When to Flip to Flower

Unless you are growing an autoflowering hybrid cannabis strain, then knowing when to flip your photoperiod female plants from their vegetative stage to their flowering phase is an incredibly important piece of knowledge for cannabis growers, as it is one of the most vital steps to guarantee the success of your cannabis plants. If you flip your cannabis to flower too early you can end up with less than impressive yields, whereas if you flip from veg to flower too late in the game you can end up with either overgrowth or burned bud sites.

In short, knowing when to transition your plants from their vegetative phase to their flowering stage can help prevent any unnecessary complications and ensure that your plants provide you with their maximum yield potential.

Before going any further, it’s worth mentioning here that if you are an outdoor grower, you don’t have to worry as much about flipping your photoperiods to flower as Mother Nature takes care of that with her own lighting schedule. However, if you’re growing your plants in pots that are easy to move indoors, then you can apply everything explained in this piece by moving them inside to get them to flower more quickly.

Knowing when to do this requires at-home growers to take into account the following factors: what type of pure or hybrid strain you are growing; the maximum height that your plant(s) can achieve; how old your plant is, which is to say how long has it been in its vegetative stage; whether you’ve grown from cannabis seed or cannabis clone, aka “weed plant clipping;” and the growing method or indoor medium you are using for your plants. However, since every strain has its own unique growing profile, what, for example, applies to a sativa strain like Cannalope Haze is not necessarily going to apply to an indica like Yumbolt. Hence, it is important for all kinds of cannabis growers to take all of the aforementioned factors into consideration before flipping to flower.

So, first off, before even getting into when to flip your plants to their flowering stage, let’s quickly cover the four weed plant stages of growth, which are provided below.

1. Germination stage: This generally takes 3 to 10 days, and is when and how you transition your cannabis seeds to their seedling stage.

2. Seedling phase: This is the time in which you replant your baby cannabis plants to their first growing medium for about 2-3 weeks.

3. Vegetation stage: The vegetative stage is when you transplant your plants to their final growing medium and start to apply any basic training techniques (or advanced growing techniques) to your plants, as well as feeding them any extra nutrients they may need. This is also the time in which you can top tall plants that will otherwise be too big for your indoor growing space. The average vegetation time can’t exactly be called an “average” as it can take anywhere from 3-16 weeks depending on the strain you’re growing.

4. Flowering stage: The flowering time for a mature plant usually takes 7-11 weeks, but some strains can take as little as 3-4 weeks. This is the time in which your plants develop their buds (aka “flowers”) that you’ll eventually be able to harvest. This is also the time in which your plants may need an increase in their water and nutrient levels, although, one week before you intend to harvest your yield(s) you’ll want to cease with the nutrients and flush your plants with water to help prevent funky flavors resulting fertilizers, etc.

Now that you know the four basic growth phases of a marijuana plant, let’s jump into the reason you’re here: when to flip from veg to flower.

Commercial growers generally wait to flip their crops to flower after they’ve spent about 6-8 weeks in the vegetative stage as they have their systems down. However, for “everyday” outdoor and indoor growers, knowing when to do so involves your taking all of the factors already discussed above into consideration before changing your light cycle in order for your plants to start to flower.

However, let’s quickly go over the light schedule for your plants before telling you “when” to flip to flower.

So, to briefly explain, if you’re growing your photoperiod pot plants indoors, then when they are in their vegetative phase you usually give them 18-24 hours of continuous light. In order to induce their flowering stage, you move to a 12-12 lighting schedule, which means 12 hours of constant light and 12 hours of uninterrupted darkness.

Some do this by giving their plants 1-2 days of total and complete darkness and then transitioning to the 12-12 schedule. Doing so is said to help give your plants that extra swift kick to get their cannabis flowering. Others prefer to somewhat mimic nature’s light schedule by slowly reducing from 18-24 hours of light to 12 over the stretch of 2-3 weeks. Finally, there are indoor cultivators who prefer to just go “cold turkey” by switching to the 12-12 cycle right away.

Now, to answer your question. There is no exact time in which you should flip to flower, instead, it’s about when your weed plant has reached its maximum potential in terms of producing luscious and healthy green leaves and height–the latter of which is also connected to the size of your growing space, as not everyone has the space to grow 10- or 12-foot tall sativas inside.

Two main factors that affect the height of your plant are as described below.

1. The genetic makeup of your plant in regards to whether it’s an indica, sativa, or hybrid combo of the two is the number one factor that will determine the height of your plant. Generally speaking, pure indicas and indica-dominant hybrids are shorter in height, and pure sativas and sativa-dominant strains are tall. When you buy your cannabis seeds from a reputable seed bank, they will provide you with the approximate amount of time it usually takes for each strain to enter its flowering stage and how tall it will be.

2. The growing methods/techniques you used: With the Sea of Green (SoG) method for indicas, you’ll usually want to flip from veg to flower once they’re about 12 inches tall; whereas if you’re using the Screen of Green (ScrOG) method, you’ll need to wait until your plants have “comfortably” spread out in the screen, which is usually placed 12-24 inches above your young plants.

If you’re lollipop-ing, which is about removing the lower growing branches and nodes that receive little to no light, then for a sativa or sativa-dominant strain you can usually flip once your plants are 12-17.5 inches tall, and for indicas or indica-dominants the general rule of thumb is once they are around 39 inches tall.

So, that’s it! Now you know the factors to consider when flipping to flower; how to flip to flower; and that it’s less about how many days or weeks have passed before you can flip from the vegetation stage to the flowering phase, but when your healthy weed plant has reached a certain height.