Shade Structures, Propagation, and Growing Media – Comprehensive Study Notes

Sun tunnels, shade structures, and propagation setups

• Overview of sun tunnels and related structures

  • Sun tunnels come in varieties: high tunnels, low tunnels, and minimally heated structures; all part of a broad category used in production and propagation.
  • The “Amish” reference (anecdotal) points to traditional, simple over-the-top covers seen on farms early spring or late fall to extend seasons.
  • How they work: crops are planted early, then covered when weather isn’t conducive; the cover is removed around midday to allow natural heating and cooling by the sun.
  • Variations include adding shade, and homeowner-style versions exist; generally forms provide protection from the elements with limited or no heating/cooling sources.
  • In larger structures, propane heaters can be used temporarily to reduce chilling.
  • Main benefit: extends production season by preventing frost-related loss, e.g., for cut flowers with short windows of harvest.

• Lath houses and shade houses

  • Lath houses and shade houses are used for protection and moisture management; they function similarly to shade structures but with specific shading configurations.
  • Pergola connection: traditional lath house concepts evolved from production to landscape contexts; pergolas are wooden or metal frames with slats that provide cooling with relatively sparse shading.
  • The lab connection: shading reduces moisture loss and supports limited photosynthesis, helping conserve soil moisture and reduce irrigation needs.
  • Practical note: shaded plants still photosynthesize and may root in place thanks to soil moisture; shading supports moisture retention and reduces transpiration.
  • In landscaping, shading lowers watering needs and labor because shaded plants dry out more slowly.
  • For overwintering, copolymer coatings can be used on some structures to improve overwintering capabilities.

• Shade as a production tool

  • Purpose of shade: reduces light intensity to limit photosynthesis and water loss, and to protect plants from sun scorch.
  • Typical shading range: 10% to 90% shade.
  • If shade is 10%, you reduce light by 10%. If shade is 90%, you reduce light by 90%.
  • Avoid shades outside this range because
  • Seasonal use: most greenhouses that produce from April through September use shade to manage transpiration and heat.
  • Practical implications for nurseries and retail: shade structures reduce labor costs and water use; many plants in big retailers are under shade structures for efficiency.
  • Snow loading: shade material can act like a magnet for snow; heavy snow/ice loads can cause collapse if structures aren’t designed for it. Plan for local snowfall and structural load.
  • Economic considerations: labor costs and municipal water pricing influence the adoption of shade structures in nurseries; water costs are a factor when plants are watered under shade.
  • Historical usage: shade has been used in production for evergreen seed propagation to reduce sun scald and moisture loss on tender seedlings.

• Propagation structures and tools

  • Tunnels and nets
  • Tunnels create a humid environment beneficial for propagation, especially for woody plants and native soils.
  • Netting protects against insects and offers improved airflow; nets can function as shade cloth and insect/disease protection when used with removal timing.
  • Mist systems and enclosures
  • Clonal propagation often uses mist systems to maintain high humidity; seeds and cuttings are placed under mists to reduce desiccation.
  • Cloning technologies are widely used in cannabis production for rapid mother/clones, with cycles around $14$ days from sticking to harvest.
  • Clonex boxes: a popular tool where cuttings are misted along the stem rather than leaves; promotes rooting while controlling humidity.
  • Small enclosures and domes
  • Mini greenhouses and gothic-style domes provide high humidity for seeds and young plant propagation; these are simple, low-cost options.
  • Historical note: earlier ideas showed that moisture conservation in enclosed environments can support plant growth even if soil moisture is kept high without direct surface watering.
  • Rooting and air layering options
  • Rooting tents and rooting carts keep cuttings hydrated in a sealed, humid environment while allowing air exchange.
  • Air layering (rooting balls) and rooting balls provide alternative propagation methods; these may involve hormone treatments, moisture retention, and wounding strategies to induce rooting.
  • Branch rooting and natural layering techniques
  • Natural rooting can occur on mulched, shaded stems (e.g., junipers); wounding a stem and encouraging rooting with hormones and moisture-trapping setups can create new plants from branches.
  • Special note on practical demos
  • Expect labs or demonstrations on some of these technologies (e.g., Clonex boxes) as part of propagation labs; cannabis production is a common context for certain cloning techniques.

• Production planning and decision-making in structures

  • Interactive planning: instructors emphasize asking key questions before selecting a structure.
  • Key decision factors:
  • What crop or plant are you producing? (e.g., finishing geraniums vs. starting cuttings.)
  • Stage of production: what size plant are you growing and for what purpose?
  • Time of year and climate: how many months are you in production? Is year-round production feasible?
  • Uses when not in production: can the structure be used for revenue or other tasks during downtime?
  • Labor and workflow: can a structure help reduce labor or improve plant quality during maintenance?
  • Common scenarios by business type:
  • Landscapers: shading and shade cloth are often the main tools for short-term plant holding.
  • Plant production nurseries: greenhouses are the primary structure for propagation and production; they may rely on others’ structures or outdoor spaces with shading as needed.
  • Wholesale vs retail: differences in workflow, customer experience, and site design (e.g., walkways, weed control, and customer safety) affect structure choice and layout.
  • Operational considerations:
  • Carrying capacity for staff: plan to keep staff occupied most of the year; layoffs have a significant rehire risk.
  • Capital decisions: equipment should be viewed as a tool for function, not status; avoid overbuilding with high-end spaces if a simpler setup suffices.
  • Example insight: a hoop-style greenhouse that fits tall plants might limit space; consider whether a smaller or alternative structure could meet needs.
  • Planning guidance: structure choice should align with business type, plant type, production timeline, and financial goals; there is no one-size-fits-all solution.

• Soil and growing media concepts

  • Dirt, soil, and growing media distinctions
  • Dirt is not the same as soil; growing media (also called substrates or soilless media) is used for plant production with little to no mineral soil.
  • Soils and growing media are discussed in other courses, focusing on mineral components (sand, silt, clay) and parent materials.
  • The three primary media ingredients discussed are peat moss, perlite, vermiculite, and related amendments; other options include wood fiber, compost, sand, and core materials.
  • Why this matters: media type affects water retention, drainage, aeration, and root health; crucials are chosen based on plant type and propagation method.

• Characteristics of growing media (essential concepts)

  • Texture: broad category describing graininess and how it influences water holding and drainage.
  • Strength and support: media should be firm and dense enough to support plants, especially young or tall transplants.
  • Water content vs air content: media should balance moisture retention with adequate aeration for roots; for seed germination, higher moisture content is often desirable, and oxygen is less critical than water availability, whereas cuttings require adequate oxygen for root formation.
  • Dense media and water balance: very dense media hold more water, which can hinder root development for cuttings due to reduced aeration.
  • Peat moss and perlite ratio guidance: if peat is used, mix with perlite at least in a 1:2 ratio to avoid waterlogging and to improve drainage; in many cases, pure peat is too water-retentive.
  • Pure perlite performance: some beautiful and successful cuttings have been produced using almost pure perlite (e.g., coleus, willow, butterfly bush, evergreen varieties).
  • Sand and perlite ratio: a 1:1 ratio of sand to perlite can be better than using pure sand; sand provides structure and drainage, while perlite enhances aeration and water retention balance.
  • Porosity and drainage/aeration: higher porosity improves drainage and air access; the trade-off is that highly porous media may retain less water, requiring more frequent irrigation.
  • Pest considerations: media should be free of plant pests; a diseased plant in a tray can spread to other plants quickly.
  • Reuse and sanitation: discuss whether media can be pasteurized or sterilized for reuse; consider disposal costs vs. reuse in budgeting.
  • Availability and cost considerations:
  • Media should be relatively inexpensive and readily available; the input supply should be reliable to avoid costly substitutions if a material is discontinued.
  • Example from daily life used by the instructor: some favorite products (e.g., a preferred boot brand) can become unavailable, illustrating why reliability of inputs is important for production planning.

• The three components of soil (basic science recap)

  • Solid components
  • Includes inorganic minerals from weathered rocks and organic matter such as decayed plant and animal material; in growing media, solids include peat moss, vermiculite, perlite, sand, core, and other solid additives.
  • Liquid components
  • Water (H2O) and dissolved minerals; soil water contains ions and minerals that plants use; the soil solution is the liquid phase inside the pore spaces.
  • Gas components
  • The air in soil pores; primarily oxygen and carbon dioxide, plus nitrogen and other atmospheric gases; these gases are critical for root respiration and overall root health.
  • Practical notes on liquids and gases
  • Pure water is rarely used in plant media; it lacks minerals and can leach nutrients or cause osmotic stress if overused; most irrigation water contains dissolved minerals (ions).
  • In horticulture, distilled or RO water is often supplemented with minerals to mimic natural mineral content for optimal plant growth.
  • Soil vs media terminology in practice
  • Soils: natural mineral- and organic-rich layers; can include minerals like sand, silt, clay and organic matter.
  • Growing media: engineered mixes designed for water retention, aeration, and root development; examples include peat-based mixes with perlite, vermiculite, or sand.

• Quick test questions and practical takeaways

  • Test concept: Three basic components make up soil/media: solids, liquids, gases.
  • Example prompts you might encounter: name the three components; identify examples of each in a growing medium; explain why balance among these components matters for rooting and moisture management.
  • Everyday considerations:
  • Accessibility and reliability of media inputs are critical for budgeting and planning.
  • When selecting a media mix, consider the plant type, propagation stage, irrigation schedule, and whether the structure will be used year-round.

• Budgeting, labor, and long-term planning notes

  • Equipment and structures are tools, not status symbols; plan for reliability and long-term maintenance rather than shiny gear.
  • Avoid overbuilding unnecessary space; it’s often more cost-effective to start with smaller frames and scale up as needed.
  • Workforce planning: the goal is to keep operations running close to 12 months if possible; plan for downtime and alternative work to minimize layoffs, since turnover can be costly.
  • Production workflow considerations influence structure choice; wholesale environments may prioritize efficiency and yield, while retail spaces emphasize customer experience and layout.

• Quick reference figures and ratios to remember

  • Shade ranges: $10\% \leq \text{shade} \leq 90\%.$
  • Tender plant shading: around $50\% \text{ to } 60\%$ shade is common for tender plants.
  • Winter snow loading concern: assume scenarios with up to $6\text{ inches}$ of snow and ice if applicable to local climate.
  • Peat-to-perlite ratio: if using peat moss, mix with at least $1:2$ (peat : perlite).
  • Sand-to-perlite suggestion: a practical guideline is $1:1$ for improved drainage and aeration.
  • Cloning cycle: cloning from cutting to harvest can be as quick as $14\text{ days}$ in optimal conditions (e.g., Clonex box with mist).
  • Year-round occupancy target: strive to utilize structures for production as close to $12\text{ months}$ as possible to keep staff employed.

• Core takeaways for exam-ready understanding

  • Structures range from simple shade covers to full greenhouses; selection should align with crop type, production stage, and business model.
  • Shade and humidity management are critical tools to control transpiration, moisture loss, and plant health during propagation and production.
  • Propagation technologies (tunnels, nets, mist systems, Clonex boxes, rooting tents) are designed to optimize humidity, airflow, and rooting success while protecting tender growth from pests and sun damage.
  • Media selection is a balance between water retention, drainage, aeration, and availability; no one mix fits all, and often a combination of peat, perlite, vermiculite, and sand provides the best results depending on the plant and propagation goal.
  • Understanding solids, liquids, and gases clarifies how roots interact with their environment and helps diagnose problems with nutrient uptake and water management.

Note: This set of notes mirrors the lecture content and includes key figures, practical guidance, and the overarching connections between structures, propagation, and soil/media for horticultural production.