Helping Your Plants get Through Winter
Switching from the warm weather to the colder temperatures is probably one of the hardest times to care for certain plants. We have all those that go gangbusters during summer (Aroids), and then really seem to struggle in winter...plants that only like spring and autumn (Peperomias), and some that hate every season (Calathea White Fusion).
I do believe that winter is when plants without well draining soil start to let us know something is wrong. We cruise through the warm months, thinking "we got this," as we see plants doubling in size and putting out leaves like nobody's business. Then all of a sudden, not so much for some of us. Brown tips begin forming on the edges, signs of an unhappy plant arise, and it can be perplexing.
I admit I still struggle with some plants in winter, I think as long as we do not have the "perfect enviornment" for a particular plant's needs, there can be issues. For instance, parts of Sydney are cold and humid--which is the perfect enviornment for fungus on delicate foliage. A lot of us do not have the space or money to build the perfect enviornment of warmth, humidity, and ample storage space. This is where paying attention to your plants is vital.
First, ensure your plant has excellent draining soil. Use at least 30% perilite with all your indoor greenery, to ensure the soil has air for the roots, and drains well. I will never use just soil, I have learned the hard way. Regular potting soil is quite heavy, some of it has even has things added to keep it moist longer. So basically your plant is sitting in a wet brick--unable to dry-- due to cold weather and the plant using less energy.
Bring plants indoors and away from drafty areas. You will notice that plants with white variegation seem to struggle first, this is usually from soil being too wet and/or being outside or in a cold spot inside. Keep in a warm, well lit place. You may still get a bit of crispy edges, but hopefully nothing worse. Pothos are all susceptible to the cold as well as Ficus plants. Alocasia's can go dormant below 15 degrees, so best to keep them in a warm, well lit room. If the Alocasia does die back, keep the plant. It will come back when the weather is warmer.
Even with great soil, it is possible to overwater--especially in large floor sized plants. It can take up to a month or longer for a 300mm pot to completely dry out, which is where having a water meter is imperative. There is no "fixed" schedule for plants and watering; they all have different needs. Learn to feel the pot when it is watered, and the weight of it-- and then when it is completely dry-- it will feel extremely light compared to before.
For your larger pots, invest in a moisture meter or a large sustee. Most plants appreciate going completely dry in between watering during colder temperatures. It will take longer for them to dry out in the lower temperatures, so be vigilant about checking your plant to ensure that it is not still wet. Expect your plant to take longer drying out, and also remember when using an air conditioner in winter, that it does take away some of the humidity in the air that plants are used to.
I hope this has helped some of you. I am still learning myself--I learn through experimenting and trying different things. Good luck and may winter be kind to us all!