How To Deal With Slow Cannabis Growth
If you feel like your plants are not growing as fast as they should then it’s most likely there’s something wrong, slow growth can be a result of a number of things. If your plants are suffering from slow root growth, or you’re asking yourself why your plants are growing so slow, here’s a couple of tips to help you fix your problem, remember these problems can affect cannabis in all stages of plant growth.
When growing cannabis there are a lot of variables that can affect the growth and final result of your harvest. From genetics, possible nutrient deficiencies, root system and pests problems to the environment, you need to make sure everything is okay if you want to have a smooth growth cycle. Providing your plants with a warm slightly humid climate will not only help you to deal with their slow growth but can result in a bigger and better harvest.
Not enough light is one of the main problems associated with slow growth. Not providing enough light will cause your plants to take way longer to develop because they don’t have a good amount of light to photosynthesize.
When your plants are still young you can see this, for example, when your seedling is stretching too much, this is a sign that your plant is not getting enough light and is trying to get closer to it.
Now, have in mind that you can also give your plants too much light (if the environment is not appropriate for the amount of light you’re providing).
This happens because most high-intensity lights have to be used in combination with higher CO2 levels so your plant can absorb the light properly, if the CO2 level is too low your plant can get stressed and show heat stress signs, resulting in slow growth.
How to deal with it
If you’re experiencing light-related problems (like heat stress symptoms), you should try to adjust the intensity (with a dimmer) or the height your light fixture is at.
A good way to test this is to keep your hands under the light for around 30 seconds, if it’s too hot for you, it definitely is too hot for your plants.
As a general guide, LEDs should be kept in between 60-100 cm from your plants (depending on the model) while light bulb fixtures should be around 30cm from your canopy.
Even though some plants can withstand harsh environments, most cannabis plants enjoy a warm slightly humid climate, it’s essential you have a thermo hygrometer to measure this and adjust when necessary.
If the temperature in your grow room is below 15°C or above 30°C for too long, you will start to see slower growth and if left like that for too long, you’ll see signs of unhappy plants like droopy leaves or the leaves starting to yellow, crisp and die.
This also applies to humidity. Humidity levels below 35% can stunt growth and if they’re even lower than that (around 25%), you’ll start to see signs of deficiency on your plant.
A humidity level higher than 70% can also have a toll on your cannabis plant, slowing your plant’s growth, making them droopy because it makes it harder for the plant to move water internally.
How to deal with it
If your seedlings are not growing or you’re wondering why your seedlings are growing so slow, this could be the problem.
To avoid environment-related problems you have to ensure your growing environment is optimal for your plants.
For your cannabis plants to thrive you need to provide a temperature of around 22-25 celsius and a humidity level of 60% for seedling, 50% in the vegetative stage, and 40% in the flowering stage.
These numbers are just a guideline, you should always look for the signs your plants give you and adjust the environment accordingly.
3. Root problems
Unless you’re growing in a hydroponic (or aeroponic) setup you won’t be able to see your plant’s roots.
Keeping a good environment for your plants also includes maintaining the medium oxygenated and with the right amount of water. Root problems are the main cause of slow growth with new growers, adjusting and maintaining a good growing medium for the roots is the best way to fix stunted growth in plants.
The lack of appropriate care with the roots can cause the following problems:
Overwatering is a common occurrence with new growers, excessive watering inhibits oxygen from reaching the roots and can result in the drowning of your plant.
Overwatered plants will start to droop, show slower growth, start yellowing, and show signs of deficiencies because they can’t absorb nutrients properly.
Underwatering isn’t as common as overwatering but can also affect your plant in a bad way.
If there’s a lack of water in the medium, your plant will show signs similar to the signs of overwatering but instead of the leaves looking “fat” because of the excess of water, they will look thin and fragile because there’s no water (or a tiny amount) in them.
Rootbound happens when you plant your seeds in a small pot or container and the roots don’t have any more room to grow.
When this happens, your plant will start to show different symptoms than can confuse you, when you see your plant getting much wider than the pot you should start thinking about transplanting it, failing to give the roots the space they need to grow will result in droopy leaves and other signs associated with overwatering of nutrient deficiencies.
How to deal with it
To avoid root problems you have to make sure you’re giving the roots enough oxygen, room to grow, and water only when needed.
You should water only when at least 60% of the medium is dry and transplant your cannabis when she’s growing out the pot she’s in.
If you’re having problems with this we recommend you try different mixes of soil, perlite, and coco fiber, this will help you provide the right amount of oxygen and water to the roots.
4. Nutrient deficiencies
Plants need nutrients to grow, depending on the medium you’re growing in, you’ll need to not only provide all the macronutrients but also a good amount of micronutrients.
You also have to remember that nutrient absorption is directly related to the pH level.
If you don’t provide the amount of nutrients your plant needs or if you fail to adjust the pH level your plant won’t be able to grow properly and will result in nutrient deficiencies, stunting growth and damaging the leaves.
How to deal with it
To fix this you need to adjust the amount of nutrients you’re giving your plant and check the pH level every day.
If you’re giving the right amount of nutrients then the problem will most likely be the pH level, remember the pH level changes according to the medium you’re growing in and you should always check it and adjust it if you want your plants to grow healthy.
It is crucial you keep your plant well fed and with the correct pH levels, if you see even the slightest yellowing on the leaves then your plant is most likely not growing properly.
5. Bugs or pests
Bugs and pests feed on your plant, they can feed on the sugars or on the plant matter, either way, they will damage your plant and slow its growth.
Some bugs like Spider mites can also rot the buds, making them unhealthy to smoke so it’s crucial you keep your plant healthy and check on them every day to spot bugs early.
How to deal with it
There are different ways to deal with bugs but the best way is to prevent them.
By checking on your plants every day you avoid bugs, you can also spread yellow sticky traps so you can spot them early.
You can also spray your plants with a mix of water and a small dose of organic insecticide to prevent them although this is not recommended, insecticides should only be used when you already have bugs and are used to eliminate and not to prevent them.
Slow plant growth can also be the result of bad genetics, even though you cannot change this once you’ve already started to grow your plant, you should always start with good genetics. This will save you time and money and can result in a bigger and better harvest.
How to deal with it
If you’re dealing with slow plant growth and can’t seem to get to the root of it, the cause of your problems can be bad genetics.
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If you feel like your plants are not growing as fast as they should then it’s most likely there’s something wrong, slow growth can be a result of a
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.