How to Transition from Vegetative to Flowering


As growers, there are a lot of little things to consider when switching your plants\transition from vegetative to flowering. Switching at the right time can guarantee the maximum output of your harvests, reduce time growing, improve bud quality, and save money on energy costs. If you are new in this field, we hope this article can help increase your success rates in your grow.

What are the vegetative and flowering stages?

Vegetative and flowering stages are both crucial periods in a plant’s life cycle. In cannabis, when we start seeing a set of pointed leaves, it means that your plants have moved beyond the seedling stage and are at the vegetative stage. During this stage, all the energy of your plants is used to grow leaves and stems (no flowers or “buds” yet). Usually, a cannabis plant takes about 2-4 weeks to mature into the flowering stage, but this depends on the strain and whether you’re using autoflower.

Your plants begin budding in the flowering stage. When this starts, you need to ensure a 12-12 photoperiod, which means you need to keep your lights on for 12 hours and then have 12 hours of continuous darkness every night until harvest, or your plants will return back to the vegetative stage and will continue to grow larger.

the Transition of Cannabis from Vegetative Stage to Flowering Stage

How do I prepare for the transition from vegetative to flowering?

We can judge when to transition through the height of your plants (in the vegetative stage). Your plants will grow quickly in height during veg—they can double or triple in height. Therefore, before you start growing you’ll need to be aware of how large your specific strain will grow and compare it to the height of your tent so you leave enough room between the plants and your light and the top of the tent (you’ll need to keep at about 12 inches between the canopy and the lamp, if it is an LED).

How to transition from vegetative to flowering?

How do you know that your plants are ready to transition from vegetative to flowering? The answer is the amount of sunlight available to the plant. Obviously, there is no sunlight in a grow tent, so a grow light like LED grow lights act as sunlight. In a grow tent, you control the transition process by controlling photoperiod—you’ll need to transition to a 12/12 photoperiod to stimulate flower product.

But, before you switch to flowering, you’ll need to distinguish the female and male plants otherwise the male plants will fertilize the female plants and your buds will grow seeds. You’ll need to look for small nodes on the points where the branches separate from the stem.

Male plants have small pollen sacs at this point—they look like small green and white seeds. The females have similar sacs, but female plants have stigmas, which catch pollens released by males. So when checking, you look for hairs that come out of the node points. A lighted loupe can help you identify whether your plant is male or female.

Additionally, male plants usually grow more quickly and taller—try to separate the males from females as soon as possible and remove them from your space if you don’t plan to fertilize your plants. We’ll be publishing another article to tell you how to distinguish between female and male plants later on, so keep a lookout for that.

A Lighted Loupe-Transition from Vegetative to Flowering

Photoperiod and transition from vegetative to flowering

  • Keep your lights on for 12 hours per day: Your plants need 12 hours of darkness until harvest every day during the flowering stage. This is the most important step—continuous, uninterrupted darkness, is important—if you interrupt the darkness, your plant may believe that it is still summer and will not produce flowers.
  • Keep your plants at a safe distance from your light: Your light can’t be too far away from your plants, or they will stretch their body to capture the light since they can’t absorb enough light. But your light can’t be too close to your plants either as the light will burn your plants.                                                                          There is no perfect hanging height for a light—it is something you’ll need to keep observing as your plants will react differently to light height, so adjust the lights accordingly. If you use an LED grow light in your tent, you can check our article How Far should Seedlings be from Grow Light to see how to adjust the hanging height of your light.
  • Increase light intensity: you’ll need to increase the light intensity after you adjust the hanging height. You can add the light intensity by 10% every day so that your plants can adapt to it. Your plants prefer the blue spectrum in the vegetative stage while they prefer the red spectrum during flowering, as red light produces Chlorophyll B, which is used to synthesize proteins that build flowers. Be aware—red light is hotter than blue light (because it is close to infrared), so don’t leave your light too close to your plants.

Humidity and temperature-Transition from Vegetative to Flowering

During flowering, the recommended humidity is 40-60% RH—the humidity in the flowering stage is lower than during the vegetative. The temperature should be between 68-82°F, depending on the time of day.

A new pot-Transition from Vegetative to Flowering

As we mentioned before, your plants will grow fast during the flowering stage, you need to measure the size of your grow space in advance if it is big enough to hold your plants. Transfer them to a larger spot before transition so your plants don’t get rootbound and can grow to their full potential.

Nutrients-Transition from Vegetative to Flowering

Nutrients can help to improve the health of your plants. However, too many nutrients will burn our plants. The main nutrients that your plants need are Nitrogen, Phosphorus, and Potassium. You need to reduce Nitrogen and increase Phosphorus and Potassium during this transition.

Pests-Transition from Vegetative to Flowering

Check the leaves of your plants regularly, especially in corners that are easily overlooked. Keep your plants away from pests as best you can.

It’s an exciting moment when your plants begin budding since the flowering stage decides the output of your harvest, plus you get to see the fruits of your labor!. You should be well prepared before you flip your plants from vegetative to flowering, so you’ve done the right thing reading this article.

As they say, sharpening an axe will not hold up the work of cutting firewood. You can message us if you are uncertain about anything, we’re here to help. If you find our article helpful, you can subscribe to VIVOSUN newsletter, we’d love to hear from you!

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