How To Grow Short And Compact Cannabis Plants

WHY ARE SMALL CANNABIS PLANTS DESIRABLE?

The majority of ordinary decent home growers have a spare bedroom, a grow tent, or perhaps just a cabinet or a wardrobe to use as their grow-op. Grow space is definitely at a premium. In order to make the most of your indoor garden, smaller cannabis plants are advantageous. You must recognise the limitations of your grow space and do all you can to utilise every centimetre. Below, you’ll find an overview of some tips and tricks to help you cultivate compact cannabis plants.

CANNABIS GENETICS

As usual, the strain or strains you choose to grow are the most important factor of any cannabis cultivation endeavour. So it pays to select your seeds very carefully. Feminized seeds are the obvious place to start. Nobody really has room for male plants. Unless you are planning to breed your own strain, stick with feminized seeds.

Skyscraping sativas, super-sized hybrids, and stretch indicas can be cultivated indoors successfully—but you’ll have to work a lot harder to keep them short. Modern autoflowering hybrids and heavy indica strains are far easier to fit in the grow-op. These varieties will rarely exceed 1m in height when mature. Short stuff like these top 10 compact cannabis plants are ideal for the occasion.

OPTIMAL LIGHT DISTANCE TO CANNABIS PLANTS

The optimal light distance can vary depending on whether you are using CFL, HID, or LED lighting. Whatever the perfect distance between the plant canopy and grow lamp is for your equipment, make sure you maintain it. If your cannabis plants are too far away from the stationary source of illumination hanging above, they will stretch to get closer.

Regular adjustment of grow lamps is standard operating procedure for indoor cultivation. Measure the distance with a ruler or a tape measure for accuracy. Get it right from the very beginning. Even seedlings will grow spindly if they are too far away from the light. Also, take care not to hang grow lamps too close to plants or they will suffer from heat stress and the tops may get burned.

SHORTEN THE PLANT'S VEGETATION PERIOD

A reduced vegetative growth cycle is a viable option if you are growing photoperiod strains. Autos will transition to bloom according to their age, so this is a no-go for those varieties. But most will start to flower in about 30 days, so it shouldn’t be a concern.

However, if you do have photoperiod plants, a shorter veg period denies them the opportunity to get too tall before flowering begins. Most photoperiod cannabis will double or triple in size during bloom. So if you have limited vertical space, it can be advantageous to switch to 12/12 early. The downside is they will not branch out as much or be as productive as plants vegged for a longer period. This is often preferred by SOG growers, which we will touch on later in the text.

USE SMALL POTS FOR YOUR MARIJUANA PLANTS

This may seem rather obvious, but small pots are for small plants and big pots are for big plants. Autoflowering and indica varieties do not require the same amount of space for their roots to develop as many vigorous indica-sativa hybrids and sativa-dominant strains. Therefore, they will not become root-bound if you grow them in smaller pots.

Of course, if you plant an indica in a huge container, it can become a monster marijuana plant—but only if you give it a long vegetative growth phase. If you do opt for a smaller pot with an indica strain, it’s best to keep the vegetative growth period brief and switch to 12/12 as soon as possible. A prolonged veg only increases the risk of the plant becoming root-bound. A transplant might be necessary to save the plant if you wait too long. 6l pots should be big enough to grow most autos and squat indicas comfortably.

LST AND HST (AKA SUPER CROPPING)

LST (low-stress training) is a great technique to manipulate the structure of cannabis plants. Bending branches and using stakes and soft ties to hold them in position takes a little green-fingered finesse, but is very doable. LST is the ideal way to create a bushier growth pattern without having to cut away branches. Best of all, after a minimal recovery period (usually within a day or two), you’ve got a healthy cannabis bush that’s no worse for wear.

In contrast, super cropping (HST) is a high-stress technique that will cost you some time. Squeezing branches until they go limp or even snapping them will stress the plant. Plus, it may take the plants a week or longer to recover. This method will bush plants out similar to LST, but you will definitely need to veg plants for longer. Neither LST nor super cropping should be attempted during flowering. In a desperate situation where a plant is just growing too tall for the grow space, LST can be attempted during bloom—but only as a last resort. Branches usually become quite rigid shortly after bloom commences, and you run the risk of completely shearing them off if you try to bend them.

MAINTAIN THE PERFECT ROOM TEMPERATURE

Indoor cannabis plants thrive within the 20–28°C temperature range. Generally, this can be achieved by most growers. Excessively high temperatures will cause heat stress and irregular plant growth. Top colas may start to grow stretchy; and if it happens during flowering, buds will develop more loosely and foxtailing can occur. Turn on the air con if you have it, or consider using less powerful grow lamps to keep temps in the comfort zone.

When the lights go off is where a lot of growers run into trouble. Temperatures below 15°C will slow down the plant's metabolism—and stunt growth. You want healthy, compact plants, not sickly, slow-growing plants. Switch on the central heating or add a small heater to the grow space to prevent temps from dipping too low. 10°C and below really puts your cannabis plants in the danger zone. It might even kill them.

MAKE SURE THERE IS PROPER AIR CIRCULATION/VENTILATION

Cannabis plants need fresh air. Suck in fresh air from outside with your intake fan and exhaust the warm, stale air with an outtake fan. At the very least, crack open a window. Make no mistake, poor ventilation is bad news for your cannabis plants. They also need a light breeze. Make sure to install an oscillating fan or a clip-on fan or two to keep the air circulating.

If you don’t, it’s an invitation to pests and pathogens. Diseased or infested plants don’t produce viable flowers. This is closely associated with maintaining optimal temperatures and dialling in the perfect environmental conditions. Ignore airflow at your peril. Remember, healthy, compact plants are the objective.

TOPPING AND FIMMING

Topping and fimming are pruning techniques to break the apical dominance of the main stem and reroute growth hormone to secondary shoots. Topping involves cutting away the tip of the stem clean with scissors, leaving a nub behind. A FIM, however, is best accomplished by pinching off 75% of the stem between the fingers.

Either way, plants will bush out more to fill lateral space and develop multiple top colas instead of just one. When applied during vegetative growth, these pruning techniques are proven yield-boosters too. Although, plants will need 3–7 days to recover. Furthermore, topping/fimming can also be combined with LST or super cropping if you’ve got the patience for a longer veg period.

SOG AND SCROG GROW TECHNIQUES

The SOG or sea of green method is a high-volume cultivation style. By using small pots and filling up the floor space, minimal vegetative growth is needed to crop a heavy harvest from many small cannabis plants.

In contrast, the ScrOG or screen of green method favours a few well-trained and/or pruned cannabis plants. However, they must be kept in veg for much longer. The goal is to drop a screen over the plants during vegetative growth and train as many shoots as possible to grow through the screen. Bend and weave until about week 3 of flowering. Yields can be comparable with a SOG if you do it right and don’t rush things.

Luke Sumpter

With a BSc (Hons) degree in Clinical Health Sciences and a passion for growing plants, Luke Sumpter has worked as a professional journalist and writer at the intersection of cannabis and science for the past 7 years.

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