Introduction to Horticulture

Plant: Digitalis

Term: Hydroponics

FoxgloveDigitalis• Plant type: Biennial, Herb, • USDA Hardiness Zones: 4a to 8a • Height: 2-5’ • Exposure: partial shade to full sun • Bloom Color: Pink, Purple, White • Bloom Time: Late spring to early summer• Landscape Uses: Border, Container, Massing,

Specimen, Woodland garden • All or parts of this plant are poisonous• Suitable for cut flowers during 2nd year• Extract used for heart medicine

Hydroponics

• The term "hydroponics" refers to growing crops without soil.

• Inert medium, such as gravel, water, sand, peat.

• A nutrient solution is added containing all essential elements needed by the plant.

• Hydroponic production is very space intensive.

Uses• Grow almost any herbaceous

plant. • High value food crops or

horticultural plants. • Commonly grown crops include

lettuce, tomatoes, cucumbers and herbs.

• The crop varieties grown hydroponically are bred specifically for greenhouse production.

COMMON HYDROPONIC METHODS

• Water culture: Crop roots are immersed or bathed in a continuous flow of nutrient solution. Often this is done in beds or troughs within a greenhouse. Tops of plants need supports.

COMMON HYDROPONIC METHODS• Aggregate culture:

– Crop plants are grown in a solid media that provides anchorage and support much like soil does.

– Materials often used as growing media include gravel, sand, perlite, soilless mixes, and rockwool.

– The media is enclosed in beds, bags or blocks. – The nutrient solution is flooded or drip irrigated past

the roots.– Plant top support is necessary for taller crops.

ADVANTAGES OF HYDROPONICS • Grow out of season or zone. • Grow at periods of lowest

supply. Best prices.• Higher crop yields from smaller

areas. Planting density is limited only by available light.

• An example of comparative yields for tomatoes is:– Soil grown: 5 to 10 tons per

acre; – Hydroponic: 60 to 300 tons per

acre.

More ADVANTAGES• Plants can mature faster and more evenly • Crops can be vine-ripened and sold

immediately. • Soil-borne insect and disease problems are

reduced • Crops do not need to be rotated. • Crops do not need to be cultivated or weeded. • Nutrient application timing and nutrient quantities

can be custom tailored to a particular crop's specific needs.

DISADVANTAGES OF HYDROPONICS

• Costs– The initial investment is high– Specialized equipment – Greenhouse heating can be quite expensive

in the winter months. • More skill is required than for traditional

methods. • The grower/operator must be highly

trained in plant nutrition and system operation and maintenance.

Movie

• Hydroponic lettuce

Fertilizer levels

• Monitored through EC readings• EC = electric conductivity• Gives a general reading of the solute

content of a liquid• Each fertilizer is different• Read the label• Peters Excel = ?

Fertilizer Ratios

• Use water soluble fertilizer• Want ~ 50 ppm N for constant flow

irrigation• Fertilizer is 20-10-20• Tub holds 50 gal, how much fertilizer

should be added?• Conversions

– 1 PPM = .0038g/gal– 28g = 1 oz

Calculate

• 1 PPM = .0038g/gal, 28g = 1 oz• 1 ppm = .0038 ÷ 28 = ? oz/gal• 1 ppm = .0001357oz/gal• 50 ppm = 50 X .0001357 = ? Oz/gal• .006785oz/gal x 50 gal = ? Oz N• Fertilizer is 20% N• 0.34 oz of N ÷ 20% = ?oz total fertilizer• 1.7 oz fertilizer

Our tanks

• Flow tube• Ebb & Flood beds• 50 or 100 gal tanks• Weigh and add fertilizer• Check EC and compare