How long should you veg cannabis seedlings for? Answered!

How long should you veg cannabis seedlings for? Answered!

A young cannabis seedling sprouts above ground!

Cannabis is a relatively short growth cycle plant that you can harvest in little time. The age old question of how long you should veg cannabis for, will really depend upon the following 7 key factors:

1. Grow space
2. Grow Lighting
3. Ventilation
4. Medium/Grow method
5. Timing
6. Genetics
7. Training

Let's take a look at each of these factors in more detail, so we can determine what role they will each play during our Cannabis growing cycle. 

1) Grow space

When determining veg times. We need to consider our total grow space (which is our effective usable growing area). Think in terms of available ground grow space and also what's usable in vertical height.

A lot of new growers make the mistake of vegging cannabis for too long and not taking into account the vertical space they have available within their setup, run out of room and then suffer from poor yields when harvest time comes around. It's important to take into account the bloom stretch phase (after flipping to 12/12) will be adding additional height to the finished plant.  When considering how long to veg for, the stretch phase will also need to be factored in. After the 12/12 stretch phase completes itself (2-3 weeks after flipping the lights) Cannabis Indica dominant plants will usually double in size, while Cannabis Sativa dominant plants can triple in size, or more!

If you only have a small grow area (horizontal and vertical space) you will want to minimise on your vegging time (or going with a SOG/Sea of Green style of grow). Micro grows should need little to no veg times.

The more grow space you have available. The longer you should veg for, to maximise on your yield. There's a delicate balance and you will find it with practice. Spend some time understanding your favorite strains and how they react to different growing conditions and variables (temp/humidity, training, feeding)


2) Grow Lighting
On top of the grow space considerations. Cannabis growers need to also take into account what type of lighting they will be using for their veg phase. CFL (Compact Flourescent Light) and LED (Light Emitting Diode) lights are typically preferred for cannabis vegetative growth due to small cannabis seedlings not requiring the intensity that HID lighting provides upon first sprouting out of the medium. CFL and LED offer good veg growth when utilising more of the BLUE spectrum of light - which small cannabis seedlings and plants favour.

For CFL lighting - you want to look for 5000K to 6500K colour temperatures as they're perfect to veg cannabis seedlings with.
For LED lighting - you can use more 330nm / 360nm diodes for veg growth to be efficient.

The general rule of thumb for cannabis seedlings and young plants is that using more appropriate BLUE in the lighting will encourage more foliage veg growth. Try to avoid using too much ORANGE/RED or else you will get lanky/stretchy seedlings that can become unruly/weak later on in their grow cycle.

NB: If you haven't already - you can also check out our article on the best types of hydroponic and indoor cannabis grow lighting to use to use for your indoor grow.


3) Ventilation
Cannabis seedlings require fresh CO2 and O2 for good growth. Take into account your ventilation when considering your veg times as the more fresh co2/oxygen circulating in your growing area will mean much better growth (which can reduce overall veg times).

Even if you have great growing lights. If your ventilation is not up to par and you don't supplement with additional co2 - you will see much slower growth, when compared to a setup with sufficient fresh air flow. Having poor ventilation may increase your overall cannabis veg time.


4) Medium / Grow Method
Consider which medium you will use as it will have a dramatic effect on your overall veg/grow time.
Hydroponic based systems tend to grow the fastest as the cannabis plants' roots will always have constant access to fresh oxygen which means more explosive growth.

Soil based grows are often the slowest to veg/grow and can often take the longest time.

Soil-less systems like Coco offer a great compromise between the speed of hydroponic growth and soil based growth due to allowing more oxygen to the roots.


5) Timing
How much time do you have? Are you in a position where you have a limited amount of time and you need to harvest by X date or are you in a position where time doesn't really matter much?

Your own personal timing/future schedule will play a role in deciding how long you should veg for. The general rule of thumb is that the longer you veg for (provided you have the root space available) the more your overall yield will be.


6) Genetics
Some plants just take a little longer to grow than others due to their unique genetic makeup. This is one of the reasons why quality stable genetics are so important when growing cannabis to ensure a good crop and smoke-worthy harvest.


7) Training
If you intend to train your cannabis plant through the use of TOPPING or FIMMING techniques (or any other training method for that matter).
Then, this will also add on to your vegetative time as the plants goes through the recovery process - growth slows down until the hormones are able to be redistributed from within the plants.

People that use the SCROG technique (SCReen Of Green) usually add on to their veg times due to the extensive training that the technique requires. Usually though, the high yields of the SCROG method can more then make up for the lengthened vegging time.

SUMMARY

Provided you have ample time and space - you should allow your cannabis plants to reach sexual maturity on their own, naturally. This usually happens during 4+ weeks of veg growth. It's easy to spot when your cannabis plants are sexually mature enough because they will start to develop pre-flowers during the vegetative phase (even with 18+ hours of light)

However, failing that. Most strains are mature enough to be put into flowering within a few weeks of true vegetative growth. There is no veg time that is set in solid stone and a lot of growers will recommend between 3-6 weeks of veg growth for cannabis seedlings depending upon your variables.

Taking into account all the above factors will give you a rough guideline on how long you should veg your cannabis plants for, to maximize on your overall harvest. Good luck and happy growing!


The following image depicts 2 sexually mature cannabis plants. Which will help you with identifying the gender of your plants. 

The plant on the left is Female and has female pre flowers (Female plants will produce flowers/buds). 
The plant on the right is Male and has male pre flowers (Male plants are only good for breeding but otherwise useless. If you spot them, pull them out ASAP as they won't produce any buds).

Sexually mature cannabis - Pre flowers (FEMALE preflowers on the left - MALE preflowers on the right)

Starting with quality feminized marijuana genetics will help to save on valuable grow time. You will have females to play with (buds!) and not have to deal with the pesky male marijuana plants.

Click Here to Buy Quality Feminized Cannabis Seeds (Discreet Worldwide Shipping)