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Ideal conditions for cannabis seed

12 Tips for Sprouting Cannabis Seeds

Every tiny cannabis seed represents a potential pound of cannabis flower. It’s crazy to think that so much abundance springs forth from such a small thing. If you’re looking to grow cannabis plants this summer, get started now with a visit to KindPeoples’ award-winning Genetics Department, where you can browse hundreds of strains in seed and clone form and pick the perfect plant to grow.

Once you’ve found the plants you’re looking for, getting started with growing cannabis is easy.

Simply follow these basic tips for germinating your seeds and planting them in soil.
  1. Look for viable, plump seeds with a telltale “tiger stripe” on the side that indicates maturity. Larger seeds tend to yield more vigorous and hardy plants.

The most common reason for lack of germination is overwatering. Don’t let your seeds get too wet or they can drown, and don’t soak for too long or they will begin to rot. If the seeds haven’t sprouted after 48 hours, let them go another day, but after 5 days the seed is most likely dead.

How to Germinate Cannabis Seeds

Germination relates to the process of a new plant growing from a seed. It is the first step when adding to your cannabis garden. You can purchase the requisite seeds from a variety of sources. On the downside, it means that cannabis seeds vary enormously in quality. We recommend looking at reputable online seed banks to get your supply. However, please note that there are legal issues to contend with if you buy seeds. This is especially the case if you decide to buy them from a source outside the United States.

When buying seeds, opt for mature options with a dark brown appearance and a firm feel. Once you have them in your possession, make plenty of space for them to grow and thrive. Learning how to germinate weed seeds correctly is crucial to enjoying years of healthy plants and fruitful harvests. In this guide, we outline the ideal germination conditions and show you five different methods.

Ultimate Guide to Cannabis Seed Germination

In theory, germinating cannabis seeds is a simple affair. They only need three things: Air, water, and heat. The famed ‘paper towel’ method is incredibly easy as long as you follow the steps outlined below. Here is a quick overview of the best germination practices before we show you the various methods.

Water

Be careful not to over-soak your seeds. Hard seeds should be soaked for a maximum of 32 hours, although 24 hours is usually enough. Soaking too long can damage them. Marijuana seeds begin to sprout when they receive the twin signals of water and heat.

Once the right conditions occur, the taproot starts burrowing through the shell of the seed.

If the root breaks through the shell and there is no water, the seedling will die. Keep the roots moist once the seed sprouts, and make sure there is ample moisture at all times.

This is arguably the trickiest aspect of germination. You have to strike a balance between ‘warm’ and ‘hot.’ Spring temperatures are ideal in a ‘normal’ year. While cannabis seeds can germinate in colder weather, the process takes longer. Seedlings also germinate faster when there is plenty of humidity in the air. If you are concerned about low temperatures, invest in incandescent bulbs, and place them over the seed area.

First and foremost, seeds perform at their best when they are left alone! When you check them for the taproot, handle with care! Try to avoid touching the white taproot because it can easily break off.

Planting

You don’t have to plant germinated seeds too deep in the soil, or whatever growing medium you choose. 0.5” – 1” below the surface is plenty. Point the white root downwards into the earth to ensure the seedling is ideally oriented.

Are Your Seeds Good or Bad?

Always opt for dark cannabis seeds as they are the most likely to germinate when kept in the right conditions. White or pale-green seeds have little or no chance of growing.

You may have heard the age-old advice on checking for viable seeds. Apparently, if you can crush seeds between your fingers, they are ‘bad.’ First of all, they won’t be good seeds because you have destroyed them! Secondly, experienced growers know that even flimsy seeds can germinate when exposed to the right conditions.

How to Germinate Marijuana Seeds – 5 Methods

1 – The Paper Towel Method

This is the easiest method and requires cannabis seeds, paper towels, and two clean plates. A word of advice: Choose cheap paper towels because they are non-porous. As a result, you can lay seeds and roots on the surface and not worry about them getting stuck. If you use high-quality paper towels, the roots will grow into them!

It is a simple method, but also a risky one. You could damage the taproot while moving the sprouted seeds, or else the paper could dry out and kill the seeds. In any case, here is the process:

  1. Use up to four sheets of paper towel and soak them in distilled water. While you must soak the sheet, make sure there is no water dripping off.
  2. Place two of the paper sheets on one of the plates. Lay the seeds down at least 1” away from one another. Cover with the other two layers of paper towel.
  3. Cover the seeds with the second plate to lock in moisture. You have created a low-cost dome! Make sure you check the seeds often to see if they have sprouted.
  4. Keep the seeds in a room where the temperature is between 70- and 90-degrees Fahrenheit.
  5. Now you must wait! Seeds typically sprout within 1-4 days, although older seeds often take up to a week.
  6. When checking the seeds, make sure the sheets are saturated. If they are drying out, add more water.

You will know that germination has occurred because the seed will split, and a little root appears. Make sure you don’t touch the taproot when it sprouts or during the transplantation process.

EDITOR’S CHOICE – Homegrown CannabisCo

Homegrown CannabisCo are the masters when it comes to seeds. Offering a massive variety of cannabis seeds that are well categorized, not only does this company create a resource for superb quality options including feminized seeds, it also provides extensive growing information for those looking for some support along their journey.

2 – Direct Planting

In nature, a marijuana seed will germinate in the soil and emerge with its taproot growing into the earth. Therefore, you can plant cannabis seeds straight into your growing medium of choice. The main benefit here is that you don’t have to worry about ‘shocking’ the seedling while transporting it.

Your seedling should instantly adjust to the new environment and grow. When using this method, dig a hole 0.5” – 1” deep in soil that is moist but not saturated. Keep things warm with a heating pad or lighting.

3 – Starter Cubes and Seedling Plugs

This has been championed as the easiest germination method. It is effectively a foolproof method. All you have to do is place the seed into the cube/plug and add water. Assuming you put the seeds in a room with the right temperature, germination should occur automatically within a few days. There is a pre-made hole for the seeds, so it is a ‘set it and forget it’ method.

The main downside with this germination method is that such plugs are generally available in packs of 50. Waste is inevitable if you only plan on planting a few cannabis seeds. The plugs dry out in a week or so and become unusable.

You can also use Rockwool cubes as they are cheap and easy to find. However, they are a terrible burden on the environment and bad for your health. Rockwool also has a high pH (which means you must rinse the cubes first) and offers a low cloning and germination success rate.

4 – Overnight Soaking

This is as simple as option #3. It involves nothing more than placing the seeds in a glass of lukewarm water overnight. It is a good idea if you’re using old and hard seeds. The soaking process can breathe new life into them. When you place the seeds in water, they float for a few hours before sinking to the bottom.

The soaking process can breathe new life into old seeds.

If you use a transparent container such as glass, you get to see the white taproot break out! You shouldn’t leave seeds soaking in water for more than 32 hours. Otherwise, seeds that haven’t sprouted yet will drown. If the seeds haven’t germinated by the 32-hour mark, put them in a warm and moist place to complete the process. You should probably use the paper towel method at this point.

5 – A Germination Station

You can purchase a readymade version online. Alternatively, attempt a DIY station by placing a plastic dome over a plate that you then add to a heating pad. Professionally made stations are relatively inexpensive and work rather well. You can buy one for under $40, and their plastic tops ensure better humidity control. With top brands, all you have to do is choose your growing media and plugs to start growing.

Transplanting Germinated Cannabis Seeds

There is no room for a delay once your cannabis seeds have begun to sprout. Now is the time to transfer the seed to its growing medium. Most growers prefer to use small pots, to begin with. Make sure you fill enough pots with loose potting soil and use a pencil to poke a hole around 0.25” deep. Remember, you could break the taproot very easily. Transfer it using tweezers and drop the seed into the hole with the root facing down. Finally, cover it with a thin layer of soil.

For the first few days, use a spray bottle to water the seeds, because adding too much water can drown them. It is worth investing in a pH meter to test the soil regularly and make sure it has enough moisture. If all goes well, the seed should sprout from the earth within a week. If it hasn’t sprouted within ten days, it will probably die.

Turn on your grow light once you have planted the seeds. The heat improves germination rates and speeds up the process of the seedlings opening their first set of leaves. These leaves will remain yellow until exposed to a sufficient level of light in any case. When you plant multiple seeds, you will find that they grow at different rates.

Inevitably, some will fail, while others will flourish. You will have seeds that pop fast and proliferate. Don’t be disappointed if you have a few failures because that’s part and parcel of the growing process. Even when you get everything right, you will inevitably lose a few seeds, and it won’t be your fault!

EDITOR’S CHOICE – Homegrown CannabisCo

Homegrown CannabisCo are the masters when it comes to seeds. Offering a massive variety of cannabis seeds that are well categorized, not only does this company create a resource for superb quality options including feminized seeds, it also provides extensive growing information for those looking for some support along their journey.

Seedling Stage: The Best Conditions for Cannabis Seedlings

In nature, cannabis plants are typically found in warm, sunny, and humid conditions with a light breeze to grow strong, resilient stems. Mimic those conditions using a propagator, a light, and a household fan, and set your seedlings up for success!

The seedling stage of cannabis plants begins when the first two rounded leaves unfurl, and lasts for 2 – 3 weeks. By this time, the seedlings will have grown their first few pairs of serrated leaves, which usually have up to five fingers. Once this has happened, the vegetation stage begins, but for now, here are the best conditions for cannabis seedlings.

When should cannabis seedlings be exposed to light?

Seedlings need exposure to light right after the sprout breaks the surface of the grow medium. This is because the first leaves you see (cotyledons) are photosynthetic, meaning they are fully capable of capturing light and converting it into energy used for plant growth. Ideal light exposure and temperature will vary between strains depending on their intended grow climate.

Outdoor seedlings and light exposure

  • To begin, keep young seedlings inside to protect them from the elements.
  • Find a sunny window and place your seedlings in direct sunlight for at least 6-8 hours for the next 10 – 14 days.
  • Gradually increase the photoperiod by an hour a day – working up to the 18/6 cycle.

Indoor seedlings and light exposure

  • Expose to light source once seedlings emerge from the soil.
  • Use a blue-light spectrum for optimal results.
  • Follow the 18/6 light cycle for the next 2-3 weeks.
  • Keep seedings at a safe distance from the light source to avoid heat stress.

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What is the best temperature for cannabis seedlings?

Your seedlings will need to be kept within strict temperature settings to ensure they grow strong stems and healthy leaves. Keep your seedlings in a warm and bright place, like a windowsill where they can get plenty of sunlight. Indoor grow temperatures are set with the use of artificial light (HID lamp, fluorescent, or LED). Keep the daytime temperature to a constant 22-25°C (70-75°F). At night, keep the conditions cooler at around 18°C (65°F).

If temperatures are too hot or seedlings are too close to the light, they can burn and chances of survival are remarkably lowered.

Safe distances for seedlings from different light sources:
  • HID lighting (metal halide lamp): 50 cm from the bulb
  • Compact fluorescent lamp: 15 cm
  • Fluorescent tubes: a few centimetres
  • LED Lights: 30 cm
Light schedule

Set your light schedule for 18 hours of sunlight and 6 hours of darkness with a blue light spectrum. This is what is commonly referred to as the 18/6 light cycle. Light intensity can be increased when 2-3 sets of healthy, green, serrated leaves have grown. That’s when seedlings enter the vegetative stage.

Intensity dimming LEDs are optimal as they provide a spectrum of light for every stage of growth.

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What is the best humidity for cannabis seedlings?

High humidity will ensure young and fragile seedlings won’t grow tired and thirsty. They use the moisture in the air to easily feed their tiny root systems. Humidity can be managed with the use of a propagator and keeping a spray bottle nearby. The ideal relative humidity (RH) for seedlings is 65 -80% RH.

How to use a propagator

A propagator is an essential item in your grower tool kit. It’s the perfect place to keep young seedlings because it offers protection and makes it easy to hold moisture in the substrate, keep in humidity, and allow for light exposure. DIY propagators are an inexpensive option, and can be made using items around the house such as plastic bottles, egg cartons, and yogurt containers.

  • Place your cannabis seedlings on a flat plastic tray with a translucent cover on top.
  • Poke a few holes to allow for air flow.
  • Check on your seedlings regularly to ensure they haven’t dried out, and spray with water when necessary.
  • Place propagator under the preferred light source or on the windowsill.

Using a propagator for outdoor seedlings

  • Introduce your seedlings to three hours of outdoor sunlight during the sunniest time of day.
  • Increase time in the sun by an hour each day (weather allowing).
  • Bring back inside during the night.
  • Repeat this every day, and after two weeks cannabis seedlings will be strong enough to live outdoors permanently.
  • Keep your seedlings inside the propagator until they grow taller than 7 cm, or a second or third pair of serrated leaves can be seen.

Using a propagator for indoor seedlings

  • Remove seedlings from your propagator once they are taller than 7 cm or 2-3 sets of serrated leaves can be observed.
  • Place a very weak fan near the seedlings, blowing near the tip of the plant.
Air flow for indoor seedlings

Wild cannabis plants grow robust stems by dancing gently with the breeze. This airflow is key to good structural integrity. It also prevents mould and helps seedlings stay healthy.

  • Set an oscillating household fan near the seedlings.
  • Set the fan to the lowest setting.
  • Direct airflow near the tip of the plant.

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How to water cannabis seedlings

During the seedling stage, as your stem grows up towards the light, the roots of a cannabis plant are growing into the soil in search of water and nutrients. Watering away from the plant base forces the roots to search for water. Fostering a minor struggle for water promotes healthy and robust growth.

  • Water away from the cannabis plant base.
  • Let medium dry before watering again.

Check whether your soil is dry by lightly pressing your finger 2-3 mm into the soil. Watering your seedlings is a gentle balancing act. Keep a close eye and ensure that the conditions stay moist.

Soil pH for cannabis seedlings

Cannabis plants require slightly acidic, moist, and well aerated soil to facilitate growth.

  • Ideal outdoor seedling soil pH: 6.5-7
  • Ideal indoor soil pH: 5.5

Pots and Containers for cannabis seedlings

A container around the size of a cup, or 250 ml, is perfect for cannabis seedlings. Once they are taller than the pot is deep, carefully transplant them to 5 litre pots, then the size of the final pot is up to you. Tip – do the final re-potting before flowering begins, to avoid stressing them.

Rockwool cubes and blocks can also be used for seedlings, and can be planted out into soil or into larger blocks as above.

For the next 14 days, pay your cannabis seedlings loads of attention. They will thank you for it. Keep your grow conditions consistent, and your plants will be healthy and ready for the vegetative stage. The foundations are set, and you have the best genetics to ensure a successful crop.

Now it’s over to you. Remember to be patient and enjoy the process. Did we miss anything out, or do you have any burning questions? Post them in the comments below. Do you have experience caring for seedlings? Drop in some tips and tricks!

Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.