Soils for Growing Marijuana Seedlings
Choosing the correct type of soil for germination and marijuana seedlings is a crucial step to growing marijuana and an easy first step to get wrong. This article will explain what you need to know to get your seeds germinated and plants growing strong for the first few weeks.
Before I get started I want to make two things very clear. First, you don’t have to use soil to germinate marijuana seeds; you can use rockwool, coco fiber or a number of other soilless mediums. Here I will only be sharing information on soils. Second, the soils you use to germinate seeds and grow your plants for the first week or two will not be desirable for later in the plant’s growth cycle. You will need to transplant into a soil that contains more nutrients within two weeks.
When choosing the right soil for germinating marijuana seeds, there are three things you need to get correct: pH, nutrients, and drainage.
Marijuana plants thrive in soil with a pH between about 5.5 and 6.5 but struggle when growing in soils outside of that pH range. As the soil gets further from the desired pH range, it becomes difficult, then impossible for marijuana plants to uptake certain important nutrients. This nutrient lockout not only deprives your plants of important nutrients which stall growth but leads to plant stress and eventually plant death. Additionally, a plant not receiving all of the important nutrients has a compromised immune system and is more susceptible to plant diseases and pest infestations.
Nurseries sell many different types of potting soils with a wide range of pH values. Each kind of plant prefers its own pH range, which is why you will see different soils marked for specific kinds of plants like geraniums, roses, and lawns. Make sure you start out with a soil in the pH range between 5.5 and 6.5 and you’ll be starting off in the right directions.
Finding a great soil for germination and marijuana seedlings also requires knowing a bit about the nutrients potting soils contain. The reasons you might choose to use soil in the first place instead of a soilless medium is that the soil already contains some of the important nutrients that your plants require. Regardless of whether you are using an organic or non-organic potting soil, most quality soils will be pre-fertilized.
Remember that your seeds already contain enough energy to sprout and get them through the first week above ground. Marijuana seedlings are delicate at this stage and very susceptible to nutrient burn. It’s best to use potting soils marked as “light” or “lightweight formula,” meaning they contain very low nutrient levels. These “light” soils won’t have enough nutrients for the later stages of plant growth but are ideal before the first transplant.
Look for soils that suggest that you fertilize within the first week and continue to fertilize throughout the plants life as this indicates that the soil contains very low levels of nutrients.
Potting soil ideal for germination and seedlings will be light and loose to allow for excellent drainage while retaining both moisture and air. Because marijuana seedlings require constant and even moisture throughout the soil, it’s not uncommon for even experienced growers to over-water seedlings. A potting soil with good drainage will go a long way to help prevent any problems that a little over-watering may cause. Look for soils with a fine fluffy consistency that won’t turn to mud when drenched or crust over when they begin to dry out.
- Don’t use garden soil from outside for starting your seeds or any other kind of indoor growing. Outdoor soil always contains some kind of pests better left outside. While they are kept in check naturally outside, they often thrive inside where temperature and humidity is ideal for rapid growth in pest population and there exists no natural predators.
- Don’t use potting soils with time-release fertilizers or high NPK values.
- Don’t use potting soils for germination for seedlings that contain guano. Guano is a super strong fertilizer and can easily burn young plants.
- Don’t use potting soils with large amounts of non-composted materials like wood chips
- Don’t use potting soils with strong harsh smells like sulphur or mold.
More In Depth Cannabis Growing Tips
- Seed Germination
- Anyone Can Do It
- Temperature and Humidity
- Dehumidifying Your Growing Room
- Harvesting and Curing
source: Marijuana Growers Headquarters
Click Image to Watch Full Germination Guide Video
Germinating cannabis seeds and caring for marijuana seedlings is one of the easiest steps in growing cannabis. That said, if you do not know what you are doing, it is also an easy step to get wrong. High quality marijuana seeds are not cheap, and ordering them can be risky. So you want your germination rates as high as possible. Here are some of the sure-fire ways cannabis growers limit environmental stresses and help cannabis seeds grow into healthy, vigorous and hopefully female cannabis plants.
Selecting Marijuana Seeds
It is not always easy to tell if a cannabis seed will germinate simply by looking at it, but it is not hard to weed out the weak ones. Healthy, viable cannabis seeds should be slightly oblong and shaped like a tear-drop with a point at one end. Size varies, but marijuana seeds are usually about 1/8th of an inch wide and 3/16th of an inch long. Their colour is usually brown, often with darker stripes like a brindle dog. Cannabis seeds that are tiny, soft (immature), greenish, yellow, white, or chipped are not likely to germinate. In the end, there is really only one way to find out: try it and see.
Cannabis Seed Germination
Germinating cannabis seeds requires only the correct amount of water, heat, and air. Nothing more is needed; nor is it even beneficial.
Water – Cannabis seeds require moisture to trigger the hormonal changes that make the germination process possible. Planting your seeds in high quality soil or pH balanced Rock-wool and watering regularly to maintain constant moisture will be sufficient for most marijuana seeds to germinate. As water passes through the seed’s shell, dormant hormones stored within the seed are activated. As the water continues to penetrate the shell, the seed will begin to grow and produce a tap-root. Constant available moisture is required to continue the seed’s growth into a healthy plant.
Ideally, you should use bottled drinking water for germination. Tap water from a municipal water supply usually works fine, but contains chlorine. Well water can contain high levels of dissolved solids that can hamper early root growth. The chlorine in municipal water is not a major problem, and will dissipate if left exposed to the air.
Here is some further information to answer any questions about water quality and growing marijuana.
Heat – Cannabis seeds can germinate in many temperature conditions, but grow best between 75 and 80 degrees Fahrenheit (23-26 C). Cooler temperatures slow seed germination and promote fungal growth such as fusarium and pythium which can rot the seed and root. Temperatures above 90 degrees can also inhibit germination.
Oxygen – Cannabis seeds require air–specifically oxygen–to germinate. After germination the roots will require air, and the leaves will require CO2. Marijuana is native to primarily arid climates, not jungles and swamps. So if the growing medium is too moist or the seed is soaked for too long, the seed will not receive enough oxygen and will drown. Covering the growing medium with plastic wrap or a seedling dome will trap moisture and limit air exchange; so do not use them. Humidity above 50% promotes the growth of fungus that can damage and kill a marijuana plant while germinating or sprouting.
To promote the highest rates of germination and optimal health you want a warm, moist but not soggy growing medium, and warm circulating air that is under 50% humidity.
Steps 1 – 4 are Entirely Optional
You can use all of these steps, some of them, or none of them at all. Older seeds or seeds that have been allowed to dry out a bit too much are likely to benefit from steps 1 to 4. Cannabis seeds stored correctly that are less than three years old should germinate just fine without these extra steps. Using these extra steps on newer seeds generally does not create problems and can increase your germination rates, though some advise against them as they increase the potential for human error. If you skip earlier steps and your seeds do not germinate, you can always go back to earlier steps and try again.
Step 1: Scuffing Cannabis Seeds
By lightly scuffing marijuana seeds with sand, sandpaper, or an emery board you can create tiny scratches in the hull of the seed making it easier for water to penetrate the hull and reach the embryo inside.
Step 2: Soaking Cannabis Seeds
Soaking cannabis seeds in a glass of water can speed up the germination process. Simply place your cannabis seeds in a glass of room temperature bottled drinking water. If the seeds float you can dunk them under a few times with your finger. The seeds should be soaked for 2 to 24 hours, but certainly no longer.
Step 3: Paper Towel Germination
Place a paper towel on a flat but mobile surface like a dinner plate and then place your cannabis seeds on the paper towel. Cover the seeds with a second paper towel and pour bottled water over the top, until the entire paper towel is soaked with water. Tilt the plate to an angle of about 45 degrees so that any extra water will run down and drip off the plate. Place the plate on a heating mat if possible and set the thermostat to 75 F (24 C). Insert the thermostat probe under the paper towels.
As soon as the cannabis seed’s shell has opened and the tap root has begun to show, the seed needs to be planted immediately. This may mean that not all of your seeds get planted at the same time. Do not let the root grow to be several millimeters long before planting, or you drastically increase the likelihood of damaging the root and killing the plant.
Note: In nature, seeds germinate under soil where it is dark; so you do not need lights for germinating. Light can be used to heat a small area if you do not have a heat mat. Take care to monitor the germination process closely, however, as the light will dry out the paper towels more quickly and damage the root once the seeds open. Also remember heating mats can overheat, and either boil your poor little seeds or cause the paper towels to dry out more quickly. So be sure you use a thermostat for your heating mat.
Step 4: Planting Your Cannabis Seeds
Soil – Fill your small pots with a light and airy potting soil. Gently press the soil down to compact it slightly. Drench the soil with clean water, making sure that all of the soil is uniformly damp but not soggy or waterlogged. Make sure to test the pH of your water and balance it to 6.3 if needed. Create a hole in the soil about half an inch deep with the end of your finger. Gently pick up the cannabis seed with a pair of tweezers and place it taproot (pointed end) down at the bottom of the hole. Gently fill the hole with loose soil to cover the marijuana seed. If you are not sure about what kinds of soil use, here are some helpful directions on the best soil for germinating cannabis seeds.
Note – If you use pots that are too large you will be taking up unnecessary space which will make it more difficult to fit your pots on a heating pad. You will also be bringing a lot more moisture into the room, which means you are wasting money on nutrients each time you water. Also, remember that as this extra water evaporates it will drive up the ambient humidity of the room, increasing the potential for humidity-related problems such as bugs, mildew and mold.
Rock-wool – Because Rock-wool cubes start with a high pH, you need to adjust the pH down by soaking the Rockwool in lukewarm water with a pH of 5.5. Let the Rock-wool soak for about half an hour and then remove it from the water, letting the extra water drain off. Next flush the Rock-wool with fresh pH 5.5 water, not the water they already soaked in. After the Rock-wool is flushed, create a small hole about half an inch deep with a pencil or screwdriver. Gently pick up the marijuana seed with tweezers and place the seed –tap root (pointed end) down–in the hole. Cover the seed with some loose Rock-wool that has also been pH-balanced.
Note – Be sure not to pack the Rock-wool around the seed, as it will need to move past or through it. Do not squeeze extra water from the Rock-wool, as this can compress it and change the intended air-to-moisture ratio that Rock-wool is designed to optimize. Also, remember when growing marijuana in Rock-wool it is important to monitor not only the pH of the water you are supplying to the seeds/plants, but also the pH of the run-off water. To keep the Rock-wool cubes from sitting in a pool of run-off water, try setting them on a thin layer of perlite.
Step 5: Watering In and Situating Stuff
If you properly drenched the soil or Rock-wool before planting, watering in is pretty easy. Just take a few spoonfuls of pH-adjusted water and re-soak the area containing the marijuana seed. This may not be necessary, but will ensure moisture to that area. It is of utmost importance to keep the soil or Rock-wool as evenly moist as possible, as dry areas will wick moisture away from the seed. If you allow your growing medium to dry out, it will likely be fatal for your seedlings. Be careful to water very gently. Otherwise, the flow of water can easily uproot a seed before the roots have taken hold. Misting bottles don’t penetrate deeply enough into the soil, so continue to water wit the spoon until the seedling is well-established.
Place the pots or Rock-wool cubes in seedling trays, and place the tray on a heat mat with the thermostat set to 75 degrees F (24 C), and the sensor probe either in the soil or the Rock-wool. The marijuana seedlings are going to need light as soon as they emerge. So you might as well turn the lights on from the start. This will give you a few days to observe the effects of the lights on temperature and humidity in the room, and make any needed adjustments. There is no need to throw huge amounts of light at tiny marijuana seedlings. I recommend T5 florescent grow lights with both Blue and Red colour spectrum bulbs. T5’s are easy to set up and take down, and much less expensive to buy and operate than the HID grow lights that you will use to grow more mature marijuana plants. They also produce less heat. Make sure the ambient temperature of the room stays in the mid to high 70’s both day and night. Maintain the grow rooms humidity between between 20% and 40% if possible, and certainly no higher then 55%.
Step 6: Caring For Cannabis Seedlings
Within two-five days the seedlings should emerge from the growing medium and, shedding their shells, reveal their ovular embryo leaves (cotyledons). Occasionally, the cotyledons are not strong enough to shed the shell, and may need some very gentle assistance. Try to avoid this if possible, as it requires a jewellers precision and can easily go wrong. If you are using T5 Fluorescent Grow Lights, they should be between six and eight inches from the tops of the marijuana seedlings. Set the timer for 18 hours on and six hours off.
For Soil – Once the seedlings have emerged, I recommend waiting a week before adding a 20% strength nutrient to the water.
For Rock-wool – You can begin feeding with diluted (20% maximum strength) nutrients as soon as you like. Remember the marijuana seedlings are very fragile at this point. Even a slight miscalculation in nutrient strength can easily kill the seedlings. If you like, you may wait up to a week to begin feeding.
What Not To Do
- Do not use humidity domes or anything else to cover the pots
- Do not use heating mats without a thermostat (80 degrees max)
- Do not use jiffy or peat pellets because the create pH problems
- Do not use soil that is high in N-P-K, “Hot” or otherwise unsuitable for seedlings
- Do not fertilize your seedlings in soil for the first week, or use more than 20% strength for seedlings in Rock-wool
- Do not water-log your seeds or seedlings, or allow them to dry out
- Do not germinate seeds where they will get too cold
- Do not deprive seedlings of adequate light
- Do not use water with incorrect pH or other problems
- Do not foliar feed or spray anything, including water and pesticides, on seedlings
- Do not handle seeds with bare hands if possible. The oil from your hands can prevent water from soaking in.
- Seed Germination
- Anyone Can Do It
- Temperature and Humidity
- Dehumidifying Your Growing Room
- Harvesting and Curing
How to Clone a Cannabis Plant
Ok guys lets do some cloning. There is tons of info about this subject already but people will always ask for more info. I think the reason for this is because most people are afraid to cut their plant. They are not fragile. Pruning and cutting usually will increase bud production. It doesn't really hurt the mother plant, the only real stressful part is on the cutting itself. Cloning is the most traumatic experience a clipping via clone will endure. You are forcing a clipping to transform into a growing plant. We are making a stem that was growing leaves to all of the sudden grow roots and undergo severe changes to survive. Because of this you should take more cuttings than you need. Don't worry, it gets easier.
Cloning. Cannabis plants can reproduce sexually or asexually. Seeds are from reproducing sexually while clones are propagated asexually. To be technical cloning is taking cells from the plant (for growers that means cuttings) and promoting its growth to become a plant all its own.
Before we start Lets talk a little about the good points and the bad points to cloning.
Good points are as followed. It reduces the the time to having a mature plant. You don't need high power lights to start clones, fluorescents work very well for cloning.Since clones are genetic copies of their mothers all clones will be the same sex. Taking a clone and flowering it will tell you what sex your soon to be mother is. Since clones are genetic copies, they grow at the same rate so other techniques like SOG (Sea of green) or SGROG (screen of green). The older the mother is the easier it is to induce flowering.
Here are the bad points. Clones grow slower than a F1 hybrid will because of the lost of its hybrid vigour. This also means a F1 can grow about 25% bigger than a clone. You have to start with a good mother because all the characteristics of the mother, the clones will have the same. Clones are less disease and pest resistant because of the trauma a clone has to undergo to become a plant. You need at least two different growing areas, one for veg and clones, the other for flowering. Some plants are very difficult to clone or its just not possible. Like certain unstable hybrids, Sativa with early flowering properties, or the Ruderalis with auto-flowering properties like the Lowrider.
Preperations for cloning. Clones develop a stronger and faster root system when they have a high carbohydrate and and low nitrogen concentration. Flush your plants one week prior to taking cuttings and feed only water for that week. Just don't drown your plants. Since I do hydro it makes it a lot easier, just change the water in the res every other day for a week. Reverse folier feeding will also help leech nitrogen from the leaves. Just fill spray bottle with water and mist your mother heavily everyday once for three to five days. Hormone content is different in different parts of the plants. The bottom of the plant has more hormones in it so the lower branches tend to root better and faster than towards the top of the plant. There are many cloning compounds out there but I prefer the gel. It coats evenly and sticks to the plant well. Which ever you use just read the instructions and make sure its for use with edible plants.
Now its time to get ready. Clean and disinfect your work areas and tools. Always use sharp scissors or a razor and clean with alcohol. Have everything ready and within easy reach like rock-wool, scissors humidity dome ect.
Cloning, step by step.grab a firm branch and cut at a 45 degree angle and take a cutting about two to four inches in length. To not damage the bottom of the cutting. Trim off the lower leaves and node points. Then place cuttings in water. A embolism is a air bubble that can get trapped in the stem and kill the clone, this is the reason to soak cuttings in water until your ready to put in grow medium. Make sure the ph is between five and six. Do not fertilize the clones.
|Light Type||Band||Daylight Watts %||Cool White Watts %||Gro-Lux - Watts %||GroLux WS Watts %|
|Ultra-Violet||380||0.186 - 2.15||0.16 - 1.68||0.10 - 1.42||0.27 - 3.16|
|Violet||380 - 430||0.832 - 9.60||0.72 - 7.57||0.70 - 9.67||1.07 - 12.48|
|Blue||430 - 490||2.418 - 27.91||1.98 - 20.78||1.96 - 27.07||1.22 - 14.29|
|Green||490 - 560||2.372 - 27.38||2.35 - 24.67||1.02 - 14.02||1.24 - 14.49|
|Yellow||560 - 590||1.259 - 14.53||1.74 - 18.27||0.10 - 1.42||0.83 - 9.77|
|Orange||590 - 630||1.144 - 13.21||1.69 - 17.75||0.44 - 6.05||1.36 - 15.93|
|Red||630-700||0.452 - 6.22||0.81 - 8.47||2.86 - 39.55||1.86 - 21.78|
|Far Red||700 - 780||0.130 - 1.53||0.07 - 0.81||0.06 - 0.80||0.69 - 8.10|
|Total||8.890 100.0||9.52 100.0||7.24 100.0|