How to grow cannabis from seed with hydroponics

The Ultimate Guide to Growing Marijuana Using Hydroponics

Cannabis growing has come a long way since then as people have experimented and perfected the best ways to produce marijuana. A modern way is through hydroponic weed planting. Hydroponic weed is fast becoming one of the most popular ways to grow cannabis. In this article, we will tell you everything you need to know to get started growing your own hydro weed.

So, what is hydro weed growing? This process is when you plant in an inert material, such as coco coir or water reservoirs, instead of soil.

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The History of Hydroponics

Hydroponic planting has been used almost as long as cannabis, although the first plants harvested this way weren’t necessarily weed.

The Hanging Gardens of Babylon, one of the Seven Ancient World’s Wonders, are believed to have used hydroponic growing in 600 BC. You can also find evidence of this process in the 10th and 11th centuries AD in Aztec culture to produce crops near Lake Texcoco.

Marco Polo wrote about hydroponics in his expedition to China in the 13th century AD. Recently, this practice became popular through William Frederick Gericke of the University of California, Berkeley. He grew a 25-foot tall tomato plant with only water and added nutrients.

Gardeners of all kinds became fascinated with hydroponics. Soon, cannabis harvesters experimented and found plants could grow faster and stronger because the roots have access to nutrients without working through the soil to find them.

Hydroponics for weed continues to be a favorite method among cannabis growers today.

Advantages of Growing Hydroponic Weed

You might already have a fantastic setup with soil that’s producing good quality marijuana. Perhaps you’re thinking, “why should I grow with hydroponics?” There are many benefits, and we’re going to list the top four.

  • Faster growth. When you use the hydroponic weed growing method, the plants don’t have to work as hard. There’s little resistance in the water, so the roots move freely and rapidly. Your plants will grow 30-50% faster than in soil.
  • Larger yields. NASA reported that hydroponic growing techniques have an 80% better yield than soil-based methods. The nutrients are absorbed directly into the plant’s roots, so it’s bigger and stronger. Overall, you can get 2 to 4 times the amount of product in the same amount of time as you would with soil planting.
  • Easy nutrient feeding. The roots are directly exposed to the food and have ample water supply. H ydroponic weed plant s are never searching for more nutrients, so you won’t have to check up on the sprouts constantly.
  • You can create a more controlled environment for your cannabis using hydroponics, which is ideal for those who are selling.

Is it Expensive to Grow Hydroponic Weed?

The expenses of hydroponic cannabis growing depend on how much you want to invest. There are cheap and expensive ways to do it.

The lower-cost option will be to use materials you already have at home and engineer them independently. Old tarps can create a growing tent. Your dorm room fan can be the ventilation system. Recycle take-out plastic containers for your reservoir.

This can be a fun way to start, but the results won’t be optimal. The DIY approach is sufficient for recreational growing.

On the other hand, if you’re growing to sell, you can invest some more money, as the yield will be worth it. You can buy supplies at the gardening store or a specialized cannabis growing shop.

What Materials Are Needed for a Hydroponic System for Weed?

If you’re interested in switching to soilless growing, you might be asking, “ what materials do I need for my hydroponic garden?” You’ll likely need to make a trip to your local gardening store, but not too much equipment is required.

If you don’t have an indoor setup already, you’ll need to construct one. You can make these with a standard camping tent, DIY tarps, or purchase a grow tent. You’ll need a ventilation system to regulate humidity and heat.

All plants need light for photosynthesis. In indoor environments, natural sunlight is low. A grow light ensures the fast and healthy growth of your marijuana.

3. Hydroponic reservoir or tank

Now, you’ll need something to hold the water or growing material. You can find these at a gardening store, dispensary, or you can craft one yourself.

If you’re going to use water, you’ll also want to have a pH meter to test the acidity. You can use other materials like coco coir or clay pebbles as well.

Hydroponic nutrients for weed help the plants grow. For cannabis, the essentials are nitrogen, phosphorus, and potassium. You should look for cannabis food that contains these, along with calcium, magnesium, sulfur, iron, chlorine, manganese, boron, zinc, and copper.

The last material you’ll need is the marijuana strains you want to grow. Put the seeds into the water or planting material with nutrients. Within a week, you’ll begin to see small roots form.

Choosing a Medium for Growing Hydro Weed

You can do hydroponic planting with just water and nutrients or use another medium. Wondering what else you can use? Let’s go over a few options.

– Clay pebbles

You can purchase clay pebbles: they help keep the marijuana plant robust but still allow water access. They’re reusable, so they’re perfect for those on a budget.

– Rockwool

Rockwool is thin rock fibers made by bringing rock to a very high temperature and spinning it. This process results in tiny threads that can retain moisture well. Make sure you soak it before using it to determine the pH is correct.

– Perlite

Perlite is a white and porous substance. Look for larger pieces for hydroponic growing. The pores can absorb water and nutrients, which keeps the plants fed.

– Coco coir

Coco coir is a material from coconut fibers. It retains moisture and assists in protecting roots from infections.

Choosing a Hydro Grow System

You can perform hydroponic growing with many methods. Depending on the size and style of the reservoir, you can determine which setup is best.

DEEP WATER CULTURE (beginner friendly)

Deep water culture is suitable for beginners. It’s one of the cheaper options and relatively easy to maintain.

How does it work? Place your plants in water-filled containers filled with nutrients and an air pump. The air will supply oxygen, so your cannabis will grow.


The drip system uses a growing medium.

How does it work? – Put the plants in the reservoir with a dripping pipe over it.

– Plant seedlings in clay pebbles, coco coir, or another substance.

– Add the nutrients through the constant dripping.

– The liquid is then drained and collected so you can recycle it.


Ebb and flow is also known as the flood and drain system. You’ll need many buckets suspended above a tray with pumps that let water in and out.

The roots won’t be continuously in water. The pump will go through cycles of flooding the tank and then draining. This results in periodic feeding.


The wick system is like the drip system, but the water comes from below as opposed to above. The roots are in a reservoir with a growing medium. At the bottom, some wicks extend into the nutrients.

The wick sucks up a small amount of water, carries it to the medium, and hydrates the plants. No pump is required.


Aeroponics systems don’t use any grow media. Instead, the plant’s roots are suspended in the air and misted with a nutrient solution. The roots are kept separate from the rest of the plants using an opaque tray to prevent light damage, and the nutrient solution is kept in a reservoir located beneath the cannabis plants.

Aeroponics systems produce huge yields, but they need to be well-maintained to avoid pump failures. Since the roots are left exposed and vulnerable, the plants won’t be able to retain any moisture if the pump fails. Novice growers are better off trying a simpler method.


Aquaponics is a type of hydroponics marijuana growing system that combines aquaculture, such as fish.

The fish provide a natural source of nutrients when they excrete waste.


This hydroponic system allows growers to drain a nutrient solution onto an angled tray, creating a film that flows through the plant’s roots.

The solution is kept in a reservoir like the ones used for ebb and flow systems, but it is pumped through the tray continuously and drained out the bottom. Cannabis plants grown using this technique will form a dense root mat at the bottom of the tray, allowing them to fan out and absorb nutrients more efficiently.

Since the nutrient film technique was one of the first hydroponic systems developed for home growers, there are plenty of options available for hobby and commercial growers alike. These systems are compact and simple, so they’re perfect for small spaces.

Traditional nutrient film setups don’t require a particular kind of grow medium, but modern growers typically use clay pellets in small pots.

The nutrient solution flows through the small holes in the bottom of the pots, gets absorbed into the clay pellets, then filters out through the drain at the bottom to be adjusted and reused.

Clay pellets are perfect for this application since their uneven texture oxygenates the water, and they retain moisture and nutrients very effectively, allowing growers to maximize the time between feedings and making the plants more likely to survive if something goes wrong.

Getting Started at Home—The Hydroponic Way

By following these steps, it’s possible to produce a healthy, great-tasting product that you’ll be proud to call your own.

Step 1. Prepare your materials

Irrespective of the set up chosen, the initial preparation of the set up will be the same. For instance, all the materials must be sterilized to kill bacteria. This is normally done using a mixture of peroxide, water, and alcohol.

Once the materials are sterilized, you can follow the instruction of the particular system to prep accordingly. Once the system is prepped, the plants can then be placed to start the growth process.

Step 2. Build a grow node.

A grow tent with a white interior will reflect the light your plants need while keeping them enclosed and pest-free. A dedicated grow tent makes temperature monitoring simpler, and it helps to prevent the pungent aroma of cannabis from filling the room.

Step 3. Select the containers in which the plants will take root.

Put the seedlings in Rockwool to start. A dark bin will keep light from seeping in. An 18-gallon bin will hold six plants. Make six evenly spaced holes in the netting so the roots can grow through.

Step 4. Set up the fan and light system.

We suggest using LEDs as they create little heat and are relatively inexpensive to operate. There is a wide range of options from which to choose, and the decision will likely depend on your budget and performance requirements.

Step 5. Fill the container with water and create a nutrient blend.

It’s important to monitor the amount of oxygen going to the plants’ roots, and an air stone/water pump combo makes it easy to do. You’ll also need to monitor nutrient and pH levels, to ensure the plants’ health and vibrancy.

Step 6. Use clones for the best results.

It’s best to start with clones, which are seeds that have already sprouted and then multiple cuttings are taken off the plant while still in vegetative phase. However, it’s essential to ensure that these clones are pest- and pesticide-free. Clones are highly susceptible to pests that can quickly destroy an entire crop, so be sure to check the source before buying.

Step 7. Hit the lights.

Your clones should have strong roots and leaves that are ready for the light. Set the grow room’s lights to remain on for 18 hours per day for the first 28 days. The length of the vegetative state and the amount of light needed depends on the plants’ strain and growth pattern. Cannabis plants are very good communicators; if there’s something wrong, they’ll tell you right away!

Step 8. Trim the plants carefully.

By supporting outward growth, you’ll use the limited space to its fullest potential.

Step 9. Get ready for the flowering stage.

This typically takes place about 4 weeks into the grow, but again, it’s strain dependent. Set the lights to stay on for 12 hours per day; this diverts energy from height and leaf production into bud growth.

It’s usually a good idea to give the plants more nutrients during the flowering stage, but it’s possible to give them too much of a good thing. Nutrient burn may cause the plants’ leaves to turn brown or yellow at the tips.

When the buds have grown big enough, give the plants three weeks to flush out any remaining nutrients. Feed them only pH-balanced water for the perfect balance of taste and potency.

Step 10. Pick, trim, and dry the buds.

When you’re planning a home hydroponic grow op, it’s important to set aside enough space for harvesting, trimming, drying, and curing the buds. A slow, steady drying process gives the flower the smell and taste for which it is known.

To prevent mold from infecting the crop, dry the buds in a well ventilated, dark area. Trim the plants with sharp scissors, taking care to remove the leaves closest to the buds. Then, remove the buds from the plant stems.

Step 11. Cure the buds.

To cure cannabis, put it inside glass jars with airtight lids. Every day, for approximately 10 minutes, open each container to let fresh air in and to let moisture out.

Hydroponic System Maintenance

All types of planting require maintenance, and hydroponic for weed growing isn’t different. These systems tend to stay cleaner because of the constant water filtration, but you’ll still have to keep up with a few things.

– Monitor pH

The ideal pH level for a hydroponics weed system is a little acidic. You can build a reverse osmosis system to generate neutral water or buy it distilled. When you add the nutrient solution, it should be slightly acidic, between 5.5 to 6.5 pH.

You should have a pH tester kit and frequently check to ensure your plants are healthy.

– Keep water temperature around 20°C (68°F)

The temperature of your water is vital because 68°F is ideal for nutrient absorption. There’s also little algae build-up.

– Feed appropriate nutrient quantities

To ensure you’re feeding your cannabis the proper nutrients, you should buy solutions at a store. On the package, it’ll describe how much to give based on how much water. This can vary depending on the nutrient’s potency.

– Keep a clean environment

It’s a good habit to clean everything every two weeks. This includes your tools, the reservoirs, and the area around the plants.

Even the slightest contamination can result in pathogens attacking and killing your plants.

How to Choose the Best Hydroponic Weed Strain

What is the best hydroponic marijuana strain? Hydroponic growing requires specific strains of weed because of its unique qualities.

Compact and smaller strains are perfect for this process because you can keep them at a manageable size . We’re going to recommend the best cultivars to use for your indoor hydro weed system.

– Mochalope

Mochalope is easy to grow and Indica-dominant strain. This provides a more psychoactive high than other types.

It’s short and has a thick stem. The leaves and hydro buds are refreshingly dense. The stocky stature of Mochalope makes it an excellent option for hydroponic planting. It grows to about 12 inches and yields 600 grams per plant.

– Lemon Garlic OG

Another Indica-dominant strain, the Lemon Garlic OG is a particular breed of the OG Kush family. It’s a blend of about 80% Indica and 20% Sativa with a very low CBD content of only 0.1%.

It grows to about 8 to 10 inches, and you harvest about 400 to 600 grams per plant.

– White widow

White Widow is a hybrid strain with 50% Sativa and 50% Indica genes. It’s an ideal combination of a psychoactive and calming experience.

The plant’s height can grow from 23 to 40 inches, making it remarkable among hydroponic marijuanas . It’ll yield 550 to 600 grams per plant in about 8 to 9 weeks.

– CBD Shishkaberry

CBD Shishkaberry is heavier on the CBD than other strains. There’s a 1:2 hydro THC to CBD ratio. This results in a calmer high with many relaxation benefits. People commonly use it for medical purposes.

The plant needs to grow for 8 to 10 weeks, and it yields about 300 to 500 grams per square meter.

Home Growing Mistakes to Avoid

Now that you’ve bought all the equipment and watched some tutorial videos, you may think it’s easy to grow hydroponic weed.

While YouTube videos may make it seem simple, there are a few mistakes to avoid.

  • Temperature. It’s best to avoid temperatures that are too high or too low. Keep the water flowing through the system at about 65°F to prevent algae buildup and facilitate the absorption of nutrients.
  • Humidity. Depending on the growth stage they’re in, cannabis plants have varying humidity requirements. For instance, seedlings need 60-70% humidity. Once they’ve entered the flowering stage, however, they’ll only need about 40%.
  • Lighting. The type of grow room lighting you choose depends on how much space you’ve set aside and the distance between the lights and the plants. LEDs are best for small grow rooms, while larger ops will benefit from HID (high-intensity discharge) lights.
  • pH levels. A plant that’s not grown in the right pH range will fail to thrive. Aim for a pH range of 5.5-6.5 for the best results. If the pH level is too high, use white vinegar to bring it down.
  • Ventilation. Don’t try to grow hydroponic cannabis in a room without proper airflow and ventilation. Protect the plants’ health by placing fans to cover the entire growing area. With proper ventilation, it’s easy to maintain the proper room temperature and ensure adequate air exchange.
  • Electrical conductivity. EC is a measure of the level of dissolved solids in the water. A reading that’s too high may result in plant damage due to an excess of nutrients, while a reading that’s too low means the plants aren’t getting enough nourishment.

Differences Between Hydroponic and Soil-Based Cannabis Cultivation

Other than the media in which they are grown, soil-based and hydroponic cannabis gardens have a few notable differences.

  • One of the most significant is the nutrients you’ll provide. Typically, soil-grown and hydroponic plants need slightly different types of nutrients, but there are universal systems that work across growth media.
  • Another big difference lies in the appropriate pH level. The optimal pH level for a soil-based garden is 6.0-7.0, while a hydroponic garden does best when the pH stays around 5.5-6.5. Even if you are using a soilless potting mix, you’ll need to use the hydroponic pH.
  • Finally, these cultivation methods differ in the level of effort required. The hard work of hydroponic cannabis cultivation starts after the system is up and running, while soil-based growers are working hard from day one.

Regardless of the method you choose, you’ll still have to take certain steps to ensure the health and vitality of the crop. These include pH testing, inspecting the equipment and the plants, and looking for signs of disease.

Why Hydroponic Growing is More Cost-Effective Than Soil-Based Cultivation

For thousands of years now, the soil has been the growth medium of choice for gardeners all over the world. However, one significant development is designed to save money, save time, and increase crop yields: hydroponics. Where the soil vs. hydroponics debate is concerned, the latter offers much more than a soilless way to grow cannabis crops. Not only does this cultivation method help growers save effort and money, but it also helps them eliminate the hassles that come with the use of conventional growth media. In the sections below, you’ll find a few reasons why today’s cannabis cultivators are turning to hydroponics.

Growing Hydroponic Marijuana is Extremely Rewarding

Like all things in life, who doesn’t want something faster and bigger? Hydroponics can speed up your growing time and yield.

Getting started might require some investment and work, but once perfected, it’s a straightforward way to grow marijuana. It’s less dirty, more controlled, and gives a great product.

If you’ve been toying around with the idea of having a hydroponic marijuana system, why not give it a go? Now you know what supplies you need, different system styles, and the strains to use, it’s time to start building and growing with hydroponics now!

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!

Supplies Needed

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!

  1. 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.
  2. 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.
  3. They should germinate in 1-4 days, though some seeds can take a week or longer (especially older seeds).
  4. 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

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.