly problematic on monstera new leaves, calathea, and tender vining growth on pothos and philodendron. They can also overwinter indoors and emerge with the new growth flush, so even plants that have been isolated all winter can show thrips in March.

Spider mites may still be present from winter — March is when you do a final winter mite inspection while also beginning to watch for thrips. These two pests require slightly different treatment approaches. See spider mites vs thrips vs whiteflies for detailed comparison.

Tasks for this month

  • Begin repotting root-bound plants. March is when repotting season starts — from late March onward as growth picks up. Signs of a root-bound plant: roots circling the surface, roots pushing through drainage holes, plant wilting quickly despite adequate watering. Go up one pot size (not two), as UMN Extension advises, and use fresh well-draining potting mix.
  • Start fertilizing at half-strength. Once you see clear new growth, begin fertilizing at half the package-recommended dose. UMN Extension advises a balanced houseplant fertilizer at half strength every two to four weeks in spring. Do not fertilize before new growth appears.
  • Increase watering frequency gradually. Match watering to plant signals, not the calendar. New leaf fully open = time to water a bit more often.
  • Inspect every plant for thrips. Check new growth particularly — tap leaves over white paper and look for movement.
  • Clean up dead winter foliage. Trim any leaves that went crispy over winter. Dead material can harbor pests and is no longer functioning.
  • Begin repositioning plants for spring. As light increases and sun angles rise, check that plants are still in optimal positions. Move light-hungry plants back from south-window glass slightly; move shade plants that survived winter in north windows to slightly better positions.
  • Check drainage. Run water through each pot and confirm it drains freely. Compressed winter soil sometimes develops poor drainage.

Plants to focus on this month

Monstera deliciosa (Monstera deliciosa)

March is monstera month. Watch for the new leaf roll — a tightly coiled new leaf emerging from the growing center of the plant. When it appears, increase watering frequency and prepare to introduce fertilizer as soon as the leaf fully unfurls.

This is also the right time to check whether your monstera is root-bound. Monstera roots are thick and assertive — if you see them circling the inner walls of the pot through drainage holes, or if the plant wilts shortly after watering, it's time to repot. Go up one pot size, 1 or 2 inches larger in diameter, per Clemson HGIC.

Monstera is toxic to dogs and cats via insoluble calcium oxalates per the ASPCA Swiss Cheese Plant entry.

Golden pothos (Epipremnum aureum)

Pothos is typically already growing by March, having started in late February. March is when to begin watering it more often than on its winter schedule, increasing frequency further as growth accelerates later in the month.

If you want to propagate pothos from stem cuttings with a node, spring is a good time: Illinois Extension notes that stem cuttings are usually taken when the plant is actively growing in spring or summer, and NC State Extension notes that pothos vines root easily in water.

Per NC State Extension, pothos "prefers bright, indirect light and survives for long periods in low light." March is when that bright, indirect light starts coming back.

Toxic to dogs and cats per the ASPCA Golden Pothos entry.

Calathea (Calathea spp.)

Calathea wakes up slowly in March, but its response to improved humidity and light can be dramatic. Plants that looked bedraggled through February often begin producing fresh new leaves in March that are much more vibrant and less damaged than the winter foliage.

March is the right time to check whether your calathea needs a new pot. NC State Extension advises repotting zebra plant (Calathea zebrina) every 2 years, and spring is the best time to repot, per UMN Extension. Use a well-draining but moisture-retentive mix (standard potting soil with added perlite works) and do not go dramatically up in pot size — too large a pot holds too much water for calathea's preference.

Non-toxic to cats and dogs per the ASPCA Calathea entry.

Heartleaf philodendron (Philodendron hederaceum)

If your heartleaf philodendron started showing cataphylls in February, by March it likely has multiple new leaves in progress. This is a fast-growing plant in the right conditions, and March conditions are right. Resume slightly more frequent watering and introduce fertilizer at half strength, as UMN Extension advises for spring.

Watch for thrips on the new tender leaves — their softer tissue makes them preferred feeding sites.

Toxic to cats and dogs per the ASPCA Heartleaf Philodendron entry.

Peace lily (Spathiphyllum spp.)

March is when peace lilies often begin their spring bloom push. If yours hasn't bloomed in a while, give it a bright, indirect light position. Peace lily is one of the few tropical houseplants that tolerates low light while still occasionally blooming.

Watering: peace lily is more drought-sensitive than most of the plants on this list and will dramatically wilt when dry, then recover quickly when watered. In March, check it regularly and water when the soil is dry to the touch down an inch or so, the Iowa State Extension rule of thumb.

Toxic to dogs and cats via insoluble calcium oxalates per the ASPCA Peace Lily entry.

What NOT to do this month

Do not fertilize before you see new growth. The first warm day in early March is not a signal to fertilize. Fertilizer applied to a dormant or just-transitioning plant sits in soil and contributes to salt buildup without being used. Wait for the leaf.

Do not jump straight to full-strength fertilizer. Start at half the recommended dose, as UMN Extension advises for spring, before moving to full strength. This is particularly important after the long winter period where roots have not been actively processing nutrients.

Do not repot plants that are not showing signs of root binding. Repotting disturbs roots and requires recovery energy. If a plant doesn't need it, don't do it just because it's spring. The rule: repot when the plant is clearly constrained, not on a schedule.

Do not stop watching for winter pests while starting to watch for spring pests. Spider mites don't quit in March, and thrips arrive in March. You need to check for both simultaneously.

Do not move tropicals outdoors yet. Even if outdoor temperatures are warm during the day in March, night temperatures in most Northern hemisphere locations are still too cold for tropical plants. Iowa State Extension advises waiting until nighttime temperatures are consistently and reliably above 50°F (10°C) before moving houseplants outdoors.

Frequently asked

When exactly should I start fertilizing in spring?

The trigger is a fully unfurled new leaf — not a swelling node, not a leaf still in the cataphyll, but a leaf that has actually opened and expanded. When you have that, you know the plant is actively growing and can use the nutrients. Start at half the recommended dose of a balanced liquid fertilizer, as UMN Extension advises, and increase to full strength once growth is steady. Iowa State Extension puts the start of the feeding season for most houseplants in March or April, depending on the plant and your light conditions.

What's the right pot size when repotting in March?

Go up one size: Clemson HGIC advises a pot 1 or 2 inches larger in diameter than the current pot. The common mistake is going up too many sizes at once, which leaves too much soil volume around the root ball. That excess soil holds moisture the roots can't reach, creating waterlogging risk in the very areas farthest from the plant. A snug new pot is better than a dramatically oversized one.

My monstera hasn't shown any new growth yet in March. Is something wrong?

Not necessarily. Monstera growth timing depends heavily on light and temperature. In a north-facing room or a particularly cold apartment, the physiological signals that break dormancy take longer to accumulate. Give it time before worrying. In the meantime: move it toward your best light source, check that it hasn't been overwatered through winter (root rot will delay spring growth significantly), and confirm it isn't root-bound in a way that's compressing the roots. If there is still no movement once light improves, inspect the root system and consider a soil refresh.

Sources: NC State Calathea zebrina, NC State Heartleaf Philodendron, NC State Pothos, UC IPM Thrips, ASPCA Swiss Cheese Plant, ASPCA Golden Pothos, ASPCA Calathea, ASPCA Heartleaf Philodendron, ASPCA Peace Lily, National Weather Service Spring Equinox, Iowa State Extension How to Care for Houseplants, Iowa State Extension Moving Indoor Plants Outside, UMN Extension Spring Houseplant Care, Clemson HGIC Transplanting and Repotting, Illinois Extension Cuttings