How to Grow Orchids In Your Greenhouse

Key Takeaways

• Humidity & Temperature: Orchids need a high humidity level with warm days and cooler nights.
• Variety Matters: Different orchid types have small differences in light and temperature needs.
• Soilless Mix: A mix of bark, peat, perlite, and moss is best for orchid roots.
• Greenhouse Size: Space for good air movement and room for plants to grow is essential.
• Raised Growing: Using benches or shelves helps protect orchids from cold ground drafts.
• Environment Control: Keep air flowing, water carefully, and provide indirect light.
• Avoiding Issues: Watch for pests, mold, and root rot with careful maintenance.
• Better Blooms: Extra light and a balanced feeding schedule help orchids flower longer.
• Winter Care: Insulation, proper heating, and extra light are key during colder months.
• FAQs: Common questions answered for simple orchid care.

Introduction

Orchids are pretty and delicate plants that can brighten up any space. Growing them in a greenhouse makes it easier to keep the air warm and moist. In this article, we explain how to care for orchids inside your greenhouse using clear, simple language. I have spent many years caring for these plants, and I will share tips that have helped me and many others.

When you have a greenhouse, you can control the air, light, and water. This article shows you the best ways to keep your orchids happy and growing strong. You will learn about the important things your greenhouse needs, the small differences among orchid types, and the best potting mix to use. I also share advice on the size your greenhouse should be and why it is a good idea to raise your plants off the ground on benches or shelves.

For extra reading on related topics, please visit our guides on Perfect Potted Dahlias, Soil Types: A Complete Guide To Uk Garden Soils, How To Grow Melons In Your Greenhouse, and Overwintering Plants Guide – Protect Them From Uk Frosts.

If you need a smaller setup, check out our Small Greenhouses.

Key Greenhouse Conditions for Orchids

Orchids need a few basic conditions in your greenhouse. Here are the five main points:

• High Humidity: Keep the air moist, around 60–80%.
• Warm Temperatures: Warm days help the plants grow well.
• Fresh, Clean Air: Good airflow is very important.
• Proper Light: Provide indirect light that suits the type of orchid.
• Night-Time Temperature Drop: The temperature should fall by 5–10° Celsius at night.

Condition	What to Do	Tip
Humidity	Use water trays and a misting system	Clean trays often to avoid build-up
Temperature	Warm days with a drop of 5–10° at night	Use a thermostat to check temperatures
Air Quality	Open vents or use small fans	Keep the air fresh and moving
Light	Indirect light is best	Use shade nets if the sun is too strong
Night Cooling	Ensure the drop happens without a cold draft	Keep plants away from direct wind

Slight Condition Changes by Variety

Not all orchids are the same. Some grow on the ground, while others grow on trees. Let’s look at two main types:

Terrestrial Orchids

• Light Needs: These plants usually need less light because they are used to shaded spots under trees.
• Temperature: They can handle cooler air as they grow on the ground.
• Growing Medium: A softer mix works well because these orchids like gentle care.

Epiphytic Orchids

• Light Needs: These orchids like a bit more light since they grow on trees where the sun peeks through.
• Temperature: They prefer slightly warmer air as they grow high up.
• Growing Medium: They need a mix that drains quickly, as they get many nutrients from rain.

Feature	Terrestrial Orchids	Epiphytic Orchids
Light	Low to moderate light	Moderate light
Temperature	Can tolerate cooler air	Prefer warmer conditions
Potting Medium	Soft, moisture-retaining mix	Fast-draining, airy mix
Growth Habit	Grow on the ground	Grow on trees or supports

Soilless Potting Medium & Temperature Control

Orchids do not use normal garden soil. They need a special mix that helps their roots breathe. This mix usually includes bark, peat moss, perlite, and sometimes moss like sphagnum or osmunda fibre. Here’s how to care for your orchid’s potting medium and manage temperature:

Potting Medium

• Bark: Offers good drainage and a firm base for the roots.
• Peat Moss: Holds moisture but does not get soggy.
• Perlite: Keeps the mix airy and prevents water from sitting too long.
• Moss: Adds extra moisture without making the mix heavy.

Component	Benefit	Tip
Bark	Provides structure and drainage	Use coarse bark for best flow
Peat Moss	Retains gentle moisture	Mix lightly for balance
Perlite	Keeps the mix airy	Use to improve drainage
Moss	Adds moisture without weight	Use sparingly for delicate roots

How Large Should Your Greenhouse Be?

The size of your greenhouse is very important for keeping your orchids happy. A proper size means good air movement and enough space for each plant to grow. Here are some tips to decide on the size:

Spacing

• Air Circulation: The greenhouse should allow air to flow freely between the plants.
• Room to Grow: Orchids should have space around them so their leaves do not touch.
• Additional Space: Consider room for storage, work areas, and walkways.

Number of Orchids	Space Needed (m²)	Note
10 orchids	About 5 m²	Each orchid has enough space
20 orchids	At least 10 m²	Consider extra space for growth
30 orchids	15 m² or more	Allows for work space and storage

Raise Plants Up

Raising your orchids off the ground can help keep them safe and allow for better care. Placing them on benches or shelves means that the plants will not get cold from the floor and will have improved air flow around them.

• Better Air Flow: Raised plants get more air from below, which helps prevent mold.
• Easier Water Collection: Water that drains off can be collected in trays underneath, helping to maintain humidity levels.
• Protection from Pests: Being off the ground may reduce contact with soil-borne pests.

Method	Benefit	Note
Mesh Benches	Allows water to drip away easily	Use sturdy, washable material
Shelves with Trays	Collects water and keeps area tidy	Clean trays often
Raised Pots	Keeps roots away from cold floors	Choose pots with drainage holes

Controlling the Greenhouse Growing Environment

Keeping a balanced environment in your greenhouse is very important for orchid health. There are four main things to watch: humidity, air flow, light, and water.

Humidity

• Ideal Range: Orchids do best when the air is 60–80% moist.
• Ways to Increase: Use water trays, misting systems, or even a small indoor fountain.
• Tip: Check the moisture level daily with a simple gauge.

Air Flow

• Fresh Air: Good air movement stops mold and helps the plants breathe.
• Ventilation: Open vents or use small fans placed near the bottom of the greenhouse.
• Arrangement: Space the orchids out so that air can move between them.

Light

• Indirect Light: Orchids thrive in soft, indirect light.
• Coverings: Use shade cloths or position your greenhouse where trees offer gentle cover.
• Supplemental Lighting: In colder months, a few extra lights can help when natural light is low.

Watering

• Balanced Moisture: Keep the potting mix damp but not soggy.
• Schedule: Water the orchids on a regular timetable and check the mix before adding more water.
• Caution: Too much water can harm the roots, so water gently.

Aspect	What to Watch For	How to Manage
Humidity	60–80% moisture	Use trays, misting, and a gauge
Air Flow	Fresh, moving air	Open vents, use fans, and space plants out
Light	Indirect, soft light	Use shade cloths and extra lights if needed
Watering	Damp but not soggy mix	Regular checks and gentle watering

How to Avoid Common Issues

Even with careful care, orchids can face problems such as overwatering, mold, pests, and root rot. Here’s how to spot and address these issues:

Overwatering and Mold

• Signs: Yellow leaves and soggy potting mix.
• Prevention: Use a well-draining soilless mix and water carefully.
• Cleaning: Gently wipe leaves with a soft cloth to remove mold.

Pests – Thrips and Others

• What to Watch: Tiny insects on leaves and flowers.
• Treatment: Wash leaves with a mild soap solution and use sticky tape to trap pests.
• Observation: Check daily to catch any pest issues early.

Root Rot

• Identification: Black, mushy roots during repotting.
• Action: Remove affected parts and repot in fresh mix.
• Tip: Clean the pot before reusing it to stop rot from spreading.

Issue	Signs	Action to Take
Overwatering	Yellow leaves, soggy mix	Allow mix to dry and use well-draining material
Mold Growth	White/gray patches on leaves	Wipe leaves gently and improve air flow
Pests (Thrips)	Tiny moving insects	Wash leaves with mild soap and use sticky tape
Root Rot	Black, mushy roots	Remove affected roots and repot with fresh mix

How to Get Better Blooms

Orchids are loved for their beautiful flowers. Getting more blooms means caring for your orchids well. Here are some ideas:

Light and Feeding

• Extra Light: A little more light each day can encourage more blooms.
• Fertiliser: Use a gentle, balanced fertiliser (like 10-10-10) at half the normal dose once a month.
• Watering: Keep the mix moist but not too wet.

Timing and Routine

• Check your orchids daily for water and light needs.
• Maintain a consistent feeding and watering schedule.
• A slight temperature drop at night helps trigger blooming.

Task	Frequency	Tip
Light Adjustment	Daily	Ensure gentle, indirect light
Watering	As needed	Check the mix before watering
Feeding	Once a month	Use half the normal fertiliser amount
Temperature Check	Daily	Monitor for a 5–10° drop at night

Winter Care

During colder months, orchids need extra care. A warm and well-lit greenhouse helps keep them safe when the weather is chilly.

Temperature and Insulation

• Keep It Warm: Ensure the greenhouse is warm enough to prevent a cold shock.
• Insulation: Use insulation on walls or covers to keep the heat in.
• Night Drops: Even in winter, a 5–10° drop at night is beneficial.

Lighting and Air Flow

• Extra Lights: Supplement natural light with extra lights when days are short.
• Air Circulation: Maintain some airflow, even when keeping vents closed for warmth.
• Avoid Cold Drafts: Block any areas where cold air might reach the orchids.

Watering and Feeding in Winter

• Adjust Watering: The mix may hold water longer; water less often.
• Feed Sparingly: Use less fertiliser during winter, maybe once every six weeks.

Winter Task	What to Do	Tip
Temperature	Keep greenhouse warm with insulation	Use a thermometer to monitor
Lighting	Add extra lights if natural light is low	Use gentle, indirect lighting
Air Flow	Keep some vents open	Ensure no strong cold drafts reach the plants
Watering	Water less frequently	Check the mix before watering
Feeding	Use reduced fertiliser	Feed lightly once every 6 weeks