Indoor Growing Environmental Factors

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So you are starting an indoor grow? Indoor growing environmental factors and their management is KEY to the most successful grow. The better you can dial in the environment, you can greatly increase yields of anything you are growing. Below I am going to talk about the most important Factors to try and control. 


Lighting if you are growing indoors is one of the most important environmental factor but easy to control. You need to control the timing, spectrum of light, and intensity of light. This is accomplished with timers, proper lights, and adjustable light hanging systems.   


Timing is how long the plants are exposed to light and in darkness each 24 hour period. This is accomplished with light timers. They work by have the lights plugged into them so a relay can turn the power on or off to the lighting system. Timing depends on the growth stage of your plants. Seedlings, Vegetative, and Flowering stages have different recommendations. These are normally tuned in depending on type of crop being grown. 

Simple Grow Light Timer
Simple Grow Light Timer

Above is a Simple Grow Light Timer that is a 24 hour mechanical cycle timer. They are very dependable and accurate. You will also see digital timers. These simple timers normally only control one lighting system at a time.

Below you will see an example of a commercial timer. These timer can be simple mechanical while controlling multiple lighting systems. But many of them now a days are digital and have remote control via WiFi or app. All your lighting systems plug into one timer in this case. They have pickup in popularity for residential grows in grow rooms and green houses where multiple lights are in use.   

example of commercial grow light controller
Example of Commercial Grow Light Controller

Light Spectrum

Light Spectrum is vey important to plant development as you need to “copy” sunlight seasonally.  Plants love more Blue spectrum during the vegetative stage then more red / orange during the flowering stage. Some lighting systems are full spectrum like many LED but others you have to run different bulbs to get the correct spectrum control. (Check out our blog on types of grow lights)

Light Spectrum Plants need for growth

Light Intensity

Light intensity is very important to proper growth of your plants. It is accomplished with light system sizing and proper distance hanging above plants. Sizing is normally based on wattage of the lighting system. Many lighting systems will tell you in specifications what Wattage is best for amount of “growing space.”

Next is spacing between plant and growing light. Spacing can be adjustable with adjustable light hangers. The spacing will vary depending on the type of lighting system for multiple reasons. Lights such as HID type which have greater “throwing” distance so can be set further away. LED types of systems need to be placed closer to the plants.  Also some lighting systems such as HID create a lot more heat so they need to be placed further than LED (Which runs very cool) so plants are not damaged. 

Grow room lighting distance explain


Temperature inside your growing environment is very important. All plants have preferred growing temperature range that should be controlled. This should be monitored with a temperature gage which can be as simple as showing you. Than there are more advanced options that have relays to control different temperature manipulating devices. These more advanced devices can turn on these devices if the temperature reading goes outside of a certain range. 

grow temperature control unit
Grow Temperature Control Unit

Devices used to control temperature can range from fans, A/C units, and heaters. Many people run fans from oscillating to inline duct fans constantly to keep air flow. A/C units and heaters are normally used for grows in non temperature controlled structures such as greenhouses and unfinished buildings / basements. 


Humidity is vey important as plants’ general overall health. It is basically the moisture level in the air. If it is too low it can cause plants to transpire too much and dry out. If it is too high than it can encourage different fungal diseases. 

You can monitor humidity similar to temperature and many temperature gages generally include humidity. Unless you are using heat which can dry out the air, most of the time humidity control is about even distribution through your grow space. Plants create humidity by transpiration so close to plants leaf canopy can have higher humidity level compared to rest of room if there is not air movement. So oscillating fans are popular to keep air circulating around the grow space. Exhaust fans can be used to lower humidity also

oscillating fan for grow room

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