How to Plant Cannabis Seeds Indoors

Co-authored by wikiHow Staff

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.

Part 1

Part 1 of 3:

Germinating the Seeds

1
Soak the seeds. To make germination easier, consider soaking the seeds in tap water for 12 hours in a bowl. Viable seeds will sink to the bottom of the bowl and non-viable seeds will float.^{[1]
X
Research source}
- After 12 hours, place the viable seeds on a towel.
2
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.^{[2]
X
Research source}

Advertisement
3
Put the seeds ¹⁄₂ inch (1.3 cm) apart on the towel. Place the blunt end of the seeds, the end that does not have a point, on the towel, spacing them apart so their roots do not get tangled.^{[3]
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.
4
Wet other paper towel and place it over the seeds. Make sure the wet towel makes contact with the seeds.^{[4]
X
Research source}
5
Store the seeds at 70 to 85 °F (21 to 29 °C). The cannabis seeds need to sit at a warm, consistent temperature to germinate. Store the seeds out of direct sunlight in a warm area, such as the top of your refrigerator.^{[5]
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.
6
Keep the paper towels moist. Spray the top towel with a spray bottle of water to keep them moist. Check the paper towels several times a day to ensure they do not dry out.^{[6]
X
Research source}
- If the seeds become too dry, they could die and never germinate.
7
Wait for the seeds to germinate. Viable cannabis seeds will usually open with 48 hours. You should see the roots start to appear within a few days, depending on the seed type. Once the tap roots are ¹⁄₄ to ¹⁄₂ inch (0.64 to 1.27 cm) long, the seeds are ready to be planted.^{[7]
X
Research source}
- 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.

Part 2

Part 2 of 3:

Planting the Seeds

1
Fill small, 2 inches (5.1 cm) garden pots with potting soil. Get plastic garden pots that are small enough to house the seeds. Look for garden pots at your local garden supply store or online. Use potting soil that is loose and airy. The potting soil should be moist to the touch. Fill the pots ¾ of the way with the soil.^{[8]
X
Research source}
- 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.^{[9]
  X
  Research source}
2
Make a ¹⁄₄ inch (0.64 cm) deep hole in the soil. Use a pen or pencil to poke a hole in the soil for the seeds. Do not poke the hole too deep or too close to the surface of the soil.^{[10]
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.
3
Use tweezers to drop the seeds in the hole. Make sure you drop the seeds with the tap root facing into the hole. The tap root is the long root that will grow out of one end of the seed.^{[11]
X
Research source}
- 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.
4
Cover the seeds with soil. Gently cover the seeds in ¹⁄₄ inch (0.64 cm) of soil so they can grow.
- 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.

Part 3

Part 3 of 3:

Caring for the Seeds

1
Keep the seeds out of direct sunlight in a moist area. Do not put the potted seeds on a windowsill or near a heater, as this will make the air too dry and hot. A closet or a basement are two good indoor spots for the plants to grow.^{[12]
X
Research source}
- Maintain a growing temperature of 75 to 85 °F (24 to 29 °C) for the plants so they thrive.
2
Wet the soil one to two times a day. Use a spray bottle to keep the seeds moist. Make sure it is moist to the touch, but not soaking or dripping wet. Avoid pooling the soil with water, as this can lead to growth issues due to overwatering.^{[13]
X
Research source}
- 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.
3
Use cool white grow lights. Your cannabis seeds need light 24 hours a day, seven days a week to grow. Use cool white grow lights that have a consistent temperature of 72 °F (22 °C). Keep the lights 2 inches (5.1 cm) from the pots. Use 3 to 5 watts of light for each pot.^{[14]
X
Research source}
- 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.
4
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.^{[15]
X
Research source}

Community Q&A

Question

How much light do the seeds need after being planted and for how long?

Community Answer

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).
Question

Is it a must for the tin to have drainage?

Community Answer

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.
Question

What substitute can I use for a white light lamp when growing weed indoors?

Joseph Madder

Community Answer

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.

Warnings

The cultivation of cannabis is considered illegal in many jurisdictions. Make sure it is legal to grow cannabis in your area.

⧼thumbs_response⧽
Helpful 33 Not Helpful 13