18 January, 2022

Succulent in Heatwaves - Top Questions Answered


It seems that summer has now officially arrived, albeit a little late to the party.

The mild start to the season was a delightful treat to everyone and their plants. Then, it seemed without notice, we were blasted into the high 30's and low 40's before we knew it - A lovely Christmas present to us all.

Up in the hills here, we actually lost power for two days over Christmas. This meant our reticulation system was out for the count and we were forced to halt the celebrations to hand water our plants. Oh, the sacrifices we make for the plants!

How did your succulents fair in the heat wave? Are you prepared for the next one?

As we head into the second month of summer (and it seems like the hot weather is here to stay), we thought we would answer some frequently asked questions we are receiving lately about caring for succulents in the heat.

How often should I water during Summer?

One old fashioned rule is to 'water when the soil or mix becomes dry'. I'm not the biggest fan of this rule, as you don't actually want the soil or mix to completely dry out - This will make it become water repellant. When you do get around to watering, the water will sit on top of the soil/mix for a second or two, and then run off to the side, away from the base and roots of the plant. 

If this is the case with your mix, don't fret, it can be corrected - You can use a soil wetting agent to improve water penetration. They come in liquid form and a granular form ( I prefer the granules, you can sprinkle over as needed with ease).

A more modern take on this watering guidline is 'Water when the soil or mix is NEARLY dry'. A little less than damp. But how often is that?

Well, it does depend on a bunch of different factors - Plants inside will need watering less often, as will those in shadier positions in the garden. On the other hand, those plants in pots (especially smaller ones) could be watered once a day in the summer months, as could plants in sunnier positions. Learn to listen to your plants, and look for the signs of dehydration - Wilted or sagging leaves, rosettes shrinking and closing up, loss of colour and brown leaves.

An Echeveria 'Domingo' with heat stress.

An Echeveria 'Domingo' showing signs of heat stress - the rosette has closed up and the leaves are wrinkled and turning brown.

Aloe striata showing heat stress

An Aloe striata in the garden that is suffering in the heat. The rosette has closed up and the leaves are browning and curling.

How can I stop leaves from burning?

There are a few temporary measures you can take to help protect your succulents from burning in the sun if you know the temperature is going to go up past, say, 38 (ish) degrees.

The first is temporary relocation - If your plants are in pots, and you are able to move them, the best option is to place them somewhere for the day, or a couple of days, where the sunlight isn't shining directly on them. Under a verandah or patio is perfect. Ideally, somewhere where they can still receive plenty of indirect sunlight.

The second option is a temporary shade sail, such as shade cloth. The key to creating a great temporary shade sail is airflow. Lift the shade cloth up with stakes as much as you can and avoid having the shade cloth touching the foliage. If it's quite low to the ground, it can create an environment too humid for succulents.

After a couple of days of being under shade cloth, your succulents can start to become leggy and green, so it's not really an ideal situation for the whole summer season, but the perfect temporary solution for those extreme days.

When should I water my succulents?

If possible, try to water your succulents in the cooler times of the day - Either early in the morning or late afternoon. The reason for this is that it can be the combination of water and heat that causes rot in your plants. Sometimes the water can pool on the foliage, especially in the case of rosette type succulents. This pooling creates a 'magnifying glass effect' with the sunlight, which can cause sun damage.

Remember to water succulents thoroughly, so they can develop a lovely strong, deep, root system. This gives them the best chance to defend themselves against the heat.

For the most part, succulents are very water wise, and generally very tolerant of the heat. But during those times where temperatures start getting above 36/38, and especially for an extended period of time, we need to provide them with just a little more TLC so they can get through the season.