If you’re an impatient gardener in the depths of a chilly winter, why not add a grow box to your gardening toolbox. Many gardeners consider building or buying a greenhouse to grow plants in the cold winter months. However, these can be expensive and a significant time commitment to get a return on your investment. A grow box, on the other hand, is small, convenient, and will allow you to grow flowers and vegetables in any climate.

Imagine fresh lettuce and tomato salads on your holiday table, fresh from your own in-home garden. Herbs are particularly good candidates for a grow box, both because of their fast growth rate and smaller size.

Because you can control the temperature, light exposure, and humidity, you’ll be able to produce vegetables out of season. Fussy strawberries put forth delicious fruits any time of year when you can give them the chill they need to flourish. You can use your grow box all year round. Grow cold-weather vegetables in the heat of July, or summer fruits in January.

What is a Grow Box?

The most complex grow boxes are entirely enclosed and contain a light source for nurturing young plants. They can also feature exhaust fans and watering systems. You can choose hydroponic methods or grow your plants in soil. Hydroponics uses a water-based nutrient mixture instead of soil. However, simpler systems feature blocks of compost-rich soil.

Grow boxes come in a wide range of sizes, depending on how many plants you hope to grow. If you have sufficient space, you can even expand your operations into a room-sized “grow room.” You’ll find some grow boxes for sale, or you can build your own.

Features You’ll Find on a Grow Box.

To optimize the environment for your plants, your grow box will need a range of features and capabilities you might not have considered. When we garden outdoors, we normally only pay attention to the most significant weather conditions, such as heat, light, and moisture.

Growing plants indoors means paying a bit more attention to other factors, including ventilation. This isn’t only for the plants, but for the health of your home, as well. You want to be sure that excess heat or moisture from your grow box doesn’t seep out into your home and affect your air quality.

Carbon Filters

These filters keep any odors from exiting the grow box and affecting your home. Although most people find the smell of growing plants to be neutral, if not entirely pleasant, you may want a filter.


All plants need light to grow, even if some prefer less than others. There are several types of grow lights you can purchase for your grow box, including compact fluorescent lamps (CFL), high-intensity discharge lights (HID), and even LED lamps. Each has its own benefits and drawbacks. Cost and energy usage are two major factors in reaching a decision.


You may not think of your plants as breathing, but they do. They simply “inhale” carbon dioxide and “exhale” oxygen. Your plants need carbon dioxide to breathe to accomplish photosynthesis. One drawback of a fully enclosed grow box is that they’re isolated from sources of CO2.

A ventilation system in your grow box will permit the free flow of air and help control the humidity and temperature of your plants, keeping them healthy and free from fungus and disease. For supplemental CO2, you can purchase cans of this compressed gas for systems that release it slowly into your grow box, so your plants can breathe.

Watering systems

For a hydroponic grow box, you’ll need drip systems to provide your plants with a nutrient solution to replace the soil and a filtering system to ensure they remain free of contaminants.

With a soil-based grow box, you may want a mister or a self-feeding system to ensure your plants get water regularly.

How to Build a Grow Box

You can build your own grow box out of a variety of materials, including old crates and broken appliances.  You can often find plans and tips online for a wide range of plants, both legal and not-so-legal. Keep your mind open when looking for instructions that fit your skills.

Depending on your mechanical and carpentry talents, you may want to start with something simple that’s only partially enclosed. These will provide the basics of warmth and long hours of artificial sunlight. You’ll need to tend to the plants’ additional needs for water, fertilizer, and humidity.

A fully enclosed grow box will take more skill, as you’ll need to add systems for lighting and ventilation in a closed environment.

Refrigerator grow box

A broken refrigerator makes an ideal grow box. It’s already well insulated and has plenty of room for your vegetables. Even tall ones like tomatoes will fit into the average fridge. You modify an old fridge into the ideal plant environment with just a little work and a good drill:

  1. Make sure the refrigerator still closes complete by checking the seals
  2. Remove anything you don’t need such as the coils or air compressor.
  3. Remove the shelves and clean it out thoroughly
  4. Line the interior of the fridge with aluminum foil to help reflect light
  5. Drill a hole through the top or back of the fridge to install your grow light large enough for the cord.
  6. Install your grow lamp in the fridge at the top or simply put it on the top shelf
  7. If you decide to use fans, cut larger holes to fit your exhaust fans in the back of the fridge
  8. Install the fans into their holes and use silicone caulk to seal
  9. Replace the shelves
  10. Add plants

Other DIY projects include converting an old armoire into a grow box that will look great in your home. You can also build your own cabinet from plywood. The most critical components are the reflective lining, the grow lamp and the ventilation fan.

If those are a bit more work than you expected or larger than you need, you can even build a mini grow box from an old PC. The fan is already built-in.

Buying a Grow Box

If you’re not handy or want a turnkey system to start growing veggies and flowers indoors, you’ll find some enclosed systems for sale with everything included but the seeds. Many utilize tents instead of boxes to keep the cost down but include lighting systems and ventilation fans.

Oppolite indoor LED grow light tent

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This complete set for hydroponic gardening includes everything you need to get started. Choose from four different tent sizes, depending on your indoor growing aspirations. You’ll get a 1200W LED grow light, grow tent lined in reflective Mylar, a 6-inch ventilation fan, and the matching filter

TopoLite grow tent room kit

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This 24 by 24 by 48-inch Mylar-lined tent grow box includes a full-spectrum LED grow light and 4-inch filter and fan kit for ventilation.

Hydrofarm GLC0100 hydroponic LED grow system

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For smaller indoor gardens, this all-in-one kit from Hydrofarm contains a hydroponic set up for a fully enclosed system. You’ll get airstones, pumps, timers, and plant nutrients for this 32-cell system. LED lights provide full spectrum light for every little seedling. And you can schedule and manage your grow box with the digital display.

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Tips for Using your Grow Box

Whether you’ve built your own, annexed an unused closet, or invested in an all-in-one hydroponic grow box, you want to know how to care for your new seedlings.

Humidity control

Although everything is self-contained in your grow box, you still need to keep an eye on things. Make sure your grow box doesn’t suffer from too much humidity. This is especially true if your growing in soil. Too much moisture can result in root rot and fungal diseases.

Temperature control

It’s just as important that your grow box isn’t too hot as it is not too cold. If you’re using it in summer or inside a heated home, make sure your ventilation system keeps it cool enough for heat-sensitive plants. Lettuce will bolt in high heat, ruining your salad crop. Tomatoes refuse to set fruit at temperatures more than 85 degrees Fahrenheit. So, make sure your grow box temperature is maintained throughout the year.

Choose the right grow light

With different types to choose from, make sure you’re using the right type for your gardening goals. You can purchase both LED or fluorescent grow lights that provide the full UV spectrum that closely mimics real sunlight. LED lights use less electricity but don’t provide any heat. HID lamps are expensive, but they can work as a heater to maintain warmth. Choose your lamps accordingly to add or reduce the temperature of your grow box.

Remember that your plants will need to rest at night, just as they do in nature, so keep an eye on your lighting timer to ensure they get at least six hours of darkness every day.

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Garden Anywhere and Any Time

Gardening can become a bit addictive. The satisfaction of watching your carefully nurtured seeds and cuttings develop into full, lush plants can become habit-forming. Home-grown vegetables just taste better than the ones you purchase at the grocery store. A grow box will allow you to start new plants before transplanting them outdoors, too, as well as growing them to full maturity any time of the year.

If you’re fascinated by exotic plants like orchids or other tropical flowers, a grow box will allow you to create the perfect jungle environment for award-winning blooms.

Have you ever used a grow box? Did you make it yourself or purchase a kit? Some indoor gardeners prefer soil to hydroponics. Please tell us about your experiences in the comments below. We’d love to be able to share your expertise with all of our readers.

Last update on 2022-01-29 at 14:37 / Affiliate links / Images from Amazon Product Advertising API


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