How to germinate marijuana seeds
Whilst it is possible to germinate cannabis seeds found in street weed, it is far more effective to select the best marijuana seeds that you can afford. There are many reputable sources to buy seeds from, particularly from the Netherlands and the United Kingdom.
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There are well over 2,000 unique marijuana strains out there and you need to pick the right type for your grow room and kind of crop you want. Do you want Indica, Sativa or a hybrid of both, indoor for hydroponics or outdoor growing, what height do you want?
When you pick a seed to germinate you need to know what that seed will produce. There are feminized seeds which are made to strict standards, chemically treated with at least 95% of them becoming female. There are also autoflowering seeds which will grow to a certain height and then automatically start flowering (budding) with no change of light timing required, you can also get autoflowering / feminized seeds. In addition you should think about what final product you are aiming for, is it more Indica smoke; normally a stronger more body stone within smaller, stocky plants or a Sativa which are known to be larger more stringy plants with a higher THC content for a more ‘speedier’ high. We also suggest checking out Haze, White and Blue seed stains.
Buying your seeds is the one time you should push your budget to the limit. We can recommend using SeedsMan or HerbiesHeadShop they have been supplying quality Dutch seeds for over a decade now, discreetly posted.
Good and bad seeds – Green or whitish marijuana seeds are usually immature and not ready to sprout. Fresh seeds look waxy, glimmer and have hard, intact shells but do range in color. If your seeds are nearly black or very dark brown then they might be too old and might not germinate well either, these can usually be crushed easily in your hand and turn to dust.
Clones – Clones were never seeds, they are taken from existing plants and if you are able to obtain a clone off a friend then this might be the best way to get started but you WILL get the exact same plant they got, so no fun surprises on quality or taste. Although that plant can be guaranteed a female if you cloned a female. We discuss marijuana cloning in more depth here.
There are many different ways to germinate a cannabis seed so we have outlined a number of the best ways here.
Germination is simply the act of getting a seed in the dormant state to sprout. After you have bought some quality, fresh weed seeds there are three main conditions required to ‘awaken’ the seed:
Light is not required and may slow or hamper the speed of germination. There are many methods for supplying these requirements and in this article we shall examine several of them.
Paper towel method of marijuana seed germination
This popular method requires a paper towel (or paper napkin or tissue paper) cut in half with each half folded in half. Place one half on a small dish and moisten. Both halves of the paper towel should be damp, but not dripping wet. If you have over-watered, be sure to squeeze out any extra moisture.
Place your seeds on the towel and allow roughly ½” of space between them so that the roots do not get tangled. Cover with the other half of the paper towel making sure it is in contact with the seeds.
Finally, place an inverted dish of the same size and type as the bottom dish on the top. This is to keep the marijuana seeds in the dark and the humidity high.
Step 1: Get a thick kitchen-style paper towel and wet it thoroughly. Make sure it isn’t dripping though;
Step 2: Place the blunt end of the seed onto the towel and leave it making sure it does not get any direct sunlight. You don’t have to cover the first piece of towel with another piece;
Step 3: Keep the seeds at about 70°F to 85°F (21°C – 29.4°C) like at the top of the refrigerator (a warm zone). Make sure the towel never dries out or you will kill the seeds;
- Check them twice a day until you see the seed case split and the emergence of a tiny root at the bottom and a white shoot at the top;
- Usually all viable seeds will have opened within 48 hours;
- Be very careful handling them at this point. They are very fragile;
- Once you can see the root and shoot, plant the seeds on their sides in the growing medium of your choice.
- Make a small hole ready for them rather than forcing them in with your fingers. Plant them about half an inch (1.25cm) deep, cover them gently with the growing medium and give them water, but not too much.
Check every 24 hours – Most seeds will ‘crack’ (break the outer hull) in 1 to 7 days. Once the tap root is ¼” to ½” long the seeds will be carefully transferred to your growing medium. The seedlings are quite fragile at this stage and must be treated with great care so as to avoid damaging the tap root.
48 – 72 hours – The first small root tip which is known as a radical will form as the water is absorbed into the seed;
10 – 14 days – You start to see the first roots appear;
21 – 30 days – The best seeds are rooted by this stage and any that are not will grow slowly and poorly and are probably not the best to keep.
Sowing your marijuana seeds
This is the act of simply throwing a large number of marijuana seeds on fertile ground and sometimes covering with a light layer of soil; sometimes not. This is quick and easy and fine if you have a large area and a huge supply of seeds. The main drawback is a huge failure rate. If you are paying a premium for quality genetics, then you want to get a near 100% germination rate to get full value for your money.
The main benefit to this method is that it avoids the possible damage to the taproot when transplanting the seedling into the medium. Also of note, is that the seed must expend its finite amount of energy in properly orienting itself in an up/down position. This is called gravitropism. When planted in soil, it only does this once and conserves energy.
Many growers like to soak their seeds in plain tap water for 12 hours before planting. This is useful for two reasons:
- Viable seeds tend to sink and non-viable seeds tend to float.
- The pre-soaking softens the outer hull and makes germination easier.
It is not mandatory, but some horticulturists prefer to sterilize their soil before germinating. This is done mainly to kill insect larvae, fungus, worms, bacteria and other pathogens that may harm your plants. You can use your convection oven for small amounts at 200F (93°C) for 30 minutes, a microwave on high for two minutes or can place the soils outside on a plastic tarp, rake the soil thin and let bake in the sun for 10 days.
Prepare your soil and water well, but do not soak. We do not want mud. Use a pencil eraser and make a hole about ¼” deep. Drop in the seed and cover with soil. Tamp lightly and give it a fine mist twice a day until the sprout appears. There is no need to cover your container as the presoaking gives the seed enough moisture to stimulate germination. However, if you choose to skip the pre-soak method, then you will need to cover your container to keep the humidity high. Clear plastic wrap works well for this.
Soilless mixes for marijuana seed germination
These include coco coir (shredded coconut husk fibers), perlite, vermiculite, peat and assorted mixes of these four, and all act similarly to soil. Even though soilless mixes do not contain any plant nutrients, they are not necessary nor recommended as the seedlings live off nutrients stored in the seed for a week or so.
Gravel pebbles hold hardly any moisture and are not recommend for germination.
Hydroton (expanded clay pellets) are in between gravel and coco coir and perlite for holding moisture and are also not recommended for germination, though it may be possible.
Tip – Scratching the hulls
We kind of view this as unnecessary, but have added it in because many people swear by it. The theory is that by weakening the tough hull, it makes it easier for the tender seed to emerge. Some gardeners use a nail file to put a small nick in the marijuana seed; others use sandpaper to thin and scratch the hull.
Peat pellets or Jiffy pots and Rapid rooters
These can be found at most garden centers in home improvement or large department stores such as Home Depot, Lowes, Walmart, etc. These are thin wafers filled with peat (Jiffy Pots) or composted bark (Rapid Rooter) and a fabric outer layer that plump up considerable when wet and only cost about 10 cents apiece when bought in bulk though most are sold with a plastic humidity dome. From experience, these are the most foolproof method we have yet to use and have a high success rate. Simply wet the wafer and after it expands, push the marijuana seed in the center just until it is no longer visible. Then place the pot in the humidity dome and wait. Several days after the sprout appears, put the peat pot in the medium of your choice. Success can be high with this method.
Rockwool cubes used for germination
Rockwool is made out of spun melted rock or mineral fibers. They hold moisture quite easily and may be used in the same manner as peat pellets. Because they are slower to dry out, a humidity dome is usually not required.
Starting the seed off in Rockwool is an excellent method of germinating marijuana seeds especially if you are going to use hydroponics for growing. One of the best characteristics of Rockwool is it contains a lot of air and is generally a nice start to your seeds life. Try and use 1 inch X 1 inch cubes, soak the cubes with water then squeeze a little excess water out, place the seeds (sideways) into a small hole in the top, pinch the hole together or cover with more Rockwool, then place the Rockwool cubes in a tray container.
You can fill the container with water later on and the Rockwool will suck it up using capillary action. Try and use good quality spring water, it can be the cheap stuff, or rain but it is better than water from the faucet which might be outside the pH required by marijuana.
Place the tray in a warm dark spot to germinate. After a day or so you will see the seeds crack open and the roots take hold in the medium. You can then transplant the entire Rockwool cube over to the main hydroponic system.
How to look after marijuana seedlings
Your marijuana plant will start to grow very quickly after germination. It is very fragile when it is small and sometime growers put a humidity dome over the top of them which protects and keeps them warmer but make sure there are holes drilled into the dome so that some air can make it in. Keep the seedlings away from draughts and use a very diluted nutrient mix when watering. Pot it up to a bigger pot once it has established itself and filled the pot or container you started it in.
Final notes on marijuana seed germination:
No matter which method you use, the temperature requirement is the same. Optimal is about 75º to 80º F (24º C to 26.8º C). Going above 90º F (32.2º C) can damage the seedling. Seedlings may still germinate as low as 65º F (18.3º C), but will take longer.
Germinating marijuana seeds is quite easy, so why do people struggle so? Too wet, too cool and too much handling are the main culprits. Many growers swear by the use of distilled or RO (reverse osmosis) filtered water. We have just about the hardest tap water in the USA, yet never have any problems. Use purified water if it makes you feel better, but personally we see no need to.
If you are or want to be a serious grower, keep different weed strains separate from each other. Be sure to label your seeds with which strain and date before you start germination.