Editor’s Note: This article was originally published May 2016 and has been updated on 4/18/2018 for quality, accuracy, and comprehensiveness
Growing in a micro grow might seem easy on the surface because the point of a micro grow is to grow only a few plants to maturity. You can also grow a number of clones or seedlings in micro grows, too, but just because it’s a small garden doesn’t mean it’s an easy task. If you’re going to scale your grow room down you’ll need to rethink your lighting, feeding, environmental control, and you may even need to rethink your grow medium.
Micro Grow Lighting
In a Micro Grow (a garden that’s approximately the size of bedroom closet or smaller) light makes all the difference because of one main factor: heat. You’re going to be growing in a confined space, so it’s going to get warm fast, and the temperature alone can dry your plants and the medium they grow in.
Depending on how tall they get, that heat can also be dangerous because if you’re using a light that gets hot and your plants get tall, you have to watch out that they’re not being scorched by the light when they touch it.
Micro Growing with HID’s
If you’re going with HID grow lights, a rule of thumb is to use a 400w grow light: they’ll produce heat but not a ton of it, and are going to be powerful enough to grow without stressing your 1-2 plants.
What you’ll want to look out for is the height of that light above your plants, because HID bulbs get extremely hot to the touch, and if you can burn your hand on a light, just imagine what’ll happen to your plant’s leaves when they touch them…
Micro Growing with LED’s
That’s why we personally suggest going with LED grow lights when you’re growing in tight quarters. Though they will produce a little heat, the amount of heat they give off is exponentially lower than an HID bulb.
That means your micro grow’s ambient temperature (as well as running temperature) will be low. If you use a full spectrum LED, all you have to do is change your lighting schedules, unlike HID’s in which you’d need to swap out the bulbs before changing your light cycle.
When using LED’s it’s vital to make sure you don’t overpower your plants. Strong LED’s may not burn your plants to a crisp, but their intense spectrum will bleach plants and impair growth. When you’re growing in a small space we suggest going with something within the 270w power range or the 360w realm to make sure your plants the perfect amount of light in their small space
Micro Growing with T5’s
Of course, these aren’t the only ways to light a micro grow. Some people use CFL bulbs (like the ones in your house lamps) to give your plants a bright light without tons of heat. Others use T5 grow lights that’ll offer a full spectrum and are relatively cool to the touch.
Just like HID’s, T5 grow lights have “bloom” and “grow” bulbs that you switch off when it’s time to flower. These style lights have been known to grow plants from start to finish, and are commonly found in micro grow’s all over the world.
They do, however, have limited strength. While they have the ability to veg and flower, you may not get the yield you will using LED’s or HID’s. Still, if the mission is to grow in tight spaces with limited heat, T5’s will get the job done.
Feeding Plants in a Micro Grow
Nutrient burn is no joke. When your plants receive too high of a concentration of nutrients your leaves will start to turn yellow and wilt, and in micro grows this is an all-too-common issue.
Nutrient burn is a sign you’re overloading your plant with nutrients. In a micro grow this problem is more than common, because most growers use the nutrient solution their feeding charts tell them. If your plants aren’t able to process all of the nutrients they receive the sodium and nitrogen in your nutrients will kill your plants from the inside out.
The measurement your nutrient bottle says to feed your plants is based on a much larger grow and not a single bucket about 1/6 of the size.
Thankfully scaling down is much easier than rounding up, so here’s what you need to do when you need to feed your micro grow:
- First calculate the ratio of nutrients to the amount of water your feeding chart recommends (i.e. find out how many nutrients you should put in to a given amount of water).
To do this, just look at your feeding chart and see how many gallons of water the nutrients are measured after. For example, if the chart says “Per 1.5 Gallons of Water” then however many mL of nutrients you use is measured per 1.5gal of water.
- Then calculate the amount of water you plan on using in your feeding reservoir
- Take the amount of nutrients you’re supposed to use per gallon and divide it by 50%. These plants will remain smaller, so you don’t want to give them the same amount of nutrients you’d give a much bigger plant.
*Note: if plants start to show signs of burn, scale the nutrients to 75% of the recommended scale and go up from there (plants will require more nutrients in the later part of its life, so be sure to keep an eye on your plants of nutrient deficiencies later on)
Micro Grow Space
The space that you set your grow up is important. Certain micro grow setup’s allow for certain advantages over others, so it’s vital you know how you’re going to house your plants in a micro grow in order to know how to take care of them.
- Grow Tents offer the most advantages. They usually have vent ports for intake and exhaust fans, fresh air intake at the bottom of the tent, and reflective material around them. They’re great for keeping bugs out while being able to keep fresh air in.
Challenges: The only disadvantage to a tent is that if you’re going for discreet growing, it’s pretty hard to hide a tent. You either have to downgrade to a very small tent or put your tent in a closet (which sort of defeats the purpose to using a tent, doesn’t it?)
- Closet micro grows are great for growers looking to simply open a door and BOOM, they’re entire grow is there. The convenient thing about starting a closet grow is that it can actually be easier to set up than a grow tent. All you really need is some reflective material, your grow light, and some fans to keep your plants growing strong.
Challenges: There are two disadvantages to using a closet for your grow, the first being pretty obvious: bugs. If you thought ants were the only thing that you had in your house, just wait until you start growing- that’s when pests you don’t even know existed come around.
The second disadvantage would be with odors. You may be using filters and duct fans to move air around, but even the best filters cannot mask the smell of a bare plant, and if you’re growing in your closet there’s lots of potential for air leaks. That air that leaks out will more than likely have the aroma of your garden, which may be fine for you, but maybe not so much to your neighbors or fellow housemates.
- Grow boxes are a great way to hide your grow in plain sight. These are for those growers looking to grow without taking up any more space in their home or apartment than, say, a dresser drawer or an entertainment console.
The great thing about grow boxes is the fact that they’re so discreet.
Challenges: Ventilation. Sure, you can use fans and ducting to cool your lights, but what about air intake? Fresh air can be introduced by opening the door of the grow box, but that lets odors out and invites pests, dust, and mold spores from the surrounding area in.
Micro Grow Environment Control
Unlike bigger grows, there are going to be some limitations to how much of the environment you can control in a micro grow.
For example, carbon dioxide (Co2) may not be the best options for a micro grow because humidity and Co2 levels will rise quickly, and combating that in such a small area may just eliminate the Co2’s use all together.
When it comes to environmental conditions, there are two major ways you can control the temperature and humidity of that grow: air flow and filtration.
- Air flow is vital to your grow, because without it your plants don’t get fresh air, and all of the air that’s in your air will become stagnant. Depending on the style of micro grow you end up using, make sure that all air intake doesn’t allow bugs to come in.If you’re growing in a grow box that might mean building an intake/exhaust port with a micro filter to keep pests out
- Blade fans and lower powered duct fans are great to keep air moving in your grow. If you have a duct fan but it’s just too powerful for a small area, you can use a speed controller to slow that air flow down to not hurt your plants.
- Filtration is important not only for smell, but for getting dust and mold out of your growing space.
Without a filter your air is blowing in to an open room. That means not only is your room (or entire home/apartment) is going to smell like your grow, but all of that “fresh” air you want is full of that bad stuff you were just trying to get out.
Micro Grow Medium
Now when it comes to the grow medium there are really only two types of mediums you’ll want to work with: soil or hydro with clay pebbles
- Soil is not only the most forgiving when growing only one or two plants, but it’s easy to maintain and is more likely to avoid getting diseases such as root rot, or being affected too heavily with nutrient lock. However, it’s trickier to get a watering cycle down, as you’ll need to constantly be checking your soil’s water content to assure proper feeding.
- Single DWC or Drip buckets are great to use because you pretty much let them run themselves. You check inon them to make sure they’re not wilting from over feeding, make sure their pH levels are on point, and watch the height.
What could possibly be the downside of these mediums? Maintenance.
If you don’t clean that reservoir of water often, expect mold in those buckets.
If you thought mold on your leaves was bad, mold on your roots will absolutely destroy your plants. Root mold leads to root rot, and in a micro grow root rot can spread quickly and attack even faster.
With one or two plants on the line, you have to make sure that you maintain your system often, which means cleaning, disinfecting, and refilling your bucket often along with controlling your temperature and humidity so it doesn’t get stagnant in there because mold loves humid, stagnant conditions.
So if you’re going to grow small, make sure you choose the best option for your budget and your home conditions. If you can spare the room and have all the right equipment, set up a grow tent or line your closet with reflective material and hang a light from the ceiling.
But if you have a limited space to grow in, a grow box might be the best option for you. Whichever way you go, be ready to maintain the growing conditions accordingly.
Remember: you have more room for error when you’re growing in a warehouse, but when you’ve only got two plants every little detail counts.