The complete guide to germinating cannabis seeds
Before you can be met with bountiful hauls of dank buds, there are several stages of cannabis growing that take precedence. Unless you can successfully germinate cannabis seeds, you won’t have a plant to harvest. Give your seeds the best possible start in life by reading our definitive guide to germination.
THE ART OF GERMINATING CANNABIS SEEDS
Often overlooked, it is all too easy to assume that the vegetative and flowering stages of cannabis growth are the most critical parts of the plant’s life cycle. However, with the chance of failure high unless you know what you’re doing, poor planning when it comes to germination can make or break your next grow. Giving your cannabis seeds the best possible start on their journey to bulging buds is a surefire way to encourage a healthy and robust plant.
Small, fragile, and in desperate need of a helping hand, there are several ways you can germinate your cannabis seeds. All methods have varying degrees of success, with both advantages and disadvantages. It is important to note that even with advanced growing expertise and top-of-the-line equipment, you may still end up with a few failed seeds. This is a natural part of dealing with a living organism. At Royal Queen seeds, we only sell feminized cannabis seeds, so there is no need to worry about removing male plants.
WHAT TO LOOK OUT FOR IN CANNABIS SEEDS
Regardless of where you get your seeds from, it is best to give them a slight (and delicate) inspection before planting. Most of the time, all seeds will germinate; however, poor-quality seeds will produce a weaker plant. Unfortunately, that is something you will not find out until well into the vegetative and flowering stages.
To avoid disappointment, seeds that have a darker colouration stand a better chance of germinating, while pale green or white seeds are likely to fail. Even if dark seeds look slightly damaged, they should be planted anyway. There is a good chance they will still germinate, even if the outer shell is somewhat crushed.
GERMINATION TEMPERATURE PLAYS A CRUCIAL ROLE
Before we jump straight into the germination methods, there are a couple of germination golden rules. For the best results, we recommend staying within these guidelines, no matter how you choose to germinate. That being said, of all the factors to consider, temperature is one of the most critical. Seeds will always seek out even the smallest amount of moisture, but they use temperature as a sign that they need to do so.
• The ideal temperature is between 22° and 25°C (71–77°F)
• Your growing environment should be damp/moist, but never wet
• Relative humidity range should be between 70% and 90%
• Seeds favour fluorescent lighting (Cool White code 33)
• Minimise the amount of seed handling you do
• In hydroponic/rockwool plugs, the ideal PH value is 5.8–6.2
WHAT IS AN EXPECTED GERMINATION TIME?
Three fundamental principles will trigger that first small taproot to appear: warmth, moisture, and darkness. With the promise of moisture, a single root will take shape before slowly developing into the cannabis plant we know and love. In the right conditions, seeds will begin to develop within 12–36 hours of moisture being introduced to them.
Timescales can vary, as it all depends on how ideal your germination environment is (see the golden rules above). Even the worst grower could make a seed germinate, but it may take a few weeks and, of course, increases the risk of a weaker plant.
CHOOSING YOUR GERMINATION METHOD
GLASS OF WATER APPROACH
Arguably one of the least effective methods, but it is still viable. Incredibly simple to facilitate, beginner growers may opt to germinate their seeds in a glass of water. Half-fill a glass or bowl with water that is approximately 22°C (71°F).
After 3–5 days, the seeds will start to open, and you should see tiny white tips appear. Once these roots reach 2–3mm in length, use extreme care to transfer them from the water to pre-prepared soil pots.
The soil pots will need small holes (roughly 10–15mm deep) for the newly germinated seeds to be placed into. Once the seeds are secure, you will want to place a fluorescent light 13–15cm (5–6 inches) away to encourage growth. Finally, don’t risk overwatering your seeds at this early stage. Use a plant mister to make sure they stay damp but not soaking wet.
WET KITCHEN TOWEL METHOD
Probably one of the most common methods of germination. The kitchen towel method comes in several iterations. Some growers use cotton wool pads or absorbent pieces of paper. For this guide, we will be using kitchen towel as it is readily available and holds moisture relatively well.
Place one sheet of damp kitchen towel on a flat surface. Space your seeds a few centimetres apart before placing the second piece of kitchen towel over the top. You need to ensure both pieces are damp, not wet. Once again, when the white root tips reach 2–3mm, move the seeds (carefully) to soil pots. Use the same guidance found above for planting techniques.
PLANTING DIRECTLY INTO SOIL
Planting directly into your growing medium prevents having to move seeds when they are at their most fragile. That first root tip is covered with microscopic filaments that are easily damaged. Given that both a cup full of water and moist paper towels are more prone to temperature fluctuations from their environment, planting in soil is a much safer option.
Start by filling pots with a premium-quality soil that has been soaked in water. Many growers also choose to lace the water with a root stimulator. Make a hole roughly 10–15mm deep. This will be your seed’s new home. Remove the seeds from their packet and place them into the pre-dug holes. Loosely cover the seeds, but be careful not to compress the soil above the seed too much. The root will struggle to penetrate solid soil, slowing plant growth. Lightly spray the top of where you placed the seed so that your growing medium stays moist.
If you don’t like the idea of pre-soaking your soil, you can use a spray to moisten the holes before you plant each seed. With enough moisture surrounding your seeds, you can still encourage a root to develop.
Your growing pots will need to be placed in a damp climate that is within the temperature range listed under our golden rules. After 4–10 days, you should see a young seedling sprout, while the roots will have begun to develop underneath the soil. The entire plant and its soil can now be transferred to a larger pot, where normal growing routines should start.
USING STONE WOOL BLOCKS
Maintaining the ideal temperature (between 22–25°C/71–77°F) and moisture for germination is tricky. Leaving seeds out in the open environment or on a windowsill is far from ideal; a DIY climate-controlled cupboard would do a much better service. A warming mat is perfect for maintaining a constant temperature, but it doesn’t tackle the issue of moisture.
You will need to invest in a few pieces of unique equipment, but by using stone wool blocks, you can create a perfect utopia for germinating cannabis seeds. Soak the stone wool blocks in the same way you would a soil medium. The wool will retain the moisture and prevent the need to water during the early stages of germination. After the wool blocks are soaked, stick them in a plastic tray that also has a lid. Large cake tubs are ideal.
The dome of the plastic container will create your seeds’ own mini tropical climate. If you then place all the components in a temperature-controlled cupboard, you will have created a self-perpetuating supply of moisture—no need to touch the seeds again until they are ready to be transferred to your final growing medium as a young seedling. Using the stone wool block method, your seeds should germinate in one to two days.
Two or three weeks after germination, your young seedlings should be ready for their new home. At this point you have two options; transplanting them into soil pots, or taking on the challenge of hydroponics. You’ll know when the seedlings are ready to be moved because the root system should start to poke out of the bottom of the wool blocks. As long as the roots haven’t begun to engulf the bottom half of the wool block, they will seek out water and nutrients in their new surroundings and continue to grow downwards.
ROYAL QUEEN SEEDS FEMINIZED STARTER KIT
There is, of course, a far simpler way to germinate seeds. Ideal for beginners, the feminized starter kit by Royal Queen Seeds has everything you need to kick-start your next cannabis project.
The Royal Queen Seeds Feminized Starter Kit contains:
- 3x RQS Critical feminized seeds
- 20x Easy-Start seedling pots
- 1x Propagator Pro
- 1x pack of Bacto
- 1x perlite
- 1x fluorescent lights
- 1x instruction manual
- 4x AA batteries
- 1x Royal Queen Seeds catalogue
*You will also need a measuring cup and a stirrer (not included in the kit).
1. Gently remove the foil from the back of the seed packet and place them carefully into a dry container.
2. You will need a shallow container that is large enough to accommodate the seed tray. Fill the container with one litre of lukewarm water (22–25°C/71–77°F). Pour in the packet of Bacto enzyme, allowing it to dissolve before setting the seed tray into the container to soak. The seed tray only needs to be immersed for 5–10 seconds. Do not discard the Bacto mixture after the seed tray has been soaked.
3. After removing the seed tray from your shallow container, poke a 10–15mm deep hole into the soil of each pot, and delicately transfer your seeds from their dry container into each hole. Remember, one seed per pot.
4. Using the supplied propagator, sprinkle a 15mm-thick layer of perlite into the bottom of the tray.
5. Place your seed tray into the propagator, adjust the walls, and position the lid. The lid comes with an on/off switch for the already-attached lights.
6. Check the water level in your reservoir once a day. Your aim is to maintain an even level. After 1–7 days, the seeds should have sprouted, with visible leaves appearing. Once the seedling is 3mm tall, transfer it to your final growing medium.
IF IN DOUBT, THINK SPRINGTIME CONDITIONS
No matter which method you choose, always think about what conditions would naturally be like in spring. In their natural environment, cannabis seeds would start to sprout in-line with the seasonal change from winter to spring. Moisture is still high, and temperatures will be naturally rising. Always ask yourself the question, “Does my germination setup replicate spring conditions”. If the answer is yes, there is a good chance germination will be a success.
Time then to whip out our packages of seeds and get to work. But how do you best set to work, to get these tiny, fragile seeds to grow without problems into small plants?
5 Fatal Mistakes For Germinating Seeds
It’s a few weeks before spring, and gardeners everywhere are starting baby plants from seed. Germinating seeds isn’t usually a difficult process, and for most veggies, the process is quite simple.
For complete instructions for starting seeds, get the seed starting guide.
But what do you do if your seeds don’t germinate?
When seeds don’t sprout, you should always take time to evaluate what happened. So I thought it would be helpful to talk about the most common reasons you might have seed germination problems.
Some years our germination is a little patchy, and occasionally whole rows of seedlings will not germinate. It is important to keep up with our germination rate to evaluate our technique and seed health.
For us, a minimum acceptable germination rate is when at least 80% of our seeds sprout. But ideally, 100% of our seeds come up, so anything less than 80 or even 90% germination rate, and we start looking at what went wrong.
Learn the 5 fatal mistakes for germinating seeds
When vegetable seeds are not germinating, there are a few common problems that you should look for.
1. You used old seeds
The first thing to consider is whether the seeds were viable in the first place. If your seeds have not sprouted within the appropriate number days (this will depend on your seeds), then you may want to consider using a pen or pencil to gently dig around in your soil and find the seed.
- If you don’t find the seed, think back. Did youforget to put the seeds into the mix? Don’t laugh! It could happen!
- If you find the seed, take a good look at it. You may see that it looks just the way it did when you put it in the soil. In this case, the cause for a low germination rate might be that it was an old seed or not properly stored.
If you have some old seeds and are unsure of whether your seeds were viable, you can always sprout a couple of them in a wet paper towel to check prior to planting.
For new seeds or seeds you saved last year:
- When you saved seed, did you put them away without letting them dry completely? This can cause seeds to rot or mold.
- Were they exposed to extreme temperatures during storage? For example, if you left seed packs in your car over the summer. High temperatures over 90 can kill the plant inside the seed.
- Was the parent plant healthy? Seeds can harbor infection from the parent plant that may prevent sprouting, however, this is not usually the case.
2. You didn’t use new or sterilized containers
Disease issues can be a factor in seed germination. Think back to last year and whether you had any disease issues with your seedlings.
- Most plastic containers can be reused for several years, but they need to be sanitized.
We clean ours by submersing them in bleach water at the beginning of the season.
If you are looking for a bleach alternative, try the environmentally friendly bleach alternatives that use hydrogen peroxide as their active ingredient.
Fungal and mold infections are the most common infection from dirty containers. If infection occurs you will notice a fuzzy growth on the top of the planting medium.
- You may also see that a seed sprouts, but then rots at its base and falls over.
This is called damping off and is caused by a funal infection in your soil. A hydrogen peroxide or colloidal silver solution can help treat fungal disease on your tender plants.
3. Your technique is not right
- If you started seeds in any mix that includes non-sterilized soil from the yard, your seeds may have been affected by disease organisms in the soil.
In order to use garden soil for starting seeds, you should sift it carefully to remove sticks and clumps. Then bake it on a cookie sheet in the oven at 180 degrees for 30 minutes. That should kill most weeds and pathogens.
You’re better off using a seed starting mix. Seed starting mix is usually a soiless mixture that has a finer grain and is free of clumps, sticks, and pathogens.
- Did you plant your seeds too deep?
Planting your seeds too deep can cause problems with sprouting. You should also avoid pressing down on top of your seeds after you plant them. If the soil in your container is too compacted, the seeds cannot sprout or form healthy roots.
4. You didn’t provide the correct temperature
The temperature of your soil is of utmost importance in getting a good seed germination.
- Temperatures that are too high or too low can cause problems germinating seeds.
Given all else is equal, even tray germination requires even temperatures. If temperatures plunge at night, or peak over 100 for a prolonged period, seeds will either remain dormant or die.
- Did you leave the heat mat too high or too low?
Even when using seed starting heat mats, accidents happen. If you forget to put the temperature probe into the seed tray, the heat mat can overheat and cook the seeds.
Sometimes heat mats get accidentally turn off, or you forget to plug it in.
An alternative to the heat mat is to put them in a sunny south facing window or on top of the refrigerator. You can also use grow lights to provide heat above, and I have even seen people use rope lights to generate warmth.
5. You watered incorrectly
Seeds need to be moderately moist to sprout.
- Seed germination is highly dependent on watering. Too dry and they won’t get the message to sprout, too wet and they will rot in the dirt.
Very young seedlings are even more tender. Seedlings do best in what we call the “Goldilocks zone.” You know Goldilocks. She likes her porridge not too hot and not too cold, but juuust right.
- Tender seedling babies can’t tolerate drying out. While young, even a short dry period can mean death after the first wilt.
On the other hand, their tender roots will be the first victim of conditions being too wet. They can’t get the oxygen they need to carry about their business, and it will stunt or kill the seedling.
What other problems have you had germinating seeds?
If you’ve had troubles germinating seeds and this article didn’t answer your question, leave me a comment below. I’m happy to help you work out what’s going on.
It's a few weeks before spring, and gardeners everywhere are starting baby plants from seed. Germinating seeds isn't usually a difficult process, and for most veggies the process is quite simple. But what's a gardener to do if they're having problems germinating seeds? The first thing to check is