Indoor culture during the summer

indoor cultivation during the summer 17

Growing cannabis indoors in the summer or beating the heat of the sun in the summer

When summer arrives, some indoor marijuana growers despair and decide to stop everything until the heat is gone. Some of you transfer your efforts to the outside… And often to remote sites… Others contemplate their empty hydroponics installation, sitting on a chair… And we realize that we have space and equipment to gardening to set up an indoor culture for the summer ... Here's how to beat the heat of the sun.

summer, heat, sun, indoor culture

Waste of capacity during the summer

We could cultivate an entire cycle from May to September and indoors. But heat issues often seem too big to overcome. The obvious solutions include installing air or liquid cooled lamps, gas and high capacity air conditioning, and other engineering that costs money ...

summer, heat, sun, indoor culture
CO2 injection ...

You can do a cost-benefit analysis to determine if it's worth doing all of this. For example, a growth room of 150 m2 to cool, can cost 450 euros… But we can expect an average of 80 euros per month by keeping the room cool during the summer months. In addition, one can harvest 1kg of excellent marijuana by making this effort. So, is it worth it to install and use a portable air conditioner during the summer? Yes ! Here are a few other ideas for how to grow marijuana indoors during the warmer months.

Eliminate heat

The first thing to remember is that your indoor production probably already has a system for removing heat. This is to keep your room in an optimal temperature range. Many of us struggle with heat all year round, especially if we use HID (high intensity) lights. These are still the only lights that generate enough intensity to give you a high yielding flowering phase.

summer, heat, sun, indoor culture

If your growth time increases steadily, heat negatively affects photosynthesis, metabolism, and sweating. Many growers use C02 in their grow room. Adding extra CO2 helps your plants revitalize their metabolism during excessive heat.

You can also strengthen your plants against heat stress by feeding them. This in combination with an increase in CO2. This produces benefits during the growing period, and a better yield from your crop.

Air conditioning of your culture medium

The main thing to remember is that if you have fans, air conditioning or other climate control functions, you can probably increase the capacity of this already existing equipment. This is to keep your indoor garden within the temperature range that cannabis favors. But the growers complained about the high temperatures, especially in the afternoon.


Pay attention to the orientation of your exterior walls. If your grow room faces west, in the afternoon, be aware that the sun is crashing on the wall. And if the wall is poorly constructed and barely insulated, the heat from the sun is transferred to the growth room ...

summer, heat, sun, indoor culture
The perfect coating ...

In general, seal your growth room by doing everything possible to insulate the interior of the building from outside temperature and sunlight. Move the grow room to another location, lower in your home, best in the basement, so that the sun doesn't hit any wall where the grow room is.

Thermal camouflage

Plant deciduous trees or shrubs to provide shade in your home. Painting the exterior walls white can be a solution. Open the walls of the growing area from the inside and put on top-quality thermal insulation. Perhaps by installing thermal and UV insulators on interior walls.

summer, heat, sun, indoor culture
Ideal camouflage ...

The same types of interventions work if your growth room is in a home with a poorly insulated attic or a very dark roof. But, most homes do not have sufficient attic waterproofing ... So retrofitting can increase insulation. This is done at lower energy costs.

UV blocking

And if you use infrared blocking insulation (plaster, paint, anti-uv coating etc ...), you can also reduce the possibility that police will use thermal radar or RFI (radio frequency interference) to detect your grow room. marijuana…

Light cycle

Instead of having your lights on when it's nice and sunny, run your light cycle as much as possible after the sun goes down and before it rises. Monitor the hottest outdoor temperatures on an hourly basis and turn on your lights during these times. It means having manual or automatic control. So when indoor temperatures rise above a certain level, your lights go out.

summer, heat, sun, indoor culture

Of course, you can also use climate / thermal / hydroponic controllers that activate your ventilation and temperature-controlled air conditioning, and whenever temperatures exceed the maximum. You can also put non-HID lighting (such as T5, plasma, LED or induction) in your marijuana grow room. Make sure the HID lights are off when temperatures are warmer.

summer, heat, sun, indoor culture

Any form of electric lighting generates heat, so turning off HIDs and / or using inferior alternative lighting is not a quick fix. But it reduces the heat load. Remember what marijuana does… You can get by without using an HID during the vegetative phase. But during the flowering phase, you really need your HIDs if you want to get max THC and good harvest weight potential.

summer, heat, sun, indoor culture
Cool HID Tube (Air Cooled)

And yes, you can get decent harvests using a non-HID setup. This especially in a closet or a grow room. Regarding LEDs, there are still many issues that discourage professional growers. The claims of LED manufacturers are mostly fanciful ...

Fight against heat stress

There are several easy-to-use supplements that protect your marijuana plants from heat stress. Many of them also increase the metabolism of plants to utilize increased CO2 and boost the vigor and overall productivity of the plant.


A hydroponic potassium silicate propellant can be used. Because silica is a major component of the physical structure of your plants. And in general, it is often insufficient in hydroponic gardens. Even in terrestrial gardening, marijuana plants benefit from a silica additive when you start feeding your seedlings or clones that have well-established roots. Moreover, it is recommended to continue throughout the flowering phase.

summer, heat, sun, indoor culture
Sodium Silicate +

Other benefits are that potassium silicate increases flower production, helps the formation of resin glands and makes the leaves, stems and flowers of your plants better resist insect bites, and heat ...

Vitamin B

You can also fuel a hydroponic formula of vitamin B that helps marijuana plants cope with stress while increasing the plants' absorption capacity. This by using nutrients for faster growth and higher, higher quality yields.

summer, heat, sun, indoor culture
Vitamin B Complex = Healthier, Stronger and Larger Marijuana Plants

The "B complex", refers to a complete formula containing folic acid, B5, thiamine, B2, B7, niacin and other B vitamins that help with virtually all the functions of the plant. When you give your marijuana plants a well-designed B-complex, you help them cope with heat, cold, drought, bright light, increased metabolism, and other stressors that can limit growth and yield.


Nature has predicted that marijuana roots will grow underground, where temperatures are well below those of the soil. When marijuana root areas or nutrient waters exceed 24 degrees, various problems may occur.

summer, heat, sun, indoor culture
A root problem can be a real disaster for your culture

These include harmful microbes and / or algae in hydroponic tanks or harmful pathogens in root areas. The roots struggle to function and to stay healthy because they are too hot to function properly. The warmer your hydroponic water is the water temperature ... The less oxygen it contains, the less your plants absorb (from the water) the necessary oxygen through their roots.

summer, heat, sun, indoor culture
Healthy roots

Some growers lower the temperature of the root zone by adding ice cubes or ice water to their nutrient reservoir or by using a cooler. Thus they manipulate the exchange and circulation of the air in the growth room to ensure that the root zone is at 20/24 degrees.

Symbiotic network

You also help the roots of marijuana by providing beneficial microbes, so that the roots are shielded and strengthened by a symbiotic network of microbes, fungi. This makes the roots more likely to grow in temperatures above optimal temperatures.

summer, heat, sun, indoor culture
The symbiotic network between plant and microorganisms

There are many commercial formulas that claim to contain beneficial bacteria or fungi. Some of these formulas are powder. Others are granular or liquid. The most common is to add carbohydrates like molasses.

summer, heat, sun, indoor culture
Benefits of mycorrhizal fungi on grass… With and without

Carbohydrates are also taken up by the roots to help your marijuana plants have more energy, especially during the flowering phase when the plants have more and more time to meet energy needs. You can add a cooler to your hydroponic tank system or adjust the temperature of your hydroponic nutrients to keep your roots in an ideal temperature range (20/24 degrees).

Adapted strains

Some strains of marijuana are better suited to growing conditions during hot summer months. Strains close to equatorial weather conditions will be used. And of course they will be heavily sativa influenced.

summer, heat, sun, indoor culture
The dreaded Panama Red, 100% sativa

An article is necessary to complete this panorama of strains adapted to summer heat. But you already know what it takes to optimize your indoor growing during the summer. What is most important. Stay cool and enjoy your summer… outdoors.

Tags : Agriculture/GrowingGenetic
weed master

The author weed master

Weed media broadcaster and communications manager specializing in legal cannabis. Do you know what they say? knowledge is power. Understand the science behind cannabis medicine, while staying up to date with the latest health related research, treatments and products. Stay up to date with the latest news and ideas on legalization, laws, political movements. Discover tips, tricks and how-to guides from the most seasoned growers on the planet as well as the latest research and findings from the scientific community on the medical qualities of cannabis.