How To Care For Your Indoor Plants In Winter

So your indoor plants have been thriving, and you have been bragging to your black-thumbed mates all Summer about how much of a great plant parent you are. And now Winter has set in, and they are going south, fast, despite you not doing anything different. 

We got you, there are a few simple changes you need to make to your routine to help plans in Winter, and we are here to walk you through them so that you can keep your green thumb status!

Even though our homes are temperature controlled, it is inevitable that they will be colder and have less natural light in winter. This results in the soil of our plants holding moisture for longer, and their need for bright indirect light becomes even more significant for plants in Winter.

Water Less, Much Less

Even if you feel like the air in your home is dryer because of constant heating, you still need to monitor your plant’s soil and will likely find that it dries out a heck of a lot slower than in Summer because of the air temperatures and because the plant is growing a lot slower. So our number one tip for any indoor plants watering schedule is to ALWAYS check the soil BEFORE adding any water. Use a soil moisture metre or dig down in the soil about 2 inches; if the soil feels at all moist, then you need to hold off on watering until it is dry.

When it is time to water, you want to add less than you did through Summer. That means no more chucking it in the shower for a good drench because the risk of it holding that moisture for too long becomes a lot higher. If there is one thing that can kill a plant almost overnight, it is too much water that can result in root rot. So, for a 20cm diameter pot, we recommend adding a tall glass each time that the top 2 to 3 inches of soil is totally dry.

Pro tip: use room temperature water rather than cold water from the tap to avoid shocking the roots of your plants in Winter.

Temperature and humidity

In Winter, the humidity in the air is low, and when we have our heaters on, it can dry the air out even more. Plants also hate being in a cold or hot draught, so make sure you move your plants in Winter if necessary and think about adding a humidifier and grouping plants together to create more moisture in the air naturally.

We aren’t big on high maintenance plants (ain’t nobody got time for that), so we never advise buying plants that require a lot of humidity and moisture (Like Calathea or ferns). Still, there are several ways to increase humidity all year round that you can read about here.

Let there be light!

Winter brings fewer daylight hours and fewer sun rays, so think about moving your plants in Winter closer to a window or a window that gets more light. A few hours of direct sun in Winter is acceptable for your plants as the intensity of the rays is much lower; remember to move them come Spring to avoid scorching their leaves.

No (Seaweed) Soup for you!

In Winter, your plant’s growth will slow if not stop, which means they no longer need any fertiliser and extra nutrients to boost their growth. So hold off on fertilising your plants in winter until early Spring when new signs of growth are showing.

See even more plant care advice on our blog or join our Indoor Plant Tips & Tricks Facebook group where you can ask any and all plant questions and hear from fellow plant lovers.

Pesky Fungus Gnats

Those tiny little sticky bugs that seem to have moved in and set up shop all over your house, particularly around your beloved indoor plants and no matter how much you swat or yell at them they won’t go away!

Breathe… you’re good, you haven’t done anything wrong. Fungus gnats are a normal part of owning indoor plants and all of us have had to deal with them at one stage in our plant parenthood journey.

These little guys lay eggs in moist soil where there is decaying matter to feed on, then the eggs hatch and the larva live and feed on fungal material while growing into an adult and then fly off to the next plant. Like a never-ending life cycle nightmare! If left untreated they can feed on the roots of your plants and cause them to yellow or even die. Gah!

The good news is we have some tried and tested solutions to combat these pesky buggers once and for all!

Treating Fungus Gnats With Neem Oil

When the top three inches of soil are dry, we have found a few methods to kill a population of fungus gnats effectively, and the most common one is using neem oil soak. Use a high quality, non-diluted neem oil and follow the guidelines on the pack to do your own dilution. We use Eco Neem Organic Insecticide- Concentrate.

Then repeat the process again in a fortnight if you see any signs of new flies.

Treating Fungus Gnats With Hydrogen Peroxide

A super common household item and fast working on the larvae and adult flies, a 3% hydrogen peroxide can be diluted with water to create a soil soak similar to the neem oil process. Mix 1 part 3% hydrogen peroxide and four parts water (one cup of HP to four cups of water) and spray on your plant’s soil (avoid the leaves) so that the first few centimetres are drenched.

Treating Fungus Gnats With Diatomaceous Earth

Diatomaceous Earth has microscopic shards of silica (a hard, unreactive, colourless compound that occurs as the mineral quartz) that will rip those tiny Fungus Gnats larvae to shreds as they crawl through it. Plus, it will also kill other common houseplant pests like mealy bugs, spider mites or aphids!).

Sprinkle a layer of the powder over the topsoil of your pot plant. Ideally, add when the soil’s surface is dry to the touch—but before your plant is in dire need of watering (soaking up water will make it ineffective).

The best bit is that it is 100% safe to use in the home around food and pets (as long as you get the food-grade version). But we recommend using gloves and a mask to prevent the tiny particles from getting into your lungs cos like any fine dust; it may cause you to sneeze or cough.

Read why we use DE to treat fungus gnats here at Green Assembly. and why we also add it to every potted plant that heads out our doors.

If you have been trying these methods for months but still seem to be losing a grip on them (and your sanity!), then you can go the hardcore method and have a go with some standard fly spray. Spray any flies that you can see buzzing and spray the top layer of soil every few days. We don’t love this method cos God knows what is in those cans of death, but desperate times call for desperate measures!