When Plants Respire, What Gas Is Released into the Atmosphere?

Plants are living organisms, and like all living things, they need energy to survive. To obtain this energy, plants carry out a vital process known as respiration. A common question in biology is: when plants respire, what gas is released into the atmosphere? The simple answer is carbon dioxide, but understanding why requires a closer look at how respiration works in plants.

What Is Respiration in Plants?

Respiration is a chemical process that occurs in all living cells, including plant cells. Its purpose is to release energy stored in food (mainly glucose) so the plant can grow, repair itself, and carry out essential life processes.

⭐ Recommended Products — Garden & Allotment Essentials for March

March is when the growing season truly begins. Seeds are being sown daily, beds are prepared and late frosts are still possible — these essentials help produce strong plants and a successful start.

Seed Trays, Modules & Propagation Kits — perfect for tomatoes, brassicas, lettuce, onions and flowers. 👉 Click here to see top options

Heated Propagators, Heat Mats & Grow Lights — improves germination and prevents leggy seedlings during cold nights. 👉 Click here to see top options

Seed & Cutting Compost — essential for healthy seedlings and strong root growth. 👉 Click here to see top options

Garden Fleece & Plant Protection Covers — protects seedlings, potatoes and early plantings from late frost. 👉 Click here to see top options

Spring Vegetable Seeds — carrots, beetroot, peas, spinach and salads can all be started now. 👉 Click here to see top options

Garden Kneeler & Seat — makes long sowing and planting sessions far more comfortable. 👉 Click here to see top options

Pressure Washer (Greenhouse & Patio Cleaning) — clean patios, paths and greenhouses before planting. 👉 Click here to see top options

Solar Garden Lights — perfect for enjoying the garden during brighter spring evenings. 👉 Click here to see top options

Unlike photosynthesis, respiration does not depend on light and takes place continuously, both day and night.

The Gas Released During Plant Respiration

When plants respire, they release carbon dioxide (CO₂) into the atmosphere.

During respiration:

Oxygen is taken in by the plant
Glucose is broken down to release energy
Carbon dioxide and water are produced as waste products

This means that carbon dioxide is always being released by plants as long as respiration is happening.

Why Do Plants Release Carbon Dioxide?

The release of carbon dioxide is a natural result of breaking down glucose. The chemical energy stored in glucose is unlocked through respiration, allowing the plant to function. Carbon dioxide is produced as a by-product and must be released from the plant into the surrounding air.

Plants release carbon dioxide through tiny pores called stomata, mainly found on the leaves.

Respiration vs Photosynthesis

Respiration is often confused with photosynthesis, but they are opposite processes:

Photosynthesis

Takes place only in light
Uses carbon dioxide and water
Produces glucose and oxygen
Removes carbon dioxide from the atmosphere

Respiration

Occurs all the time (day and night)
Uses oxygen and glucose
Produces energy, carbon dioxide, and water
Adds carbon dioxide to the atmosphere

Even during the daytime, when photosynthesis is happening, plants are still respiring.

Do Plants Release Oxygen or Carbon Dioxide Overall?

At night: Plants only respire, so they release carbon dioxide
During the day: Both respiration and photosynthesis occur, but photosynthesis usually happens at a faster rate, so plants release more oxygen overall

This is why plants are considered essential for maintaining oxygen levels in the atmosphere, even though they do release carbon dioxide through respiration.

Why Plant Respiration Is Important

Plant respiration is crucial because it:

Provides energy for growth and development
Supports processes like nutrient uptake and cell repair
Keeps plants alive and functioning

Without respiration, plants would not be able to survive, even though they produce their own food through photosynthesis.

Join our new daily newsletter for tips, advice. recipes, videos plus lots more. Join for free!

📘 Learn How to Grow Your Own Fruit & Vegetables

Growing your own veg is one of the most rewarding things you can do on an allotment or in the garden — saving money, eating better, and enjoying the process from seed to harvest.

Allotment Month By Month: Grow your Own Fruit and Vegetables, know exactly what to do and when, with clear month-by-month guidance that makes growing easier and more successful.

👉 Take a look at this book on Amazon