The big difference respiration photosynthesis have is what they do with food. One makes it and one uses it up. Your plants run photosynthesis to build glucose from CO2, water, and sunlight each day. Respiration breaks that glucose down to give your plant energy to grow and repair. These two do the opposite of each other in your garden.
When I first moved my peace lily from a sunny window to a dark office corner, it looked fine for a few weeks. Then the leaves started to yellow and drop one by one over the next month. My plant was burning more energy through respiration than it could make with photosynthesis in that dim spot. Without enough sugar to fuel its cells, the plant began to starve right before my eyes. I had to move it back to bright light fast.
Photosynthesis happens in the chloroplasts inside your plant's green cells. These tiny organs use light to split water and grab carbon from the air around them. They combine the pieces into glucose and release oxygen as a leftover product. Your plant stores this sugar for later use or ships it to growing parts that need the fuel. The whole process only runs when light hits your leaf surface during the day.
Respiration takes place in the mitochondria found in every cell of your plant. Here each cell breaks glucose apart and mixes it with oxygen to release energy. The outputs are CO2 and water. Those are the reverse of what photosynthesis makes. When you make a photosynthesis and respiration comparison, you see how they flip. Your cells burn fuel all the time to stay alive and keep growing strong and healthy.
Another key point is when each process runs in your garden plants. Photosynthesis only works while light shines on your leaves since light drives the whole thing. Respiration runs all day and all night without pause in every living cell of your plant. Your plant makes sugar during the day and burns some of it around the clock to stay alive. At night only the burning side runs, so your plant must dip into stored energy to survive.
The gases flip between these two opposite plant processes as well. Photosynthesis pulls in CO2 and pushes out oxygen into the air around your plants. Respiration pulls in oxygen and pushes out CO2 in return all the time. During the day when both run at once, photosynthesis usually wins in bright light. Your plant gives off more oxygen than it takes in while the sun shines on its leaves. When you look at respiration vs photosynthesis, you see mirror images that work all day long.
In my experience, your plants need good light to keep this balance in their favor over time. I tested two cuttings from the same pothos vine in different spots for three months. The one in bright light grew thick stems and large leaves all over the pot. The one in a dim hallway stayed small with thin, pale leaves that looked sick. Your cuttings can't make enough sugar to grow well without enough light to power them up each day in your home.
Your plants stay healthy when photosynthesis beats respiration most days of the growing season. Give them enough light to build up sugar stores for growth and nighttime use in your home. Watch for pale or dropping leaves as a sign that your plant may be losing its energy battle. Move struggling plants to brighter spots so they can make more food than they burn each day and thrive in your home all year long.
Read the full article: Respiration in Plants: The Complete Process Guide
