Vegetative Stage For Indoor Marijuana Plants

Page content

Vegetative Stage For Indoor Marijuana Plants

Vegetative Stage For Indoor Marijuana Plants

While all plants share similarities in how they grow, the cannabis plant has its own independent quirks and foibles that set it apart. There are a number of steps you can take during the vegetative stages of growth that will help you later down the road, such as what you feed your plant and when you do it.

During the initial growth period of the plant, it builds up structural integrity (stem and roots). It’s only after that the plant begins to develop foliage. During these early stages of growth, your plant will require a lot of nitrogen supplied to it. Early leaves will begin the photosynthesis process, absorbing sunlight and furthering the plant’s growth. After your plants have germinated and begun to stabilize, consider taking out any late-germinating seeds or stunted seedlings. That way these won’t compete with your other plants for light and nutrients.

Once your cannabis plant has a stable root system and the environment is set up properly, it should just be a matter of upkeep to make sure you end up with a good yield. The plant will continue to grow and develop given proper nutrients and light, developing a strong structure necessary for the flowering phase. As the plant continues to develop and mature, it will require additional fertilizer, water, light, and higher levels of carbon dioxide in the environment. It will also require more nitrogen. You want to make sure you’re providing for all of the plant’s needs.

In this article, we’ll talk about cannabis seedlings, the vegetative phase, and how to manage foliage development. It’s all about maximizing growth in this vulnerable early phase and making sure you keep your plant healthy and strong right up to the home stretch.

The first leaves

First leaves cannabis seedling

The leafy foliage of the cannabis plant grows in a series. Every series produces a certain number of leaves. Generally, the first series produces a single leaf. The second series will put out three leaves, the third series will produce five leaves, and so on. The number of leaves produced in a single series usually caps out around ten. You may sometimes see leaves referred to as ‘lamina’ in growing literature.

After about two to three weeks of growth, your cannabis plant should have experienced about 5 or 6 different rounds of growth. You should be producing a regular and steady amount of leaves with every new series. You’ll also notice that the branches are beginning to develop and expand outward.

Feeding Seedlings

Feeding seedlings cannabis nutrients

You’ll want to make sure your young cannabis seedlings get lots of nitrogen early on in their development. Using fertilizers comprised of worm meal, blood meal, or bat guano will help you get the nutrients you need from natural sources.

Other options include various algae compounds, nettle blends, or fish compounds as your organic fertilizers. There are several factors that make organic fertilizers a better choice for growers than chemical fertilizers. One of the major reasons it’s better is that it can be very easy to overfeed your plants and damage them when using powerful chemical fertilizers.

Download my free marijuana grow guide at this link for more growing tips

When the first leaves pop out, you’ll want to measure the electrical conductance of your nutrient solution. You want to measure very close to 1 at the beginning. As the plant grows and matures, it’s ok for the electrical conductance to be raised up higher. When a cannabis plant has at least 4 or 5 different levels of foliage, you can raise the electrical conductance up again, to about 1.5.

Once branches begin to develop on the plant, you can raise the electrical conductance up to about 2, but be careful about too much nutrient solution and water. Overwatering your plant can cause it to grow more in the stem then the buds, which is counterproductive for most growers. Allow your plants root systems to air out and rest between irrigations. Remember to start adding plenty of nitrogen to your plant as soon as the first leaves develop, but make sure you are keeping the electrical conductance at around 1 to start with.

Environmental factors

Environmental factors cannabis seedlings

The rest of the environment is also something you want to make sure you are optimizing throughout every stage of growth, but particularly during the early phases. You have a couple options when it comes to lighting. After your plants get past the seedling stage, you can expose your plants to light for a full 24 hours, but it’s better to simulate night and give the plants up to six hours of darkness every 24 hours. You’ll want sodium vapor or metal halide type lamps to make sure you’re providing the right kind of light.

Keep the air temperature in your grow room somewhere between 68 and 78 degrees Fahrenheit. The roots should be slightly cooler, around 65 degrees Fahrenheit. Despite this, make sure the soil is warm enough, especially early on. If roots don’t develop properly, the rest of the plant will not either.

Don’t forget to measure the humidity in the room as well. This will affect the efficiency of your plant’s respiration, and also the early health of the plant. You want the humidity in your grow room somewhere between 50% and 70%. When the plant matures, it will be less sensitive to humidity.

Controlling these environmental factors will help optimize your plant. However, genetics still play a huge role in determining how the plant develops, and what sort of yield you’ll get. Even if everything is perfect, you can’t turn bad genetics into a great product. Still, if you are meticulous and careful throughout the cannabis cultivation process, you can always optimize the plant, however high its potential yield might turn out to be.

Vegetative Stage

Vegetative stage cannabis indoor

A good growth period will be followed by a strong flowering phase. As a grower, it’s your job to get your plants everything they need to develop properly before they flower. This means healthy foliage, a tough structure to cope with the weight of heavy buds, and a strong root system. Keep an eye on the light, nutrients, carbon dioxide and temperature of your grow room throughout the process.

Especially during the vegetative stage of growth, be careful when irrigating and watering your plant. As the plant grows larger and larger, it will require more water to keep up with the development. This means it’s easy for the plant to become dehydrated at this point. Watch out for curling or yellowing in the leaves, and monitor the electrical conductance of your nutrient solution if you’re implementing a hydroponics system in your grow room.

Temperature, humidity and nutrients

Temperature humidity nutrients vegetative cannabis

Once your plants hit the peak of their growth phase, you can expose your plants to light for a full 24 hours, but it’s better to simulate night and give the plants up to six hours of darkness every 24 hours You’ll want sodium vapor or metal halide type lamps to make sure you’re providing the right kind of light.

Keep the air temperature in your grow room somewhere between 68 and 78 degrees Fahrenheit. The roots should be kept at a slightly lower temperature, around 65 degrees Fahrenheit. Despite this, make sure the soil is warm enough, especially early on. Remember, your roots need to develop properly for the rest of the plant to.

Download my free marijuana grow guide at this link for more growing tips

Don’t forget to measure the humidity in the room as well. This will affect the efficiency of your plant’s respiration, and also the early health of the plant. You want the humidity in your grow room somewhere between 50% and 70%. When the plant matures, it will be less sensitive to humidity.

Keep adding nitrogen, too! You want the electrical conductance to measure somewhere between 1.5 and 2. If you are using soil, make sure to continue adding liquid fertilizers and monitoring the moisture in the soil.

Determining sex

Determing sex vegetative cannabis

There are two commonly utilized methods of determining gender in Cannabis plants. Gender is definitely something you want to be certain of because mixing male and female plants in your grow room has the potential to ruin your crop.

The first method for determining gender is to carefully examine the 5th series of leaves on your plant. You’ll want to do this right before the plant should flower. Indicas and hybrids with Indica genetics will display their sex between the leaves of the plant right before they flower. If you look very carefully, you should be able to see a tiny white fiber if the plant is female. If the plant is male, it will have a small ball instead of a fiber or tendril. This method is easy, but it’s not the most reliable, and sometimes it’s very difficult to find the developed sex organs on the plant because they are so small.

The better method is to take cuttings. Once your plant is in the vegetative stage, you can take cuttings from the plant and root them in another room. Expose the newly rooted cuttings to 12 hours cycles of light and darkness. The plants should flower within several days. If any of them are male, you’ll want to remove them from the grow room.

Forced Flowering

Forced flowering vegetative stage cannabis

After you’ve gone through and made sure that you don’t have any male plants in your grow room, make sure you’re ready for the next stage of growth: flowering. Set all the plants up neatly and double-check to make sure they aren’t fighting over any sources of light. Keeping your plants well spaced is a good way to help ensure a healthy yield. Double-check the roots to make sure all the plants have enough space below the surface as well.

Make sure to buy marijuana seeds in our online seed shop

If you need to transplant your Cannabis because the root system has grown too large, now is the time to do it. Root systems expand rapidly during the vegetative stage of growth. You need to make sure the plant isn’t suffocating. If it can’t pull up and absorb the nutrients it needs, it won’t do well during the flowering phase.

Night and Day

Night day flowering vegetative stage cannabis

You can force your plant to flower by adjusting the light cycles in your grow room, mimicking a change of seasons. You’ll want “shorter” days, with roughly 12 hours of light exposure followed by 12 hours of darkness. The easiest way to manage these changes in the light cycle is to use an automatic switch that turns your lights on and off at the required intervals.

Make sure that you stick to these cycles once you start. All it takes is a single exposure to light during one of the cycles of darkness to interrupt your flowering. If the flowering cycle is interrupted, the plant might start growing again. This sort of stress is bad for the health of the plant, and it can result in reduced yield and unpredictable side-effects. If you do mistakenly expose the plant to light during a cycle of darkness, try to repeat the process again, and this time don’t interrupt it. Don’t be tempted to look in on your plant while it’s “night-time”!

Thanks for reading. Please leave comments or questions below and don’t forget to download my free grow bible


Download the Ultimate Grow Guide for FREE!
Learn the basics of growing marijuana and get started today
  • How to get the biggest yields from cannabis plants
  • What you need to get started, without wasting money
  • The most common mistakes you do not have to make
We guarantee 100% privacy.

Comment Section

26 thoughts on “Vegetative Stage For Indoor Marijuana Plants

By Ken on 9 June 2015

Wow! These are all great articles. Thanks ILGM.

By lee&jo on 20 June 2015

can i re-pot my plants, 1st stage of flowering ?.

By latewood on 24 June 2015

Not sure what you mean by 1st stage. how many weeks into flower are you? I have re-potted in flower, but I carefully remove plant, and place it gently in new pot. New soil can encourage more root growth. A trick I used to employ was to take the flowering plant and place it right into a bag of potting soil; No pot at all. Very easy on the plant, and it will thrive. If you are more than 2-3 weeks in flower…I might ride out the grow in the smaller pot, just to be safe.

By MJCTHC1 on 1 August 2015

I have noticed that a lot of information on this site is contradictory due to language barriers and typo’s, I feel a proof reader is required to make this site even better than it is. A good example is when you speak of light leak then you say try doing it again but don’t disturb them ( contradictory ) , this is in no way meant to sound detramental to you. I do feel it would be advantageous to all users of this site.

Kindest regards


By J milam on 29 September 2015

Good info on veg state article. I’m sure I’ll be reading more, thanks

By Jennifer ILGM on 29 September 2015

Come back anytime!

By Justin on 22 October 2015

Please help my plants not doing well the under leaves are yellow n I lost two of the bottom leaves my temp is 81.1 humidity is 52 the soil level is ph 4 phosphorus is 5 potassium is 6please help

By latewood.ILGM on 22 October 2015

Without more information it is hard to give you an informed answer.

Please join our Support forum, and some of our many members and expert growers, will be able to help you out. 🙂

When you join, look in beginners forum, and fill out a support ticket.

By Mark on 23 December 2015

Hey my name is Mark and I wanted to know how can you tell the sex of a plant if its 2 1/2 weeks in veg?

By Thomas De Costa on 28 February 2016

How are to you, I’ve requested several times for your free grow bible, I still haven’t received it, ??

By Dennis on 26 March 2016

I have 4 White Widow plants growing under lights. They are still only 3 – 4 inches tall, very leafy and green but I’m thinking they should be double the size by now ? I am using a 4 ft. 4 bulb florescent fixture. Supplemented by a full spectrum bulb. Are they on track ?
May have to try again. I am using Miracle Grow on them

By John on 24 May 2016

Robert love the site seeds and info. However I have tried multiple times to download the grow bible and have had no emails received or success to the download.

By Duane. on 9 July 2016

Great read. Guys and gals know your junk..and grass. Thanks!

By William Marshall on 21 July 2016

Can a plants night cylce be interrupted in veg stage with no side affects?

By latewood.ILGM on 22 July 2016


It all depends on how long the dark period was interrupted. But most likely nothing will happen. If the lights were left off for 2 long this could have an affect on the plant but, leaving the lights on too long just promotes vegetative growth.

Happy growing, 🙂

By Enrique Ramos on 29 July 2016

Thanks for all the info, I am a new grower and I was lost until I found this site, thank again.

By Brandon Medlin on 1 September 2016

I’m using a 65w T5 light for verging. With 5 plants. Is that enough light… First time grower

By latewood.ILGM on 5 September 2016


I am not sure how much light penetration you are going to get once the plants start bushing out. I suggest you join our support foerum. We have many experienced growers there willing to help 🙂

By Tina on 5 September 2016

Hi guys, i just want to know if two 18w 2 feet fluorescent uv lights can be used in the vegetative stage. this is our first grow and after putting this uv light, with a few LED red and blue strips, the plants seemed to have started becoming much healthier. And how many weeks should i leave it in the veg stage? thanks so much!

By latewood.ILGM on 5 September 2016


You really need to join our forum. The blog is not set up for wholesale grow support. More simple Q & A.

A 2 foot fluorescent is good for propagation and early vegetation only.

Happy growing.

Leave a Reply