How Winter Weather Can Affect Your Indoor Garden

By Jeff Walters
Published: January 15, 2017 | Last updated: February 7, 2017 10:42:32
Key Takeaways

Even though you are snug and warm inside your house when the weather turns nasty, your indoor garden can still feel the effects of the outdoor air. As an indoor grower, you need to know how to deal with the cold and to protect your plants from the elements so your garden prevails. It is the only way to truly get maximum yields year-round.

Gardeners new to indoor growing often overlook how the outside weather systems affect the plants growing in their completely sealed rooms.


The extreme cold is a drastic issue to overcome and just as with extreme heat, you have to eliminate it.

Here are some considerations to make when it comes to winterizing your growroom.


When building your growroom or setting up your grow tent, pay special attention to how the cold weather will affect that area.

If you’re building a separate enclosed area in an outside shed, in the garage or even the attic, use insulated foam boards to help keep in as much heat as possible during the winter.

These rigid foam boards come in various thicknesses and have a reflective barrier surface designed to help trap the surrounding air temperatures.


If using a grow tent or other semi-portable enclosed grow space, the use of a lightweight radiant heat barrier is the way to go.

Simply line the walls, ceiling and floor with this super-reflective barrier and you will notice a welcome change during the cold winter months.


Most hydroponics stores carry this type of reflective material in large rolls that are four-feet tall and can be cut to any length.

Otherwise, using a poly-style tarp with a painter’s cloth over it will increase the warmth of the floors of sheds and basements.

Next, elevate your soil containers by either placing them on pallets or boards to form a barrier between the cold ground and your plants’ root systems.

For larger containers, you may want to use furniture dollies or other wheeled platforms to help move the heavy containers around and to keep them off the floor.

Electrical heating blankets or pads can also come in handy, but they can get damaged fairly easily when heavy items are placed on top of them.

Instead, wrapping the bottoms of the containers or nutrient feeding lines with foam insulation can help keep the cold out. Simply wrap your nutrient feeding lines with insulated foam the same as you do your indoor or outdoor water pipes to prevent form freezing.

During the winter months, a supplemental CO2 release system helps increase indoor temperatures a little bit because CO2 also acts as a barrier that can trap heat in enclosed areas.

CO2 will help keep more heat trapped in confined spaces, making winter a great time to think about supplementing CO2 if you’re not doing so already.

Sealing up cracks and other areas with either removable tape or insulating foam is another way to protect your plants form the outside weather conditions. With the lights out, look for areas where you see daylight seeping in from the outdoors and simply seal them up.

Use fan speed controllers to help establish positive airflow. Positive airflow is essential to plant health and can also help to establish a barrier that cold air cannot get through.

Dealing with Growroom Humidity in Winter

Moisture is another weather-related obstacle that can be hard to deal with. When the rainy and snowy weather pick up, be on the lookout for molds, pests and other moisture-related problems.

Most indoor growers use dehumidifiers to remove the excessive moisture in the air that is being pumped in from outside as well as the moisture from displaced nutrient solutions. This works well, but remember you still need to have some humidity inside for a successful garden.

Since you’ll be generating more heat inside in the winter, the amount of humidity in the room will also rise. There is a difference between relative humidity, which is the outside weather, and proper humidity, which is what the indoor grower strives to maintain in order to have a successful garden.

Here is one example: Tomatoes do very well in the 45-70 per cent humidity range. Proper humidity and temperature levels help the plants take in water from the root system and evaporate that water intake through their leaves and flowers.

Known as transpiration, this is how plants breathe and cool themselves down as needed. If the proper level of moisture being enclosed in the growroom is not tolerable for your plants, they will show signs of stunted growth, wilting and other noticeable ailments.

When dealing with cold weather, it pays to be prepared. Constant monitoring is the best way to evaluate your growroom even when you have the most up to date equipment running.

Equipment failures happen every now and then, so being able to respond quickly can make the difference.

Also, the addition of a backup battery system is another great thing to consider. Remember, as an indoor grower, not only do you need to know your garden, you also need to know what to do when the cold winter winds blow.


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Written by Jeff Walters

Profile Picture of Jeff Walters
Jeff Walters is a former marine who spends most of his time outdoors fishing, hiking, hunting and gardening. He is a self-educated former martial arts instructor, published author, hot rod enthusiast and co-founder of many outdoor-related websites. His current focus in on green energy and learning how to live a sustainable lifestyle.

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