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How to Control Stretching of Cannabis Plants?

Stretching can reduce yield and quality to a great extent if it's not avaoided early. Find out how to prevent stretching in this article.
4 weeks ago
5 min read
How to Control Stretching of Cannabis Plants?

Contents:

Cannabis plants grow very well without a lot of maintenance during their vegetative stage. They put out pretty green leaves and prepare for the reproductive or flowering stage. There isn’t a lot to do during the growing stage, but the flowering stage definitely requires maintenance. From pests to diseases to stretching, there can be too many headaches to count. If you’re wondering how to control stretching of cannabis plants, this article will show you simple steps that will help you harvest great yields.

It’s not that the plants don’t stretch during the vegetative stage – they do – but it’s a lot more during the flowering stage. Stretching is nothing but a natural spurt of growth and is common for all cannabis plants. However, it works only if it’s moderate. Stretch too much and the plants start putting out buds that are airy and tiny.

On the other hand, when plants don’t stretch too much and grow sideways, you get healthy buds. This means that one must control stretching to prevent loss of yield, not to mention quality. Stretching occurs due to multiple reasons out of which genetics plays a role too. This is why some plants that remain small and compact will also produce offspring that grow in a similar fashion. Even lanky plants will only give you plants that grow tall and lanky.

So, is all hope lost, you ask? No… You can control stretching in various ways, so let’s take a look at them.

What happens when plants stretch?

Stretching is not that big a deal if you’re growing plants outdoors. Like other plants, cannabis plants also enjoy growing outdoors and you don’t have to worry much at all. Sometimes, the plants can stretch too much even when outdoors, but you can control them using training methods like LST. For the most part, stretching occurs when the plants are indoors.

As mentioned already, stretching invites problems and instead of growing plants that grow compact with thick buds, you’ll have a bunch of plants growing upwards. They become spindly and tall and stop focusing on the buds while diverting all their attention on stretching. When this happens, the quality of the buds take a hit and you’ll lose quite a bit of the yield too.

Why do cannabis plants stretch?

Pineapple Express by Squirrel_master

Stretching usually occurs indoors. If the plants aren’t genetically inclined to stretch, they could be stretching due to the lights. If the distance between the plants and the lights is too much, the plants start growing upwards in search of more light. In an effort to go close to the source of light, the plants experience a growth spurt that’s otherwise known as stretching.

Stretching also occurs when there are too many plants in a grow room. If the grow room is overcrowded, the plants have no other option other than competing with each other for light. Last but not the least, the type of light you use matters too. Whether they are HPS or LED lights, plants tend to stretch if there’s a lot of red and orange light. You can prevent this by supplementing blue light along with the red lights during flowering since it encourages thicker stems and branches.

You also need to provide a strong source of light. For instance, if you’re growing a couple of plants with only a 100W CFL as the light source, the plants will start stretching since the light isn’t powerful enough. It’s recommended that you provide at least 50 to 70W of light per square foot. Anything less than this will most definitely encourage the plants to stretch to their maximum.

How to prevent stretching of cannabis plants

1. Choose the right strain

Okay, this is the first thing you need to do because you can do everything and the plants will still stretch if it's in their genes. And, this will happen even if you grow clones or plant seeds! Thus, find the right strains.

Most Indica strains tend to grow sideways rather than upwards. At the same time, many Sativa strains are notorious to grow upwards searching for light and are adept at producing airy buds. Of course, you’ll see that they are many exceptions. Not all Indica plants grow sideways and not all Sativas grow tall and lanky. However, since most of them do, choose Indica strains - Cream Cookies Auto, for example - that grow in a uniform fashion so that the light can be distributed evenly to all plants.

Cream Cookies Auto
Cream Cookies Auto
Genes
Mostly Indica
Genetics
Girl Scout Cookies
Flowering
10 weeks
Harvest
XL
Height
60 - 90 cm
THC
Very High
CBD
Low
Autoflowering
Yes
Learn more

2. Manage the heat

When a lot of heat builds up in the grow room, the plants are forced to stretch upwards. Temperatures over 28 degrees C will force plants to grow taller. And as the plants grow closer to the light, they stretch even more. This makes them weak and they can even fall over themselves if you don’t keep an eye on them.

To prevent this, make sure that there’s a lot of fresh air circulating in the grow room. Not only will it keep the grow room cool and the plants happy, but the plants will force themselves to develop thicker stems whenever there’s a lot of breeze blowing in their direction. The plants naturally become stronger as a defense mechanism against the wind like it happens in the wild.

3. Reduce the vegetative period

Hawkbo Cream Cookies

When plants start stretching during the flowering period, growers panic because there won’t be a lot of roof space for the plants to continue growing. Ultimately, they grow too close to the light and experience light-burn that bleaches the buds and leaves as well.

If you’re growing a strain with a tendency to stretch, you can reduce the vegetative period so that there’s a lot of time and roof space for the plants to stretch in the flowering phase. Growers growing photoperiod plants can switch from the vegetative to the reproductive stage by altering the light schedule from 18/6 light/dark cycle to 12/12 cycle.

This isn’t necessary if you’re growing autoflowers because they will grow regardless of the light cycle. However, you can control stretching to a great extent by cutting the growing stage short so the plants have enough time and space ahead to stretch all they want.

Gorilla Glue Auto
Gorilla Glue Auto
Genes
Sativa/Indica
Genetics
Gorilla Glue autoflowering
Flowering
9-10 weeks
Harvest
XL
Height
60-100cm
THC
Very High
CBD
Low
Autoflowering
Yes
Learn more

4. Employ training techniques

There are several techniques including LST and SCROG meant specifically to prevent cannabis plants from stretching.

LST

Lemon AK by philindicus

Also known as Low-Stress Training, this method involves bending the branches of the plants to the sides of the containers. Growers continue bending the branches throughout the growing cycle and this prevents the plants from growing upwards. Yes, the branches try their best to stand upright, but it will remain bent if you use strong wires to fasten them to the sides.

SCROG 

Buddingbuddha

This is a method where the growers allow the plants to grow as much as they want in the vegetative stage. However, during the flowering stage, a screen is placed on top of the plants where the branches are tucked in as soon as they try to peek out.

Known as Screen of Green, this technique prevents the plants from growing too much upwards as the screen prevents them. You can remove all the leaves below the screen but as you tuck the branches growing on top of the screen, you’ll notice many buds forming just because there’s an even canopy that allows uniform distribution of light.