Cannabis Seed Sprouted But Stopped Growing

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. If you want to learn about the different elements that can affect your cannabis seedlings, how to identify the problems and fix them, make sure to read along! Why won't my cannabis seeds germinate? Why are my seedlings weak? Find out the answers to these questions, and their solutions, in our troubleshooting guide.

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.

Cannabis cultivation, cannabis history, cannabis culture

“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.

9. OVERWATERING

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.

See also  Cannabis Seed Germination Rate

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.

Common Cannabis Seedling Problems and How To Fix Them

Problems with seedlings are common and can end up affecting them further into their life cycle so it’s vital you detect and fix them as soon as you can. Yellowing or deformed leaves, burnt tips, or even slow growth are signs of cannabis seedling problems, even though your seedling may be able to recover, it may have a toll on the final size and yields of your cannabis plants. It’s definitely not hard to detect when something’s wrong, but if you’re a new grower, first you should know what a healthy seedling looks like.

1. Healthy Cannabis Seedlings

Cannabis seedlings start with two tiny round leaves called “cotyledons”, these leaves are already formed inside the seed and open up once the seed has been successfully germinated, after a couple of days, the first serrated leaves will appear, which indicates that your weed seedling is starting to grow.

As your seedling start developing, the first pair of true leaves will appear, the true leaves are the typical fingered leaves everybody knows, all of the leaves up to this point should be bright green, if not, it’s a sign that something is wrong, to help you diagnose what you may have, here are the most common cannabis problems.

2. Overwatering

Overwatering is one of the most common cannabis seedling problem amongst growers, even though weed plants need water to grow, they also need oxygen to properly develop, and when overwatering, you may end up drowning your plants because of the lack of oxygen. What about plants grown in hydroponics? Well, in hydroponic setups, about ⅓ of the roots are kept out of the water, this way they can breathe at the same time that they absorb water so even though the roots are in the water, they still get the oxygen they need.

When your plants don’t get the amount of oxygen they need, the leaves will start getting droopy and if you don’t treat it for long, the leaves will start to get yellow. If you are seeing any of these symptoms, it’s most likely the problem is being caused by any poor drainage or watering too often.

How to fix it

  • Don’t leave plants sitting in runoff water.
  • Get better containers such as Smart pots or Air pots.
  • Mix perlite into the soil to increase drainage and oxygenation.
  • Make drainage holes on the bottom of the container to allow water to drain.

3. Underwatering

Just like overwatering, underwatering is very common, especially among new growers who want to prevent overwatering and it can be quite confusing because the symptoms are basically the same as when overwatering.

It’s essential you ensure your plants have access to water at all times, the roots should be kept moist always because plants are constantly losing water through the process of transpiration and they need to be able to replenish the water in the leaves. When there’s not enough water, cannabis plants stop performing their basic processes and dry out, eventually killing them so even though you should be careful when watering, you should definitely keep your plants watered to avoid seedling problems.

How to fix it

  • Ensure the top part of the soil is always moist.
  • Mix soil with coco fiber or vermiculite to improve water retention.

4. Nutrient Problems

Just like the symptoms of overwatering or underwatering, plants that suffer from a nutrient excess (overfeeding) will start to get yellow leaves or yellow spots, burnt tips, or show slower growth. Seedling problems related to nutrients are usually caused by giving nutrients too soon, giving too many nutrients at once, or “hot” super soil or pre-amended soils. Giving too many nutrients at a time can cause problems overnight, so we recommend watering your seedling with plain water and taking a look at the following table so you prevent any seedling problems related to nutrients.

The ideal water for seedlings
Medium pH PPM
Soil 6.0-7.0 100-250
Coco, clay pellets, and hydro 5.5-6.2 300-400

Have in mind that these are estimates and you should check every day for problems and lower or increase these numbers if you see signs of deficiencies. Giving nutrients too soon will overload the soil, and consequently, your seedling so remember that you shouldn’t feed for the first couple of weeks or at least give a low nutrient dose.

See also  Dutch Cannabis Seeds

This can also happen with organic super soil, even though it’s organic, you need to wait until your super soil isn’t “hot” anymore, “hot” soil means that the mix is still undergoing biological activities so you will have to wait around 30-45 days before you can use it, although this is not the case with all super soils so make sure you get more information on the product you’re using to avoid seedling problems.

How to fix it

  • Ensure you adjust the nutrient dose according to the medium you’re growing in.
  • Wait at least 10 days before you start feeding your plants.
  • Read the instructions on the products you’re using.

5. Excessive Heat

Excessive heat can also affect your plants, which will end up showing signs of heat stress, you will see the edges of the leaves turning up like tacos and they will start to get dry and crispy, and in more extreme cases, the leaves will start showing a yellowish-green color.

This can be caused by elevated temperatures, low humidity, or even the fans being too strong, but luckily, this can be easily spotted before your plants start showing the symptoms because you will see the soil is dry and sometimes it will start to crack.

How to fix it

  • Make sure the temperature and humidity are at the right levels.
  • Place your hand under the light fixture, if it’s too hot for you, it definitely is for your plants.
  • Ensure your fans are not too strong for the stage your plants are in.

6. Too Much (or Too Little) Light

Another common problem among new growers is not providing enough or providing too much light in the seedling stage, if your seedlings are not getting enough light, they will start stretching and the stem will get super long, which is a bad thing because they can easily snap and there’s no way to fix it.

Now, when your seedlings are getting too much light, or the lights are too close to them, the seedling will get dehydrated and the leaves will get burnt, showing symptoms like burned and wrinkled leaves.

How to fix it

  • Adjust the light fixture’s distance from the seedling every day, try to find the sweet spot.
  • Use CFLs instead of potent LEDs or HPS to avoid this kind of problem.

7. Seed Shell Stuck on Seedling

Sometimes, when a seedling comes out of the substrate you’ll see how the seed shell is stuck on the seedling and won’t come off naturally. When this happens, your seedling won’t be able to develop properly and you’ll probably see a lot of stretching, and if left for too long, the seedling can end up dying. This happens because of the humidity levels, so in order to minimize the damage, there are a couple of things you can do.

How to Fix It

As mentioned, this happens because of humidity levels, low humidity levels to be precise, so what you need to do is hydrate the seed shell. So go ahead and spray the seedling with plain water or just drop one or two droplets of water on the seed shell, this will hydrate it enough for the seed shell to fall off. Keep in mind that sometimes the seed shell falls off but a membrane covering the cotyledons can remain stuck and your seedling will not be able to open so make sure to grab some tweezers or remove the membrane with your fingers but do it very, very carefully.

If you need to do it asap and don’t want to wait for the seed shell to fall, you can remove it by hand without spraying it but keep in mind that if the seedling’s roots have not grown enough, you can end up removing the seedling from the soil so do not use excessive force. It’s highly recommended to hydrate the seed before just to avoid shock or stress, especially to avoid removing the seedling from the substrate completely.

  • Make sure to keep the humidity levels in range with the help of a humidifier.
  • Place a plastic dome (like a cut-out plastic bottle or plastic cup) on top of the seedling to help keep higher humidity levels.

8. What To Have in Mind During The Cannabis Seedling Stage

In order to avoid all the cannabis problems mentioned throughout the article, here are the main tips that will help you avoid them and keep your cannabis seedlings healthy and happy.

The Perfect Environment

The relative humidity and temperature will directly affect how your seedling grows so make sure the light is not too strong but your cannabis is still getting enough light and the temperature is around 21-23 ºC and the relative humidity ranges from 70-80%. Failing to provide good conditions can affect plant growth and can ultimately kill your plants if left untreated for too long, so here’s what to expect in the different conditions:

Substrate is too wet

If the substrate is too wet, the seeds can drown. Despite seeds being germinated in water, it’s not okay for the substrate to be extremely wet so always make sure the substrate is moist but not soaking.

Substrate is too dry

Cannabis seeds need moisture to germinate so make sure the substrate is moist but not excessively wet as excessive dryness can make your seeds not germinate and die.

Watering Properly

Watering cannabis seedlings properly is the hardest part for beginner growers, watering too much can result in an overwatered cannabis plant, and watering too little can result in an underwatered weed plant so make sure you start watering with around 100 ml and increase the amount according to how your plants grow.

Seeds were planted too deep

1 – 3 cm is the deepest you should go in order to provide support to the roots and cover the seeds with the substrate. If you plant the seeds too deep the seedling could have a hard time sprouting out of the substrate so do not plant it too deeply.

Environment is not warm enough

Seedlings prefer warmer temperatures ranging from 22 -26 celsius and will grow at a slower rate in colder temperatures.

Environment is too humid

It’s recommended to use a plastic dome for newly born seedlings but remember to remove them as soon as the seedling starts developing the first pair of one-fingered leaves after the cotyledons as a high humidity can cause damping off, which results in seedlings folding over and dying.

Light Intensity

Marijuana light burn can indeed hurt your plants if the light is too strong. Seedlings are more fragile than adult weed plants so make sure you dim down the light or adjust the fixture’s light to avoid stressing them. Also, if your seedlings are stretching a lot it means they need more light so, if this happens, increase light intensity or place the light fixture closer.

9. FAQs About Cannabis Seedling problems

Here are the most frequently asked questions about cannabis seedling problems to help you understand a bit more and help you deal with them. Just remember that different problems may have similar symptoms so make sure you are 100% sure about what the problem is before taking drastic measures.

“Why are my seedling’s leaves turning yellow? Could it be a cannabis nutrient deficiency?”

When the leaves start yellowing it’s probably a sign of nutrient problems, this means they’re either lacking nutrients, are getting too many nutrients or getting the wrong type of nutrients.

“When should I remove the plastic dome of the seedlings?”

The plastic dome helps raise humidity for faster germination so you can remove it as soon as your plant has completely developed a pair of leaves (after the cotyledons).

Remove the plastic dome once the seedling has developed the first pair of leaves after the cotyledons.

“Why are my cannabis seedling’s leaves curling down?”

This usually happens when you overwater your seedlings or when they’re exposed to higher temperatures so make sure the temperature ranges from 20 – 25 ºC and pay attention to how much water you’re watering with.

“When is it safe to put my cannabis seedlings under the light?”

Well, your seedling needs to be under light since germination but you can use a 15-20 W fluorescent light during the first 1-2 weeks and once the first pair of true leaves have completely developed, you can go ahead and place it under the LED or MH bulb.

“Is there a better light schedule for marijuana seedlings?”

The best light cycle for both autoflowering and photoperiod cannabis seedlings would be 18/6 from seed.

“Is the substrate super important for seedlings?”

Of course, the substrate mix is super important for a healthy start. Some growers prefer a “light mix” which can provide nutrients for the initial weeks and others make their own blends with perlite and coco fiber. There’s no best substrate but a substrate mix that allows for good oxygenation and water retention is ideal.

“Why are my marijuana seedlings growing so slow?”

This is the hardest question because it can be caused by several things. Your cannabis seedlings may be lacking nutrients or it could be caused by lack of proper lighting and extreme temperatures or humidity.”

“How far should the grow light be from the cannabis seedling?”

If you’re using a CFL light, the lights should be 5 – 10 cm from the seedlings. If you’re using HPS or MH, the light should be around 25 – 40 cm from the seedlings and if you’re using LEDs, the fixture should be at around 75 cm from the seedling with 40% light intensity if possible.

“How long does it take for the seeds to germinate and the seedling to come out of the soil?”

The germination process is usually quite fast but depending on the quality of the seeds, it may take up to 5 days or even more. Once the seeds have germinated and been planted in the pot, the seedling should take around 3 days to come out of the soil if the growing conditions are proper.

“Is it possible to know my plant’s sex during the seedling stage?”

No, you’ll only be able to tell whether your marijuana plant is a male or female during the pre-flowering stage. This happens because cannabis plants need to sexually mature in order to show either male pollen sacs or female stigmas.

See also  Cannabis Ruderalis Seeds

10. In conclusion

Marijuana seedlings are super fragile and sensitive so you should take good care of them, avoiding cannabis growing problems at this stage is vital because even though your baby plants may recover, the size and structure may be affected, which will end up affecting your harvest.

If you have tips you can share with fellow growers to help them take care of their baby plants, feel free to leave a comment in the comment section below!

Cannabis Germination Troubleshooting

Here we offer numerous tips on avoiding issues during the germination and seedling phases of your cannabis grow. If your seeds aren’t sprouting, or your seedlings are struggling to grow, you’re likely to find the reason for your problem, and its solution, in this guide!

Before you can start tending to your crop of weed plants, you have to get those sprouts out of the ground first! Germinating cannabis seeds can be quite a fiddly process, as can looking after the newly hatched weed seedlings. Find out the common issues cannabis growers face during the germination and seedling stages, and their solutions.

Common cannabis germination issues

Throughout the whole cultivation process, but especially in the earliest stages, careful and exact practice will make success much more likely. Seeds and seedlings are vulnerable and can die or become stunted easily, or even fail to germinate at all.

Below, we’ll break down each potential issue you could experience during these early stages of your grow, and what you can do to remedy the situation.

Cannabis seeds not germinating (day 0)

If your seeds aren’t germinating at all, it could be for one of the following reasons.

Poor-quality seeds

Maybe you found some seeds in a bag of weed and thought you might try growing them, or perhaps you bought them super cheap somewhere. It could even be that you got seeds from a great breeder, but they’re just duds. In any case, poor-quality seeds have a much lower chance of germinating or producing viable plants.

Solution:

Get some good seeds! This needn’t be too hard. Genuinely good-quality breeders perform rigorous germination rate and quality tests, meaning the vast majority of them should be healthy and capable of sprouting. Of course, there will always be exceptions, but buying from a good breeder or seed bank will greatly increase the chances of successful germination.

Click here to browse countless varieties of regular, feminized, and autoflowering cannabis seeds from the best banks in the world.

Handling seeds with bare hands

Hands can carry all sorts of pathogens, such as bacteria and fungal spores, that can contaminate seeds and seedlings. At this young stage, they are very susceptible to infection, so avoiding direct touch is best!

Solution:

Be hygienic! If you want to be properly sterile, wear latex gloves or use sterilised tweezers to handle your cannabis seeds. If you don’t want to do this, then at least thoroughly wash your hands prior to handling your weed seeds or seedlings.

Water quality

Depending on where you live, tap water could be full of compounds that will inhibit your seeds from germinating. Chemicals such as chlorine can be very harmful to seeds and young cannabis plants. Later in a plant’s life, tap water is a much safer bet—although it’s worth figuring out its mineral content so you can feed properly.

Solution:

Use purified or bottled water. It might seem indulgent, but they’re only young, and this is a crucial stage in their little lives, so give them what they need, and they’ll reward you later on!

Seeds not buried deep enough

If seeds aren’t buried deep enough, they won’t have enough moisture, and can dry out. Moisture is what triggers the sprout to break through the seed shell, so this is really crucial.

Solution:

Generally, it’s recommended to germinate seeds around a knuckle (0.5–1cm) deep in the soil. This is the optimum depth for them. On top of this, germinating in propagation chambers will maintain a high and correct humidity range (around 70% RH or more), increasing the moisture content and likelihood of germination.

Propagator Pro 2

Low temperatures

In nature, cannabis seeds sprout in spring, as the temperatures warm up. So if they think it’s too cold, they won’t germinate. Moreover, certain pathogens thrive in cool temperatures, so even if they do germinate, they may not fare as well.

Solution:

Keep them warm! If growing indoors, this shouldn’t be too hard. A propagation chamber situated in a comfortably warm room should do the job. Even if you intend to grow outside, you can still germinate indoors to give your marijuana seeds the best start and keep them safe from sudden cold snaps. If you want to carry out the whole process outdoors, you’ll have to hang on until you’re certain of mild nights and warmer days, otherwise you seriously risk unfortunate results.

Soil packed too tight

Tightly packing the soil over your seeds, or just burying them too deep, can be a real issue. First, a freshly “popped” seed is (unsurprisingly) not the strongest being on the planet. In fact, it’s incredible how strong new shoots actually are. But bury them too deep, and they will not have the strength to push above the earth. Moreover, they could suffer from oxygen deprivation if the soil is too compacted or they’re buried too deep, and this will stunt development entirely.

Solution:

As mentioned, bury them only a knuckle deep in the soil, and lightly brush a covering back over them and pack it down with only the lightest touch. There’s no need for the soil covering to be compact.

Underwatering

Like we said, seeds need moisture to trigger germination. If you haven’t supplied enough water, they won’t sprout.

Solution:

You don’t need to soak the soil by any means, but you want it pretty damp. If growing in a propagation chamber, you may consider misting the inside with water to promote moisture and high humidity.