The Dawn of a Dank Decade: Inside a Pro's 2020 Growroom

By Michael Coffey
Published: December 18, 2020 | Last updated: May 26, 2021 05:45:07
Key Takeaways

Want to know everything you need to set up your indoor grow? Cannabis growing pro Michael Coffey takes us through every item needed for successful indoor weed cultivation, along with some tips for big-bud success.

It’s 2020 and time to get your grow on, whether you are a green enthusiastic first-timer or a veteran cultivator. If you are starting an indoor grow-op from scratch, this guide will help you overcome many of the fundamental challenges all growers must overcome to successfully bring a top-shelf cannabis crop to harvest. Also, I’ve included the details of my own indoor grow-op and equipment configurations.


What Cannabis Strain to Grow?

This question is related to how frequently you want to grow. You need to figure out approximately how much of a stash you require by estimating your annual personal consumption. Then you can compare this with the projected yields from the cannabis strains you are considering.

You must also factor in the flowering times of the varieties you fancy. Moreover, if you desire cannabis concentrates as your finished product, you must refine your selection criteria to the most resinous strains with the greatest extract potential.


Furthermore, look for similarities in growth patterns and feeding habits in addition to desirable traits like a short flowering period, pest/pathogen resistance, potency, and flavor.

Read also: Purple Pot: Picture Perfect

Taking time to evaluate your own consumption, time constraints, and several potential cannabis strains before committing to a course of action with a strain is recommended. Don’t rush to buy cannabis seeds and/or clones! A little research will help you to customize your indoor grow-op, produce bigger buds, and make the cultivation experience more enjoyable.


I have a taste for dessert cannabis and I also covet frosty purple weed, so I chose Purple Punch Auto by Barney’s Farm to kickstart my 2020 indoor cultivation. The promise of 18 per cent THC, delicious purple nugs with a diverse mouth-watering terp profile in as little as 50-60 days from seed was too dank to resist. I’m looking forward to savoring apple crumble and Kush flavours and fragrances. Reputation is everything and you only want seeds from master breeders and clones from artisan growers that care for their cuttings meticulously. Genetics are the number one critical factor of cannabis cultivation.

Cannabis seedlings in humidity dome


Where to Grow Cannabis?

Well, if it’s an indoor grow-op it’s either a garage/spare room/ basement converted into a growroom or a grow tent set up somewhere in the dwelling. Grow tents are pretty much standard kit for the indoor home grower. It comes down to the dimensions of the area you have dedicated and designated as a grow space. Other considerations are access to fresh air, power sockets, ventilation, air circulation, and air filtration. Sometimes a window cracked open covered by a blind is enough to maintain airflow and security. Other situations necessitate air conditioning, lots of ducting to connect intake fans for fresh air, and exhaust fans with carbon filters for stale air and odor control.

Grow-ops heat up when the lights are on and the more heat, the more old-school the lamps with higher demands on the ventilation system to maintain optimal temps within the 68-82°F range. Then there is the down swing in temps overnight or lights off period where heating may be required to keep temps in the 65°F range and prevent relative humidity from getting excessively high. As you might have guessed a thermo hygrometer is an essential piece of kit to monitor environmental conditions, the good news is they are modestly priced.

Read also: 5 Reasons to Grow Autos This Year

LEDs can significantly reduce the heat output and temperature swings of the grow-op and can be more economic to run long term. Dialing in environmental controls can be a lot simpler with this technology as most of the output is light and significantly less heat than HID lights. However, the high cost of LED systems to match, and in some cases exceed, the performance of HID renders the best LED kits prohibitively expensive to ordinary decent home growers. Commercially they could certainly be a viable alternative for a cannabis farm or if you are a committed home grower who will reap benefits of this medium- to long-term investment.

My personal grow-op is a humble Hydro Shoot 100 grow tent by Secret Jardin set up in a spare bedroom. The powerplant is a simple conventional 400W digital ballast. For odor control I have strategically deployed several ONA blocks throughout the property. My window is cracked open for fresh air and I have a small nine-inch oscillating desk fan for air flow inside the tent.

Why HID Lights?

I decided to purchase a great big aluminum reflector, 400W dimmable Lumatek ballast and a 400W Sylvania Grolux dual-spectrum HPS bulb because they were widely available online in bundle deals at a reduced price. The easi-roll hangers were included for free, too. Old-school grow tech is cheap and with only a lamp to replace every nine months. Lumii Grow glasses for eye protection, not as stylish as the Method Seven eyewear, function over form for my budget.

Running costs for a 400W HPS lamp are comparable with a far higher priced LED that would have similar performance and perhaps even close to 400W actual power draw.

Granted an MH bulb for vegetative growth followed by an HPS bulb for bloom would be better use of the old-school tech, but I’m growing autos and the dual-spectrum HPS bulb has 80 per cent red with 20 per cent blue spectrum, which should be just fine. I’ll be running a continuous 18/6 lights on/off schedule from seed to harvest. By gradually increasing the intensity of the lamp from 250W to 275W then to 400W or even to the extra (super lumen) 440W setting is very efficient and optimal for my grow-op. I may move back outdoors for a summer grow so this could be my only (8-10 week) indoor grow this year. If you are planning multiple grows year-round, then LEDs could be worthwhile as electricity savings will likely offset a chunk of the purchase price.

Young cannabis plant in soil

Why Soil and Organic Nutrients?

Soil is natural and organic fertilizers are always preferable to chemicals. They are a match made in herbal heaven. When it comes to choosing a specific organic substrate, the choices are endless from lightly fertilized peat blends to exotic bat guano-enriched premium potting mixes. Few homegrowers have the time and resources to develop super soils themselves so the majority buy their dirt in a bag.

Coco coir is an inert substrate common to many soilless mixes and is a great amendment for soils. Perlite is perhaps the most popular amendment added to both soil and soilless mixes to increase drainage. I’m personally experimenting with a 50-50 blend of Plagron Light Mix with Coco brix’s and perlite.

Soil and coco have a more forgiving 6.0-ish pH than hydro substrates like clay pebbles and Rockwool. Moreover, even if the water or nutrient solution pH is not quite perfectly tuned, both soil and coco act as a buffer for the root zone. In contrast, hydroponic grow-ops demand precision with 5.5-6.5 pH nutrient solutions and frequent automated watering with heavy use of synthetic fertilizers.

Read also: Veganic Weed: Superior Method, Superior Product?

Getting back to nutrients, richer soils require less nutrients and some hardly anything more than regular watering of 6.0-7.0 pH water. Organic fertilizers have closed the gap between synthetic nutrients and most of the popular brands carry organic base nutrients and a selection of organic supplements. Pumping plants full of chemicals in pursuit of the biggest fattest colas to the detriment of all other elements is not exactly de rigueur. I prefer to keep it simple, feeding light and often watering by hand.

It’s 2020 and us home growers need to clean up our act starting in the grow-op. I’m opting for an organic dominant fertilizer regime with Base Nutrients Iguana Juice Bloom, BioBizz BioHeaven stimulant, Advanced Nutrients Rhino Skin for tough plants with thick stems, BioBizz TopMax to promote juicy, tasty buds, Cal-Mag Extra by Advanced Nutrients (because it’s better to have it and not need it, than to need it and not have it), SuperThrive, and a sachet of mycorrhizae for the roots.

To monitor the pH, I’ve got a basic GHE pH color chart test kit with dropper bottle of solution with colour chart. I’m already familiar with my feeding regime so I know I can keep my nutrient solution close to a 6.0 pH if I stick to low-medium doses of my fertilizers. But I’ll check to make sure.

If you want the highest quality cannabis, it’s got to be organic. It’s that simple. And the same reason why I want an organic free-range chicken instead of the factory farmed soaked-in-chlorine-quasi-food kind. Coconut water has become a staple of my cannabis plants’ diet — It’s the best organic supplement and natural PGR you can find on a supermarket shelf.

Cannabis growing in air pots inside a grow room

How to Grow Cannabis?

As I’m expecting compact branchy plants from my Purple Punch Auto seeds, I decided three-gallon air-pots would be perfect for a couple of plants to either grow natural without worrying about running out of vertical space or prune and train comfortably. Factoring in a 400W HPS optimal light distance is somewhere between 18-24 inches (30-45cm) leaves ample room. I couldn’t tell you how high to hang an LED (they vary so much so make sure to check the manufacturer’s instructions).

I got a three-pack of seeds, so with my last Purple Punch Auto bean I went even bigger with a 6.5-gallon black square plastic pot with plenty of drainage holes in the bottom. This larger pot is the same height as the air-pots but much wider allowing me to really go for it with more topping and perhaps a four-way low-stress training (LST) for this plant, although three-gallon air-pots are still sufficient for plenty of LST too.

Another essential piece of grow kit you don’t want to overlook is a good set of trimming scissors for pruning and trimming your buds at harvest.

Read also: How to Grow Marijuana Outdoors in Raised Gardens

Sowing seeds directly into first and final containers would be fine for the two three-gallon size pots, but since I have one seed destined for a big 6.5-gallon pot, I will do it by the book beginning by using the paper-towel method to germinate my seeds, then sowing the seedlings in the safe and humid confines of rooting cubes housed in a propagator with my HPS above dialed down to 250W. A good start is crucial for autoflowers and advantageous to all growers.

If you want to keep your cannabis plant numbers low, perhaps just one to four plants per 10.5 square feet or per crop, mastering advanced high-yield cultivation methods such as the screen of green (SCROG) and/or mainlining is a real asset.

With time and practice you will gradually enhance your cultivation skill set and make incremental improvements to your grow-op. The SCROG is a high-volume, high-yield strategy really only suited to commercial marijuana production. A second grow tent for mother plants and/or cuttings is a practical investment if you plan to preserve genetics and for quicker crop rotation.

In total I spent about $445 putting my complete indoor grow-op together. When you think about it, that’s a start-up cost of less than two ounces. Make 2020 the year you become a self-sufficient home grower.


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Written by Michael Coffey | Cannabis Cultivator, Writer, Photographer, & YouTuber

Profile Picture of Michael Coffey

Michael Coffey, aka Top Shelf Grower is a cannabis cultivator, freelance writer, photographer, and YouTuber originally from Dublin Ireland. These days he’s on the loose creating dope content from an off-the-grid location somewhere. In 2018 he self-published his first book, Cannabis Cultivation a 21st Century Guide, available on Amazon.

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