Growing Cannabis 101: The Vegetative Phase

Like any kind of cultivation, growing cannabis requires being in tune with the life cycle of the plant. And the first part of that life cycle is the vegetative phase. If you want to learn how to grow marijuana, understanding this phase—and how to care for your plants during it—is absolutely necessary. That’s why we’re going to look at the vegetative phase in this exciting installment of Growing Cannabis 101.

What is the Vegetative Phase?

The vegetative phase, or “veg phase,” is the first part of the life cycle of a plant. During the veg phase, plants will develop most of their roots, stems, and branches. They also develop a lot of leaves, too. The veg phase comes before the flower phase, which is when buds start developing.

One distinctive feature of the veg phase is its light time. Photoperiodic plants (or non-autoflower variants) depend on the amount of light they receive to guide the progression through a life cycle. Plants will only stay in the veg phase as long as they’re getting at least 16 hours of light per day. This is because days are longer in the summer and shorter in the fall, when the plant typically begins flowering.

Growing Cannabis in the Veg Phase

Keeping your plant healthy and happy during the veg phase is a critical part of the cultivation cycle. A hardy veg phase will set the stage for a solid flower phase: That means better quality buds and higher yields on harvest day.

Here are two tips to help ensure your plants thrive throughout their veg phase.


Light is likely the single most important aspect of the veg phase. Like we mentioned before, photoperiodic strains will switch into the flower phase if they get less than 16 hours of light per day. However, as long as you stay above this threshold, the plant will continue to be in its veg phase. In fact, some industrial-scale gardens leave their lights on for 24 hours at a time in the veg phase. That’s likely a little extreme for a home garden, but as long as your plants are looking happy, you can leave your lights on as long as you want.

When there is darkness in your garden, it needs to be absolute. Even a pinprick of light can shock a cannabis plant into “herming.” This happens when a plant gets too stressed and thinks it’s going to die. It essentially impregnates itself and starts making seeds. You don’t want this to happen, since a herm won’t develop any THC. Long story short, when your garden is dark, it needs to be totally dark.


Maintaining a proper environment is right up there with light when it comes to keeping plants happy and healthy in the veg phase. Ideally, you want to keep your garden’s temperature between 72 and 82 degrees fahrenheit. That’s just one part of the puzzle, though. You’ll also want to maintain a relative humidity level between 50% and 60%.

The Vegetative Phase: Wrapping Up

Growing cannabis isn’t easy. But if you follow these tips, you should have happy plants during the vegetative phase.

Ready to get started? We can help you get gardening with clones from Green Goddess Collective. Browse our selection of clones here.

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