When to Flower Indoor Weed: How Long Should You Veg Your Crops?

indoor weed production

Cannabis is such a beautiful plant. Growing it is easy, but bringing it to yield copious amounts of resinous flowers takes time and dedication. When growing weed indoors we are responsible for maintaining all aspects of our plants’ environment. Learn when to flower indoor weed for the best results.

Short Answer: 4-8 weeks

Long Answer: It’s complicated...

They say timing is everything. When it comes to cultivating cannabis indoors the sentiment couldn’t be more relevant. A great indoor grower has their operation completely in sync. When mature plants are getting harvested, veg plants are getting flipped to flower, and more clones are getting cut.

Most indoor growers are after a perpetual harvest. Forever growing ganja and harvesting beautiful buds is something of a commitment though. When it comes to achieving that balance in your indoor setup one of the most crucial aspects is timing the flip from vegetative to flower.

About the Vegetative State

It may seem somewhat rudimentary to explain what the vegetative state is. With laws on cannabis shifting though, there are a ton of new growers out there that are asking about the basics. 

You’ll often here experienced cultivators referring to their plants by how many weeks they’ve been vegging. Describing a plant in its third week of veg gives some insight, but without context, it’s essentially useless, especially if you’re talking to a beginner.

Clones vs. Seeds

From clones, some say that the veg state begins once the clone is well rooted and has been transplanted, which is pretty accurate. From seed, some say the veg state is beginning once the plant breeches the soil. 

Others say that it begins when the seedling has produced its first set of true leave. True leaves being leaves that look like marijuana leaves as opposed to rounded seedling leaves.

It doesn’t really matter how you define the beginning of the veg phase. What matters is the context of your setup. What method are you using to grow, a sea of green or full-term seed plants? Are you growing from clones or seeds and are you planning on super cropping your plants?

When we talk about how long we should veg cannabis, it really depends on numerous factors including: 

  • Strain Genetics
  • Growing Style
  • Training Methods
  • Grow room size
  • Plant Health

Cannabis Grow Methods

Defining your veg time depends a lot upon the method of growing you’re implementing and the size of your grow space. When plants flip to flower they typically double in size, more or less.

If you veg your plants to 3ft. tall but there’s only 5ft. between the growing medium and lighting, you could find your buds getting burnt from the lights before they’re ready for harvest. Remember that and your veg time to be in accordance with your grow room size.

When to Flower Indoor Weed: Sea of Green

Growing in a sea of green requires minimal vegging. Plants in this method are flipped while small and pruned to grow one big cola or top. In a sea of green setup, plants are kept relatively short and many are packed into a small space in order to maximize production.

Plants should be switched to flower once they’ve reached six to twelve inches in height, which could take anywhere from 1-3 weeks of veg time. Indica strains will be better suited for this setup because they don’t continue vertical growth as much as Sativas do during flowering.

When to Flower Indoor Weed: Screen of Green

A screen of green (SCROG) is a great way to maximize horizontal grow and vertical space indoors. A netting or trellis is set up across the canopy at one to two feet above the growing medium. Plants are grown into the netting and the tops are trained horizontally into the trellis.

When your plants are tall enough to be trained sufficiently into the netting, you can then switch them to flowering. This could take anywhere from two to six weeks depending on how tall your netting is set, grow lights, and strain genetics.

When to Flower Indoor Weed: Supercrop

A super crop is essentially restricted to growing horizontally. Plants can be vegged until they’ve filled up your grow space. With super cropping, vertical space doesn’t become an issue because all of the plants are horizontal.

Depending on your grow space, vegging a super crop could take four to eight weeks. Similar to a screen of green setup, a super crop focuses on producing wide, bushy plants with multiple bud sites. As opposed to thick, vertical growth with big buds on top and larf underneath, a super crop, SOG, and SCROG, setup will maximize horizontal canopy space.


The best way to measure the moment at which you should flip your plants from veg to flower is by height. Most growers’ forums will give advice in weeks, but that’s just not really helpful without context.

Longer veg times means bigger plants, which means bigger buds. However, it also means more nutrients, more watering, and more time waiting for skunky nugs to be ready. Also, if you can’t manage large plants indoors, you’re wasting your time vegging out for two months and could jeopardize your harvest.

Consider you grow room size, strain genetics, and method of growing, and you’ll be able to easily figure out ideal veg time approximations. You’ll need to adjust your plans according to how tall and fast your girls grow too.

I hope this helps out the novice or soon to be growers out there searching for advice on cultivation. Be sure to check out our other articles on cannabis cultivation for more growers’ tips. Thanks for reading and stay tuned to slyng.com for all your cannabis content and news needs.

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  1. Anthony Franciosi The Seven Key Stages Of The Marijuana Plant Life Cycle. Retrieved February 13, 2018 from https://honestmarijuana.com/marijuana-plant/

2. Robert Bergman Sea Of Green (SOG) Marijuana Growing. Retrieved February 13, 2018 from http://www.ilovegrowingmarijuana.com/sea-of-green-sog-marijuana-growing/

3. How to Grow Weed Indoors – The Definitive Guide. Retrieved February 13, 2018 from https://www.raysace.com/how-to-grow-weed/

4. Amir Abyaneh to say that you "larfed" instead of laughed, because, well, laughed is plain and ordinary and is used for every day situations, while larf is the result of. Retrieved February 13, 2018 from https://www.urbandictionary.com/define.php?term=larf