ดินปลูกมอนสเตอร่า ฟิโลเดนดรอน กันรากเน่า 2026

Ever had this happen? You water your Monstera the usual way, but suddenly the leaves turn yellow and the stems go soft, even though you did not water more than before. The late rainy season into early winter is when we see this most often. This article is about adjusting the potting mix for Monstera (Monstera deliciosa) and Philodendron so it drains well. The short answer: make airy materials such as pine bark, perlite and charcoal about 50-60% of the total mix, and use a pot with good drainage holes. The roots can breathe and are far less likely to rot.

Why Late Rainy Season to Early Winter Is a Root Rot Risk

The air is humid, sunlight is weaker and temperatures drop, so soil in the pot dries much more slowly than in summer. Monstera and Philodendron roots need oxygen. If the soil stays soggy for several days, the roots are starved of air, and moisture-loving fungi such as Pythium and Phytophthora can attack more easily.

A common myth: yellow leaves mean thirst, so water more. In this season, yellow leaves usually come from overwatering. Before every watering, push your finger about 2-3 centimeters into the soil. If it is still cool and damp, do not water yet.

Warning Signs the Roots Are in Trouble

Lower leaves turn yellow and drop one by one while the soil is still wet
The base of the stem is soft or brown-black
The soil smells musty, like mud
Leaves look dull and droop even though the soil is moist

A Well-Draining Soil Mix for Monstera and Philodendron

In nature, Monstera and Philodendron are climbing, semi-epiphytic plants. Their roots cling to big trees and very loose leaf litter, not dense soil. In a pot, we should imitate that as closely as we can.

Material	Proportion	Purpose
General potting soil or good peat moss	40%	Holds moisture and basic nutrients
Pine bark (small-medium)	25%	Creates air pockets, drains fast
Perlite or volcanic rock	20%	Stops the soil from compacting
Crushed charcoal	10%	Absorbs odors and reduces stuffiness
Chopped coconut fiber	5%	Adds airiness, keeps moderate moisture

This mix works for Monstera, split-leaf Philodendron (such as Philodendron bipinnatifidum) and vining Philodendrons. If you grow them in an air-conditioned room or a low-light condo, add a little more bark and perlite, because the soil will dry slower than usual.

5 Ways to Adjust the Soil Before Winter

Add pine bark and perlite: If your current soil is dense and holds water for long, raise the airy materials until they make up more than half of the pot.
Choose a pot that fits the roots: An oversized pot holds extra soil that dries slowly. Pick one only about 1-2 inches wider than the current root ball.
Line the bottom with airy material: A thin layer of volcanic rock helps, but the pot must still have real drainage holes, not just rocks.
Switch to a double-pot setup: Keep the plant in a plastic pot with holes, set inside a ceramic pot. Lift it out to water and let all the water drain away every time.
Water less often as the weather changes: In the late rainy season to early winter, most plants need watering about every 7-10 days, but go by soil moisture, not the calendar.

Repotting Monstera and Philodendron Without Shocking Them

Do not rush to repot every pot at once. If the plant is healthy and the soil is still loose and drying normally, leave it. If the soil is compact, stays soggy or smells musty, follow these steps.

Prepare the new mix and a clean pot first
Gently pull the plant from the old pot and shake off the old soil lightly
Check the roots. Healthy roots are white to cream, firm and springy
Cut off rotted roots, which are brown-black, mushy and smelly, using scissors wiped with alcohol
Pot in the new mix at the same depth as before, without burying the stem deeper
Water thoroughly once, then keep the plant in bright indirect light for 5-7 days before moving it back

What to Avoid After Repotting

Do not fertilize yet. Wait at least 3-4 weeks until new leaves or roots establish
Do not put the plant in harsh sun, because the roots cannot take up enough water yet
Do not keep watering out of fear of dryness. The airy mix dries faster, but you still wait until the top layer is dry

Winter Care in Condos and Offices

Condo rooms and office desks usually have low light and still air. Monstera and Philodendron like bright, soft light, so a spot near a window with gentle morning light is just right. In an air-conditioned room, keep the leaves away from direct cold airflow, which can cause crispy edges or wilting.

If you have dogs or cats at home, be a little careful. Both Monstera and Philodendron contain calcium oxalate that irritates the mouth and throat, so we recommend placing them on a high shelf they cannot reach.

If you want an easy start, our garden has plants already potted in an airy mix suited to our Thai weather. Come adopt one and take it home, and we will keep helping if you run into any trouble.

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How often should I water Monstera in the late rainy season to early winter?

Water only when the soil 2-3 centimeters deep is dry. Most of the time that is about every 7-10 days, but do not follow a fixed number of days, because humidity and light differ in each room. Use your finger or lift the pot to compare weight. If the pot still feels heavy, the soil is still moist enough.

Can I use cactus soil for Monstera?

We do not recommend it. Cactus soil is too loose and dries too fast for Monstera, which prefers steady, moderate moisture. It is better to use general potting soil mixed with pine bark and perlite as in the recipe above, which gives both airiness and the right moisture.

Can a plant with root rot be saved?

Yes, if some white or cream roots remain. Cut off all the rotted parts, repot in airy soil and a pot with drainage holes, and avoid unnecessary watering. If the stem base is badly rotted, cut a healthy top section with a node and aerial roots and propagate it in water or sphagnum moss instead.

Do I need to fertilize in winter?

Reduce or skip it. Cool weather slows growth, and leftover fertilizer can build up and burn the roots. If the plant is still pushing new leaves, use a half-strength fertilizer once a month at most.