Top 5 Germination Mistakes To Avoid When Growing Weed
Germinating cannabis seeds is necessary in order to sprout seedlings that develop into mature, healthy cannabis plants. However, complications with light, humidity, heat, and more could result in cannabis seeds failing to sprout. Find out what to avoid to ensure successful germination.
Germination is where the magic begins. Cannabis seeds must first germinate in order to sprout and begin their journey as living, breathing plants. However, if the germination process is done incorrectly, or is thwarted by some other variable, seeds can fail to sprout, leaving you with useless, spent seeds instead. Here are the top five mistakes to avoid when germinating cannabis seeds.
GERMINATING BAD SEEDS
One of the most common reasons seeds fail to germinate is because they are simply duds. Typically, healthy cannabis seeds should look a specific way and be of a specific colour. Viable seeds will appear round, not flat, and should be a beige to dark brown colour with subtle tiger striping. Seeds that have been flattened or are pale in colour may have a tough time sprouting into healthy cannabis plants.
Seeds that have been improperly stored may also fail to germinate. These tiny packages of DNA prefer to be kept in a cool, dark place with moderate humidity. Exposing them to heat, light, or extreme humidity levels (both high and low) could result in seeds losing their viability. As long as you source your seeds from reputable seedbanks and store them appropriately, you shouldn’t have to worry about bad seeds ruining your chances of successful germination.
TOO MUCH LIGHT
Generally speaking, seeds require a dark environment in order to germinate. After all, in nature cannabis seeds find their home in the dark embrace of soil. It can be hard to determine exactly how much light is too much for your seeds; however, err on the side of caution and germinate out of direct light. There’s no need to use your grow lights until after germination has occurred.
It is also likely that the quality of your seeds will affect their ability to handle direct light. Seeds that are already having a tough time germinating will have an even worse time doing so if they are exposed to excess light.
TOO MUCH OR NOT ENOUGH WATER
The amount of water you supply your seeds during the germination process will also affect their ability to successfully germinate. Some growers attempt to germinate by “drowning” them in a glass of water. While this ensures they will not go thirsty, it can actually be more harmful than helpful.
Once they pop, seedlings are very delicate and must be watered carefully. When germinating, your medium should be damp, but not overly wet for best results. On the other hand, a dry environment is basically a death sentence for your seeds. They need a constant source of moisture to sprout, otherwise they’re good as duds.
Cannabis seeds require a specific temperature range in order to germinate. Regardless of the germination medium you are using (soil, paper towels, etc.), the temperature in the environment should consistently sit in the 26–28℃ range. Seeds need to be kept warm during the germination process. At no point during germination should seeds be exposed to temperatures below 20℃.
There are some techniques that can be used to ensure your seedlings remain in this temperature range. Some growers choose to use special warming mats that can be set to a specific temperature and placed underneath the seedling containers. Another strategy is to place a timed heater close to your seedlings to warm them up occasionally. Once your seeds have sprouted, they will be much more resilient to fluctuations in temperature.
GERMINATING IN SOIL
Many people choose to germinate their seeds using paper towels. However, others choose to do so directly in soil. Of course, germinating your seeds in soil isn’t inherently bad, but it can come with its own set of challenges, and is generally not recommended unless necessary.
For instance, the upper layer of soil can dry out within 48 hours, making it more difficult to give your seeds the right amount of water they need without overdoing it. Giving your soil too much water during germination could result in the seed rising up or dropping down further, inhibiting its viability. Moreover, seeds that are planted too deep in the soil could experience a host of complications. They could suffocate before coming into contact with enough oxygen, and be unable to access sufficient light to progress into the seedling stage of their life cycle.
Seeds may also be unable to germinate if the soil they are planted in contains contaminants. Mould and pests can easily kill a mature, healthy weed plant within just a matter of weeks. It should come as no surprise then that they could also prevent a small seed from germinating. If your soil contains traces of these contaminants, it is possible that your seed will never actually open and sprout. This also applies to fertilisers. Even small amounts of fertiliser in your soil can effectively kill your seed, making it completely useless.
Floating Seeds in Water – Is This a Good Seed Viability Test?
How do you know if your seeds are still viable? Simple, do a seed germination test. Place the seeds in some water. The ones that sink are still viable – the ones that float are dead.
This advice is all over the internet so it must work? But how reliable is it?
Floating Seeds in Water – Is this a Good Seed Viability Test?; source: Pens & Pencils
Do the Floating Seed Test Properly
If you check out a number of sites that describe this test you soon realize that there are several different ways to do it. Some people add soap to the water to reduce it’s surface tension. Others put the seed in a jar and give it a good shake or they might soak the seed for 24 hours before doing the test.
There is no agreement on how to do the test properly. That means the test results reported on social media are not very reliable since they rarely include the details of the method used.
There are also silly claims like “this method is not 100% accurate and it only works with freshly harvested seeds of certain fruits such as melon, watermelon, cucumber, squash, peppers and tomatoes”. There are thousands of different types of seeds. Why would it only work on some vegetables and what does “not 100% reliable” mean? Maybe it only works 10% of the time?
Another site says, “the test only works for melons or cucumbers if the seeds are fresh and have not dried out.” So it doesn’t work on purchased seed. This same site went on to state that you need to ferment tomato seeds to get them to germinate, and I have already shown that this is a myth.
This gardening technique is so poorly defined that it is not possible to know how to do it correctly.
Citizen Scientists – Floating Seed Test for Viability
A number of gardeners have done tests to see how well the floating seed test works.
Pulsatilla albana ssp. armena – the Pulsatilla ‘seeds’ are actually fruits – achenes with “fluffy tails”, source: BotanyCA
I had some red pepper seeds from a store bought fruit and tried floating the seeds without drying them. Half floated and half sank. I removed the floaters and used them to try the test again. Half floated and half sank. I then tested this last group of seeds for germination. The ones that floated and then sank had 8/10 germinate, and the ones that floated twice had 3/10 germinate. So it is possible that floaters have a lower germination rate, but the floaters in this test were certainly not all dead.
I tested some Camassia seeds; 38 of 48 (79%) sinkers germinated and 12 of 16 (75%) floaters germinated, after a month in the fridge using the baggy method.
Someone from our Garden Fundamental Facebook Group tested Briza maxima (quaking grass) and found better germination with floaters.
Marijuana seed that floats will germinate on top of the water in 24 hours.
Twelve different kinds of pepper seeds were tested in this video and both floaters and sinkers had good germination.
I’ve germinated quite a few clematis seeds and most of them have fussy tails. They all float. Many seeds have this characteristic including some grasses and pulsatilla.
Both floating and sinking peppers seeds germinate, source: Daisy Dawes
The top picture in this post shows two jars. The one on the left contains black pepper seeds – they sink. You can distinguish them from papaya seeds that float, and are frequently added to spices since they look like black pepper but are much cheaper.
Science on Seed Viability Using the Water Float Test
Acorns have very low germination because many seeds don’t develop completely inside the nut and because various pests lay their egg in viable seeds which are subsequently eaten by the larvae. Floating them is a common way to eliminate many of the non-viable seeds. Even with this test, too much agitation of the water will cause viable seed to float.
Juniperus polycarpos, the Persian juniper, also produces a low number of viable seeds. Floating in water is not a reliable means of separating the good from the bad, but floating in a sugar solution does work. Sugar water has a higher density than water and this difference can be used separate seeds of various densities. The heavier viable seed sinks.
The float test “works well with hard-seeded peas in the family Fabaceae (e.g. Daviesia, Chorizema, Gastrolobium and Gompholobium) and Mimosaceae (e.g. Acacia), and has also been used on species in Hemigenia with good success. Do not attempt this test on seed of Allocasuarina. Allocasuarina seed is mucilaginous. This means it has a mucous membrane around the seed that gets very sticky on wetting.”
Arabidopsis seed forms a sticky mucilage on the outside of the seed as it absorbs water. Mutations of arabidopsis have been found that don’t produce this coating, allowing them to be separated from normal types with a float test. This is an example where within a single species, some seed floats and some does not, depending on genetics that has nothing to do with seed viability.
Arabidopsis wild seed (WT) sinks while a mutation (mum) floats. The floaters germinate in 24 hours siting on the water, source Helen M North
“Wheat was used in one set of experiments, and the average of all tests showed a germination of 68.3 per cent for the sunken seeds and 72 per cent for those that floated. In another set of experiments lentil was used, and it was found that 75.4 per cent of the sunken seeds and 86.7 per cent of those that floated germinated.”
The floating characteristic of seeds depends very much on their weight, surface coating, shape and specific gravity. Some seeds do develop a large seed coat which can be empty and these likely float. The specific gravity of a seed is controlled by the environment (moisture) and internal enzymes and hormones. Some dead seeds sink, while some spongy seeds like spinach float even if viable.
Does The Seed Float Test Work for Testing Viability?
There are cases where a float test can be used to identify viable seed, but when science reports on these they are quite specific about the type of seed and the method used.
On the other hand gardeners tend to simply lump all seeds into one category and say they all work, without specifying the method that works.
As a general rule, gardeners should assume that the float test does NOT work for testing seed viability, unless there is evidence it works in a specific case.
A Better Way to Test Seed Viability
Use my baggy method if you want to test seed germination. You will actually see the root come out of the seed and know for certain that the seed is viable.
Germination Troubleshooting Guide
Our reputation as a reliable seed company is based on constant and strictest quality control by our breeders. From production to packaging we scrutinize the quality of every seed and select by hand. Our selection is so strict that we also dismiss perfectly healthy seeds simply because of a smaller size or unusual shape.
All our seeds are pre-tested. and we mean ALL seeds from all strains. Every single seeded mother plant has been tested for perfect germination prior to sale. This ensures that there are no "bad batches".
We are specialized in quality and not quantity. All seeds are fresh seed stock (3-12 months) and sales turnover is quick among distributors and resellers. There is never any old seed stock on the market regardless of where or when a customer buys our strains.
Poor germination results can only be the result of negative outside influences after purchasing the seeds and are beyond our control. This does not necessarily mean that the grower is at "fault". Even the most experienced grower can run into unforeseen problems such as fungus infected soil, a technical malfunction on an EC meter, etc. Often growers buy the wrong soil because it is recommended by the manufacturer or retail store (consult our Soil Guide for more info).
In some rare cases frost during delivery can damage seeds. If your seeds are subjected to freezing temperatures (such as lying outside in a mail box) you should dethaw them slowly. Put them in the refrigerator a couple of hours for this purpose.
In addition to the germination rates we also control other important factors of quality such as a high level of healthy seedlings. Seedlings should not appear crippled, feeble, tiny, with dehydrated leaf tips, etc. However, this is a biological product and despite the best production methods a minor % of seedlings (calculations based on 100+ seeds) may not appear healthy and need to be removed. It is therefore always best to germinate an extra seed or two as a back-up, especially if you are only growing a few plants.
We work with distributors who enjoy the best reputation in the industry for professional storage and service. Our resellers are supplied by us directly or through our distributors. Although we make an effort to identify any black sheep in the cannabis seeds market it is impossible for us to monitor resellers all the time.
Customers should make sure that they receive their seeds in the original Mandala Seeds packaging to prevent fraud. We cannot guarantee authentiticy for seeds that have been removed from the sealed Mandala packaging. When you purchase our seeds from a reseller you should receive 1st class seeds: mature, healthy colouring, with well-defined mottled skin. If you get seeds that are tiny, greenish/yellow, scuffed, or immature, these are not original Mandala Seeds!
We are not responsible for the sales and services offered by resellers. However, if you have any serious suspicion or complaint regarding your purchase please contact us with a copy of your order transaction and reseller details.
A very small percentage of plants turn out to be triploids (ie. have three sets of leaves) among thousands of specimens. This does not impair plant health and is a feature unique to cannabis as a plant species (ie. not restricted to our genetics). For more info on triploids please see our FAQ. Also very rare, but not a reason for concern, are twins. These appear when there are two embryos in one seed. If both seedlings are the same size you should separate them quickly before roots get entangled and then you have two plants for the price of one! If one seedling appears inferior just remove it. If a seedling has fused cotyledon leaves or a young plant has fused leaf tips on a leaf this is nothing to worry about and it has absolutely no impact on growth or flowering. Nature is always trying out new combinations and that cannot be prevented in selective breeding.
Please read our Germination Instructions before germinating your Mandala seeds. Due to the high quality and fresh stock of our seeds we advise against soaking the seeds in water or germinating in paper tissue. Germination results will vary when pre-soaking seeds. Fresh seed stock can germinate under these conditions, but not always. Most often, only pre-germinating in moist paper tissue works for fresh seeds. But this is also not full-proof and should only be done if you have enough seeds to spare.
This does not mean that pre-soaking should never be used with seeds from other sources, or that we criticize growers who prefer this method. We are aware that some breeders recommend it for their products. But to prevent complications and achieve the consistent level of high germination rates that you should be getting from your Mandala seeds please trust our advice and follow our guidelines.
Please take note that customers who soak their Mandala seeds in water or wet paper tissue do so at their own risk. We are not accountable for any failure in germination or complications caused by this method.
Seeds did not germinate
The first step is to look at what happened to the seeds.
There are 3 possibilities:
a) the seeds all look the same like when you planted them (intact, healthy colour).
b) some or all seeds are intact, but have noticeably changed colour and are darker; some may also have a whitish substance coating the rounded end, or the embryo inside has turned soft or slushy.
c) some or all of the seeds cracked open and the taproot appeared – but there was no further growth.
Possible causes for:
a) Healthy & intact seeds don't germinate if the substrate is too dry. This could mean that it was too dry from the start, or that the substrate dried out before the seed could absorb enough moisture to trigger germination. Open some of the seeds to check the embryo. If it is healthy, white and firm then the seeds required more water to germinate.
Second probability is that the seeds are damaged from frost.
b) Dark seeds indicate fungal attack. A whitish substance is visible fungal mycelia. Fungus spreads under cold, wet, & anaerobic conditions. Several combinations of factors can lead to seeds rotting: poor soil quality (infected, bad pH, or high EC), pre-soaking seeds in water, substrate is too wet, substrate is in a cold environment, and/or excessive high humidity caused fungal growth in substrate (due to humidity dome/propagator, pots covered with plastic, poor ventilation).
Open some of the seeds to check the embryo. In rotted seeds the embryo is soft, yellowish, or almost like liquid (slushy).
A #1 seed killer is a closed humidity dome/mini-greenhouse.
Humidity domes are only required for rooting cuttings.
Many growers make the mistake of thinking that they need a high ambient humidity for germination or seedlings. The high humidity and lack of fresh ventilation quickly causes fungus in the soil or growing medium and the seeds rot!
Cannabis is not a swamp plant! The seeds need a well aerated growing medium to germinate well. Seedlings also cannot tolerate high humidity and can easily be attacked by fungus such as fusarium and pythium. Only the soil or growing medium should be moist for optimal germination and seedling growth. Ambient humidity is best below 50%.
You can use a humidity dome/mini-greenhouse as a tray for germination but you must keep the lid half-way open or completely seperate to ensure fresh air exchange and humidity levels below 50%.
c) This can happen for the same reasons as in b). But there can also be other factors involved. If a heating mat was used the substrate may have been heated up too much. In rockwool a high EC can kill the emerging seedling. Check the EC of your substrate and make sure your EC meter is functioning correctly. A sudden dry spell in the substrate is also lethal at this stage.
Also check your water quality. In some areas municipal water is extremely low quality. It can have an excessively high salt level and can be contaminated with minerals/heavy metals which stunt plant growth. High levels of chlorine and fluor are dangerous. You can smell chlorine – let it evaporate before use by filling a bucket with hot water. If you are in doubt about your tap water buy bottled mineral water (without gas). The pH should be adjusted to 6.5 for soil and pH 5.6-5.8 for rockwool..
Watering with organic teas or various other products is definitively counterproductive. During germination and seedling stage you should use pure pH adjusted water.
Jiffy's, peat pellets, and other types of starter plugs with an alkaline pH inhibit germination in cannabis seeds. Some substrates such as coco coir may also be pre-fertilized and have a high EC (salt) level Untreated coco coir contains toxic levels of sodium and chloride. Or they could have been treated with fungicides and pesticides. If you have used a particular product with poor results you should stop using it and switch to rockwool or soil.
Things to avoid
- soaking seeds in water/wet paper tissue
- mini-greenhouse with cover
- heating mat too hot
- covering pots with plastic
- germinating in jiffy's and peat pellets
- wrong soil for germination
- fertilizing seedlings
- too much/too little water
- cold and dark germination room
- wrong pH of water
- bad water quality
- high EC of nutrient solution in hydroponics
- spraying seedlings with water/organic teas/pesticides
Some or all seedlings grow weak and tall
The major cause is lack of light. The seedlings are stretching in search of light. This leads to elongated and weak growth. Give your seedlings as much light as possible. Move them closer to the lamp. Put them under an HPS lamp if available. If you are growing near a window move the plants to the sunniest spot or supplement grow time with a lamp. Outdoors you should also provide as much light as possible. Support the seedlings with a stick or looped wire while they regain strength. As soon as they have sufficient light they will grow vigorously.
Some or all seedlings fell over and died
This is usually caused by a fungal disease called "damping off". The cause is infected soil, waterlogged substrate, high humidity. any conditions that promote fungus. The fungus attacks the soft tissue in the stem which withers at the base or midway. The seedling collapses and dies. Another possible cause is that the seedlings died from lack of water or a high salt level in the substrate (which basically has the same effect of drying out the plant). Seedlings have only a small amount of roots and few leaves. They cannot retain much water and quickly dry out. High humidity in the grow space does not compensate for a desiccated substrate. Your soil/rockwool has to be moist enough to sustain healthy roots and provide water to the plant. Photo shows “damping off”.
Outdoor frost can kill seedlings overnight. Keep your seedlings indoor until there is no danger of sudden frost. See our GERMINATION GUIDE for great product tips on how to keep your seedlings warm outdoor or in the greenhouse.
Seedlings cannot open their first set of leaves
Sometimes the seed hull and the inside skin is still attached to or enclosing the leaves. This happens if the seed was not planted deeply enough. Usually the seed hull is detached as the seedling emerges through the substrate. Spray the seed hull with mineral water and wait 1/2 hour for the moisture to soften the dry skin and soil residues. Then gently and slowly pull it off from the leaves. If it does not move easily spray more water. It is very important to remove it carefully because if you tear off the leaves the seedling dies.
We hope that this guide has been helpful in detecting the probable cause for any problems that you have encountered. The next step would be to run a test under improved conditions. For this purpose it is best to germinate just a few seeds as a trial. If everything goes well you see the results within 7+ days and can germinate the remaining seeds with confidence. A novice grower will also find this helpful advice before losing all of the purchased seeds on a set-up that requires modification!
If you are new to cannabis growing it is not advisable to start with hydroponics. Don't make your first cultivation experience unnecessarily complicated! In hydroponics you have to constantly monitor EC and pH, choose the correct nutrient formulas and feeding schedule, clean and flush your system, invest in expensive equipment, etc. If you are insecure about germinating and growing in rockwool or other hydroponic substrates, switch to soil or start with a small test group to gain experience.
Especially with our genetics you will find growing on soil very easy and rewarding. It is highly probable that any benefits you may be expecting from hydroponics, such as a higher yield, will be much simpler and securer to achieve with a straightforward soil cultivation!
Choosing the correct soil for germination and seedlings should not be difficult. However, some growers feel overwhelmed and insecure by the seemingly endless jungle of products, whilst others may live in countries with a very small and unsatisfying range of products. Please refer to our SOIL GUIDE for tips and recommendations.
What you need to know about growing in soil, how to buy the best soil product, organic additives, etc.
Quick, easy, effective. the most important gardening tips & tools explained in simple language.
Essential reading before you germinate your Mandala seeds! Please read our advice carefully.