Differentiating Cotyledons (First Leaves) from True Leaves

Once your plants start germinating and grow into sprouts, their next stage in life depends on your evaluation of their growth. Don’t worry, it’s simple!

Keep reading to learn how to tell the difference between your plants’ first leaves, called cotyledons, and true leaves, which resemble the mature plant’s leaf shape on a smaller scale.

Fully visible true leaves are 1 of 3 signs your plant is ready for its first taste of plant food!

Cotyledons are the first pair of leaves plants grow from seed. These leaves may not resemble the mature plant’s leaf shape. Cotyledons get their energy from the seed itself, which is why seeds and young sprouts don’t need any plant food!

Nope! It's normal for cotyledons to yellow or dry up after the plant's true leaves grow. Depending on the species, cotyledons' lifespan ranges from a few days after germination up to a year.

Yellowing cotyledons

True leaves are the second set of leaves to grow, and they resemble the mature plant’s leaf shape on a smaller scale. Unlike cotyledons, which feed themselves from the seed’s stored energy, true leaves perform photosynthesis to start supplying the plant with food for its next growth stage.

Once you notice your plants’ first leaves, start checking on them daily to see if any have grown their true leaves. It typically takes 1-4 weeks for true leaves to grow after the cotyledons unfurl.

Look at your sprouts closely. Do you only see one set (2 individual) leaves? If so, those are still the cotyledons. Do you see a second set of leaves, making 4 total leaves present on your plant? If so, these are true leaves! 

Not sure what you’re looking at? Young plants can survive with just their true leaves for up to 2 weeks, so when in doubt, don’t rush it!

Instead, let your plants take the lead and keep watching them closely. If you’re unsure what a specific plant looks like when mature, check out its page in the Plant Book to find the leaf shape you can match to its true leaves.

Congrats! This means these plants are ready to receive plant food.

If you've been germinating yCubes on your Gardyn (whether for the first time with your Welcome Kit, or because you've started fresh with a new generation of plants) be sure to review our guide on adding plant food for the first time.

If you've been germinating yCubes off your Gardyn, such as in the Nursery or in a tray with a ventilated lid, only move the yCubes with true leaves, roots growing .5-inch outside the rockwool, or discolored cotyledons to your Gardyn. Keep all other yCubes off your Gardyn until they are ready for plant food, too! 

Some plants, like Chives, don't grow true leaves. For any yCube, another sign of plant food readiness you can look for is roots growing .5-inch long outside the bottom of the yCube to know the plant is ready for plant food!

Questions? Reach us at support@mygardyn.com, or chat with us. We're here to help!