You are here1st Grow in My Garage - Auto Northern Lights in Grow Box Under 400W HPS - 5.35 oz Harvest

1st Grow in My Garage - Auto Northern Lights in Grow Box Under 400W HPS - 5.35 oz Harvest

by im4potato

View im4potato’s photo albums featuring pictures from all his grows:


Quick Grow Snapshot

  • Strains: 3 x Auto-flowering Northern Lights
  • Grow medium: Soil
  • Grow Light: 
    • Vegetative: 6400k T5 Grow Light
    • Flowering: 400W HPS with digital ballast and air-cooled hood
  • Nutrients or Additives: Fox Farms Soil Nutrient Trio

May 5, 2012: Seeds sprouted
July 29, 2012: Harvest!

Total Time - Seed to Harvest:
85 days (2 months, 24 days)

Final Yield
5.35 oz

A preview of the cannabis plants in this grow journal - just before harvest!

View full grow journal below!



Getting Started - Pre-Grow

With space to grow in the garage, I decided to build a grow box and try my hand at growing marijuana, even though I'd never grown anything before.

In addition to learning grow skills, building my box was a big test of my carpentry skills, or lack of skills I guess I should say. I'd never built anything like this before.

Planning My Grow Box

Build grow box out of plywood and 2x2s with 2 chambers so I can swap the plants between the chambers when it's time to flower.

The dimensions of the box are 4'W x 2.5'D x 5'H.

Sketch for my grow box

Albums of building grow box for garage

The grow box cost me about $135 for the lumber, screws, caulk, sandpaper, wood stain, and hinges.

Take a look at the grow box im4potato built for his garage

You'll see how the box is divided into 3 sections. I want to put a vent in the ceiling of the bottom right section and a vent in the top of the wall in the left section so that both of them feed into that top part where my carbon filter will be.

What would be the best way of ducting both of those vents into a single carbon filter?

Choosing The Right Grow Light

I was concerned about heat and light usage for my small space.

I looked at LEDs when I first started my research, but I kept reading things about them being kinda sketchy. A lot of people seemed to think they didn’t live up to all the hype.

I considered using T5 grow lights for both the vegetative and flowering stage (6400k bulbs for vegging and 2700k for flowering) because they produce such low heat.

I was hesitant about using a T5 in flowering, though. Some growers seemed to be getting good results with them, yet I was worried that a T5 was not going to be intense enough to get good yields in the flowering stage.

I decided to go with a 400W HPS light with an air-cooled hood and exhaust fan for the flower chamber. It was hard to resist getting a bigger light, but I knew that a 600W was going to be too big/hot for my space.

Final Setup

Grow Lights

  • Vegetative: 6400k T5 Grow Light
  • Flowering: 400W HPS with digital ballast and air-cooled hood

Grow medium

  • Fox Farms Ocean Forest Soil


  • Fox Farms Soil Trio


  • Feminized Northern Lights (from Pyramid Seeds), ordered them from Attitude

    I probably wouldn't order seeds from this breeder again. The seeds ended up being an autoflowering strain even though it was advertised as being a photoperiod strain. It all ended up working out, but I would have been happier if I'd received the seeds I ordered.


My First Grow In Pictures!

I started germinating my seeds in a shot glass. 

Put seeds in a shot glass filled with water to germinate them
I put the seeds in a shot glass filled with water to germinate them

Seeds sprouted roots
Seeds have sprouted roots

I've got a pack of these pellets to start them in. I did a test run by putting a pellet in a cup of water, damn those things expand!

Here is what I ended up doing, I tried to cut out any extra steps and just put the pellets directly into the soil from the start.

Seeds are starting to sprout

I put bottles on top to help retain extra humidity (like a humidity dome).

Ultra cheap humidty dome :)
My ultra cheap humidity domes

It's a steady 85 degrees F in there, no idea about the humidity in the bottles.

Seedlings under my T5 Grow Light
Seedlings under T5 Grow Light in Veg Chamber

Day 7 from seed - Full album:

Day 7 - Marijuana seedlings - Auto Northern Lights strain
Seedlings - Day 7

Day 13 from seed - Full album:

Day 13 marijuana plants - Auto Northern Lights
Day 13


Day 19 from seed  - Full album:

Day 19 - leaves are starting to look sick
Plants started looking a little sick on Day 19 from seed

Leaves started looking sick on Day 19 I thought they may have used up all the nutrient in the soil (I haven't been feeding extra nutrients until now). I started feeding them with Fox Farms Nutrient Trio.

I also considered it might be stress from the wind of the fan, so I got a lot more careful about blowing air on the seedlings.

With these two changes, the problem seemed to sort itself out.

Day 39 from seed - Full album:

Moved plants to flowering chamber of garage grow box
Moved plants into flowering chamber under 400W HPS

I moved the plants into the flowering chamber with the 400W HPS grow light.

At this point, I continued to keep them on a 18/6 light schedule, which should have kept them in the vegetative stage. I wanted to let the plants get a bit bigger before switching them to flowering.

I did not yet realize that these were autoflowering plants.

Day 41 from seed - Full album:

3 Plants in my garage grow box - day 31 from seed- Autoflowering Northern Lights strain

Today is also the first day I've tried to LST (low stress training). I know it's generally recommended to start LST earlier, but I was trying to avoid it on my first grow just to see how my yield would be with no training.

I ended up LSTing one of the girls who was getting too tall.

I was surprised to see my plants start flowering (you can see a couple of flowers starting to appear in the picture above).

I’d purchased non-autoflowering seeds. Guess I’ll never order from that seed vendor again. At first I thought I was seeing pre-flowers, but I soon realized my plant was producing full-on flowers.

Then I saw something even more scary, a hermie banana...

Hermie banana - this female marijuana plant is showing male parts, which means she is a hermaphrodite (hermie)

On the advice of others, I plucked this single banana and finished flowering my girls. This was the only hermie sac I saw throughout the grow, and I'm glad I ended up finishing the girls because I had a fantastic harvest.

Day 45 from seed - Full album:

Closeup of trichomes on the buds and surrounding sugar leaves
Closeup of trichomes on the buds and surrounding sugar leaves

Day 53 / 54 from seed - Full album:

Northern Lights bud is fattening up
Buds are fattening up

The plants in the grow box definitely smell at this point, but it only became noticeable to me within the last few weeks. Even now it's not too bad, and you would have to be in the same room as them to smell it.

Day 63 from seed - Full album:

3 Happy plants in a garage grow box under a 400W HPS

Incredible closeup of trichomes
Closeup of trichomes


Day 79 - End... The final days - Full album:

At this point I still don't have a fan hooked up to my vented hood and I've been relying on a wimpy little one and keep the door cracked open to let the heat out.

For my next grow I'll have a real ventilation system set up and heat shouldn't be a problem. I've been running my light at half power (200W) for the past couple weeks to control the heat. I'll have much better ventilation my next grow so I'll be able to run it at 400W the whole time.

Day 79 from seed - Northern Lights autoflowering in garage grow box

Day 84 from seed - Day before harvest

Day 84 - day before harvest, they're ready to be cut down!
Ready to be cut down

I'm really happy with how they turned out.

For my 2nd grow I'll have 4 plants instead of 3 and I'll be LSTing from the start.

Also, I will finish my grow box by hooking up a fan to my hood (with a carbon filter), and I put mylar up on 2 of the remaining walls where I still need to cut some holes.

My light has only been running at 200W for a majority of the grow because the weather has been so hot and my ventilation sucks.

I'll be really interested to see how much doubling the light, making all the other minor improvements, and avoiding all my previous mistakes will affect my yield.

Day 85 - Harvest!

I ended up having to go to a pet store and buying some activated carbon to control the smell of my drying buds. I knew it would smell, I just didn't think that much!

Harvest - my auto Northern Lights buds are drying

Harvest Final Weight 5.35 oz!

Harvest final weight was 5.35 oz! Very pleased with my first grow

My 2nd Grow in Pictures!

Stay tuned for my second grow in pictures.

Here’s a quick preview...

Incredible fat bud from im4potato's 2nd grow!




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Jump to...

Growing Marijuana Indoors vs. Outdoors

5 Ways to Increase Yields When Growing Indoors

Autoflowering vs Photoperiod Strains - What Growers Need To Know

Help, My Leaves Are Dying!

Frequently Asked Growing Questions (FAQs)