Cannabis Plant in the Vegetative Stage Part One: The Pot

by Alex Robles

Take a moment to pat yourself on the back because that seedling you agonized over is now a plant in the vegetative (veg) stage.  Most new grower usually make mistakes and their plants pay with their lives before they get to veg.  So again, good job on getting your plant this far.  Now that we’re done celebrating we have to plan our work and work our plan because that plant is going to need more of our attention now.  

In this next series of I’ll start pulling together different parts of this site to help explain the simplest ways I know of to grow quality cannabis at home in a small garden. I’ll mostly be talking about how to grow in dirt, in a container without fancy bottled nutrients with flashy labels.  If you feel like something need a little more explanation, please let me know.

The three main parts that I’m going to focus on are

  1. The Pot: The container, the medium, top dressing and how to water.
  2. The Plant: What to expect of a plant in vegetative growth.
  3. The Environment: Light cycle, temperature and humidity.

Let’s get started

The Pot

When I talk about the “pot” I’m talking about the container, the soil, the amendments I top dress with and how to keep it all moist and healthy.

  The Container

3gal Rocket Pot

When I build my pots I make what are known asRocket Pots.  They’re a combination of a fabric pot and nursery transplant pot.  Click the highlight to link to that DIY.  I build these pots mostly to help aeration (air movement) around the root zone.  When my plants are only going to be in a pot for 8-10 weeks at a time, I’m not to worried about them getting root bound.  On the other hand if I’m caring for a mother these pots really help keep them from getting bound up and stretching.

Growers Note:  The bigger the pot the bigger the plant because the roots have more area to grow in.  One way to control a plant’s size is to control the pot size.

When I fill the pots with dirt I don’t fill it to the lip or rim of the pot.  I need to leave room to top dress the plant and so I can water it without having everything run off the top.  I also don’t pack the soil in, this could compact the soil and make it hard for water to drain, air to circulate and slow down healthy root growth.

  The Medium

Whatever material I use to grow my plants in is called a “grow medium”.  In my opinion the easiest way to grow cannabis is in soil.  When I don’t have the time or the space to build a soil, I’m going to have to use a bagged commercial mix and top dress with amendments (soil additives).   That means I’m going to be real picky about what bag I pull off that nursery shelf.

Remember, plants in containers are using a small amount of dirt to thrive in.  They can’t grow roots very far to look for food and water like they would if they were growing in the ground.  So I want that soil to be able to hold onto and provide as much nutrient to the plant as I need it to.  I like it to be light and fluffy because that usually means it’ll drain really good but still hang onto moisture.  If water can’t drain away it could suffocate the roots or cause disease (root rot).  Plus fluffy soil should let air move through it easier which helps healthy root growth.  I go into more detail (what I specifically look for in a bagged soil) in a past article.

Whatever soil I choose, I’m going to mix in 25% worm castings into it.  This soil mixture should have enough nutrient to keep the plant well feed for the first two weeks after transplant and I’ll only give it water for that time.  After that it’s up to me to make sure that the plants has all the nutrients that it needs.

Grower’s Notes:  Some strains are heavy feeders and may need to start top dressing sooner than others.

  Top Dressing

When I start top dressing (putting amendment on the top of soil) plants in veg, I like my amendments to add up to between 15-20 NPK (no lower than 15 or higher than 20).  It doesn’t have to be exact, that’s just the range I like because I know I’m going to add in more nutrients when I water.   Cannabis thrives with high levels of N and equal or lower levels P and K when it’s in veg.

For every gallon of dirt I top dress these amounts every 3 weeks.

  • 2tsp of alfalfa meal
  • 2tsp of fish bone meal
  • 1tsp azomite
  • ½ cup of worm castings so the beneficial microbes can start breaking everything down and making it plant available.

I’ll water in more microbes (Recharge) and liquid fish/kelp fertilizer with molasses every time the plants needs to be watered.  This feeding schedule will get me threw an 8-9 week veg cycle.

Growers Note:  The bigger your plant gets the more you will need to feed it, this recipe may need to be adjusted.  Every two weeks I brew a worm cast tea and use that for watering but I don’t store the tea, I use what I make.  For every 5gal of dirt I’ll add 1Tbsp of nematodes in vermiculite, buried about 1 inch under the soil.

Nematode Live Cycle


Now some of you may think this is a ridiculous thing to go over but we’ve all over watered a plant at some point or let it die of thirst.  Before I water there are a few things that I do figure out if my plant needs it.

The first thing I’ll do is look at the plant and make sure she doesn’t look droopy because if it does that means that I’ve let it get way too dry and that’s not good.  If I underwater it too often it will stunt growth and stress her out unnecessarily.  Also, when soil gets too dry it makes the beneficial micro-organisms struggle to survive and reproduce.  I can’t let that happen, those little things are processing the nutrients in the soil and fighting pests and disease for me.

If the plant doesn’t look droopy, the second thing I look at is the top of the soil, is it wet or dry?  If it’s dry, great I’m one step closer to watering.  If it’s wet I need to figure out how long it’s been wet and should it be drier?  When it stays wet too long and everything else in my grow is in balance, it usually means that the soil has compacted and there isn’t enough drainage and aeration in it.  To solve this problem I’ll repot it, making sure to add more perlite or coarse sand to the soil mix to add space in the dirt for air and water to move around.

Growers Note:  I don’t use play sand because It’s a finer than coarse sand and I’m trying to add space in between the dirt particles.

The next thing I do after I see that the top is dry, is lift or move the pot a little bit.  A 5gal pot that I just watered will feel heavier than a 5gal pot I watered 2 days ago.  If the soil looks dry but the pot feels heavy, I know I can wait to water a day or two longer.  When it feels lighter, I know it’s time to water.

If I’m still not sure, as a last resort I’ll stick my finger in the pot to feel where the moisture level is in the pot.  I don’t like doing this because I compact the dirt as I push my finger in and I’m breaking some of the roots in the root ball.  I don’t know how much damage it’s doing but I try not to do it that often.

Since my plants are in 3gal-5gal pots I’m able to water two different ways.  The first 3-4 waterings after I top dress I water from the top.  After that I’ll put the pot in a drip pan and fill that every time the plant needs water.  The plant will take up the water using capillary action. This helps keep the top layer of my soil dry, I go into in more detail in the article about nematodes.

I hope this helps fill in some of the gaps that are left when you’re doing research online and growing without a mentor or teacher.  Check in later for Part 2 so we can talk about the plant itself.  Don’t forget to subscribe and remember.

Grow, Learn, Teach

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