Quick Summary:
An outdoor greenhouse for plants offers a controlled environment to extend your growing season, protect delicate plants, and boost harvests. Essential tips include choosing the right size and type, proper ventilation, effective watering, temperature regulation, and selecting suitable plants. Following these guidelines makes greenhouse gardening accessible and rewarding for beginners.
Dreaming of fresh tomatoes in early spring or vibrant flowers well into autumn? An outdoor greenhouse can turn that dream into a reality! Many gardeners find it frustrating when unpredictable weather ruins their hard work, limiting what they can grow and when. But what if you could create your own perfect growing climate, no matter what’s happening outside? You absolutely can! This guide will walk you through everything you need to know to set up and enjoy your very own greenhouse for plants outdoors, making gardening easier and more bountiful than you ever imagined. Let’s get growing!
Why Every Gardener Needs an Outdoor Greenhouse
A greenhouse is like a plant’s personal spa, offering a safe, temperature-controlled haven. This controlled environment is crucial for several reasons, especially for beginner gardeners who might appreciate the extra protection. It allows you to:
- Extend Your Growing Season: Start seeds earlier in spring and continue growing crops later into fall. This means more fresh produce for longer!
- Protect Plants from the Elements: Shield delicate seedlings, exotic plants, or tender vegetables from frost, harsh winds, heavy rain, and pests.
- Control Growing Conditions: Manage temperature, humidity, and light to create the ideal environment for specific plants, leading to healthier growth and better yields.
- Experiment with New Plants: Grow plants that might not typically thrive in your local climate.
- Prevent Pests and Diseases: While not a foolproof barrier, a greenhouse can significantly reduce exposure to common garden pests and airborne diseases.
Choosing Your Greenhouse: Size, Type, and Location
Selecting the perfect greenhouse involves a few key decisions. Think about your space, your budget, and what you plan to grow. Getting this right from the start will save you a lot of hassle later on!
Greenhouse Sizes: From Tiny to Terrific
Greenhouses come in all shapes and sizes:
- Mini Greenhouses/Cold Frames: Perfect for small spaces or balconies. These are great for starting seeds or overwintering small plants.
- Lean-to Greenhouses: These attach to an existing wall of your house or shed. They benefit from the building’s heat and are a good option if space is limited on multiple sides.
- Freestanding Greenhouses: Available in many sizes, from small hobby units to larger structures capable of housing serious gardeners.
For beginners, a smaller freestanding or lean-to greenhouse is often a great, manageable starting point.
Greenhouse Types: Materials Matter
The main difference between greenhouse types is their covering material. Each has pros and cons:
- Polyethylene Film Greenhouses: These are typically the most budget-friendly option. They use a frame (often metal or PVC) covered with plastic sheeting. They are lightweight and easy to set up but may need replacing every few years as the film degrades.
- Polycarbonate Greenhouses: Polycarbonate panels (twin-wall or single-pane) are more durable and offer better insulation than film. They are impact-resistant and provide good UV protection. This is a popular choice for its balance of cost and durability.
- Glass Greenhouses: Traditional and beautiful, glass offers excellent light transmission. However, it’s more expensive, heavier, and prone to breakage. It requires a sturdy frame and careful installation.
For a durable and energy-efficient option that’s easier to manage than glass, twin-wall polycarbonate is often recommended for beginners.
Location, Location, Location!
Where you place your greenhouse is as important as the greenhouse itself. Consider these factors:
- Sunlight: Aim for a spot that gets at least 6 hours of direct sunlight per day, ideally morning sun. Avoid areas with heavy shade from trees or buildings, especially in winter.
- Drainage: Ensure the site has good drainage to prevent waterlogging around the base of your greenhouse.
- Wind Protection: While you want sun, excessive wind can stress your greenhouse and increase heating costs. A sheltered spot or windbreaks can help.
- Accessibility: Make sure you can easily access it with water, tools, and your harvested produce. Proximity to your house is convenient.
- Level Ground: The spot must be level for stability and proper door function.
Setting Up Your Greenhouse: A Step-by-Step Guide
Once you’ve chosen your greenhouse, it’s time for setup. Many kits come with instructions, but here’s a general overview of what to expect.
Step 1: Prepare the Site
Clear the chosen area of any debris, grass, or weeds. Level the ground thoroughly. You might want to lay down a weed barrier fabric if you’re placing it directly on soil. For more permanent structures, consider a gravel base or concrete footings for added stability. Tools like a spirit level and a shovel will be essential here.
Step 2: Assemble the Frame
Follow your kit’s instructions precisely. This usually involves connecting various pre-fabricated poles or panels. Take your time to ensure all connections are secure. A helper can make this step much easier!
Step 3: Install the Covering
Carefully attach your chosen covering (polyethylene film, polycarbonate panels, or glass). For plastic film, you’ll often stretch it taut and secure it with clips or tape. For panels, they typically slide into channels or are screwed into place. Ensure a snug fit to prevent drafts.
Step 4: Install Doors and Vents
Make sure doors open and close smoothly. If your greenhouse came with vents, install them according to the manufacturer’s directions. Proper ventilation is crucial, and we’ll discuss more on that later!
Step 5: Anchoring (If Necessary)
Depending on the size and type of your greenhouse, you may need to anchor it to the ground. This is especially important for lightweight structures or in windy areas to prevent it from blowing away. Follow the manufacturer’s recommendations for anchoring kits.
Essential Greenhouse Management Tips
Setting up is just the beginning! To make your greenhouse truly thrive, you need to manage its environment and care for your plants.
Ventilation: The Key to Happy Plants
Overheating is one of the biggest dangers to plants in a greenhouse. Good airflow is vital to:
- Regulate Temperature: Prevents plants from baking on sunny days.
- Reduce Humidity: High humidity can lead to fungal diseases.
- Provide Fresh Air: Plants need CO2 for photosynthesis.
- Prevent Powdery Mildew: This common fungal disease thrives in stagnant, humid air.
How to ventilate:
- Manual Ventilation: Open doors and roof vents on warm, still days.
- Automatic Vent Openers: These clever devices use heat-sensitive fluid to open vents automatically when the temperature rises, and close them as it cools. They are a fantastic, low-maintenance solution.
- Fans: A small circulation fan can help move air around, preventing hot spots and improving overall air quality.
Aim to open vents whenever the temperature inside begins to rise above what your plants are comfortable with, typically above 75-80°F (24-27°C).
Watering Wisely
Greenhouses can dry out faster than outdoor gardens due to increased sunlight and air circulation. However, overwatering is also a risk, especially if ventilation is poor.
- Check Moisture Levels: Stick your finger about an inch into the soil. If it feels dry, it’s time to water.
- Water in the Morning: This allows plants to dry off during the day, reducing disease risk.
- Water at the Base: Try to water the soil directly rather than wetting the leaves, especially for plants prone to fungal issues.
- Drip Irrigation/Soaker Hoses: Consider these for consistent watering and water conservation.
You might find yourself watering more frequently than usual, so regular checks are important.
Temperature Control: Keeping it Just Right
Maintaining the correct temperature is key for plant growth. You’ll need to monitor it and adjust as needed.
- Monitoring: Use a reliable thermometer inside your greenhouse.
- Heating: In cooler weather, you might need supplemental heat. Small electric greenhouse heaters or oil-filled radiators designed for such spaces are options. Always ensure they are safely installed and suitable for humid environments.
- Cooling: On hot days, ventilation is your primary cooling method. Shade cloth can be draped over the greenhouse to reduce direct sun intensity. Misting can also help lower temperatures temporarily.
Different plants have different temperature preferences. Research your chosen plants to understand their ideal conditions. For example, many vegetables like daytime temperatures between 70-80°F (21-27°C) and nighttime temperatures slightly cooler.
Lighting: Harnessing Natural Light
Greenhouses are designed to maximize natural sunlight. However, during short winter days or on very overcast days, plants might need supplemental light.
- Clean Your Covering: Ensure your greenhouse panels or film are clean to let in maximum light.
- Reflective Surfaces: Painting interior walls white or using reflective materials can bounce light back onto plants.
- Supplemental Lighting: For serious growers or those with limited winter light, grow lights can provide essential illumination. LED grow lights are energy-efficient and effective.
Air Circulation: Beyond Just Vents
Stagnant air is a breeding ground for pests and diseases. Even with vents open, a small fan can make a big difference.
- Recharge the Air: A circulating fan helps distribute heat and moisture evenly, preventing pockets of stale air.
- Strengthen Plants: Gentle air movement can help make plants develop stronger stems as they sway slightly.
- Discourage Pests: Many flying pests dislike constant air movement.
What to Grow in Your Outdoor Greenhouse: Beginner-Friendly Plants
The beauty of a greenhouse is the variety of plants you can successfully grow. For beginners, here are some excellent choices:
Vegetables
- Tomatoes: The quintessential greenhouse crop! You can grow indeterminate varieties that produce fruit all season long.
- Cucumbers: Similar to tomatoes, cucumbers love warmth and can be trellised upwards.
- Peppers (Sweet and Chili): These thrive in heat and will produce abundantly.
- Eggplant: Another heat-loving veggie that benefits greatly from greenhouse protection.
- Leafy Greens (Lettuce, Spinach, Kale): You can grow these even when it’s cooler outside, extending their season indoors.
- Radishes and Carrots: Quick-growing and easy, perfect for early harvests.
Herbs
Most herbs do wonderfully in a greenhouse, especially those that love warmth:
- Basil
- Mint
- Rosemary
- Thyme
- Parsley
- Cilantro
Flowers
Brighten your space with beautiful blooms:
- Petunias
- Geraniums
- Impatiens
- Begonias
- Annuals for early starting (Marigolds, Zinnias)
Table: Greenhouse Essentials Checklist
Here’s handy checklist to ensure you have the basics covered:
| Item | Purpose | Notes for Beginners |
|---|---|---|
| Greenhouse Structure | Enclosed growing space | Start small, choose durable materials like polycarbonate. |
| Thermometer | Monitor temperature | Essential for preventing overheating or freezing. |
| Ventilation (Manual/Automatic) | Regulate airflow & temperature | Crucial for plant health and disease prevention. |
| Watering Can/Hose with Sprayer | Provide water | Water at the base, in the morning. |
| Shade Cloth | Reduce intense sun | Useful for hot summer days. |
| Potting Soil/Compost | Growing medium | Use a good quality, well-draining mix. |
| Pots/Trays | Containers for plants | Ensure good drainage holes. |
| Seeds/Seedlings | Your plants! | Choose varieties suited for greenhouse growing. |
| Fans (Optional) | Improve air circulation | Helps prevent fungal issues. |
| Heater (Optional) | Provide supplemental heat | For extending the growing season into colder months. |
Common Greenhouse Pests and How to Deal with Them
Even in a controlled environment, pests can find their way in. Early detection and intervention are key.
Aphids
What they look like: Small, pear-shaped insects, often green, black, or red, found on new growth and undersides of leaves.
Damage: They suck sap, weakening plants and distorting leaves.
Control: Blast off with water, use insecticidal soap, or introduce beneficial insects like ladybugs.
Whiteflies
What they look like: Tiny white flying insects that swarm when disturbed, often found on the undersides of leaves.
Damage: They also suck sap and can transmit viruses.
Control: Yellow sticky traps are effective. Insecticidal soap or neem oil can also be used.
Spider Mites
What they look like: Tiny, almost invisible little specks that thrive in hot, dry conditions. You’ll see fine webbing and speckled or stippled leaves.
Damage: They suck sap, causing leaves to yellow, dry out, and drop.
Control: Increase humidity by misting plants regularly. Use insecticidal soap or horticultural oil. Blast with water.
Fungus Gnats
What they look like: Small, dark flies that hover around the soil surface. Their larvae live in the soil.
Damage: Adults are mostly a nuisance, but larvae can damage young roots. They thrive in overly moist soil.
Control: Allow soil to dry out between waterings. Use yellow sticky traps. Bacillus thuringiensis israelensis (Bti) is a safe biological control for larvae.
Remember, good airflow and avoiding overwatering are your best defenses against many of these pests!
Frequently Asked Questions About Outdoor Greenhouses
Q1: How much does an outdoor greenhouse cost?
A: Costs vary widely. Small, simple polyethylene hoop houses can be as low as $100-$300. Mid-range polycarbonate kits might range from $500 to $2,000. Larger or glass structures can cost several thousand dollars or more. DIY options can be budget-friendly if you source materials wisely.
Q2: Do I need a foundation for a small backyard greenhouse?
A: For very small, temporary structures, a level ground might suffice. However, for most kits, a simple gravel base, wooden frame, or concrete footing will provide better stability, drainage, and longevity. Always check the manufacturer’s recommendations.
Q3: How do I heat a greenhouse in winter?
A: For mild climates, good insulation and covering might be enough. For colder regions, small electric greenhouse heaters, propane heaters (with proper ventilation and safety measures), or even compost heating systems can be used. Automatic vent openers are critical to prevent overheating on sunny winter days.
Q4: Can I grow food in a greenhouse year-round?
A: Yes, with proper heating, ventilation, and lighting management, you can extend your growing season significantly, and in some cases, achieve year-round production for many crops, especially in milder climates or well-equipped greenhouses.
Q5: What are the biggest mistakes beginners make with greenhouses
