Does heat or rays of sun hurt plants? Short answer: yes, they absolutely can.
Like us, plants have their limits. Too much sun and extreme heat can cause heat stress in plants, which affects their health, growth, and productivity. In this season there are plenty of challenges: Scorching temperatures, intense UV rays, unexpected droughts… and plants that are clearly struggling.
The good news? There’s a lot you can do to prevent damage, and even more ways to help your plants bounce back after a heatwave.
In this blog, we’ll explore:
• What heat stress means and how it affects plants
• How to recognise signs of heat stress
• What types of plants cope best in hot weather
• Practical strategies to keep your garden cool, hydrated and thriving
• And the Atami products that can help your crop stay strong, all summer long
Whether you grow outdoors or indoors, you’ll find practical tips to protect your plants and maximise results — no matter how high the temperature climbs.
Let’s dive in!
What is Heat Stress and How Does it Affect Your Plants?
Picture this: it’s mid-July, the sun is blazing, and it’s over 30°C in the shade.
Well, if that sounds uncomfortable to you, your plants probably feel the same — unless we’re talking about a cactus, of course.
When temperatures rise beyond what they can comfortably handle, they experience what’s known as heat stress, a physiological response that can seriously affect their health and productivity.
But how do you know if your plants are struggling?
Here are the most common heat stress plant symptoms to watch for:
• Sunburn on the leaves
The most obvious sign. The leaves may have pale green to whitish spots which turn brown where they have been exposed to direct sunlight.
• Wilted leaves
Another common symptom are the wilted leaves. Leaves might droop, curl, or develop dry, crispy edges — especially during the hottest part of the day.
• Slow or stunted growth
High temperatures can affect photosynthesis and root development. If your plants seem to be “paused”, it could be due to heat stress.
• Flower and fruit drop
Heat-stressed plants may abort flowers or drop developing fruits in an effort to survive. This is their way of conserving energy, but it comes at a cost to your harvest.
• Soil drying out too quickly
If you’re watering regularly but the soil is bone dry again within hours, the heat may be evaporating moisture faster than your plants can use it.
• Limp, weak-looking stems
Lack of internal water pressure due to dehydration can make stems soft and bendy, especially in younger or container plants.
If you notice these signs, don’t ignore them. Acting quickly is key to helping plants after a heat wave, whether that means giving extra shade, adjusting your watering routine or giving your plants a health boost with the right nutrients and support.
Now that you know the signs, let’s look at how to prevent heat stress before it happens, including practical growing tips and smart product support that can make all the difference.
Choose Wisely: Not All Plants Love the Heat
Just like us, every plant has its comfort zone. While some absolutely thrive in the heat, others wilt at the first sign of a scorcher. Knowing your plants’ heat tolerance is the first step to a thriving summer garden.
Each species — and even each variety — has its own optimal temperature range. So, when planning your summer grow, it pays to pick those that can handle a bit of sunbathing.
Here are some great options if you’re looking for heat tolerant container plants:
• Tomatoes – They love the heat, as long as they get enough water.
• Peppers – Chillies and sweet peppers both enjoy sunny spots.
• Aubergines (eggplants) – Ideal for warm patios.
• Geraniums & marigolds – These flowering beauties are excellent heat tolerant plants for pots.
• Succulents & herbs like rosemary or thyme – Drought-resistant and perfect for forgetful waterers.
If you’re in a dry or particularly hot region, consider adding some drought and heat-resistant plants to your setup. Look for varieties bred for resilience — or that naturally come from arid regions.
Tip: Plants in containers heat up (and dry out) much faster than those in open soil. So, choose larger pots, use quality soil mixes, and keep an eye on water levels throughout the day.
Smart Strategies to Prevent Heat Stress
Once your plants are in the ground (or in their pots), it’s time to help them stay comfortable when the heat hits hard. Here’s how to protect your plants from heat and keep them growing strong:
o Environmental Control
The midday sun can be brutal — and even sun-loving plants appreciate a little break. Offering partial shade during peak hours is one of the best ways to avoid heat stress.
• Use shade cloths, parasols, or even DIY frames with breathable fabrics.
• Place plant pots and containers where they get morning sun and afternoon shade.
• Consider moving your plants to cooler areas if possible, during a heatwave.
Another pro tip? Look after the soil!
• Use a well-draining substrate to avoid soggy roots.
• Apply organic mulch (straw, bark, or compost) around your plants to lock in moisture, regulate temperature, and feed the soil over time.
o Smarter Watering
When the heat rises, so does your plants’ thirst but more water isn’t always better. The key is to water deeply, consistently, and at the right time.
• Water early in the morning or late afternoon to reduce evaporation.
• Increase frequency in very hot spells but avoid overwatering.
• Always check your substrate before watering. The top may look dry, but deeper layers could still be moist.
To avoid water stress, consider drip irrigation systems or programmable timers. These helps deliver just the right amount of water directly to the roots: no waste, no guesswork.
Next up, we’ll cover how to give your plants an extra edge against the heat — including why silicon is your secret weapon this summer.
Strengthen Your Plants to Beat the Heat
Even with perfect watering and smart shading, heat stress in plants can still take its toll. So, how can I protect my plants from the heat in addition to the methods mentioned above? Build in resilience from the inside out!
And this starts with proper nutrition.
A healthy, well-fed and hydrated plant is much better equipped to cope with stress, that’s a fact.
If your plant is already suffering from deficiencies, it will struggle to survive the summer, but don’t worry, follow a balanced fertilisation plan is easier than you think. Focus on:
• Potassium – Improves water regulation and supports flowering and fruiting.
• Magnesium – Essential for photosynthesis, especially under strong light.
• Calcium – Helps maintain strong cell walls and prevents blossom end rot.
• Micronutrients – The plant doesn’t need large amounts, but they are essential! Iron, zinc, and boron all play vital roles in heat resilience.
• Recover them after a heat wave with stress-relieving additives like Alga-C or B’cuzz Booster Uni.
• Silicon – a game-changing element that even though it’s not essential it’s super special:
o Creates a natural armour on leaves and stems
o Improves drought and heat resistance
o Strengthens plants so they can better handle pests, wind, and heavy yields
o Enhances nutrient uptake, especially potassium
Boost Their Natural Defence with Silic Boost
Silic Boost is rich in bioavailable silicon This means that your plants will be able to benefit from all the advantages we have listed above.
This innovative product works fast and lasts long – even with just 0.1 ml per litre of water!
Whether you’re growing on a balcony, in a greenhouse or out in the open field, Silic Boost makes your plants more resilient to the challenges of summer. It’s easy to add to your usual feeding schedule, and you’ll notice the difference quickly.
No more wilted leaves or drooping stems — just strong, vibrant plants ready to face the sun.
Summer’s tough — but maintaining your plants don’t have to be
Healthy plants start from the ground up with the right substrate, a smart watering routine and, most importantly, proper nutrition.
Get those three right, and your crops will be ready to take on the heat like champs.
And if you want to go one step further… don’t forget to add Silic Boost to your routine. Its high concentration of silicon helps your plants stay resilient, not just against heat, but also wind, pests and stress.
Because summer doesn’t have to mean struggling.
It can mean growing stronger. Happy growing and happy summer!
