Prevent Hydroponic Plant Problems

The smart solution to the most common troubles that afflict indoor gardens is to stop them before they start.


Water Choice

Threat: Additives and other unnatural compounds in tap water can contaminate nutrient solutions.

Know: Water from municipal treatment plants often has chlorine and other chemicals.

Do: Install a reverse osmosis filtration system (starting at $150) or buy a pitcher with a filter that purifies water.

Acid Test

Threat: When your nutrient solution’s pH is outside the healthy range, your plants may be malnourished.

Know: Plants need a pH of 5.5 to 6.5 to efficiently absorb nutrients. Be aware that synthetic fertilizers—high in salts—lower the pH.

Do: Use organic fertilizer. Adjust pH as needed with natural white vinegar (acetic acid) or baking soda (sodium bicarbonate).

Light Touch

Threat: Grow lights are hot and can scorch leaf tips. If plants are too far from the light, the stems grow tall and thin.

Know: The bulbs of high-intensity grow lights can get hotter than 400 degrees Fahrenheit.

Do: Set up lights 6 inches (for 250-watt bulbs) to 2 feet (for 1,000-watt bulbs) above the plants and raise the lights as the plants grow to keep the distance constant.

Even Temperature

Threat: A hot grow room is a breeding ground for fungi that rot plants and clog hydroponic systems.

Know: High-powered lights throw off heat that, with the moisture in the room, raises the humidity.

Do: Eliminate and prevent fungal diseases with nontoxic, sulfur-based fungicides. A dehumidifier reduces the moisture in the air and makes the room less hospitable to fungus.

Air Supply

Threat: Stale air deprives plants of the oxygen and carbon dioxide needed for photosynthesis.

Know: Talking to your plants actually helps (because you exhale CO2), but they also need constant fresh air.

Do: Run small fans or—even better—set up an exhaust fan and vent system.

Pest Prevention

Threat: Whiteflies, spider mites, thrips, and other pests find their way even into indoor growing rooms.

Know: These pests suck on plant juices and leave behind sooty mildew that is just as damaging.

Do: Use sticky traps to capture flying pests and use a neem-based spray to eliminate pests’ eggs and adults climbing on your plants.

Clean Counts

Threat: Plant diseases lurk everywhere—on your hands, tools, and every surface in your grow room.

Know: You spread disease when you handle healthy plants after you’ve touched afflicted ones.

Do: Discard diseased plants immediately. Sanitize your hands, tools, and surfaces with rubbing alcohol.

Remember: Like people, stressed plants are more vulnerable to diseases and other problems. Synthetic fertilizers promote unnatural growth that strains plants energy.