Choosing the right greenhouse for your needs can seem overwhelming at first. With so many options on the market, how do you decide what is best for your climate, budget, and gardening goals? Picking out the perfect greenhouse is much easier when you know what to look for. In this comprehensive guide, we will walk you through the entire process of selecting, purchasing, and installing a greenhouse that is ideal for you.
Determine What You Want to Grow
The first step when choosing a greenhouse is deciding what you want to cultivate inside it. The types of plants you intend to grow will inform many factors of the greenhouse you pick, including size, materials, and accessories needed. Here are some key considerations:
- Vegetables vs. flowers: Vegetable gardens require more space, headroom, and sturdy support structures than flowering plants. Lean toward larger greenhouses with tall ceilings and strong foundations.
- Warm weather vs. cool weather crops: Warm weather plants like tomatoes and peppers need temperatures between 60-80°F. Cool weather plants like lettuce and spinach grow best around 45-75°F. Select a greenhouse with good ventilation and temperature control systems for your desired crops.
- Sun-lovers vs. shade plants: Fruiting plants, herbs, and vegetables need at least 6 hours of direct sunlight daily. Leafy greens, orchids, and begonias thrive in brighter shade. Choose greenhouse glazing and accessories to match light needs.
- Perennials vs. annuals: If growing perennial fruits or flowers, invest in a durable greenhouse that will last many years through tough winters and storms. Annuals can do fine in hoop houses or portable greenhouses.
Once you know your gardening goals, you can zero in on the right greenhouse for your needs. Taking the time to think this through will pay off tremendously down the road.
Consider Your Climate and Location
The climate you live in will significantly influence the type of greenhouse you choose. Carefully consider the typical weather patterns in your area before making a purchase:
Temperature
- What are the average high and low temperatures year-round? Select a greenhouse with systems to handle both extremes.
- How much does the temperature fluctuate day to night? Opt for a well-insulated model.
- Are summers very hot? Make sure the greenhouse has good ventilation.
- Do winters get bitter cold? Choose a greenhouse with heating capabilities.
Wind and Storms
- Is your area prone to high winds? Anchor the greenhouse securely into the ground.
- Do tornados, hurricanes, or blizzards hit your region? Select an exceptionally sturdy model rated for high winds and snow loads.
Sunlight
- What direction does your yard face? Maximize sun exposure by orienting the greenhouse properly.
- How many hours of direct sun does your location get? Supplement with grow lights if needed.
- Is it often overcast? Opt for a greenhouse with bright glazing to let in more ambient light.
Rain and Humidity
- Does your area get high rainfall? Ensure the greenhouse has good drainage and ventilation.
- Is the climate very humid? Choose anti-condensation glazing and fans for air circulation.
- Is it arid? Consider an evaporative cooling system to add moisture.
Zoning Laws and Permits
- Check with your city on any zoning restrictions for greenhouses in residential areas.
- See if a building permit is required, especially for permanent models over a certain size.
Your specific climate challenges will point you toward the ideal greenhouse. Be sure to select one engineered for your location.
Determine the Right Size
Greenhouses come in a wide range of sizes, from tabletop mini-greenhouses to huge commercial structures. The right size for you depends on:
- The number and types of plants you want to grow
- How much space you have available
- Your budget
- How ambitious your gardening plans are
Measure the area where you plan to put the greenhouse. Most home greenhouses range from 8’x6′ for small starter models up to 14’x20′ for generously sized ones. Mini-greenhouses under 100 sq. ft. are best for seedlings and potted plants. For in-ground beds, larger vegetable gardens, and bigger plants, go with at least a 12’x12′ or larger.
If unsure, size up. It’s better to have extra room than to outgrow a greenhouse too quickly. You can always start smaller and expand later.
Compare GreenhouseStyles
Once you’ve determined the ideal size and features, it’s time to look at greenhouse construction. There are five main styles, each with pros and cons:
Hoop House Greenhouses
- Made of PVC or metal hoops covered in plastic sheeting
- Most affordable option
- Easy to install
- Good for temporary or portable use
- Less durable than other styles
- Limited temperature control
- Can’t install permanent amenities like sinks or benches
Polycarbonate Greenhouses
- Aluminum frames with polycarbonate paneled walls and roof
- Lightweight rigid panels block UV rays
- Offer good insulation and temperature retention
- Panels resist impact and protect against hail/storms
- More expensive than plastic film greenhouses
- Not as durable or energy-efficient as glass models
Glass Greenhouses
- Iron or aluminum frames with glass walls and roofing
- Most attractive visually with clear views
- Exceptional insulation, heat retention, and durability
- Maximum sunlight penetration for plants
- Withstand harsh weather extremely well
- Most expensive to construct
- Glass is vulnerable to breakage
- Can be difficult to install
Geodesic Dome Greenhouses
- Interlocking hexagons or triangles form dome framework
- Covered in plastic film, polycarbonate, or glass
- Interesting geometric shape
- Promote excellent air circulation and light diffusion
- Complex construction requiring specialty parts
- Not easily expanded or customized after building
Dutch Barn Greenhouses
- Gabled roof shape resembles upside-down ship’s hull
- Vertical side walls maximize interior space
- Often built partially underground for natural insulation
- Durable wooden or metal frame construction
- Heavy foundation required
- Low profile can limit headroom
Take time to weigh the advantages and disadvantages of each when making your selection. The right style depends on your budget, site, climate, and gardening needs.
Select a Strong Framework
The greenhouse frame or skeleton is the backbone that holds everything together. This is a critical component not to skimp on. The best options include:
- Aluminum: Extremely strong yet lightweight, resistant to rust and corrosion. Often used for commercial greenhouses. Holds up well to weather and requires minimal maintenance. Provides clean lines and visual appeal. More expensive than other options but a sound long-term investment.
- Galvanized Steel: Provides excellent durability and structural support. Vinyl or powder coating prevents corrosion. Does not need frequent repainting like wood. Prone to condensation dripping so use corrosion-resistant fasteners. Can have a high upfront cost but will last decades with proper maintenance.
- Wood: Traditional choice for home greenhouses with an attractive appearance. Cedar and redwood naturally resist rot. Use pressure-treated lumber rated for ground contact. Provide good ventilation and airflow to prevent excessive moisture. Requires periodic sealing, painting, or staining. Generally the most cost-effective option.
Avoid frameworks made of PVC, thin aluminum, or low-grade metals. These won’t hold up well to wind, snow loads, and weather over time. Spend a little more on a sturdy base – it will extend the life and performance of the entire structure.
Choose the Right Glazing Material
Glazing refers to the transparent or translucent sheets that make up the greenhouse walls and roof. Greenhouse glazing serves several key functions:
- Maximizes sunlight penetration
- Insulates and retains interior heat
- Protects plants from exterior elements
- Withstands impact from hail, snow, debris
- Resists clouding, yellowing, and wear over time
Here are the most common glazing options:
Glass
Pros:
- Exceptional optical clarity and light transmittance
- Long lasting with minimal discoloration
- Excellent insulation value
- Highly resistant to impact damage
Cons:
- Relatively heavy, requiring a sturdy frame
- Breakable if hit hard by debris
- Small panes can be installed incorrectly causing leaks
- Expensive compared to plastic options
Polycarbonate Panels
Pros:
- Lightweight rigid plastic sheets span large areas
- Block over 99% of harmful UV radiation
- Resilient against hailstorms and falling objects
- Maintain transparency well over time
- Often have structured surface that diffuses light
Cons:
- Not as clear optically as real glass
- Can yellow and degrade over 10-20 years
- Large sheets prone to buckling in high winds
- Condensation and algae can build up on panels
Polyethylene Plastic Film
Pros:
- Most affordable glazing option
- Available in wide sheets to minimize seams
- Weighs very little for easy handling
- Sheds condensation effectively
- Easy to install and replace when worn
Cons:
- Durability only 1-4 years before replacement needed
- Can sag, tear, or fly away in storms if not reinforced
- Provides less insulation than rigid panels
- Often becomes brittle and opaque when exposed to UV
Select greenhouse glazing that best balances affordability, visual clarity, insulation, longevity, and durability for your climate and budget.
Incorporate Adequate Ventilation
Proper ventilation is one of the most critical factors in an effective greenhouse. Greenhouses essentially function by trapping heat while allowing ventilation. To maintain the ideal growing environment, air needs to freely enter and exit based on conditions:
- Passive ventilation relies on natural wind and convection via vents and openings. Roof vents are positioned to catch rising warmer air and allow cooler air to enter through low vents on sides. Roll-up sidewalls provide maximum passive airflow on calm days.
- Powered ventilation uses electric exhaust fans and intake louvers controlled by a thermostat. These actively circulate air and prevent overheating on hot, still days.
- Evaporative cooling humidifies and cools air using water evaporation. This is very effective in arid climates but can promote mold in humid areas.
Ensure the greenhouse you select incorporates multiple ventilation options to handle both intense summer heat and cold nights requiring insulation.
Pro Tip: Install twice as many vents as recommended to provide better circulation. Vents should equal ~20% of the floor footage. Open sidewalls are ideal for maximizing passive airflow.
Add Supplemental Heating
Greenhouses allow gardeners to extend the growing season far beyond normal outdoor conditions. However, most need supplemental heat sources to maintain temperatures on cold nights and during winter months. Here are common greenhouse heating systems:
- Gas unit heaters provide radiant warmth from propane or natural gas. Energy-efficient models run on convection and need no electricity. Ensure proper ventilation to avoid buildup of fumes.
- Electric heaters range from space heaters to ceiling-mounted radiant panels.Choose UL-listed, waterproof models with emergency shut-off valves. Use a dedicated high-amp circuit.
- Wood pellet stoves burn compact wood fuel to generate gentle radiant heat. Models with thermostatic controls work well. Ensure proper clearance from combustibles.
- Electric heated mats laid under planting beds or along the perimeter provide root zone warming right where plants need it most.
- Passive solar utilizes special glazing, mass thermal sinks, and site orientation to maximize heat gain in winter and minimize it in summer.
Ideally, combine two heating methods like a gas heater on really cold nights along with mats for supplemental root warming.
Install Insulation
Insulating a greenhouse helps regulate interior temperatures by preventing heat loss. This allows greenhouses to stay significantly warmer than outdoor conditions on cold nights and during winter. Options for insulating include:
- Bubble insulation – Double poly sheets encasing insulating air pockets. Provides an R-value around 1.25.
- Rigid foam panels – Polystyrene or polyurethane panels add insulation value 2-5+ to walls and ceilings.
- Fiberglass batts – Not as effective in moist greenhouse environments. Use specially coated humidity-resistant batts.
- Cotton insulation – Ultra-absorbent recycled denim or natural cotton for greenhouse insulation. R-value 3-4 per inch.
- Straw bales – Stacked along perimeter or made into interior walls. Provide natural insulation around R-3 per bale.
- Curtain systems – Insulated curtains deployed at night to separate warmer and cooler zones. Automated systems available.
- Thermal mass – Materials like water drums, rocks, and concrete absorb and slowly release heat.
Layering multiple insulating elements (e.g. thermal mass + foam panels + bubble wrap) provides the best temperature regulation in greenhouses.
Add Functional Accessories
The right accessories can make working in your greenhouse infinitely more convenient and enjoyable:
Benches
- Durable greenhouse benches allow you to comfortably work at waist height.
- Metal frame with wire mesh surface promotes drainage and airflow.
- Benches running along walls maximize usable space.
- Rolling benches make it easy to rearrange plants and access beds.
Sinks and Water Access
- Install a sink with running water for cleaning and irrigating.
- Position near entry to conveniently wash hands when entering.
- Collect rainwater from the roof in tanks for off-grid water access.
- Include a long hose that reaches every corner.
Shading and Curtain Systems
- Automated shade cloths moderate intense sunlight in summer.
- Thermal curtains separate warmer and cooler zones as needed.
- Blackout systems allow flowering plants to be tricked into blooming off season.
Shelving and Storage
- Take advantage of vertical space with shelving for starting seedlings.
- Hang baskets from the ceiling rails to get tender plants up away from cool floor.
- Add hooks, racks, and bins for convenient tool storage.
Lighting and Electricity
- Supplemental grow lights guarantee adequate light levels.
- Install electric outlets every 6 feet or so for plugging in tools.
- Overhead LED strip lights improve visibility for working on overcast days.
Environmental Monitoring and Control
- Smart greenhouse systems track temperature, humidity, light levels and automatically control vents, fans, heaters and more to optimize conditions.
- WiFi monitoring lets you check on your greenhouse environment from anywhere.
Choose Durable, Low-Maintenance Materials
Greenhouses contain a lot of components exposed to moisture, UV rays, and the elements. Using the right materials ensures your greenhouse will last for many years instead of needing frequent repairs and replacement. Look for:
- Aluminum: Resists corrosion and needs little maintenance besides occasionally tightening fasteners. Withstands weathering better than galvanized steel.
- Vinyl: PVC glazing panels and accessories hold up well. UV-stabilized formulations resist sun damage. Easily washed clean.
- Stainless steel: Hardware, fasteners, benches, and sinks made of stainless steel resist rust much longer than other metals.
- Cedar or Redwood lumber: Naturally rot-resistant softwoods that require minimal preservative treatment compared to pine. Avoid creosote-soaked railroad ties.
- Laminated wood beams: Engineered beams and framing won’t warp, twist, or crack like solid lumber. Use forSubscription model greenhouses.
- Concrete blocks: Great material for stem walls that won’t degrade like wood or rot like lumber in ground contact.
- Reinforced polycarbonate: Main glazing panels made of strong UV-blocking polycarbonate instead of plastic sheeting.
- Anodized aluminum: Frames made of anodized aluminum treated to create an oxidized coating that won’t corrode or need painting. More scratch-resistant than plain aluminum.
Choose the most durable materials within your budget to minimize repairs down the road.
Understand Greenhouse Maintenance
All greenhouses require regular maintenance and upkeep to maximize their lifespan and performance. Be prepared to:
- Wash glazing several times a year using mild cleaners to remove dust, dirt, and salt deposits. Take care not to damage polycarbonate panels.
- Caulk cracks immediately before they spread and cause leaks. Check glazing sealants and frames annually.
- Keep gutters and downspouts cleared. Prevent debris buildup on the roof.
- Lubricate hinges, rollers, and moving parts on vents. Adjust opening mechanisms for smooth operation.
- Tighten loose screws and fasteners which can deteriorate quickly in moist conditions.
- Keep an eye out for algae, mold, and condensation buildup and take steps to improve airflow and circulation when found.
- Watch for tears, holes, and deterioration in plastic glazing and seal with greenhouse repair tape or replace as soon as possible.
- Regularly wash out pots, trays, and tools and disinfect benches and hard surfaces to prevent diseases.
- Check automatic equipment like sensor probes, thermostats, and irrigation timers periodically for correct operation. Replace batteries in wireless systems once a year.
- Tune up supplemental heating equipment yearly. Replace worn parts and filters. Clean intake vents to increase efficiency.
Staying on top of maintenance right from the start will pay off for many years down the road.
Choose Between Greenhouse Kits vs. Custom Builds
Purchasing an all-inclusive greenhouse kit or building a custom greenhouse from scratch are the two main options. Here’s how they compare:
Greenhouse Kits
Pros:
- Complete ready-made