Cannabis Seeds sprout easily with our step by step guides for germinating weed seeds in soil, water, tissue, rockwool, & more! Starting cannabis from seed is an affordable and fulfilling way to start growing. It all starts with germinating cannabis seeds, followed by creating the ideal warm, humid environment for seedling growth. Giving your seeds (and then the seedings) the best support from the very start, you'll set yourself up for success Fail-Proof Guide to Germinating Seeds in Hydroponics Plus, How to Care for Hydroponic Seedlings… We have a cannabis seedling germination page which has everything you need to know about all
How to germinate marijuana seeds
Germination begins the life of your plant, so it is essential to understand precisely how to do it. There are many methods for germinating marijuana seeds – some more successful than others.
This guide will discuss the many ways to germinate your seeds as well as some strategies for ensuring you get the best results possible. But if even the right methods fail I stand by my seeds and replace non-germinated seeds for free.
About germinating cannabis seeds
Too long to read? Watch the video
It starts with the seed
Like all plants, marijuana starts as a seed. What looks like a pebble is actually an entire plant conveniently stored with a few days supplies of food to support itself. During germination, this food is converted into sugars that the plant uses to break through its shell and form its roots. From that point forward, the young seedling depends on its environment to provide the nutrients it will need to survive.
Germination brings a seed out of its slumber and triggers the growth process. A seed will begin germinating once it receives enough moisture.
At that point, it will increase in size and break open its shell. A germ opening forms and a root will emerge, which will help the plant absorb nutrients from the earth.
Nature and gravity ensure that the root grows downwards and the stem upward, creating a young seedling that can survive off light and earth.
Since all marijuana grows from a cannabis seed, many people want to know how to identify a healthy seed.
Honestly, it is difficult to tell if a plant will be healthy based on its seed alone. There are, however some tell-tell signs.
Planning your first grow? Check out my easy beginner seeds and grab an all-in-one Pot for Pot solution
Generally speaking, a pale-green, white, or very dark marijuana seed may have trouble germinating well. But this does not always reflect the outcome of the plant and is always worth trying.
If you are unable to use all of your seeds, store them in a cool, dark and dry place until you can. A refrigerator is ideal.
Planning for germination
Seeds are designed to germinate, but they are more likely to do so if given the ideal environment. There are many methods of germination, but they will all require:
- Moisture to help the seed expand and break through its shell
- Minimal interference so that delicate structures aren’t accidentally broken that mimic springtime (between 20°-22° Celsius or 68°-72° Fahrenheit)
If you remember these three things, your germination attempts are more likely to be successful.
It should go without saying that successful germination is important. Your seed is the foundation for your plants – which is why many successful growers choose to start with high-quality seeds.
You can also improve your germination attempts (and possibly speed up the process) by soaking your seeds in 1% hydrogen peroxide or a compost tea solution for 12 hours before using them. This process will kill any infectious agents.
3 Simple ways to germinate your seeds
The best germination method is the one that works for you, and if you are like me, you’re going to want something simple and natural.
My favorite way to germinate seeds is a 24-water soak followed by soil germination, but something else may work better for you. Here are three of the easiest ways to germinate seeds.
Germinate seeds directly in soil
Planting your seeds in the soil that you intend to grow in is the most common and often, most successful method of germinating marijuana seeds.
This method is perfect for ensuring young seeds have minimal interference since the fragile root is protected by the soil. It’s also the most natural way for marijuana plants to grow.
How to plant marijuana seeds directly in soil
The first step in learning how to plant marijuana seeds directly in soil is to first make sure you use the right type. Use mildly fertilized potting soil or a seed starter. It should have a pH of approximately 6.
This type of soil will have spores and minerals that help young marijuana plants thrive. Do not add nutrients – potting soil has enough nutrients for at least the first two weeks of the plant’s life.
If you add any more nutrients, you risk killing your seedlings due to a nutrient overdose. Place your soil in a small pot.
In my free Grow Bible you will find even more tips for sprouting seeds and how to germinate weed seeds
- Grow with my Quick Start Guide
- Discover secrets to Big Yields
- Avoid common grow mistakes
Steps to germinating cannabis seeds
To prepare the soil for your seed, push your finger into it to create a small hole that is up to 1.5cm (0.6 inches) deep.
You can also use a pen or pencil.
- Place one seed into the prepared hole and cover it with soil. If you’ve already germinated, the seed will have a root – place the root facing downward (more on that later).
- After you’ve covered your seed with loose soil, do not mess with it.
- That includes pushing it down further – this will happen naturally as you water it.
- Use a plant sprayer to moisten the soil and place the pots under a fluorescent lamp.
- Don’t use a windowsill, because the temperature is not stable enough for germination.
- The temperature of the soil should be 22° Celsius or 72° Fahrenheit which is easy to achieve with lighting.
- Keep monitoring your soil to make sure it stays moist.
- Within a week (or as little as 4 days) you should start seeing stems emerge from the soil. You now have a seedling!
- Once your plants are 2 to 4 inches tall (5 to 10 centimeters), transplant your plants into a larger pot with the stems further in the ground. Your plant will now have many roots that will support it for the rest of its life.
Germinate seeds in water
As I mentioned above, germinating in water is my favorite way to start my seeds.
It may seem like a bad idea, as there are more water and light than recommended when using this method, but it works! I’ve found that it is around 90% effective.
The “trick” is not leaving the seeds in water too long.
Usually, 24 to 48 hours is enough for the seeds to show their tail, but you can leave them soaking for up to 7 days without too much of a worry.
Water germination is useful because it assures that there is the right amount of moisture to begin germinating.
If done for just a short period, it can help crack open the shell, pre-sprouting the plant right before your eyes.
Water germination shortens the process by making it easier for the plant rather than having to push through the soil.
- To germinate with water, fill a glass with tap water and allow it to reach room temperature over a few hours.
- The temperature should be around 18° C or 65° F. Do not add nutrients. Drop 2 to 3 cannabis seeds into the water and watch for any changes.
- Refill the glass with fresh water every other day while maintaining its temperature.
After about 2 to 4 days the seeds should start to split.
You can place your seeds in the soil at any point, but once the roots are 3 to 5 mm (.1 to .2 inches) long, they must be planted.
These are the basic instructions from my store that I share with new growers:
As much as I prefer to germinate my seeds in water, it does have its downside.
At some point, you will need to handle your seeds, and this is risky. Germinating seeds are delicate, and the roots are especially fragile. If you harm them in any way, your plant might not develop well.
Be very careful when placing your sprouted seed into the soil, and if possible place the root facing down.
Germinate with cotton pads or paper towels
Another easy way of germinating your seeds is to use cotton pads or paper towels.
This is a common way of doing it because cotton pads or paper towels can keep the seeds moist and protected.
While cotton pads (or balls) or the best for this method, cheap, non-porous paper towels will work as well.
Just make sure they are plain single-ply paper towels – the cloth-like ones may cause your roots to grow into the towel.
- To germinate using cotton pads, place a few seeds between two cotton pads and moisten with a plant sprayer.
- When using a paper towel, place the seeds in between two paper towels and store the towel-cushioned seeds in between two plates, under an upside-down bowl or in a plastic bag.
- Keep the temperature around 22° Celsius, or 72° Fahrenheit, and (once again) do not place the seeds on a windowsill.
- In about 2 to 5 days, the seeds will start to split open, and a tiny root should appear.
- Place them in the soil when they are 3-5 mm or 0.1- 0.2 inches long.
Read my free Grow Bible to learn more about germination and caring for your plant.
- Grow with my Quick Start Guide
- Discover secrets to Big Yields
- Avoid common grow mistakes
Like the water method, germinating this way has its risk. If you are not careful, you can damage fragile roots while transporting them to the soil. You can also tangle the root in the wet paper towel if you are not extremely careful.
Explore the beginner cannabis seeds in my shop and start germinating your first seeds!
Use your fingers or tweezers to move delicate sprouts, and don’t allow the root to grow too long before moving it into the soil.
Other germination methods
Water, soil, and cotton pads or paper towels are the easiest ways to germinate your seeds, but they aren’t the only ways. You can also use starter cubes or plugs for germinating cannabis seeds. Simply drop the seed in, add water, and wait for it to germinate.
They aren’t always as successful, but they eliminate the risk of damaging your root when transporting a young sprout to its final growing home.
Below are two types of starter materials that can safely germinate your seeds.
Germinating seeds in rockwool
Rockwool provides the perfect environment for germinating seeds.
It is mineral wool that is made from volcanic rock and other materials (such as basalt and limestone). Rockwool is man-made by melting its ingredients into molten lava that is quickly spun into threads. These threads are then compacted, cured, and cut.
Rockwool is an ideal growing environment, but it will need to be amended slightly for marijuana plants.
First of all, you will need to add some fertilizer before you use it to start seeds. The TDS should be around 600ppm. You’ll also need to lower the pH since Rockwool has a pH of 7.0, which is too high for germination.
To lower the pH, soak Rockwool plugs in water for at least a day. Since water has a pH of 5.5, this will bring down the pH.
It should also be noted that there are some serious drawbacks to using Rockwool.
Because it does not occur naturally, it’s not the best for the environment.
It’s also not the greatest for your health; wear gloves and cover your mouth and eyes when handling this stuff.
Because of the extra steps involved (such as adjusting the nutrients and pH) and handling issues, this method is not recommended for beginners, although it is not terribly difficult to do.
You’ll need to purchase and TDS meters for the most successful germination, but outside of that, the material is very affordable and easy to find.
Because it does not require soil, this method is ideal for those who plan to grow hydroponically.
Germinating seeds in peat pellets
Peat pellets are another way to germinate seeds without the risk of damaging young roots.
Peat pellets are compressed peat, which is made of partially decomposed vegetable matter and is simply yummy for young plants.
The pellet enlarges when you add water to it, forming a container of nutrient-dense soil alternative around germinating seeds.
Unlike Rockwool, peat is already optimized for cannabis germination.
It has a pH of 5.5 and a TDS of 625, so you don’t have to worry about making any adjustments. The only preparation required is soaking the pellets in warm water.
Once the roots become visible, (by popping out of the peat), simply move the entire pellet into the soil, rock wool, or coco coir, where it will continue growing.
This type of germination is not recommended for hydroponic setups.
Peat pellets have a good germination rate, are easy to use, and are suitable for beginners. They are also ideal for cloning.
I recommend the Jiffy brand of peat pellets which can be purchased on Amazon.
In addition to the material used to germinate your seeds, the grow environment you provide will play a huge role as well.
Your seeds will need the correct temperature and levels of moisture to sprout into a strong, healthy plant.
“Weak plants are the result of weak seeds and poor growing conditions.”
Below are some tips for creating the perfect germination environment.
How to water sprouting seeds
Watering is essential throughout the cannabis life cycle, and germination is no exception.
Not enough water and your seeds do not germinate, too much and that root doesn’t survive.
Excess water keeps oxygen from the roots and can attract mold, which is why you have to be very careful not to overdo it.
When germinating weed seeds indoors using soil or another growing medium it is relatively easy to monitor the water levels. You should water your seed until you see water dripping out from below (and not more).
Even though the seedling cannot absorb that much water, it will evaporate quite quickly, so you need to make sure there is always enough around.
If you water it until it reaches this point, it should supply enough moisture for a few days.
Lighting and temperature
Like water, lighting is essential to a cannabis plant. In a mature plant, light enables the plant to form sugars from carbon dioxide and water.
Buy feminized seeds
- High-quality feminized seeds
- Guaranteed germination
- Incredible high yields
- F or grower’s of all experience
The plant then uses those sugars to power its growth – something we humans call photosynthesis.
For a seed, lighting is important as well because it provides heat, which a seed needs to push open its shell and send its root into the earth.
The best way to give your seeds the temperature it needs is with fluorescent lights. (T5 high output with a color temperature of 6500K).
Fluorescent lights are ideal because they do not use too much power, and they don’t give off too much heat.
You can place them as close to a young plant as you need, and although your seed doesn’t need it at this point, it will as soon as those first leaves start peeking out from the top of the soil.
Incandescent bulbs can also be used because they are great at generating heat. You can’t use them as grow lights, but for germination, they work just fine.
You can also use a seedling heating pad (available at most gardening stores). These heat the seeds from the bottom instead of the top. They will not be enough once your plant has started growing, however.
Keep the temperature of the soil around 72 degrees.
Seeds germinate best in warm, humid temperatures, similar to springtime.
To create a humid environment, wrap plastic wrap around your pot, creating a biodome for your plants. Just remember to remove the plastic wrap the minute you see any sprouts emerge from the soil.
If the soil, or water, or whatever you are growing in is hotter than 72 degrees Fahrenheit, move the lamp further away from the plant.
Dry air won’t kill seedlings, but if you can reduce it, even better.
Where to germinate seeds
When you’re planning your outdoor grow and you received your seeds, it’s best to germinate them indoors. This is because indoors it is much easier to maintain the correct temperature, water levels, and light exposure.
Even if you plan to grow your plants outdoors, you do not want to try starting them outside (unless you absolutely need to).
Outdoors you must worry about rain, clouds, and plenty of other things that could keep your seeds from sprouting.
You’ll also have to wait until the final frost has passed, meaning your growing season may be delayed compared to if you had started the seeds inside.
Starting indoors gives you a head start and your plants a better chance at survival.
If you still plan to germinate outdoors, choose a location that will support the plant its entire life. You will not be moving the plant so choose wisely.
- Plant seeds when corn is typically planted in your area.
- Dig 6x6x6 holes at least three feet apart and fill them with potting soil.
- This will give the seeds enough nutrients to start.
- Then, dig a small, quarter-inch deep hole into the potting soil and drop the seed in.
- Soak that soil with water, and water it again in a few days if the weather is warm enough.
- You can use row covers to protect your seeds and keep the area warm but be careful to not leave them on too long – young plants will need the light once they break through the soil.
In my free Grow Bible you will find even more tips for sprouting seeds and how to germinate pot seeds
Grow Guide: How to Start Cannabis from Seed
Starting cannabis from seed is an affordable and fulfilling way to start growing. It all starts with germinating cannabis seeds, followed by creating the ideal warm, humid environment for seedling growth.
Giving your seeds (and then the seedings) the best support from the very start, you’ll set yourself up for success come harvest. Here are the basics to growing cannabis from seeds.
Where to Find Cannabis Seeds
At this point, there are hundreds of different online options for sourcing cannabis seeds . If you are growing indoors, the world is your oyster, as many websites are willing to ship nationally (or even internationally). Plus, if you master the indoor environment, you can recreate perfect conditions for even the most demanding of strains.
For those growing outdoors, try to locate a local breeder who also cultivates outside. These cultivars will be adapted to your unique climate and will likely produce better results.
No idea where to start? Seed Finder is an excellent resource for sourcing specific genetics and breeders in your area. But this is just one place among many in today’s weed-friendly world.
How to Germinate Cannabis Seeds
What You’ll Need:
- Cannabis seeds
- Paper towel
- Plate or tray
- Ziplock bag
- Heating mat (optional)
The first step to growing cannabis from seed is learning how to germinate them. Place cannabis seeds on a sheet of paper towel, laid on top of a tray. Dampen the towel with water so it’s wet but not soaking.
Fold the towel in half to cover the seeds, and enclose it inside a Ziploc bag. Place the entire tray on a heating mat, the top of a fridge or other warm area of your house. Cannabis seeds germinate between 71 to 77°F (22–25°C).
Check back every day for signs of life. If your seeds are viable, they should sprout within a week. If you are still waiting for a few to emerge after a week, toss those and begin again. If no seeds have sprouted, your seeds are no longer viable.
Ed Rosenthal recommends soaking seeds for 12 hours before germination. His formula uses water, a cannabis rooting solution and hydrogen peroxide.
This solution is a good option for commercial and large scale growers, as it reduces the risk of fungal infection and encourages rapid sprouting. Compost tea is another excellent option for a natural alternative.
Ideal Conditions for Cannabis Seeds and Seedlings
What You’ll Need:
- Germinated Cannabis Seeds
- Potting Mix (or Root Riot Plant Cubes )
- Propagation Tray with Dome
Once germinated, you must carefully move these tiny seeds into the soil or soilless growing medium like Root Riot Plant Cubes. When you start cannabis from seed, the aim is a warm and relatively humid environment.
Starting Cannabis With Soil
If using soil, choose an organic potting mix suitable for seeds and starts. Water soil mixture before use, and fill potting containers that have a drainage hole. Avoid pellets that are commonly sold at garden centers, as they don’t retain moisture well, and it’s challenging for cannabis roots to break free of the netting.
Using a popsicle stick, tweezers or a toothpick, lower the germinated seed into a premade hole roughly two the three times the height of the seed. As you gently fill in the hole, be careful not to damage the sprout.
Starting Cannabis for Hydroponics
For hydroponics, you’ll want to use Rockwool cubes or Root Riot Plant Cubes. These come pre-cut into perfect starter plugs, often with a hole in the middle for the seed.
Before use, soak the cubes in water and rooting solution until they are wet but not dripping. Gently lower the germinated seed into the hole using a popsicle stick, tweezers or a toothpick. Be extremely careful not to damage the early sprout.
Whatever option you choose, keep the seedlings at a consistent temperature: 68 to 77°F (20 to 25°C). Depending on where you live, a heating mat may be necessary. Use a propagation tray with a clear dome to trap the humidity in, but open up once a day to encourage a bit of airflow.
Lighting Requirements for Cannabis Seedlings (& How to Eliminate Stretch)
Seedlings and starts require 16 hours of light a day and eight hours of dark. You can even bump this up to 24 hours a day, and the seedlings will continue to eat it up.
What kind of grow light do you need for this early stage of development? Not the same capacity you’ll need for veg and bloom. Higher wattage types of HID lights (Metal Halide and High-Pressure Sodium) are far too powerful for sensitive seedlings.
Most growers use a simple LED grow light or a CFL fixture. Ed Rosenthal recommends 40 to 60 watts per square foot.
While these may not be entirely enough for veg and bloom, they produce enough light for seedlings without the added heat. This means you can place the lights close to the tops of the seedlings.
Place lights as close as possible to the tops of the starts, without raising the temperature over 77°F. You want seedlings to get enough light without burning them.
The goal is to avoid early stretching in your small cannabis seedlings. Healthy seedlings are short and wide, not tall and skinny. Stretching is when the sprout reaches tall for the light without putting out leaves.
Typically, under outdoor conditions, plants remain short for the first few weeks as they focus energy on building structure and root development. Stretching inside demonstrates the seedling is not getting enough light. The light source is either not intense enough or too far away.
When to Transplant Cannabis Seedlings
The primary goal for starting cannabis seeds in small pots is to encourage healthy and strong root development. Once the seedling has three to four sets of leaves, begin checking root development. This will likely be three or more weeks after germination.
Another telltale sign it’s time to transplant is when you notice roots begin to creep out from the drainage holes. If working with Rockwool, a key indicator it’s time to transplant is when the roots begin to outgrow the cube. A plant’s growth trajectory slows down if it is root-bound. If the roots have consumed the available space, it’s time to move up a size.
Cannabis Seedlings From Germination to Transplanting
Starting cannabis from seed gives growers access to a much larger genetic pool than what you can find locally from a clone supplier. Plus, if you’ve got the time to invest, it’s a much more affordable way to grow cannabis. Finally, if you are already set up with a veg and bloom room, you have everything you need to get started from seed.
Fail-Proof Guide to Germinating Seeds in Hydroponics
Plus, How to Care for Hydroponic Seedlings…
We have a cannabis seedling germination page which has everything you need to know about all the different germination methods, but this tutorial is different. In this hydroponic seedling tutorial I’m going to share exactly how I do my seeds from beginning to end in a DWC/bubbleponics setup!
Just follow these instructions and you’ll end up with healthy, fast-growing plants that germinate in just a few days. It’s pretty much fail proof!
Learn How to Start Seedlings So You Can Grow Hydroponic Cannabis Plants Like This!
1.) Get Cannabis Seeds
There are a few different ways to get cannabis seeds, with the most common being ordering seeds online and growing seeds you find in weed that you buy. Learn how to research and find the right strain.
Here’s a picture showing several healthy and viable cannabis seeds
2.) Germination for Hydroponics
I’ve tried a bunch of different germination methods over the years, and the technique I prefer is for hydroponics is starting with the “Paper towel method” to germinate, putting the germinated seeds into Rapid Rooters, and installing the Rapid Rooters directly into reservoir. Lots of other germination methods as well, but this has worked best for me!
Paper Towel Method
This method is hard to mess up if you follow the instructions!
- Place your seeds inside a folded wet paper towel, and place it between two paper plates (or regular plates) so that they don’t dry out.
- Check on your seeds every 12 hours but try not to disturb them. When they’ve germinated, you’ll see the seeds have cracked and there are little white roots coming out.
- They should germinate in 1-4 days, though some seeds can take a week or longer (especially older seeds).
- Keep them warm if possible. One thing you can do to get seeds to germinate a little faster is to keep them in a warm place (75-80°F). Some people use a seedling heat mat but in most cases that’s unnecessary.
These seedlings were sprouted using the paper towel method!
3.) Place Germinated Seed in a Rapid Rooter
The Rapid Rooter should be cut open lengthwise
Gently place the germinated seed inside, root down
Most seedling plugs will go back into place easily, and you’ll barely be able to tell it’s been opened
4.) Prepare Hydro System for Its New Guest
If you haven’t put your hydroponic system together yet, now is the time! Make sure your pumps are all running, and that you’ve made a reservoir with seedling-strength nutrients. You need a home to put your new plants!
Hydro Tips & Hints
- Air bubbles – have lots and lots of bubbles in your water reservoir. That means your air pump needs to be on all the time for the full grow. The main benefit of hydro is your plant roots are getting an unlimited amount of both water and oxygen. This is achieved by dissolving a lot of air into the water via an air stone and air pump. In order to get the fast growth, you want a lot of bubbles! A highly-oxygenated tank is also far less likely to get root rot, or suffer from other unwanted organisms growing in the reservoir! – This supplement contains a specific bacteria that was first found in rice paddies in Japan in the 40s! It’s been common in Asia for years but only in the last several years has it been available in the US from a company called Botanicare. I highly recommend, even insist, that all hydro growers get this cheap-but-effective supplement to keep plant roots healthy!
- Add seedling level nutrients from the beginning. A lot of growers, especially soil growers, will tell you not to add any nutrients for the first few weeks of the plant’s life. That makes a lot of sense in soil, because there are lots of nutrients contained in the soil itself for your young cannabis seedling, and giving more right at the beginning can end up giving way too much for such a young plant. However, in hydro, the only nutrients your seedling gets is what’s in the water, plus what little was contained in the seed itself. Because of that, I highly recommend giving seedling-strength nutrients to your plants from when you first fill your reservoir. Seedlings grow a LOT faster with light levels of nutrients than if you only give plain, pH’ed water at first. from the beginning of your plant’s life to end the of your plant’s life
5.) Install Rapid Rooter and water the seedlings until roots reach the water reservoir – Turn on light to keep seedlings warm for best results!
Make sure to always keep the Rapid Rooter moist but not soaking wet.
If you have a top-feed, place the tube near the bottom of the net pot so the water isn’t soaking the seedling’s roots. You just want water dripping out the bottom so the root can use it for oxygen and water until it’s fully established in the reservoir.
Add your Rapid Rooter(s), and fill around the edges with extra clay pellets to hold each one in place.
Since your seed has already sprouted and been in placed into the right growing position, it’ll often pop its head out within just 12-24 hours! Sometimes you see just the leaves, but occasionally you actually see the seedling push the shell above ground. I keep the grow light on even before the seedling appears. It helps keep it warm and guide it toward the light.
When this happens the shell usually falls off on its own as the seedling grows!
The Rapid Rooter in this picture is a little too wet, which makes the seedling prone to “damping off.” If you ever notice the Rapid Rooter actually looks wet or shiny, it’s too much water. Try turning the top-feed off every few hours, or hand-watering the seedling at first. Too much moisture can kill!
Don’t use a humidity dome on seedlings unless it’s very dry where you live. If you do use a dome, consider keeping a vent open and watching the humidity. A young seedling doesn’t require high humidity, and they tend to get “wet feet” and stop growing in constantly wet conditions.
Now that your seedling in in the tank, it’s time to learn how to….
6.) Take Care of Hydro Seedlings
Here are tips for taking the best care of hydroponic marijuana seedlings:
- Leave roots alone as much as you can with young seedlings in a hydroponic setup. It takes them a little while to get all established in the tank, almost like a fish, and during that time seedlings are much more sensitive to their roots being touched or being moved around. If at all possible, try to let the seedling grow in the same place without being moved for at least a few weeks until you put them in their final home, or even just start them in their final home!
- Avoid reservoir changes for a few weeks if you can – Going along with what I said before about leaving the roots alone, I’ve found that young seedlings often don’t respond well to reservoir changes. Instead of changing the reservoir, just top off with half-strength vegetative nutrient water until the plant is at least 3 weeks old. It won’t be using enough nutrients to mess with the ratios, and as long as you maintain the pH and use Hydroguard your young plant will be fine with being topped off.
- Check the pH dailyto prevent nutrient deficiencies
- Warm but not hot temperature– I recommend hydro growers aim for 75°F, and try to stay between 73-80°F.
These seedlings are a few weeks old, and the grower plans to move them all to the
This is a time-lapse video of a cannabis seedling sprouting and growing over 13 days.
Cannabis seedlings just getting their bearings – try to avoid moving or disturbing them until they are growing fast, with new leaves every day!
Big cannabis plants ready to switch to the flowering stage
I thought hydro plants liked it cold?
Just like in soil, cannabis plants in hydro tend to grow faster in relatively warm temperatures. This is a somewhat controversial statement because a lot of hydro growers prefer to keep their temperature lower in the grow space to help prevent root rot. In fact, there are some growers right now who are reading this and shaking their heads at me.
There’s good reason to believe that hydro plants would grow better with a cool reservoir. For example, the bad microorganisms that make root rot don’t survive well at lower temperatures. Additionally, water can physically hold more oxygen at lower temperatures, which seems like it would be great for faster plant growth. Because of this, lots of growers will AC their room to 60°F, and/or get a water chiller to cool their water reservoir to a similar temperature.
I do agree that if the temperature is above 80°F, your plant is a lot more likely to get root rot. However, I personally have not found that cool temperatures are adequate to prevent root rot. Even if the temperature is 60°F, you still need lots of bubbles and a “good bacteria” supplement like Hydroguard to prevent root rot in many cases.
I’ve seen several growers buy a water chiller and still get root rot. So I personally don’t believe cold temperatures are the best way to go to keep roots healthy.
The other reason I recommend to keep it warmer is because the plants just grow faster around 75°F in hydro. If your roots go from 60°F to 75°F, you’ll see the plants start growing faster in just a day or two, just like how plants in soil grow faster when it’s warm!
Just like in soil or coco, cannabis plants in hydro grow fastest when it’s a little warm, around 75°F!
Although there may be more oxygen dissolved in the water at lower temperatures, at least in my grow tent that apparently isn’t the limiting factor to growth, because plant growth speeds up at warmer temperatures.
I’ve found that if the grow space feels cool to you, it also feels cool to your plant most likely, and it may not be growing to its full potential. Some Sativa strains are particularly sensitive to the cold, though some Indica strains from cold climates will still thrive at lower temps.
Autopsy: Why Aren’t My Seeds Sprouting?
If your seeds still aren’t sprouting and growing properly, consider the following factors.
If there’s no germination at all…
- Temperature may be too hot or cold – aim for 75-80°F
- Too wet – seeds and seedling roots should always be moist, but should not stay wet
- Too dry – if a root dries out the seedling can die!
- Bad seeds – It might not be you, it could be the seeds themselves! How can I tell if seeds are viable?
If seeds sprout, but then stop growing…
- Temperature is too hot or cold – aim for 73-78°F
- Too wet – even though your plants are growing with root directly in water, new seedlings don’t like “wet feet”. They don’t like for it to be too wet near the seed for too long, so make sure your Rapid Rooter or growing medium nevers looks shiny or muddy, as that means there’s too much water! Young roots that stay too wet for too long start to get mushy and die. For this reason, it’s also usually recommended to avoid using a humidity dome with seedlings unless your air is dry. Although clones love humidity domes (they need water from the air because they don’t have any roots to get water), seedlings like it a little more dry or roots tend to get mushy.
- Too dry – less common unless you live in a very dry area, but sometimes your medium dries out too fast if you’ve got a heavy-drinking, fast-growing seedling!
- Too much light – if the seedlings get blasted with high levels of light right away, it can shock them. They may need some time to adjust to higher light levels. Simply starting your grow light a little further away that normal is usually enough.Think sunny window at first, and start ramping up after a week of healthy growth.
- Not enough light – if seedlings are growing long and stretchy without growing new sets of leaves, it means it wants more light.
- No light for more than a day – if the sprouted seed doesn’t get light within 24 hours after sprouting, it may die. Once seeds are sprouted, get them in a Rapid Rooter and under at least some amount of light as soon as possible!
- Roots damaged – If somehow your roots got damaged, it can sometimes stop the seedling from growing
Unfortunately sometimes you will never know why certain seeds just don’t thrive! It’s all part of nature