Hydro 101

hy·dro·pon·ics

noun: the science of growing, or the production of plants in nutrient-rich solutions of moist inert material, instead of soil.

An eight-step guide to successful indoor hydro gardening. Work through it in order — environment first, water second, everything else after. Get those two right and the rest is much easier.

Step 1

The right environment

Key components include relative humidity, temperature, CO2, and air circulation/exchange
Ideal humidity is between 40–60%
Some plants like higher humidity, but that can lead to problems with fungus and disease
Ideal temperature is between 68–75°F
Plants need CO2 to grow — with good air circulation and exchange, a room will naturally have between 300–400 PPM without supplemental CO2

Step 2

Start with good water

Water quality is essential to plant growth
PPM (parts per million) or EC (electrical conductivity) measure salts in a solution
Start off with a low PPM or EC and add nutrients specific to your plant variety requirements
A reverse osmosis system can reduce PPM/EC
pH (potential hydrogen) measures acidity or alkalinity in a solution on a scale of 0–14
Nutrient “lockout” occurs at too high or too low pH levels

Step 3

Choose a method

Ebb & flow gardens flood and drain a tray of plants with a nutrient solution at regular intervals
Drip gardens provide a nutrient solution to each plant through tubes and emitters (drip stakes)
Aeroponic gardens mist an oxygenated nutrient solution directly to the roots of the plants
NFT (nutrient film technique) gardens flow a slow-moving nutrient solution over the plant’s roots
Organics are possible using many methods, and are often grown in container gardens

Step 4

Choose a media

Growing mediums act as the root anchor system
Coco is made from the husks of a coconut, is pH stable, and provides moisture retention and aeration
Expanded clay pebbles provide moisture retention and aeration, and are reusable if sterilized
Rockwool stone is heated and spun into fibers then compressed; provides an excellent oxygen-to-water ratio, though flushing and conditioning is recommended
Silica helps slow transpiration, provides moisture retention and aeration, and is reusable if sterilized
Peat mixes can be altered to varying air/water ratios

Step 5

Nutrients & fertilizers

Liquid and dry nutrients can be organic or synthetic
Over- or under-fertilizing can cause burning, curling or yellowing of plants
Most nutrient bottles are labeled with N-P-K (nitrogen, phosphorus and potassium)
Additives and supplements can bolster microbial activity at the root zone, strengthen plant cell walls, increase flower sites, shorten length to harvest, and increase size, flavor and aroma of fruits and flowers
When used together, nutrients and supplements will help you achieve maximum results

Step 6

Grow lighting

MH (metal halide) and HPS (high pressure sodium) are types of HID lights used in grow rooms
MH lamps = blue spectrum, for vegetative
HPS lamps = orange/red spectrum, for flowering
T5 lamps are high-output fluorescents with low heat and energy consumption, ideal for cuttings, mother plants and short growth cycles
DE (double-ended) lighting is a full-spectrum HID lamp with a higher PAR reading than single-ended
Plants in vegetative stage need 15–18 hours of light
Plants in bloom stage need 10–12 hours of light

Step 7

Testing equipment

There are many meters available for testing solution pH, PPM and EC
Environmental controllers and meters are available to automate and more accurately control and maintain temperature, humidity, CO2 and lights
Testing equipment for the water-nutrient solution, light, room temperature and humidity, CO2 and air circulation is the key to providing optimal conditions for a bountiful garden

Step 8

Optional accessories

Grow room accessories are essential for optimized growth and harvest
Atmosphere-driven devices such as fans, blowers, CO2 emitters and integrated timers are a grow room’s greatest accessory
Trellising, stakes, supports, shears and labels are useful when growing fruiting and flowering crops
Pest and disease control may be needed, and there are many organic options available

Ready to build it? Shop the pieces: water & irrigation · growing media · nutrients · lighting · climate · meters

Or come in and we’ll spec it with you — Webster & Milford, 508-461-5850. Free classes run every Saturday. Growing in soil instead? See Indoor Soil Gardening 101.