Slow Cannabis Plant Growth And What You Can Do About It
When your cannabis plants grow slowly or stop growing altogether, there is always a reason. It could be a problem with nutrients, an environmental factor, or something else entirely. Let’s explore the reasons your cannabis plants or seedlings may experience slow or stunted growth.
“Why are my plants growing so slow?”. Sometimes, marijuana plant problems occur out of the blue. Your baby may not have shown any signs of an issue, but now you notice that development has halted and have no idea why. Here are some possible factors behind the slowed growth of your cannabis seedling or plant.
18 REASONS FOR SLOW OR STUNTED CANNABIS GROWTH
1. SEEDS ARE OLD OR LOW-QUALITY
Old seeds don’t just take longer to germinate (if they germinate at all); plants grown from aged seeds can also sometimes grow at a reduced pace. Likewise, good genetics are essential for healthy and vigorous growth from seed to harvest. A random bagseed will not perform nearly as well as quality seeds obtained from a reputable seedbank.
2. CLONE STRESS
Sometimes cuttings don’t root well, which hampers their growth. To prevent this from happening, apply a little bit of rooting hormone immediately after taking your cuttings.
Also, make sure your environment promotes root growth. The medium should be humid (but not too moist) with a pH level of about 6.0. Keep your cuttings at a temperature of around 22ºC. If they get too cold, they won’t root at all, and if it’s too hot, the roots will die.
3. ROOT HEALTH
When your plant’s roots can’t receive enough oxygen, metabolic functions slow down. In some cases, a lack of oxygen may stop their growth altogether. One common reason for this is overwatering or using substrates with poor drainage.
What to do about it? Create a light and airy growing medium with good drainage. You can improve poor-draining soil by adding some perlite.
The root zone for your cannabis plants should never get much hotter or colder than room temperature. Likewise, physical damage to the roots, mould, or bacteria can severely affect the growth of your plants. Always use non-transparent planters so light doesn’t reach the roots, as this is bad as well.
4. CANNABIS PLANTS STRETCH TOO MUCH
Stretching among seedlings can be particularly problematic. Multiple factors can induce this response, but the most likely culprit is a lack of light.
If your seedlings are spindly, increase light intensity or bring the lights closer. Prop them up with dowels as an aid during recovery. As a last resort, you can (carefully) replant them deeper into a new pot.
5. PLANTS ARE NOT GETTING ENOUGH LIGHT
Although requirements can vary from strain to strain, light is nonetheless a critical factor for the development of all cannabis plants. A lack of “good” light can absolutely lead to slowed growth. If you grow indoors and suspect that your plants aren’t getting enough light, try to decrease the distance between your lamps and the tops of plants. If you grow outdoors in pots, move your plants to a sunnier spot.
6. PLANTS ARE GETTING TOO MUCH LIGHT
Any type of stress on your cannabis plants, including many hours of exposure to direct sunlight without rest, can also halt or slow down growth. If you grow indoors and suspect light exposure to be the source of stress, decrease the intensity or move lamps further away from the canopy if possible. Know that seedlings are particularly sensitive to intense light! If you grow outdoors and you’re able to, move your plants into a spot where the light is diffused, such as around a shade tree.
7. INCORRECT LIGHT SPECTRUM
How fast and how vigorously plants grow are influenced by the spectrum of light they receive. Make sure you use the correct type of light according to each stage of growth. For healthy vegetative growth, you want a cooler light with more blue in its spectrum, a so-called “vegging light”. Lights with a warmer, more reddish spectrum are used for the flowering phase.
8. LIGHT STRESS: DARK CYCLE INTERRUPTION
Light is essential for all plants to grow. Any changes in light intensity or exposure will have an effect on growth. Flowering cannabis is especially susceptible to interruptions in the dark cycle. A light leak in your tent, stray light from a street lamp, and even a red light from a camera can disrupt flowering, and in a worst case scenario, can turn plants hermaphroditic. For that reason, it is very important to maintain complete darkness during the lights-off hours.
Exposing weed plants to irregular light hours can cause a hormone imbalance that confuses their internal clock. Your plants could flower prematurely, or they could revert back to the vegetative stage. If this happens, growth and yields will greatly suffer. For that reason, make sure to keep your light cycle consistent.
The above suggestions predominantly apply to photoperiod strains, as autoflowering cannabis flowers based on age rather than light exposure.
Overwatering is one of the most common mistakes made by new cannabis growers. It’s like suffocating your plants, and one of the main reasons behind slow growth, nutrient deficiencies, root rot, fungus, and many other problems. Don’t water too often and do not water on a fixed schedule. It is better water less frequently so that the soil can dry out between waterings. A good way to test whether you should water or not is to lift up the pot itself. If it feels quite light, it is time to water again.
10. NOT ENOUGH NUTRIENTS
Although not as common as overfeeding cannabis plants, an insufficient amount of nutrients for healthy growth can well be the reason for slow growth. Know that the nutrients found in most commercial potting mixes will only last for 3–4 weeks; afterwards, you will have to administer some more quality nutrients. Check the label of your nutrient products for the recommended dosage for healthy growth. Also know that your plant’s nutrient requirements are closely linked to the light intensity your plants are exposed to. Plants under intensive lights grow faster and will require more nutrients than plants under fluorescent lights, for example.
11. CALCIUM DEFICIENCY
Calcium is among those vital elements that your plant needs for healthy development. A lack of calcium can manifest in the following symptoms:
- Fresh growth is slow, twisted, and curled
- Young shoots are discoloured and turn purple or yellow
- Overall plant growth is slow and lacks vigour and vitality
- You can avoid a calcium deficiency by adding dolomitic lime to your soil or growing medium
Address a calcium deficiency immediately with commercial CalMag products that contain liquid calcium. You can add these products to your nutrient solution or administer them as a foliar spray.
Be aware that some growing media, like coco, increase the risk for a calcium deficiency. If you grow in coco, you should use special coco nutrients and/or regularly add CalMag to your nutrient regimen.
12. INCORRECT PH LEVEL
Incorrect pH level of your nutrient solution is among the most common reasons for cannabis growing problems, including slow growth. The reason for this is that cannabis thrives only in a relatively small window of suitable pH values. If the pH is off, the plants are unable to take in nutrients, even if they are present.
Make sure to dial in the correct pH level depending on your growing method. If you grow in soil, make sure the pH level is from 6.5 to 7.0. If you grow in hydro, an optimal pH level is 5.6 to 5.8. For soilless grows, such as coco, a pH level of 6.0 to 6.3 is optimal.
13. TEMPERATURES ARE TOO LOW OR TOO HIGH
Cannabis likes it warm to grow healthy, and does best at daytime temperatures between 25–30°C. Temperatures lower than that will slow down your plant’s metabolism, resulting in slower growth. But excessive temperatures are not optimal either. At very high temperatures, heat stress can also slow down or even halt plant growth altogether. If you grow indoors, adjust your temperature to a comfortable level. You can also provide some cooling with fans that blow a mild stream of air over your plants. This can also help prevent hot air pockets from forming inside your grow room.
14. PLANTING POTS ARE TOO BIG
Cannabis growers often start their seedlings in small cups. Later on, when the plants have reached an adequate size, they will “pot-up” to larger containers.
If you start your cannabis plants in containers that are too big, there is a high risk that you’ll overwater them. The issue is that seedlings cannot absorb all the moisture that is held in a large container, unlike mature cannabis, which can “drink” much more. Furthermore, a large pot will also take much longer to dry out.
To avoid the problems that come with too much soil and moisture, start seedlings in smaller containers until they’re growing vigorously. Once they have a set of 5–6 real leaves (not counting the cotyledons), then transfer them to a larger container, at least twice the current size.
If your seedling is already in a big container and you don’t want to or can’t move it into a smaller cup, water only a small area around the seedling.
• What Is The Right Size Pot For Your Cannabis Plant?
Use this rough guide to determine what size pot you should use for your cannabis plant:
- Plant height 30cm: 7.5–11l container
- Plant height 60cm: 11–19l container
- Plant height 90cm: 18–26l container
- Plant height 120cm: 22–37l container
- Plant height 150cm: 30–37l+ container
15. STRESS CAUSED BY PESTS / DISEASES
Insects, pests, and disease can cause damage and compromise a plant’s immune system. In a best case scenario, your plant may survive, but you will have poor yields. In the worst case, your plants could die.
Insects may feed on the leaves, affecting a plant’s ability to retain water and transpire. Other pests may damage the roots or cause additional problems. Any time your plant is sick or infested with insects, it will spend most of its energy defending itself and recovering from damage, which will slow down growth.
If your plants are infested, you’ll want to treat them immediately with appropriate measures. Even better, you can use preventative methods (e.g. neem oil, slug barriers, etc.) to minimise the risk for pest infestations. During all stages of growth, ensure that you regularly check for symptoms of pest infestations, including under the leaves.
16. STRESS CAUSED BY TISSUE DAMAGE
Physical damage, such as broken branches, can significantly slow your plant’s growth. Any damage will make the plant redirect valuable resources to repair wounds—resources that could be better spent on growing or flower production.
If you’re growing outdoors, situate your plants in an area sheltered from strong winds and heavy rains, and use chicken wire and stakes to maintain support.
Seedlings and young cannabis plants are especially vulnerable. Allow your seedlings to mature indoors for some weeks before setting them outside.
17. STRESS FROM CANNABIS TRAINING TECHNIQUES
Tissue damage from high-stress plant training techniques always causes some delay in plant development. But when you’re pruning excessively or too frequently, your plant may ultimately spend more energy repairing itself than growing.
If you plan on pruning, don’t overdo it. Be aware that each pruning can delay the development of your plant for days, if not weeks.
If you’re using other plant training techniques such as topping, make sure you start as early as possible. If you’re growing autoflowers, don’t use any plant training techniques that involve tissue damage, such as pruning and cutting.
18. AGE STRESS
Older cannabis plants have different nutritional requirements than young plants. Their tissues become hard and woody, they’re less vigorous, and they’re unable to take in as many nutrients.
Because of this, you’ll want to adjust your feeding regimen accordingly. Otherwise you risk overfeeding, which in turn results in stunted growth, deficiencies, and disease. Keep this in mind if you’re keeping mother plants around for a long time.
Why is my cannabis plant growing slowly or not at all? Find out the answer to this question and see what you can do to solve it.
The Wonders Of Micro Growing – High Quality Cannabis In Tiny Spaces
You probably thought about growing your own weed sometimes, but concluded that it’s too much of a hassle? Look no further, micro growing has everything you’re looking for and more.
As cannabis and its cultivation is more popular than ever and it seems that trend won’t stop soon, we see more and more people wanting to grow their own cannabis. Most beginners to growing don’t have the necessary experience or knowledge to start a full-blown indoor or outdoor growing operation, so they opt for a simpler option – a micro grow. Take a couple of seeds and plant them in a cupboard or a similarly small space, trying to get the best possible results of it – or in other words – micro growing. It is a natural way for beginner growers to get that needed experience and to experiment with no fear of ruining a big and expensive operation. This article will cover the basics of micro growing and the differences between it and a standard indoor grow, so let’s get started.
THE BASICS AND THE DIFFERENCES
Micro growing would best be described as a process of growing a small batch of cannabis in a limited space, trying to get the best possible results. That being said, micro growing is a type of indoor growing, just smaller in proportions. The main difference between a micro grow and a usual indoor grow is exactly that – the amount of space. Due to the lack of space, all the other basic aspects of cannabis growing – light, water and air supply, soil, the choice of strains – differ slightly from your regular indoor grow. Almost any space you imagine can be used for micro growing, from cupboards to computer cases. The main idea (and challenge) is to create the optimum conditions for your plants to thrive in that space.
CHOOSING A SUITABLE STRAIN
When it comes to micro growing, choosing the right strain is very important due to the limited space available. One of the things to watch out for is the height of your cannabis strain. Sativas grow higher and more slender than indicas, which tend to be short and bushy.
Furthermore, during the flowering phase sativas undergo a 200-300% increase in height, while Indicas increase only by 50-100%, which shows that indicas are more compatible with micro growing.
Another reasonable option would be autoflowering strains. No matter what the conditions, autoflowering strains stay small due to their genetics (a great many of them even smaller than indicas) and aren’t dependent on the light regime, which means they will have a shorter harvest time.
Most plants you see occupy the same volume beneath the ground as above. The reason behind this is because the root system is vitally important to a plant, being the part of the plant where it takes up nutrients and water. The amount of space occupied by a plant’s root system has a great influence on the plant’s size. We can use this correlation to our advantage as micro growing is concerned. The volume of the pot you use to grow your plant in is directly related to how large the plant will grow. To give you an impression:
- Around 12 liters and more: average plant height
- Around 5 liters: height of plant up to 60cm
- Around 2-3 liters: height up to 24cm
- Around ½ liter: height up to 13cm
A thing to note is that due to the small quantity of soil your plants will need more fertilizer and water than regular plants.
You can’t grow cannabis at all without light and you can’t grow good quality cannabis without proper lighting. Choosing the optimal lighting for your micro grow is an important decision and you have a variety of lamps to choose from – fluorescent tubes, CFL (energy-saving lamps), HPS, HPI and LED bulbs. When choosing a lighting you got to keep an eye out for the wattage and the heat the lighting produces. When it comes to wattage, an average of 400W is required for a square meter.
HPS and HPI lamps are the go-to lightings of indoor growers because of their high light output and 400W is lightweight for this kind of lamps. But, the problem with this kind of lighting is that it produces excess heat, which especially won’t help with your micro grow. Due to the lack of space things get very hot very quickly and your plants will be in danger of drying out.
But, fear not, this is one of the reasons we have fluorescent tubes and CFLs. They are very similar and both have a great light output, don’t dissipate much heat and are available in different light colours. You can help your cannabis plant with different light colours – a plant in the vegetative state needs more blue light, while a flowering plant requires more red light.
And at last, LED lamps. A good choice for micro growing, because they have a wide light spectrum and virtually don’t heat at all, but they come with a hefty price and may not be suitable if you’re planning a certain budget.
AIR AND WATER SUPPLY
As with light, your plants can’t live and grow without water and air. Having a good and clean ventilation and water supply system is a necessity for any grow, including micro grows.
The movement of air is necessary to a grow, because CO2-rich air is quickly depleted and that is a requirement for your plant’s photosynthetic process, which causes new plant cells to grow. The heated air due to the lighting needs to get out of the grow too, as it dries out the plants. Usually, table fans are used in indoor grows, combined with ventilation systems, but that is probably not practical for your micro grow. A neat solution is a computer fan. You put one at a low point that will act as your intake fan and put another one in a higher position to act as an exhaust fan. This way, as heat rises, the hot air will come out first, replacing it with cooler and fresher air. Don’t forget to use some kind of filters on the fans which will help you battle unwanted pests and odors.
Watering your micro grow becomes tricky after a while, as the plants become bushier and expand in width. You will need to use a small water system or make the grow accessible from the side to water your plants from the bottom. Don’t forget that plants in micro grow need more water than plants in regular grows, as they have less root space.
It was mentioned before, that space is the main difference between micro growing and a regular indoor grow. This lack of space usually calls for shorter and bushier plants, which is shown in the choosing of the right strain. There are other ways to influence a plants growth, such as various growing techniques: topping, super cropping,screen of green (ScrOG) and low stress training (LST).
Topping is the process of cutting off the very top of the plant, which stimulates the plant to grow new secondary branches. This way, the plant grows in width and not height, growing in a bush-like shape and creating more buds. Super cropping (or HST – high stress training) on the other hand, requires you to break the stem of the main branch. This technique needs to be done carefully. You need to break the stem in such a way, that the plant thinks it is gone for good and starts growing side branches, but not completely, so that the main branch can recover and grow to a smaller height.
The ScrOG technique requires you to put a mesh wire screen between the soil and the light source. Once the branches grow through the screen, you can tie them to the screen to force them to grow horizontally, hence the name. With ScrOG you manage the height of the plant and all the tops get the same light. LST is a somewhat similar technique, where you tie your plants higher branches to the soil, forcing the plant to grow side branches and more colas, with the end result being a higher yield in a smaller space, perfect for micro growing.
Beginner growers need to know that a micro grow isn’t a worthy substitute for a real indoor or outdoor grow. But, it is perfect as a starting point to develop that green thumb and to learn about the important things you need for a good cannabis grow. Feel free to try out and experiment with new strains, techniques and instruments, as long as you treat your plants with care. The whole process of growing a plant is a reward in itself, not to mention the harvest, so what are you waiting for?
3 GREAT STRAINS FOR MICRO GROWING
1. ROYAL DWARF
Royal Dwarf truly is a miniature cannabis specimen that can remain at tiny sizes of 40cm tall when trained in the ways mentioned above. This plant was bred for one reason and one reason only: stealth. Growers can easily cultivate multiple Royal Dwarf plants in their home without a single suspicion being raised. She can easily be grown within modified kitchen cupboards, wardrobes, boxes, and computer towers. Small LED lights can also be used within these tiny spaces to avoid giving off too much heat. Royal Dwarf is essentially the autoflowering version of the legendary Skunk, and was made using a Skunk strain along with a specific ruderalis cultivar. She offers stimulating but subtle sativa highs fuelled by THC quantities of 13%. She can therefore be smoked all day long whilst allowing the user to stay on top of their game and not get too high. Her small yet compact flowers offer sweet and citrus tastes.
Royal Dwarf will be ready to harvest a mere 8–9 weeks after seeds have been germinated. Plants grown indoors will provide yields of up to 200g/m² and won’t exceed 70cm in height. Plants grown outdoors within garden beds or guerrilla grow spots will produce harvests of 30–80g/plant and reach heights of between 50–90cm.
You want to start your own cannabis grow? Micro growing is a perfect way to start learning about growing cannabis and experimenting on your own terms.