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sowing cannabis seeds

Marijuana seeds can be acquired from an array of sources and can vary in quality. For more info on how to buy marijuana seeds, check out our Guide to buying cannabis seeds.

Check out Johanna’s full video series on how to grow weed on Leafly’s YouTube .

Seeds found in finished cannabis buds can develop for a number of reasons. For example, a male plant may have accidentally pollinated a flowering female during the growing process. But more commonly, they’re a sign of stress and can be attributed to high temperatures during the final stages of flowering or an exaggerated spike in climate or environment.

What are high-CBD cannabis seeds?

You might also find a mature seed that has been physically damaged through poor handling, like rough trimming. In those cases, it probably isn’t worth the effort to try and germinate the seed.

For the typical homegrower, it may be easier to obtain cannabis seeds rather than clones. Growing from seed can produce a stronger plant with more solid genetics.

These are referred to as “bagseeds” and whether or not you can grow one will depend on where it came from.

CBD, or cannabidiol, is one of the chemical components—known collectively as cannabinoids—found in the cannabis plant. Over the years, humans have selected plants for high-THC content, making cannabis with high levels of CBD rare. The genetic pathways through which THC is synthesized by the plant are different than those for CBD production.

Start by filling pots with a premium-quality soil that has been soaked in water. Many growers also choose to lace the water with a root stimulator. Make a hole roughly 10–15mm deep. This will be your seed’s new home. Remove the seeds from their packet and place them into the pre-dug holes. Loosely cover the seeds, but be careful not to compress the soil above the seed too much. The root will struggle to penetrate solid soil, slowing plant growth. Lightly spray the top of where you placed the seed so that your growing medium stays moist.

Your growing pots will need to be placed in a damp climate that is within the temperature range listed under our golden rules. After 4–10 days, you should see a young seedling sprout, while the roots will have begun to develop underneath the soil. The entire plant and its soil can now be transferred to a larger pot, where normal growing routines should start.

• The ideal temperature is between 22° and 25°C (71–77°F)
• Your growing environment should be damp/moist, but never wet
• Relative humidity range should be between 70% and 90%
• Seeds favour fluorescent lighting (Cool White code 33)
• Minimise the amount of seed handling you do
• In hydroponic/rockwool plugs, the ideal PH value is 5.8–6.2

WET KITCHEN TOWEL METHOD

Maintaining the ideal temperature (between 22–25°C/71–77°F) and moisture for germination is tricky. Leaving seeds out in the open environment or on a windowsill is far from ideal; a DIY climate-controlled cupboard would do a much better service. A warming mat is perfect for maintaining a constant temperature, but it doesn’t tackle the issue of moisture.

To avoid disappointment, seeds that have a darker colouration stand a better chance of germinating, while pale green or white seeds are likely to fail. Even if dark seeds look slightly damaged, they should be planted anyway. There is a good chance they will still germinate, even if the outer shell is somewhat crushed.

If you don’t like the idea of pre-soaking your soil, you can use a spray to moisten the holes before you plant each seed. With enough moisture surrounding your seeds, you can still encourage a root to develop.

You will need to invest in a few pieces of unique equipment, but by using stone wool blocks, you can create a perfect utopia for germinating cannabis seeds. Soak the stone wool blocks in the same way you would a soil medium. The wool will retain the moisture and prevent the need to water during the early stages of germination. After the wool blocks are soaked, stick them in a plastic tray that also has a lid. Large cake tubs are ideal.

When the growing medium’s surface is dry (0.25 inches [1 cm] deep), it is time to water. Remember, there are few roots to absorb the water early in life and they are very delicate.

Hard Cases

3) Drain the water from the dinner plate by tipping it to the side.

Other Tips for Germinating Cannabis Seeds

Some seeds have a very hard outer shell (testa) and are difficult to germinate. Such testy cases can be softened or scarified to allow water to penetrate. To scarify, line a matchbox with a piece of fine-grain sandpaper or emery board. Put the seeds in the matchbox and shake for 10 to 15 seconds. Remove the seeds and make sure they have been scuffed a bit. Just a little scuffing will allow water to enter and set germination in motion.

2) Remove seeds from the water. Pour water out onto two paper (or cloth) towels on a dinner plate. Fold the towels over the seeds to cover them.

A shallow flat or planter with a heat pad underneath may require daily watering, while a deep, 1-gallon (3.8 liter) pot will need watering every three days or more. A properly watered flat of rockwool cubes needs water every three to five days when sprouting seeds.

1) Set seeds in a matchbox with an emery board or sandpaper on the bottom.