While hemp cultivation has undergone rapid changes in technology and technique over the last decade, many of the basics remain unchanged. To this end, both commercial producers and hobbyist growers must follow the baseline principles of controlled environment agriculture to find success. This includes understanding basic grow room design as well as the role of essential equipment.

Many hobbyist growers set up indoor gardens in small spaces such as closets and grow tents. In designing these operations, you must decide what approach best fits your needs. This decision-making process balances spatial constraints with garden functionality, as well as the financial costs of horticultural equipment. Whichever path is most predominant in your planning process, it’s possible to produce top-shelf plants in the privacy of your own home - without breaking the bank.

A popular choice for burgeoning growers is cultivating hemp in tents and closets. For this line of inquiry, we are going to investigate the environmental constraints plus the grow devices that will most affect your grow. As will be seen, these two important topics inform one another when it comes to achieving ideal climate conditions while growing in small spaces.

Environmental Constraints

Growing hemp in a tent or closet often affords growers little “wiggle-room” for error concerning environmental limitations. This is namely because small changes in temperature and humidity can rapidly influence ambient conditions in such tight quarters. Nonetheless, closets and grow tents afford new growers a great opportunity to learn about the basic requirements of successful cultivation.

When setting up an indoor grow space, your best bet will be to achieve temperatures ranging from 75 - 80 degrees Fahrenheit. It can be challenging to achieve this temperature range in confined spaces because of the heat produced by grow equipment as well as outdoor weather (especially during summer months). For example, while a 1,000-watt grow light doesn’t have much impact on ambient temperatures in large spaces like garages, it can quickly make smaller areas extremely hot. This excessive heat can impact growth and potentially offer the ideal breeding ground for harmful infestations.

Humidity levels will fluctuate based on the plants you aim to grow. As the hemp species is native to dry and arid climates, these plants do best with humidity levels around 50%. It can be tricky to keep this consistent, as the confines of a tighter space make fluctuations in humidity difficult to avoid. Your chosen irrigation method will directly influence the humidity, so be sure to take that into account when planning your grow space. Also be careful not to let too much moisture into the air, as pathogens like powdery mildew and bud rot may appear.

The notion of airflow is immediately tied to the environmental constraints of heat and humidity, as well as your grow devices. The most important takeaway here is that airflow is your best tool for dealing with climate while growing in a tent or closet. By counteracting these factors with exhaust systems or air conditioning (which we discuss more in the next section), you can achieve the ideal balance of heat and humidity in your small grow space to maximize resistance against bugs and pathogens.

Growing Equipment

Cultivators have a plethora of equipment options to choose from when prepping grow tents or closet gardens. To this end, while many small-scale growers will choose devices by price, others are willing to spend more for the perfect fit. Either way, the equipment you choose to power your grow will be extremely impactful on the success of your crop.

Airflow for Grow Tents & Closets

Exhaust fans offer the simplest and most affordable method for regulating the environment in tents and closets. They accomplish this by expelling hot humid air while pulling in fresh, CO2-rich air from the outside. In best-case scenarios, you can run the exhaust out of your grow space to a window or vent leading directly to the outside. However, depending on your setup, you can also exhaust a grow tent or closet into the larger area of your home or garage.

Air conditioners are used by growers in situations where exhaust fans aren’t sufficient to handle excessive heat and humidity seen in the summer season or tropical climate locales. While they work great to regulate these environmental constraints, they pose challenges for planning. This is namely because portable AC units take up valuable square footage in an indoor garden and must be positioned in a spot that allows them to dispel heat and humidity to the outside.

Horticultural Lighting

Because they can potentially produce excessive heat, grow lights are extremely impactful on the temperature of small indoor gardens like tents and closets. However, you have three primary choices that are powerful enough for both vegetative growth and flowering phases: SE HPS lights, DE HPS lights, and LED lights.

Single-ended HPS lights are the most affordable option for growing cannabis in a small space. Yet, SE HPS lights produce excessive heat that oftentimes must be counteracted with cooling. Therefore, SE HPS setups generally require more planning and materials for growing than other options like LEDs. While extra work and added materials are a deterrent for some people, others are willing to “go the extra mile” to save some money with a SE HPS setup.

While commercial growers have come to love double-ended HPS lights, they simply aren’t practical in small indoor spaces. Namely, because DE HPS lights produce excessive heat while not offering options for air cooling. Even more, because DE HPS lights must be positioned 5 ft. above the garden canopy, they will not be as conducive to small spaces.

Due to their electrical efficiency, cool-running temperatures, and operational longevity, LED lights have taken the hemp industry by storm. Even more, because they don’t produce much heat, LEDs are the best choice for growing in more confined spaces. Unlike SE HPS lights that must be integrated with an air-cooling system, LEDs operate well in tighter areas without additional materials and planning. The wide range of LED options available makes it possible for new growers to find an effective and cost-friendly choice.


While it’s undeniable that indoor cultivation practices are changing with the times, many of the basics remain the same. By following the guideposts of such fundamentals as heat, humidity, and lighting, you can affordably learn the growing process and adopt your preferred method.

In parting, it’s worth noting that small indoor gardens like tents and closets offer newbie growers a great opportunity to hone their skills. Not only can you learn the basics of controlled environmental agriculture, but you can also experiment with the latest cultivation technology. By perfecting your craft on a small scale, you can take your knowledge onto larger operations if you desire.