Carbon Dioxide and Better Indoor Harvests

Most of us think of carbon dioxide (CO₂) as “bad,” thanks to today’s news of global warming, but without CO₂, plants wouldn’t thrive. In this article, we’ll talk about CO₂ in general terms: Why plants need it, and why it is such an important element in getting hardier, healthier plants and better harvests.

Carbon dioxide and plant growth cycles

Plants have controlled the carbon cycle for nearly 400 million years on land; they do this by using photosynthesis to convert CO₂ from the atmosphere into the molecules that plants need for energy and growth. Humans and animals breathe oxygen, exhale carbon dioxide, and give plants what they need to thrive; the cycle continues as plants breathe carbon dioxide and exhale oxygen, giving us and the animals what we need to thrive.

The photosynthesis cycle in the grow room

This same process occurs in the grow room. Plants use carbon dioxide, light, water and nutrients to make glucose and other molecules; they depend on glucose for the energy to grow. In turn, they expel oxygen. However, a recent discovery proves that carbon dioxide may be the greatest of all of these factors when it comes to plant health and growth. Why?

Flowering plants need CO₂ for best growth

The dry matter in most plants is comprised of 90% carbon, hydrogen, and oxygen. Almost all of that matter has now been proven to come from carbon dioxide. That means that CO₂ is *the* most important ingredient for growth since it provides the carbon needed for the plant to live and grow. In general, you should use CO₂ during the day from the seedling phase through the harvest.

Achieving the right balance: Photosynthesis during the day, respiration at night

CO₂ is essential for plant growth during the day, but the process reverses at night. Then, plants take in oxygen, just as humans and other animals do, and exhale carbon dioxide.

In the next article, we’ll talk about how to supplement CO₂ during the day for better plant growth and harvests.