How to achieve the perfect grow room environment.

It’s winter, and you know what that means. Cold temperatures and dark nights. Wherever you choose to grow, it’s not uncommon for the conditions outside to have an effect your plants inside. To stay one step ahead it is essential that you create the perfect environment for your plants to thrive, so they can get the biggest and highest quality yields possible.

What are the benefits of a perfect growing environment?

  • Your plants will grow faster
  • You can harvest bigger yields
  • Your plants will be healthier, greener and overall hardier
  • The quality of your produce will be noticeably better
  • Better smelling, tasting produce
  • More resistance to issues such as over/under-watering, heat stress, light stress, pests, mildew and other diseases.


Firstly, consider a grow tent. This is the easiest way to have ultimate control of your environment. Essentially, a grow room is a room in itself, often lined with reflective material for an even spread of light and heat. A grow tent shuts your plants off from any elements outside of it, creating a fully customisable and purpose built space for you to create the ultimate environment.


We all know that plants need light to grow. Photosynthesis is the process used by plants which captures light energy and converts water, C02 and minerals into oxygen and energy-rich organic compounds. So it’s no surprise that for a health plant to bloom it needs access to fairly strong and consistent lighting. The amount of light your plants are provided with is one of the main factors that will determine your yield, and with smaller, less powerful grow lights your yield will be limited no matter what nutrients it receives or what other measures you have in place. Some LED grow lights use custom colour spectrums as different spectrums can produce different effects to how your plant grows. This really comes down to personal preference and what works from grower to grower. It is possible however to give your plants too much light, especially with some of your bigger grow lights, so make sure your light source is not too close to your plants as this could result in light burn and light stress which can be avoided quite easily.



Temperature is important all year round, but you might want to take some extra care in maintaining a consistent warm temperature in your grow room during the winter as houses are known to get very cold especially during mornings and nights. A handy rule of thumb is if it’s comfortable for you, then it’s probably comfortable for your plants. It may be wise to invest in a heater for the colder months to keep your grow room nice and warm, plus a thermometer so you can read the temperature of your grow room and keep it at a level that suits your plants needs.

Air and Ventilation

Like humans, plants also desire a gentle breeze and some fresh air. Not only does this mimic outdoor conditions, good air circulation helps to prevent problems such as white powdery mildew, bud rot, and pests such as fungus gnats and spider mites. A small gentle breeze travelling over, through and under your plants provides the perfect amount of air circulation in your grow room, aim for your leaves to be gently rustled by the breeze you have provided. A small breeze is also beneficial to strengthening your stems for when your produce begins to grow in mass and become heavy. You do not want your fans pointing directly at your plants as this can cause wind burn, however you do not want any leaves sitting in still, stagnant and hot air. A small clip on, floor, or pedestal oscillating fan or two can work wonders for moving air through your leaves. 

Although making sure you have air moving around your grow room, it can be equally as important to vent warm air out of the room, especially if the room is starting to get too hot while your lights are running. Although it’s common knowledge among growers that ventilation is needed for powerful HPS lights, please note that ventilation can be required for grows using LED, LEC, CFL, or T5s if the wattage is high enough. With every light the higher the watt, the more heat is produced. If you notice heat regularly exceeding 30 degrees Celsius you should consider venting out the heat to keep the temperature under control. So if need be, get yourself an extractor fan system to cycle out the old air and bring in the new fresh air and CO2 from outside to boost your plants growth and yield.

Reflective Material

You’ve paid for your lights, so don’t let any of it go to waste! Reflective material bounces the light once it hits the surface, so if your tent is fully lined with reflective sheeting then you know every single bit of that light energy is being used and is multiplying. If you haven’t got a grow tent lined with reflective material then don’t worry there are still alternatives. You can line your room with specialist reflective sheeting from your grow shop, or you can even use aluminium foil on your walls as it has the same effect. Even white paint works as a reflector, so if you’re on a budget or don’t have the space for a tent this is an option you can use to create a better environment and to use your grow light to it’s max!


Finally, unless your humidity is either on the very high or very low end of the spectrum, it shouldn’t cause any major problems with your grow. If your humidity levels reach over 70%, moisture buildup and too much humidity in your grow room can result in rotting, like bud rot or flower rot. This is the worst, especially because the results can’t be seen until you’re harvesting, and at that point, it’s too late to fix any problems. White mould can collect on your leaves, preventing them from taking in light and water. White mould will feed off your plants, and if not detected early enough, can render your yield useless.

If your humidity levels are too low in your grow room, often below 40%, growth will become stagnant- If your plant feels it will become dehydrated, it can also result in the closing of the stomata, which means the plants won’t be able to take in much (if any) water.

In addition,

Plants love to take in water vapour through their leaves, but when there’s not enough water in the air, your plants will need to get their water somewhere else, their roots. When your plants are thirsty and taking up lots of water into their roots, nutrients will follow. Too much nutrient uptake is bad for your plants, and you’ll start to see nutrient burn on the tips of your leaves.

If your humidity levels are spiking either below 40% or over 70% then it may be a good idea to purchase either a humidifier or a dehumidifier, in order to add humidity or decrease your levels accordingly, providing a much better environment for your plants to thrive.


There is no ‘perfect’ environment, some plants may respond differently to environmental factors than others, but if you follow this guide and pay attention to these factors, and know what to look out for, this one size fits all approach will be very beneficial to your plants growth and wellbeing. If everything goes well, you should be able to harvest plentiful, weighty, and amazing produce.

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