How to Build an Indoor Grow Room


If you can garden outdoors year-round or have a conservatory on the sunny side of the house, a grow room might not seem to have much benefit. Many individual plants survive in the constant warmth, low humidity and low light levels of a building's interior, but rooms that house many plants must have nocturnal temperatures 10 degrees Fahrenheit or more below daytime temperatures and higher levels of humidity and light to thrive.

Bringing the Outdoors In

  • Porous wall board and wood trim are interior materials -- and you must protect them against the exterior elements you'll be duplicating indoors. Before painting walls and woodwork with a semi-gloss, mildew-resistant, antimicrobial paint, clean them well with a solution of 1 cup bleach per gallon of water to clean and kill any stray mildew spores. Some paints recommend sanding the surface before application. Caulk any gaps between woodwork and adjoining surfaces and re-tape corners where necessary before painting. Remove all carpeting -- it makes a great home for mold. You'll also need a programmable thermostat for this room to provide nocturnal temperatures 10 degrees Fahrenheit or more below daytime temperatures.

Construction Notes

  • Use materials for your grow room you'd consider for an outdoor deck. Install composite wood, vinyl flooring or mold and mildew resistant indoor-outdoor carpeting with a waterproof adhesive. Build growing racks with plenty of space between shelves so you can hang the supplemental light bars on chains and raise them as plants grow taller. Check the strength of your floor's under-structure -- or ask a housing inspector to give you an opinion. If it's strong enough to support a water bed, it can probably support containers full of moist soil.

Light of Day

  • Your plants will have varying light requirements, so a light meter is basic equipment. Low-light plants can survive with as little as 50 foot-candles of light, but light-guzzlers, including many flowering plants, demand at least 1,000 foot-candles. Although windows do admit light, glass -- particularly dirty or energy-efficient glass -- can decrease daylight from 30 to 70 percent. A mixture of cool and warm fluorescent bulbs hung 6 to 12 inches from the growing tips of plants will serve as daylight. Reflectors built into plant stands, light-colored walls and other reflective surfaces help maximize light levels. Plants that also receive daylight thrive with 12 to 14 hours of supplemental light. Plants in rooms without windows might require up to 18 hours of supplemental light. Run supplemental light during daylight hours -- all plants need nocturnal periods to complete their respiratory cycles and daylight period changes often cue growth and flowering.

Foggy, Foggy Dew

  • Plants use water and carbohydrates generated by photosynthesis to convert nutrients into living tissue, so humidity is an essential element of the grow room. Some homes with central heat experience humidity as low as 10 percent relative humidity in winter -- enough to desiccate the leaves of all but the toughest cactus. Add a humidifier and pebble-filled trays filled with water to elevate moisture levels. High humidity can encourage mold and plant diseases, though, so ventilate your grow room with an exhaust fan and add a dehumidifier if relative humidity levels rise beyond 50 percent.

Related Searches


  • Photo Credit evgenyb/iStock/Getty Images
Promoted By Zergnet


You May Also Like

  • How to Set Up a Grow Room

    For many gardeners, the winter months simply mean growing vegetables, flowers and herbs indoors rather than out. Setting up your first indoor...

  • How to Build 4X8 Grow Room

    It would be wonderful to grow flowers, vegetables, and fruits year-round, but the climate in most regions does not allow this. A...

  • How to Build a Cheap Grow Room

    Growing indoors is a great way to keep a steady supply of your favorite vegetables and herbs on hand no matter what...

  • How to Vent a Grow Room

    One of the most important aspects of a grow room is good air flow. Consistently refreshed air promotes plant growth and prevents...

  • How to Make the Ulimate Grow Room

    Horticulturalists and home gardeners alike dream of having an ultimate grow room. A grow room for your plants and seedlings makes a...

  • How to Set Up an Indoor Gardening Room

    Even avid gardeners don't always have the room to build a greenhouse or plant a garden. Don't let space stop you from...

  • How to Build a Closet Grow Room

    Growing vegetables, herbs and flowers in a closet is a convenient way to keep them alive year-round, regardless of the weather outside....

  • The Best Indoor House Plants

    Indoor houseplants are ideal for anyone seeking a rewarding hobby or an addition to their home décor. Some plants require a lot...

Related Searches

Check It Out

How to Make a Vertical Clay Pot Garden

Is DIY in your DNA? Become part of our maker community.
Submit Your Work!