How to Plant Cannabis Seeds Indoors
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Growing cannabis at home can be a fun project and a nice way to have your own cannabis plants on hand. You may want to grow cannabis indoors due to inclement weather in your area or due to a lack of green space in your yard. Start by germinating the seeds. Then, plant the seeds in soil or in a starter cube. Once the seeds have been planted, care for them properly so they grow and thrive.
- After 12 hours, place the viable seeds on a towel.
Wet one paper towel and put it on a plate. Paper towels are thick enough to retain the moisture needed to help the seeds germinate. Place one paper towel under running water until it is wet to the touch, but not dripping wet. Use a ceramic dish or plate, as it will be strong enough to hold the towels and the seeds. The paper towel should cover the dish or plate.  X Research source
- If you do not have enough space on one plate for all your seeds, soak two more paper towels and put the remainder on a new plate covered in a wet paper towel.
Wet other paper towel and place it over the seeds. Make sure the wet towel makes contact with the seeds.  X Research source
- You can try using a heat lamp near the seeds to keep them warm. Do not warm the seeds up too much, as you do not want your heat source to dry out the paper towels.
- If the seeds become too dry, they could die and never germinate.
- Be very careful with the seeds as they open. Avoid prodding, pulling, or touching the seeds, as you do not want to damage the roots.
- Any seeds that have not opened and grown roots within a few days should be discarded, as they are not viable.
- As an alternative to soil, you can use starter cubes from your local nursery or online. Starter cubes are pre-cut growing pods made of composted bark. They contain a hole where you can place the cannabis seeds and grow them in good conditions. Basic starter cubes are inexpensive and easy to use.  X Research source
- If you make planting holes that are too shallow, the seed’s roots will not have enough soil to grow well. If you make the planting holes too deep, the seed will have a difficult time sprouting.
- Do not pull or tug at the seeds when you pick them up with tweezers. If they are stuck to the paper towel, wet the towel with water to make the seeds easier to pick up.
- Do not press hard on the seeds when you cover them, as this can disturb their growth.
- If you are using starter cubes, pinch the top of the holes in the cubes closed.
- Maintain a growing temperature of 75 to 85 °F (24 to 29 °C) for the plants so they thrive.
- Stick to a regular watering schedule so the plants get enough moisture. You can plan to spray the plants in the morning and then again at night so they get the water they need.
- Grow lights range from $200 to $1,200 USD depending on the size and model.
- You can get cool white grow lights at your local hardware store or online.
Avoid touching or handling the seeds as they grow. Touching or handling the seeds can damage them and stunt their growth. With the right growing conditions and care, your seeds should sprout and poke out of the soil within five to ten days.  X Research source
More than 12 hours of light a day for about 4-6 weeks as the plant matures will be enough. Once the plant is a decent size, you may induce flowering. Switch the plant to a timer of EXACTLY 12 hours of strong light (the more sunlight the plant gets, the more energy it can devote to flowering).
Yes, it is bad for the plant to have water constantly sitting at the bottom of the pot. It could make the roots rot over time.
You can actually find LED lamps made for growing plants online. If you don’t want to bother with that, you can just get a purple light to grow them under. There are many articles online talking about the effects of colored lights on plants.
If you plan on growing short, fat plants, they should be at least 6′ apart. You don’t want the plants rubbing on each other or shading the other plants. You will also want to select a spot to ensure all plants will receive maximum sunlight.
You can start as soon as you see two little leaves budding. During that time, make sure to use distilled water when watering them.
Cannabis thrives in a comfortable room temperature when grown indoors, or a little warmer – not too dry, not too humid. If it feels too hot or too cold for you, it’s probably too hot or too cold for your cannabis plants.
You can’t. You can try keeping it by a window, but you still won’t have much success. Lights aren’t that expensive, look on Amazon.
Yes, rain water is fine for any plant. The use of distilled water is to keep from adding tap water contaminants.
Keeping the plant from “stretching” is simple. Place the lights closer to the top of the plants. There are good video examples on YouTube showing two seeds started at the same time and placed under lights at different heights. The plant with inadequate lighting actually “reaches” for the light, growing tall and thin with longer internodal gaps. The seedling with closer light grows short and squat, with less stem between leaves (internodal distance), which means a better frame and plant structure for supporting the massive buds that you want to grow. As the plant grows, raise the lights with it. (Most folks suggest somewhere in the 16-30 inch range from source to canopy.)
The cultivation of cannabis is considered illegal in many jurisdictions. Make sure it is legal to grow cannabis in your area.
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About This Article
This article was co-authored by wikiHow Staff. Our trained team of editors and researchers validate articles for accuracy and comprehensiveness. wikiHow’s Content Management Team carefully monitors the work from our editorial staff to ensure that each article is backed by trusted research and meets our high quality standards. This article has been viewed 1,323,730 times.
To plant cannabis seeds indoors, first soak the seeds in lukewarm tap water for 12 hours. Discard any seeds that float to the top. Then, place the seeds on a damp paper towel on a plate with 1 inch (2.5 cm) of space between each seed. Cover the seeds with another damp paper towel. Keep the seeds in a spot that remains between 70-80°F (21-27°C), and spray the paper towels with water whenever they start to dry out. The seeds will sprout in 2-3 days. When they do, fill pots or a growing tray 3/4 of the way with loose potting soil that has a pH between 5.8 and 6.3. Press the soil down lightly, leaving some air in it. Then, use a pencil to poke 1 inch (2.5 cm) holes in the soil. Place the sprouted seeds vertically in the holes and fill the holes with potting soil. Water the soil thoroughly and place the pots or tray in a spot that’s always 75°F (24°C) or warmer. Set up a grow light over the seeds and leave it on at all times. Water the seeds every day so the soil doesn’t dry out. The seedlings will emerge in 2-4 weeks. To learn how to use cool white grow lights to help your cannabis seeds grow, keep reading!
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How Deep Do I Plant Pot Seeds?
First-time cannabis growers have a plethora of questions when it comes to the first phases of marijuana cultivation. Even though growing marijuana plants is not much different from growing other plants (since every plant needs soil, light, nutrients, and water in order to thrive), the difference is in how much of these factors the cannabis plant needs.
In order to end up with a good Sativa, Indica, or hybrid marijuana strain, growers need to take into consideration the unique requirements that each strain needs.
To help you become more confident and informed when you set out to start marijuana cultivation, we’ll get into the subject of germination and planting of cannabis seeds, providing you with everything you need to know in order to grow Marijuana.
Tips Before You Start With the Germination of Marijuana Seeds
There are a few things you’ll need before you begin germinating seeds:
- Get high-quality seeds from a reputable seed bank.
- Keep your marijuana seeds under a specific temperature for germination that should be about 72 degrees Fahrenheit (22 °C).
- Keep your germinating seeds away from direct sunlight (don’t keep them on your windowsill or near a heater since they will get dry, and seeds need moisture).
- For the germination stage, you’ll need jiffy pellets or starter plugs that are designed specifically for germinating weed seeds.
- For indoor cultivation, you’ll need grow lights that will be used after you plant the cannabis seeds in pots.
Guide for Planting Cannabis Seeds
In order for the marijuana cultivation process to result in a harvest, the marijuana plant needs to go through 4 stages: germination (3-10 days), seedling (2-3 weeks), vegetative stage (3-16 weeks), and flowering (8-11 weeks). The first and second stages are the most crucial when it comes to planting pot seeds.
The first stage (germination) begins when the dry cannabis seed is placed in water until it sprouts. Some seeds may germinate, while others may not, depending on the quality of the seeds. Good cannabis seeds should be brown in color and should feel hard and dry to the touch.
Transplanting (Planting the Seed)
Once your seed has sprouted, it’s ready to be placed in soil so that it can start growing. Its taproot will grow downwards, while the stem grows upwards. As the plant grows, two cotyledon leaves grow out of the stem these take in sunlight to help the plant grow healthy and stable.
Germination: The Wet Paper Towel Method
This germination method includes germinating your seeds with damp paper towels and has been a tried-and-tested method for germinating seeds. Two pieces of paper towels are soaked in tap water and the seeds are stored between the sheets. Additional water is added over the next few days to keep the seeds moist.
Sprouting times tend to vary, but the seeds will generally take between two and four days to sprout, and if they take longer it’s best to throw them away, as they probably aren’t viable. After a few days, tiny roots should appear, and that is an indication that the seed is ready for planting.
Germination: Soaking Seeds in Water
Another method for germinating cannabis seeds that works well with harder seeds is the soaking method. This method requires you to place the seeds at room temperature tap water and keep them soaked for 32 hours.
After you’ve put the seeds in water, some of them will sink to the bottom. These seeds are viable. The non-viable seeds will float, and they need to be thrown away. After 32 hours, you can use the paper towel method on the seeds that sank, and after they sprout, you can plant them.
Planting the Seeds Directly
This is a harder germinating technique and one that isn’t recommended for first-time growers. In order for it to work, growers need to be informed about the plants’ required nutrients, humidity levels, and the appropriate pH soil levels that are needed.
For this type of seed germination, you’ll need to plant the marijuana seeds in moist soil, about an inch deep. You’ll also need to have some additional heating system to keep the plants warm for the first few days. Even though planting the seeds directly may not be the best option for novice growers, it does have its benefits, like not risking breaking the taproot off when you’re transferring the plant to another pot.
Transplantation of Germinated Marijuana Seeds
After germination, you can plant the germinated seeds in a pot. Remember that the cannabis seedlings and its taproots are fragile in this early stage and you need to handle them with care, so it might be good to use tweezers when you do this.
Fill small pots (2 inches) with potting soil that is loose and moist to the touch. The pots should be filled ¾ of the way. Make half-inch pre-drilled holes by using your finger, and carefully place one sprouted seed in each hole.
Cover the seed with soil, spray it with water, and refrain from pressing the soil. It will take about one more week for the germination process to conclude, after which a stem will surface, and the taproot will produce secondary roots.
The best soil for sprouting cannabis seeds is a seed starter with only a little bit of fertilizer, as cannabis seedlings need loose soil in order to grow easily. For hydroponic cultivation, you may want to germinate in rockwool cubes because they retain moisture better.
Replanting for Healthy Growth
Young plants need to be planted in smaller pots before they’re replanted into bigger containers, so that they can grow a stronger root system. That’s because small plants that are planted in bigger pots may find it harder to get oxygen when they’re surrounded with too much growing medium, which can result in stunted growth.
It’s best to replant your cannabis plant as it outgrows its pot. Avoid leaving your plant in a small pot for too long as that can result in you having a “root-bound” plant (the roots grow too large for the pot and the plant can asphyxiate and die.)
Some growers will directly plant the seedlings in the final container. However, this is not recommended because it will be harder for the plant to get oxygen when it is surrounded by too much growing medium. On the other hand, if you find that your plant absorbs water within a day, it might be time for a bigger pot.
If the thought of transplanting your weed seeds sounds tiresome and challenging for you, then you can always plant directly in the final container. But do expect slightly slower growth, and make sure you are careful when watering the plant so as not to give it too much water.
Cannabis plants require specific conditions in order to thrive and produce a good harvest. However, taking care of marijuana seeds isn’t as hard as you may initially think. Planting these seeds is similar to planting any other seeds when you’re gardening fruits and vegetables. All you need to know is how to properly germinate and transplant your young plants. With a bit of knowledge and practice, you’ll be well on your way to becoming a seasoned cannabis grower.
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Hopefully all of you aspiring growers have been able to get your seeds so we can move to the next step: germination.
Take great care handling seed and seedling. Most flower and vegetable seeds are simply planted directly in the soil, but because of the value of cannabis seeds, germinating seeds prior to planting is encouraged. Growers can achieve a much higher survival rate by germinating in a non-soil medium and then transferring the seed to soil once the tap root has emerged from the seed.
Here is one of the simplest and most successful methods: Put a double layer of paper towels on a dinner plate, then thoroughly soak the towels with water and tilt the plate to drain off the excess. Place your seeds on top of the wet towels and cover with another double layer of soaked paper towels. Be sure excess water is drained off—you don’t want the seeds to be swimming.
Cover the plate with an upside-down plate or pot lid. A plastic bag or plastic wrap also works. Don’t make the seal tight—you want to leave some openings to allow air flow.
Keep the germinating seeds away from direct light. For best results, keep them at about 75 degrees Fahrenheit. A radiant heat source, like a heating pad, helps expedite the process. If you’re using a heating pad, be sure to keep the heat setting on low and place a folded hand towel between the heating pad and plate: Direct contact between the plate and heat source can cook your seeds.
Under the right conditions, seeds usually open in one to five days, so check them daily. Do not allow the towels to dry, and add water as needed to maintain moisture. Some seeds can take as long as 10 days to germinate, but if seeds have not opened within 10 days, they are not viable.
When the seeds open, the first thing to emerge is the root. Once the root sprouts it can grow quite fast.
When the root grows to a few millimeters in length, the seed is ready to be transferred to soil. Always take great care not to damage the tap root when handling. The best soil to use for a sprouting baby ganja plant is a “seed starter” or “seedling” mix. These are light neutral blends with very little fertilizer. Heavily fertilized soils will kill seedlings quickly, and cannabis seedlings prefer loose, aerated soil that their roots can easily penetrate. A bag of good starter soil is easily identifiable: When you pick it up, it should feel light and fluffy. Soils that are heavy and compact are not good for seedlings.
Now, on to potting (no pun intended). A healthy seedling will be ready for transplanting into larger container, with richer soil, in about a month. A 16- to 20-ounce container is ideal for a seedling’s first home (many growers use a Solo cup). The container must drain, so punch some holes if needed.
Fill your container with pre-moistened soil and create a hole about a half-inch deep for your seed. The tip of a pencil works well for making the right sized hole. The seed should be about a quarter-inch below the surface.
Place your germinated seed, root down, into the hole and cover lightly. Do not pack the soil on top of the seed; a light protective layer of soil is all that is needed.
Once they sprout in one to three days, new seedlings will need lots of light, and fluorescent grow light works best. Give your baby ganja plants 16 hours of light per day.
It’s very important to have a breeze on your plants immediately. A fan placed at the proper distance and speed should create a breeze just strong enough so your plant “dances,” but not so strong that it’s bent in one direction.
Without a breeze, indoor ganja plants won’t receive the stimulus needed to develop sturdy stems and branches, which the plant will need to bear the weight of big, sugary buds.
The Potanist is written by Bud Baker and Herb Green (yes, those are pseudonyms; yes, they are real people). Reach them at [email protected]
Graphics by Stephanie Rudig
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