How To Avoid Heat Stress On Cannabis Plants

How To Avoid Heat Stress On Cannabis Plants

Discover the essential techniques to prevent heat stress on cannabis plants and ensure a healthy, thriving crop. This guide will provide you with practical solutions to control temperature, humidity, and ventilation, while also addressing the importance of proper marijuana strain selection and ideal growth conditions. Maximize your plants’ potential by avoiding heat stress and securing a bountiful harvest.

How Hot Is Too Hot For Flowering?

Cannabis plants need the correct amount of heat during flowering stage in order to grow and stay healthy. Aim for a temperature of 18–26°C throughout the flowering phase. If it gets too hot, the plant can suffer from stunted growth and other health issues detrimental to its quality. Too much heat can cause your flowers to degrade, so be sure to create an optimal environment for your plants.

Warm weather regions pose a particular challenge because the temperature is often too high for proper flowering. In these circumstances, you will need either air conditioning or effective fan systems to keep temperatures down.

Ensure that all your equipment is working properly and pay close attention when temperatures start creeping up – it’s easy for things to get out of hand quickly if left unchecked! With some planning and consideration, you can make sure your cannabis plants remain happy and healthy throughout their flowering period.

How Can You Identify Heat Stress?

How Can You Identify Heat Stress?

Heat stress is one of the most dangerous threats to a healthy plant and can easily be identified if you know what to look for. One telltale signal of heat stress is when the tips of fan leaves begin to curl upward, becoming dry and withered.

This indicates that the damage is due to heat rather than malnutrition, as the plant would exhibit different signs in this case. As a result of excess heat, leaves will develop large brown spots or blotches along the edges that are often accompanied by yellowing patches.

You should focus on areas like the top canopy or exterior perimeter of your plants since these areas are more likely to be affected directly by extreme temperatures.

Dealing With Heat Stress Indoors

Explore the world of indoor cannabis cultivation and learn the ins and outs of dealing with heat stress. This comprehensive guide will cover essential techniques for temperature regulation, humidity management, and effective ventilation within your grow space. Master the art of creating an optimal environment for your plants and safeguard your indoor cannabis garden against the damaging effects of heat stress.

Place Fans in the Grow Space

In your grow space, the use of fans is one of the simplest and cheapest solutions for cooling down your environment. Having a fan in your space will help disrupt any still, hot air temperature that might be lingering and create a convection current to bring cooler air into the area.

Not only will this help cool things down, but it will also provide gentle wind-induced stress on your plants that helps further their growth. The wind generated by the fan can help prompt stronger stems by forcing them to restructure and support themselves which, in turn leads to increased hardiness all around.

Set up wise, you’ll want to aim your fans gently at various areas around the space so they are able to blow adequate amounts of air while creating this effect without being overly aggressive or damaging any delicate parts.

Use Air Conditioning

Air conditioning is a great way for indoor growers to maintain optimal climate conditions for their plants. Air conditioning units circulate cool air throughout the grow tent and remove hot, humid air from it, helping to keep temperatures in check. This helps to maximize the health of the plants and avoid issues such as heat stress which can cause wilting or other serious problems.

Change the Position/type of Lighting

When it comes to lighting your indoor growth setup, the importance of positioning and type of light should not be underestimated. If you notice signs of heat stress in your plants, then it’s essential that you first assess how close they are to the grow light source.

If only the top fan leaves are showing symptoms, then readjust the position of your lights so that they hang further away. This can often make all the difference when dealing with cannabis heat stress in greenhouses.

Install an Exhaust System

Installing an exhaust system in a grow space has many advantages that can help maximize yields and ensure healthier plants. The purpose of an exhaust system is to remove hot and stale air from the environment in order to bring in cooler, fresher air and regulate temperature.

A proper exhaust system includes a fan that creates negative pressure, sucking out the old air while simultaneously allowing fresh air to enter. If you are also running fans at the same period of time, it helps replace the outgoing air with newly supplied oxygen which will benefit your plants’ growth.

Use Supplements to Treat Damaged Plants

Using supplements to treat damaged plants is gaining traction in the indoor growing community. Seaweed and kelp extracts are a popular choice, as they are loaded with minerals and nutrients that make plants more resilient to heat stress while also strengthening cell walls and helping to absorb key nutrients like zinc, copper, and phosphorous.

Silicon is another effective supplement that can be used to remedy the effects of heat stress. It increases resilience to changes in temperature and can boost nutrient absorption levels.

Read More: Do Autoflower Plants Produce Autoflower Seeds

Mycorrhizal Fungi

Mycorrhizal Fungi

Mycorrhizal fungi are a group of species that form a symbiotic relationship with plants, such as cannabis. This type of fungus sends tiny filaments known as hyphae into the roots of the cannabis plant to aid it in surviving various sources of stress.

When these filaments enter the root system, special opportunities arise for nutrient exchange between the two entities. The cells of the plant then enwrap those of the fungus and an interlocking structure called a mycorrhiza forms.

In this connection, plants give off sugars created during photosynthesis which the fungus consumes while simultaneously helping out the plant by expanding its root network.

How to Protect Against Cannabis Heat Stress Outdoors

Outdoor growers have no option but to face up to the risks posed by extreme weather events, such as high temperatures and humidity. Cannabis heat stress occurs when temperatures outstrip the capabilities of a plant to regulate its temperature by transpiring.

This typically happens in regions closer to the equator, where temperatures can spike suddenly and dangerously for plants not adapted to those levels. Symptoms of heat stress include wilting, yellowing leaves, tissue death, reduced photosynthesis, decreased fertility, and sometimes outright death.

Time Your Watering Well

Watering your plants at the right time of the day and in the correct quantities is essential for promoting healthy foliage. If done incorrectly, cannabis leaves can start to curl up and suffer from cannabis heat stress.

The amount needed depends on the size of your grow area – larger raised beds require more water less frequently than pots, for example. It’s important that the top few centimeters of soil dry out before applying more water; this prevents root rot, a common problem amongst novice growers.

Ideally, watering should take place either in the early hours of the morning or after sunset when temperatures are cooler and evaporation is reduced.

Additionally, you should only apply foliar sprays during these times so as not to damage delicate leaf tissues. This helps to maximize absorption and limit wastage, helping keep your plants properly hydrated all year round.


Mulching is an important process for gardeners and landscape professionals as it plays a key role in retaining soil moisture and protecting plants from extreme temperatures. Dead mulch involves applying a layer of dead, organic material to the surface of the soil.

Common options are hay, straw, shredded leaves, sawdust and pine needles. This insulation helps protect feeder roots from drying out in the extreme heat of the sun while also shielding beneficial microbes living in the topsoil or around the root beds.

Avoid Stress

Avoid Stress

Plants naturally come with a built-in defense mechanism to handle stressors and other environmental variables. For example, when exposed to cannabis heat stress cannabis plants are capable of bouncing back quickly under normal environmental conditions. To help ensure the health of your sunbaked crop it is important to minimize the amount of additional stress that you place upon it.

There are several common techniques and practices used during the growing cycle that can expose cannabis plants to varying levels of stress. Transplantation from a small pot into a larger pot or bed is one such technique, however doing so can add an increased level of shock to your plants as they establish their root systems in new soil.

This is especially hazardous if executed in high temperatures, as the plant’s ability to cope will be reduced. Therefore, it is best practice to avoid transplanting during particularly hot days and to provide adequate shelter wherever possible in order for your cannabis plants to adjust safely and successfully.

Pots Are More Portable

Pots Are More Portable

Pots are a great choice for anyone looking to maximize portability when planting outdoors. With pots, you don’t need to worry about making sure your plants get the right amount of sun or rain in a given area – if the hot climate is too intense for them in one spot, you can simply pick up and move the pots to another.

This convenience is especially handy for growers who want to avoid seasonal weather changes, as they can easily transport their crops indoors during more extreme climates.

A further benefit of pot-grown plants is their smaller footprint, because the crop doesn’t need to be spread out over a large area like ground planting requires, container gardening takes up much less room and can fit into small spaces that even traditional window box containers cannot.

Set Up a Temporary Shelter

Creating a temporary shelter for your plants is an effective way to protect them from harsh elements during summer’s peak heat. Not only does a shelter help to combat oppressive temperatures, but it also helps to protect plants against sudden weather shifts like heavy rain and wind. Setting up a temporary shelter is easy in most cases and can be done with any fabric or tarpaulin available.

To set up the shelter, begin by deciding where best to place the support poles of the structure. Poles should be spaced no more than 3-4 feet apart so that they can provide adequate support for your fabric covering.

Make sure when connecting poles together that you use either metal pipe clamps or zip ties so that it will remain sturdy even in strong winds.

Once secured, drape your chosen shade cloth over the top of the poles and then carefully secure it using rope or bungee cords to form a dome-like shape providing shade suitable for most plants. For additional protection against wind, you may also add a weighted bottom such as sandbags on each corner of the shelter.

Outdoor Plants Can Benefit From Supplements as Well

Outdoor plants can benefit from supplements just like their indoor counterparts. Seaweed and kelp extract can help boost plant resilience when added to the soil. This supplementary nutrient helps protect plants during extreme weather events, like drought or heavy storms, as well as providing other essential nutrients.

Additionally, some species of seaweed and kelp contain enzymes that can help break down organic matter in the soil, allowing your plants to absorb more nutrients from their existing environment.

Can Plants Recover From Heat Damage?

Heat damage to plants can be devastating, especially in hotter climates, however the good news is that it can usually be fixed with some simple care and maintenance. The most important thing to do when your plants have been affected by heat damage is to optimize your watering schedule.

Make sure you’re not underwatering or overwatering them by checking the soil regularly or investing in a wireless moisture sensor to be sure you’re giving your plants just enough water while also improving drainage.

To reduce further stress on your plant, lay down mulch and move any containers that are exposed to direct sunlight into a more sheltered spot for a few days. If you think defoliation could help your heat-stressed plants recover faster, resist the urge until visibly recovering, removing leaves will bring even more strain on an already distressed plant.

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