We all know how important it is to slip, slop, slap during the warmer months.

But how do you keep your indoor plants happy over summer, and especially during a heatwave?

We asked Melbourne plant store owner Samantha Roxas and Brisbane horticulturalist James Mudge to find out. 

Protect plants by keeping them out of direct sunlight

Turns out, some of the same sun-smart principles that humans use apply to plants too.

One of the best things you can do for your plants when it's hot is to keep them in the shade.

Even if your plants like a north-facing window most of the year, Ms Roxas says you might need to move them out of direct light, or to a south-facing window, during the hotter months.

"You totally do not want your plants getting any afternoon sun [because] it's super harsh," she says.

"You'll find that plants start burning, bleaching, the colour will fade, and there'll be lots and lots of crispiness."

On particularly extreme days, for example when temperatures soar above 38 degrees, Mr Mudge says it could also be worth moving your plants into a cool, dark area like your bathroom.

"Whack them in the bath, spray them in the morning and give them a nice water down, [then] leave them there for the day," he suggests.

Watering often in hot weather is key

Your plants will be thirstier than normal over summer, so it's important to make sure you're giving them a big, deep drink whenever they need it — which will probably be more often than in the cooler months.

Even on days when you're not watering them, misting your plants leaves can help keep them cool.

"The best way I can describe it is when we are exercising, we start to sweat — putting liquid on a surface with airflow reduces the temperature, essentially," Ms Roxas says.

Airflow and aircon can affect overheated plants

While air conditioning can be a welcome relief for humans when it's hot, it's not so helpful for plants.

"Aircon basically destroys the humidity in the air," Mr Mudge explains.

"A lot of indoor plants are rainforest plants, so they need that humidity to do well, especially in the warmer months."

If you tend to keep your aircon on over summer, he recommends moving your plants if cold air is blowing directly onto them.

Then, try and and find other ways to increase humidity, such as grouping plants together around bowls of water, to create a microclimate.

On hot days, Mr Mudge says you will want to make sure your plants have some airflow if you live somewhere that gets hot and stuffy.

You can do this by opening some windows, or popping on a ceiling fan.

One plant care tip to avoid in a heatwave

While Mr Mudge says it can be a good idea to fertilise your plants before summer to get them strong and healthy, it's not something you want to do once the heat sets in.

"What can happen in extreme heat events is plants go into survival mode … and then fertiliser can stress them out and burn them," Mr Mudge says.

Ms Roxas also says to be careful using pesticide oils on your plant if they're getting any bright summer sun.

"If you're putting some sort of oil [on your plant], as soon as it's touched by light it will crisp. It will really burn the plant," Ms Roxas says.

If you do get a pest infestation over summer and want to treat it with oil, Ms Roxas recommends applying it at night so the plant has time to absorb it.

Then if possible, keep the plant in a shady area for a day or two, just to make sure there's no oil residue left on the plant.

SOURCE: https://www.abc.net.au/everyday/how-to-take-care-of-indoor-plants-in-hot-weather/100640610