As the rest of the world moves towards brighter and warmer days, I’m bracing myself and my plants for the cold and darker days here in New Zealand. The changing seasons always come with unexpected weather changes and significant temperature fluctuations. Like when I woke up today, the sun was shining which deceived the fact that it’s chilled to the bone. I knew it was time to dust off my grow lights and heat mats for my plants.

Light

Light is arguably the most important factor for growing healthy plants indoors. All plants require light for photosynthesis, which literally means “putting light together”. It is the process whereby a plant turns carbon dioxide and water into carbohydrates that it needs for its food. Without light, this process doesn’t happen.

In autumn and winter when sunlight is much shorter and sometimes non-existent for days when it’s raining, supplemental light is crucial to make sure our house plants still get enough energy to survive, similar to when we take vitamin D supplements in winter. A great way to do that is to use grow lights.

There is a wide variety of grow lights to choose from nowadays. It can be super overwhelming when google returns millions of suggestions on grow lights. A key factor that helps narrow down my choices is full-spectrum. The light spectrum is composed of red, orange, yellow, green, blue, indigo and violet light. Sunlight provides all colours of light. A full-spectrum grow light resembles natural sunlight the most, whereas fluorescent or LED bulbs used around the house are often white light only.

The main grow light I’m using here is a 60W full-spectrum LED grow light. This works perfectly for this corner here because I can adjust the angles of the light so that it works for both my plant shelf and my plant buffet table. I also love that this one emits clear light even though it's full spectrum. 

Another one that I'm using for my propagation station is this clip-on full-spectrum LED light. The thing I love about this one is that I can adjust the light intensity and set up a timer so that it automatically turns off after a certain time. This one works particularly well for my wine cart converted propagation station.

Right now, as it’s still relatively bright throughout the day, I only turn them on for 3-4 hours at night time to make up for the reduced daylight in autumn. In winter when it’s much darker and sometimes we don’t see sunlight for days, I keep the lights on all day. They’re both LED so they’re energy efficient and don’t overheat.

Temperature

Apart from good lighting, the right temperature plays a key role in keeping house plants happy. Just like us, most plants like to be kept in a constant room temperature of 18 - 24 degrees Celcius. Significant temperature drops in autumn and winter can be a shock to house plants. When it’s cold, we put on layers of clothes or wrap ourselves in blanket.

For my plants, I bring out heat mats for my propagation station and move bigger plants away from window sills and doors to avoid cold draughts.

Heat mats produce gentle and consistent heat despite very little electricity consumption. They are particularly helpful for small cuttings and seedlings which is why I place them under my propagation boxes.

I also move my fussier tropical plants to the living room and kitchen area where the heat pump is on regularly on cold winter days.

Watering

Even with the supplemental lighting and heat mats, plant growth slows down significantly in colder months. Hence, reducing the watering to the bare minimum is key. More plants die from overwatering than from any other cause.

As someone who tends to overlove my plants, a moisture meter is life-saving (for my plants). In winter, the surface of the soil may look dry but the undersurface soil is still very much damp. It’s important to check the undersurface as well as plants’ foliages to determine if they need more water.

Some plants like peace lily or pothos droop dramatically when they’re thirsty. Plants with thick leaves like peperomia or string of hearts go soft. Plants do have different ways to communicate their needs. It’s just a matter of noticing them.

Humidity

Humidity is something that I don’t prioritise as much as the other three factors. I know it makes a huge difference to plant growth and health. But living in Wellington I don’t want to risk having a damp and mouldy house so I refuse to get a humidifier. My way around it is grouping my plants together to create a humid microclimate area. Plants release moisture from their leaves through the “transpiration” process. When they grow around each other, the moisture is trapped and thus creates a humid ambient.

I also have this belief that by living in a less than ideal environment and adjusting themselves, my plants become much more resilient and healthier. Much like us human who only know what we’re capable of when we have gone through adversity.

Caring for plants is not hard. It just requires a lot of patience and awareness. It makes me become more in tune with the seasonal changes and the little ways I can learn to adjust to them. There are seasons of growing and thriving. And there are seasons of slowing down and recharging.