Greenhouse Soils and Soilless Culture - Soils and Soil Supplements - Lecture Slides, Slides for Biology. Ankit Institute of Technology and Science


Description: These are the lecture slides of Soil Supplements. Key important points are: Greenhouse Soils and Soilless Culture, Materials Used For Rooting Media, Formulating, Pasteurizing Rooting Media, Methods of Watering, Timing, Fertilizers, Amendments Common, Greenhouse Cultures, Horticulture
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Unit 17: Greenhouse Soils & Soilless Culture

Unit 17: Greenhouse Soils & Soilless Culture


• Challenges & rewards of greenhouse plants • Materials used for rooting media • Formulating & pasteurizing rooting media • Timing & methods of watering • Fertilizers & amendments common in

greenhouse cultures


• Horticulture vastly growing industry • Great reliance on container-growth plants • Ability to start/grow plants in favorable

conditions • Match plant preferences to potting media • Greater ability to manipulate climate, fertility,

water etc.

Root Media

 Soilless culture can yield much higher per acre than soil culture –not realistic  Expensive  Difficult to manage  More consistent aeration, water retention  Important Properties of Root Media  Stable organic matter or low C:N  Water retention w/ adequate aeration  Moderate/high CEC  Suitable pH

Root Media

• Stable organic matter – Moderately decomposed – don’t want it to shrink

too much decreasing aeration

• Greenhouse media tends has little natural fertility, needs ability to retain nutrients

• Components of Root Media Mixes – Peat moss

• Decompose slowly • High water-holding capacity • Can be acidic

Root Media

– Bark • Can replace peat moss • Less expensive • Should be composted

– Sawdust, straw, manures • Sawdust & straw should be composted 1-2 mos. • Manures

– Used little due to ammonium toxicity – Can be good in certain situations

Root Media ▪ Vermiculite ▪ Silicate material ▪ High water holding capacity ▪ Great aeration ▪ High CEC, w/ some K, Ca, Mg ▪ Sand ▪ Best drainage & aeration ▪ No CEC or nutrient availability ▪ May work for starting plants ▪ Perlite ▪ Heated volcanic rock ▪ Sterile & inert ▪ Good substitute for sand

Root Media Mixes

 Soil-Based Root Media  1/3 sand, 1/3 peat moss, 1/3 soil  Keep clay content low  Can make at home/lab w/ ability to sterilize soil  Soilless Root Media  Materials to use ▪ Vermiculite, organic matter, sand, perlite, sphagnum

peat moss ▪ Can mix yourself, or buy premixed  Pay close attention to fertility management

Pasteurization of Media

 Pasteurization controls  Weed seeds, pathogens, insects, nematodes  Steam pasteurization  Most used  Pump steam through soil mixture to kill most

pathogens  Chemical pasteurization  Cheaper  Must allow to aerate after treatment  Chemicals are nasty to handle

Pasteurization of Media

– Methyl bromide • Severely injurious to humans • Can be damaging to some plants

– Chloropicrin (tear gas) • Can’t use where plants are growing


• Incorrect watering most frequent cause of reduced crop quality or failure

• Watering Guides – Use well drained rooting medium – Wet entire root media w/ each watering (till it

drips) • Leaching can then remove excess soluble salts • All root area is wet

– Wet before dry stress occurs


Watering Systems  Hand ▪ Frequency often questionable ▪ Quantity inconsistent ▪ Plant damage  Automated ▪ Sprinklers, drip, microirrigation, water tables & capillary

action ▪ More consistent timing, and amount ▪ Must have good equipment, proper air flow, humidity



• Plant Nutrients – Vary w/ rooting media & crop – May need to pay close attention to micronutrients

• May are available as mixtures or can be incorporated into irrigation

• Slow-Release Fertilizers – Release over first 3-4 mos

• Some may be 6-15 mos

Soil & Tissue Testing

• Many greenhouse production problems related to soil fertility

• Can sample root media (every 3 mos) • Tissue sampling can be done to troubleshoot a

problem – May be critical in large greenhouse production

operations w/ high value crops

Hydroponics: Solution Culture

• All nutrients must be supplied in solution – Can control fertility very specifically – Takes specific equipment for metering

• Plant support – Fixed above, or floating – Keep aeration in water, or w/ wool, perlite, sand

• Used commonly in research on roots to keep soil out of way

Hydroponics: Solution Culture

• Root Aeration & Darkness – Bubble air – Baffles in water flow – Keep root system in dark

• Inhibits algae growth


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