Whether you’re just starting your plant journey or already have a house full of greenery, understanding photosynthesis can help you take better care of your plants. But what exactly is it—and why is it so important?

At Planteka, we help people connect more deeply with plants—through expert-led workshops, personalized consultations, and practical content like this. Whether you’re struggling to keep your plants alive or dreaming of transforming your space into a green haven, we’re here to guide you with clarity, confidence, and community.

Let’s break down the magic of photosynthesis in simple terms and explore what it means for everyday plant care.

What is photosynthesis?

Photosynthesis is the process by which green plants make their own food using light, water, and carbon dioxide. It takes place in special cell structures called chloroplasts, which contain a green pigment called chlorophyll.

In simplified form:

☀️ Sunlight + 💧 Water + 🌬️ Carbon dioxide (CO₂) → 🌱 Sugars (energy) + 🌬️ Oxygen (O₂)

Here’s how it works:

1. Chlorophyll in the chloroplasts absorbs energy from sunlight. Within these chloroplasts, structures called thylakoids are where the key chemical reactions happen.
2. The plant absorbs water through its roots (and in some cases, a small amount of moisture through its leaves—especially in certain tropical or epiphytic plants).
3. Carbon dioxide enters through tiny pores on the leaves called stomata, which also help regulate water loss.
4. The plant uses the captured sunlight energy to convert water and carbon dioxide into glucose, a type of sugar that fuels its growth.
5. As a byproduct, the plant releases oxygen back into the air.

💡 While glucose is the main product of photosynthesis, plants use it to build more complex molecules like cellulose (for structure), amino acids, and lipids, which are essential for growth and reproduction.

But wait—don’t plants also “breathe”?

Yes! Plants perform both photosynthesis and respiration.

🔁 During the day, photosynthesis dominates: plants take in CO₂, produce oxygen, and make energy from sunlight.

🌙 At night, photosynthesis stops (no light = no photosynthesis), but respiration continues, using oxygen and releasing carbon dioxide—just like we do.

Why is this important for plant care?

Photosynthesis explains many of your plant’s needs and behaviors. Here’s what it means in practical terms:

1️⃣ Light is essential

Without light, plants can’t photosynthesize. That means they can’t make energy, grow, or thrive.

✔ Bright, indirect light is ideal for most indoor plants.
✔ Low light = slower growth, smaller leaves, or legginess.
✔ Consider grow lights if your home doesn’t get enough natural light.

2️⃣ Water is necessary—but needs balance

Water fuels photosynthesis—but too much of it can suffocate roots and cause rot.

✔ Always feel the soil before watering.
✔ Understand your plant’s preferences—ferns like consistent moisture, while succulents prefer to dry out between waterings.

💧 Want to try a safer method? Learn about bottom watering here.

3️⃣ Plants need air, too

Your plant takes in carbon dioxide through the stomata on its leaves. Poor airflow can limit this process and invite mold or pests.

✔ Don’t overcrowd your plants.
✔ Crack a window occasionally or use a fan to improve air movement.

4️⃣ Don’t forget about nutrients

Photosynthesis creates sugars, but plants also need minerals from the soil to build vital compounds.

✔ Nutrients like nitrogen, phosphorus, and potassium are essential for healthy growth.
✔ Use a balanced fertilizer during the growing season.

Read more about macronutrients that your plants need in our article. We also covered micronutrients here.

5️⃣ Clean leaves = better photosynthesis

Dust on leaves can block light and reduce your plant’s ability to photosynthesize efficiently.

✔ Wipe leaves with a damp cloth or use a soft brush regularly.
✔ This also helps prevent pest infestations.

6️⃣ Winter slowdown is normal

In winter, shorter days mean less light—so photosynthesis slows or even stops for most of the day. That’s why:

✔ Growth slows down.
✔ Watering needs drop.
✔ Fertilizing should pause until spring.

Your plant isn’t sick—it’s just saving energy during the darker months.

Bonus: Why are leaves green?

Leaves look green because chlorophyll absorbs red and blue light but reflects green wavelengths. That’s what gives plants their color—and why grow lights often emphasize red and blue tones to boost photosynthesis indoors!

In summary

Photosynthesis is how plants turn light, water, and CO₂ into energy. For you, that means focusing on:

🌞 Enough light
💧 Proper watering
💨 Good airflow
🧪 Balanced nutrients
🧼 Clean leaves

When you understand photosynthesis, you’re not just guessing what your plant needs—you’re speaking its language.

Ready to grow your plant knowledge?

🌱 Join our Gardening course for beginners —available in Barcelona, Madrid, Valencia, and online. Or book an online session with one of our Plant doctors to troubleshoot light, watering, or nutrient issues.

💬 What’s one thing you just learned about photosynthesis? Let us know in the comments—we’d love to hear it!