Hydroponics

Phyllis Putnam

Jean Johnston

Jessica Garner

Introduction-- From Greek - Hydro = water and pronos = labor

-- First users of hydroponics

-- Earliest book, Sylva Sylarum: Or a Natural History of Francis Bacon, 1627          

-- German scientists develop the first nutrient formula, 1929

-- World War II successful hydroponic operation

-- 1970s and 80s and on to Mars

AdvantagesAbility to grow vegetables year round

Grow plants in smaller spaces (apt, balcony)

Sterile Medium - No weeds, No soil-borne pests

Healthy Plants - All necessary growth elements readily available in solution

Plants mature faster (earlier crop)

Smaller root system (smaller spaces again) - Roots don’t have to spread out to reach food

Ability to automate system with a timer - Reduces time, Gardener can be gone for long periods of time

Eliminates need for vast farmland

Can raise crops in desert sands - Water is reused, Less water is used

Lettuce is cleaner (no soil on leaves)

No tillage

Plants often larger and healthier

DisadvantagesCost: Expensive to set up system (fixtures, water pumps, etc)

Nutrient solution must be kept at original volume - Water evaporates; add water, Solution can become toxic if too much nitrates (low light)

Use beneficial predators to control insects

Water quality can be a problem, poor plant growth - Excessive alkalinity or salt, Softened water, too much sodium

Roots need oxygen - Need a bubbler or continuous flow

Plants need to be supported (no soil to support)

Cost too high for most commercial growers (grow expensive crops)

Types of Hydroponic Systems

Aquaculture AggregateAeroponicsContinuous Flow

Aquaculture/AquaponicsEasiest set-up

Roots totally immersed in nutrient solution

Must: Support plant above solution, aerate solution and prevent light from reaching solution

Change solution every 1-2 weeks

Continuous Flow SystemTypically used in commercial hydroponics

Nutrient solution pumped or flowed by gravity to growing pipes

Bathes the roots then returns to holding tank

Solution aerates itself as it flows back

PVC pipe is commonly used.

AeroponicsRoots of the plant grow in a closed container

Misting system of nutrient solution

Near 100% humidity to prevent drying

A-Frame containers are most popular

Aggregate CultureUses some form of inert material (i.e. sand) to support plant roots

Pump and return solution using 1 of 2 methods

Flood and drain method

Trickle feed method