How Deep to Plant Marijuana Seeds

With more and more states in the U.S. legalizing recreational marijuana, including at-home growing, more and more individuals are looking for information on weed seeds and how to grow their own weed plants in their homes and/or gardens.

One of the most frequently asked questions by beginner growers is: “How deep should I plant my cannabis seeds?”

This article is intended to answer that question and help you get started so that you can choose the right kinds of cannabis seeds that are easy to grow, and have the foundations you need to have you confidently germinate, plant, and tend to your marijuana seedlings.

Before you can even start the germination process, you first have to procure some cannabis seeds and decide what type of seed you want to get, such as autoflowering seeds or photoperiod seeds or, if you are a breeder or expert grower, regular cannabis seeds.

If you’re a beginner grower, you’ll probably want to go with an autoflowering strain as they tend to produce hardy plants due to the presence of ruderalis in their genetics and often have a shorter vegetative growth phase and flowering stage. In short, they are perfect for inexperienced growers thanks to their genetic engineering that allows them to flower automatically with little effort on the part of the cultivator.

The other key thing to check for when choosing your recreational or medical strain(s) is to make sure you are getting feminized seeds, as there’s a 90+% chance of ending up with female plants; whereas with regular seeds, you have a 50/50 chance of ending up with viable cannabis seeds in terms of getting flowering female plants. Fortunately, reputable companies like Growers Choice Seeds, only sell feminized cannabis seeds that they back up with a seed germination guarantee, which means they offer pretty much all-viable seeds.

Now that you have your feminized cannabis seeds, and are ready to grow them, first, you’ll need to germinate them. While this may sound like some kind of master cultivator specialty process that involves building some high-tech marijuana seed germination area, it’s actually incredibly simple and low-tech where even those with the blackest of gardening thumbs can do it.

Although there are several different germination methods, such as using seedling cubes, starter plugs, seedling plugs, etc., if you only ever learn the paper towel method you’re pretty much guaranteed successful germination, plus it’s incredibly cheap as your basic setup just requires cannabis seeds, a glass, water, and cheap paper towels.

1. Soak your seeds in a glass of water (spring, rain, or distilled water are all fine so long as you have clean water) for 14 to 18 hours. If your pot seeds haven’t sunk to the bottom of the glass of water within the first few hours, just gently tap them until they do.
2. Once your still-ungerminated seeds have finished soaking, pour both the water and seeds onto a layer of paper towel on a plate or tray, making sure to drain off any excess water.
3. Fold the now-wet paper towel in such a way that your soaked weed seeds are completely covered, thereby giving you a sort of “seed tray” (or seed plate)
4. Place your seed tray (or plate) in a warm and dark space. The ideal temperature is between 75 to 80 degrees Fahrenheit and needs to be maintained as such so that the marijuana germination conditions stay at a consistent level. Some place their seed tray in a windowless space, like a closet or in the basement, etc., install a reptile heat lamp, or place their seed tray on a heat mat to maintain steady and constant temps, in order to ensure the optimal germination conditions. (Larger-scale growers may choose to be a bit more elaborate and create a germination station in their home with a rack of seed trays over a station with a heat mat etc.)
5. Throughout the germination process, which usually takes 3-10 days in its entirety, but can take as long as 14, make sure to keep your paper towel well saturated but not to the point that it’s sitting in a pool of water.
6. Once you start to see the white tap root begin to grow, which generally takes a couple of days, wait until it’s about .25 to .75 inches long (2 to 3 mm)

And that’s it. That is really all you need to do. Now you need to plant your cannabis seedlings!

If you’re new to cannabis cultivation, growing your cannabis plants indoors is the best option. This is due in part to the fact that growing indoors allows you to control things via your indoor setup as it makes the careful monitoring of all your weed plants’ needs that much easier. It lets you maintain proper humidity levels either via the use of a humidity dome or humidifier and how many hours of light per day your plants have by using grow lights. It also allows you to ensure your plants are growing in consistent temperatures, as weather conditions are not something you can guarantee outside.

While there is many an option for growers by which to grow their weed plants indoors, such as the use of a soilless medium like a hydroponic setup using rockwool cubes or jiffy pellets, etc., along with there being several methods and plant training techniques for shortening the vegetative stage and/or flowering time of your plants in order to have the fastest growth rates, maximizing your yields, achieving optimal growth, and so on, we’ll just cover the most basic method of planting indoors in soil, as becoming a hydroponic cannabis grower is something that takes some previous cannabis cultivation knowledge.

However, let’s first just quickly cover the container size for your baby plants.

If you’re growing a photoperiod strain, you will want to start off with a plant pot that is only one to two liters because if the ceramic or plastic container is too big, the young cannabis plant roots might not be able to absorb all of the water that is contained in the soil. (The converse is true if you use the too-small container as then the cannabis plant roots won’t have space to grow etc.) As your plant grows you will be able to eventually transplant your healthy plants to a larger container. It’s also important to plant your seedlings in a container with holes in the bottom so that you don’t end up with excess water in your soil, which could result in severe damage to your cannabis roots.

However, if you are growing an autoflowering strain, which has shorter vegetative growth and flowering stage times and produces hardy plants, it’s best to grow your weed plants in autoflower plant pots as autoflowering seeds do not handle being transplanted as well as photoperiod seeds do. What this means is you’ll need to know the approximate height your weed plants will reach when fully grown, which is information that reputable cannabis seed companies provide with all of the different types of cannabis seeds that they have to offer.

Basically, smaller autoflowering strains should be grown in pots that are between 1.75 to 2.5 gallons. For larger indoor plants or ones that you are growing outside, then 2.5 to 4-gallon plant pots should be a decent size.

Finally, while you can use peat pots, many prefer not to as they tend to wick moisture.

Planting directly into the soil is probably the easiest, most affordable way to grow your cannabis seedlings. In addition, it requires the least amount of previous cannabis cultivation experience and comes with the added bonus of preventing you from having to move your seedlings when they are at their most vulnerable stage.

To grow your marijuana plants in soil, you’ll first need to fill your small plant pots with high-quality, balanced potting soil until it’s about .25 inches below the edge or lip of your pot. It’s important that you don’t pack the potting soil too tightly packed as the cannabis roots will struggle to grow and could even suffocate.

So, once you’ve filled your plant pots with well-balanced potting soil that is rich in cannabis nutrients you’ll want to make a small planting hole in the ground that’s a few centimeters deep. You don’t want to make a deep hole as the further down your feminized seeds are planted the harder it is for them to get enough light etc. and then the stem of your marijuana plant could be too fragile resulting in weaker plants.

Next, you will need to carefully transplant your marijuana seedlings from their seed tray into their new planting holes, being careful to not break or damage any of their white roots and tiny filaments, gently cover them with your potting soil mix, and then water.

If you used the wet paper towel germination method and your cannabis seedlings are stuck to the paper towel, attempting to loosen them could easily result in damaging the white tap roots. Instead spray them until you have a slightly damp paper towel, which should loosen up the white roots so that you can safely transfer them to their new home.

Note that when you water your seedlings and cannabis plants, using clean water (i.e. filtered or distilled water) that is at room temperature is best. Furthermore, it is extremely important that you keep your cannabis seedlings or plants moist but never waterlogged as excess water can be just as damaging as not enough.

Many outdoor growers start their young female plants indoors for about two weeks, or until they can withstand a gust of wind, before planting their young cannabis seedlings outside. Also, before your plant your seeds in the soil outside, you’ll need to wait for prime spring conditions with warm temperatures for you to do so, which should be around April and mid-May, unless you live in a colder climate where springtime conditions don’t become consistent until later in May.

The best kind of potting soil mix to use is one that does not have high levels of nutrients, as too high a dose of nutrients can also inflict damage on a young plant. As your plants mature, you can add extra nutrients as needed. If you’re a beginner grower you may want to use a coco-based soil, like coco coir, as it contains the right strength of nutrient levels that should last a few weeks.

Once again, you will want to ensure your planting holes aren’t too deep. They should instead be more than .75 to 1 inch, as this should ensure that the cannabis plant roots have enough space to grow.

Once planted, then gently cover the seeds with soil, and use clean or distilled water to water making sure to not create pools of water in the soil.

As previously noted, because only Mother Nature can control the environmental conditions, growing outside is better for those who aren’t new to growing weed. While there are many advantages to growing outside, including not having to spend much money on grow setup items, dealing with issues like excessive light due to too much exposure to nature’s natural light system, aka the sun; not enough hours of darkness; too little or extra humidity levels, etc. are all things that can overwhelm a new grower as all of these elements impact the stages of growth for your weed plants and can turn otherwise healthy plants into weaker plants or damage the cannabis root system if they get too waterlogged due to excessive water from constant thunderstorms, etc.

So, now that you not only know how deep to plant your weed seeds, but how to select good viable seeds; use a solid germination method for your still-ungerminated seeds, and set up the optimal germination conditions using a wet paper towel to create your own seed tray; some basics on plant pots and not using potting soil mix that has too many extra nutrients; how to identify new cannabis roots growing from your seed sprout; and how to transplant them you should be good to go.

Provided that your young plants are getting adequate light and water, are in the semi-dry or moist environment that they require, and are getting the right cannabis nutrients and hours of darkness that they need they should thrive in their stages of growth transitioning from their vegetative stage to their flowering stage.