Just in case we are blessed with warm summer like last year and I think heatwave is coming (again) this weekend, here are some of my tips:
If you are growing your succulent indoor, it's time for them to face the sun for growth and cute blush. I tend to recommend all indoor growers to place them near south-facing window that's where the plants are exposed to the hottest sun. However please make sure there's adequate ventilation to promote air circulation for the succulents. Despite they love the heat and the sun, they do not love the humidity and stuffy environment.
You should also be aware of the bugs (ie spider mites, mealy bugs, scale, aphids, thrips, whitefly, and fungus gnats too). Quickest way to remove them are using cotton bugs and alcohol (rubbing alcohol or vodka, why not). For prevention, I would commend mix neem oil (1 teaspoon) + some dish liquid (act as binding agent) + water (1 litre) and spritz it all over your succulent.
However if you are moving your indoor babies to outdoor babies, you will probably would have to deal with indoor bugs issue too. But as I have been growing mine outdoor and I have been using this personally as spray on my babies every 2 weeks.
Allow me to share my experience, I first bought a small 3-tier covered greenhouse from Wilko and placed my then-small collections of succulents. There was a sudden heat wave and killed most of them.... WHY? They don't cope with high heat and humid environment, imagine yourself being trapped in the sauna for the whole day! So if your succulents are living in the greenhouse, please unzip the cover or replace the cover with shading net.
All my succulents are completely exposed to the weather and I only protect them with:
1. polysheet for the heavy rain
2. shading net for the hot sun over 25 degrees
3. grow in high porosity growing media
4. most importantly a reliable weather forecast !
If the weather forecast showing there is 70% chance of raining, DO NOT WATER them few days before. They will much prefer slight acidic rain than your alkaline tap water. In fact I always collect rainwater whenever there's a storm. Personally I tend to cover them whenever I feel sorry for them if they have been sitting in the rain for days. The chances of them getting rotten is extremely high if I don't cover them. I think I have lost 5-6 babies last year due to rotten stems.
Shading net is extremely important if you are growing them outdoor and facing the sun during afternoon. Bear in the mind the summer sun tends to have higher UV value and the high heat will damage your precious babies if you are not careful. Shading net provides a layer of sun protection whilst promoting enough air circulation for them.
Nothing is more important than survival of my precious babies...
Please note all the young or newly potted succulents are recommended to grow under the shaded area or ideally facing morning sun or late afternoon sun.
Ohh did I forget to mention that all your babies will probably lose all their stressed colours too? As the weather is generally 10-25 degrees which the full sun would normally hit UV value 5-7 during day time, it's probably too much for babies to stress eventhough the night might be slightly cooler. It's ok, summer is all about the survival.
As you can see my Chrissy n Ryan has lost all her stressed colour during summer..
Extremely green Onslow
If you are looking to get new babies during summer, you will find that they root way quicker and make sure you grow them in right growing media. You probably think that I'm crazy on spending so much on high porosity growing media but this is the time when growing media with high porosity is extremely vital. Growing media with high porosity allows the roots to dry faster (than normal soil) and less likely to rot.
Always remember that succulents with healthy roots are most likely to survive extreme environment.