Jack Frost Landscapes & Garden Center blog for updates on sales and products as well as gardening tips and tricks, recipes, crafts, and more! Time then to whip out our packages of seeds and get to work. But how do you best set to work, to get these tiny, fragile seeds to grow without problems into small plants? Struggling with your cannabis seedlings? Click here for 3 simple steps to growing healthy seedlings, alongside tips for mastering the cannabis seedling phase.
Stages of Growing Cannabis
Cannabis, weed, marijuana, kush, ganja – whatever you want to call it, it’s now legal to own and grow in the state of Virginia. So what does this mean for those interested in growing it?
Growing Cannabis for the first time can be quite overwhelming. A quick Google search will lead you to hundreds of results with more information than you can ever sift through. There’s so much to learn – lighting, pH, soils, training methods, curing, and so much more. Where does one start?
It’s really easy to fall down the rabbit hole of information online. The sheer amount of information can almost hinder you when you’re first getting started. I think it’s easiest to just get started and learn as you go.
Starting with gaining a general understanding of the stages of growing Cannabis is a great place to begin before you try growing for the first time. It will help you have a decent idea of what to expect along the way.
How long does Cannabis take to grow?
How long Cannabis takes to grow can vary based on the variety of the plant and conditions it is grown in. On average, from seed to harvest, it takes anywhere from 10-32 weeks (about 3-8 months). It’s a quicker process if you start with a clone (rooted cutting) or an autoflower seed. The biggest variability in how long a marijuana plant takes to grow will happen in the vegetative stage—after the seedling phase and before flowering.
Stages of Growing Cannabis
Every plant begins with a seed. Cannabis seeds should be germinated just like any other seed. They can take anywhere between 3-10 days to germinate, although it can happen in as few as 24 hours or as long as 2 weeks. To germinate, you can place the seeds in a damp paper towel, which you should then place in a dark place, such as inside a drawer. Check on them after a few days to see if the primary root, called the radicle, has emerged. This will look like a little white “tail” coming out of the seed. Once germinated, move them to damp soil.
Alternatively, you can place the seeds directly in damp soil to germinate and grow, without having the trouble of moving them. For this method, I would recommend a seed starting mix. These are usually lighter and fluffier than traditional potting soil, which gives your fragile germinating seeds a start on the right foot. We carry Coast of Maine Sprout Island Blend Organic Seed Starter Mix. It has additional perlite that aerates the soil and helps prevent damping off. It also has mycorrhizae, worm castings, lobster meal, hen manure, and kelp to get your plants off to a healthy start.
2. Seedling Stage
Once your seed has germinated, it’s now time to move the germinated seed from its paper towel to a growing medium. If you started them in a seed starting mix, you will want to move them from the seed tray to a larger pot with a high-quality potting mix, such as the Coast of Maine Stonington Blend Grower’s Mix. This is a super soil, that works especially well for growing Cannabis. It contains mycorrhizae, kelp, alfalfa meal, fish bone meal, worm castings, perlite, manure, peat, coir, and lobster compost that feed your plant throughout the growing cycle, with no need to use additional nutrients.
Plants are considered seedlings for about 2-3 weeks after germination. During this time, the plant should be moved to a spot with direct sun, if growing outdoors. If growing indoors, set your grow lights to run for 16 hours a day.
3. Vegetative Stage
After the seedling stage, Cannabis plants move to a vegetative stage. This is the time when the plant focuses on leaf production. It will not produce flowers at all during this stage, as the plant needs to grow plenty of leaves to take up enough photons (sunlight) to create the necessary energy to produce large flowers. The vegetative stage can last anywhere from 3 to 16 weeks, depending on the variety.
During this stage, indoor plants need 16-18 hours of light per day, and outdoor plants need at least 6 hours of direct sunlight (“full sun”), plus several hours of indirect sunlight. They will also need plenty of Nitrogen during this point, as Nitrogen is the nutrient that promotes healthy leaf growth.
The flowering stage is the last stage of the Cannabis plant life cycle. This is the time when your plant will stop putting as much energy into leaf growth and will instead focus that energy on creating the flowers (buds), which are used for medicinal and recreational purposes.
Stages of Flowering – Source: Katie Plummer
Cannabis is triggered to flower when the hours of light it receives are reduced. If you’re growing outdoors, you’re at the whim of the seasons and will have to wait until the sun starts to go down in fall for it to flower and then harvest. If you’re growing indoors, you get to play mother nature and can force your plant to flower at any point. When you’re ready for plants to start the flowering stage, change your lights to a 12/12 cycle ( 12 hours with the light on and 12 hours with it off ). You will see signs of flowering in 1-3 weeks . On average plants will be ready to harvest after 8-11 weeks of flowering.
Your plant will be ready to be harvested once flowers are compact and the pistils turn orange/brown. These pistils look like “hairs” coming out of the flowers.
To dry your Cannabis, hang sections of the plant upside down in a dark, cool space, such as a closet. You want to aim for 55-65% humidity and 60-70°F in the spot that you’re drying your plants in. Prolonged periods of light, friction from handling, and humidity/dampness can degrade resin glands, so you will want to avoid all of these.
During the drying process, plants lose roughly 75% of water weight, which increases the cannabinoid to weight ratio. It also helps equalize moisture content, preserve cannabinoids, and shed chlorophyll.
Cannabis is ready to trim once the stem snaps when bent, typically after 3-7 days of drying.
After your plant has dried, it’s time to trim! Trimming makes your fingers very sticky, so wear gloves if this is something you want to avoid. Simply trim off the larger leaves and stems. You can leave smaller sugar leaves if you’d like, as these still contain a good amount of cannabinoids and terpenes that provide the medicinal properties of Cannabis. It’s all personal preference of exactly how much you trim off. And you can save all the trimmings to make edibles, tinctures, salves, and more.
Curing is an essential part and the last stage in growing Cannabis. It helps the buds achieve full aroma. Curing is as simple as placing your freshly trimmed buds in a glass jar with a lid, like a mason jar. You’ll then want to place the jar in a cool, dark place, such as inside a drawer or in a cabinet.
During the first week of curing, you will want to “burp” your jars. This means you should open the containers once or twice a day for a couple minutes to allows moisture to escape and replenish the oxygen inside the container. After the first week, you only need to burp containers once every few days.
You should allow buds to cure for at least 2 weeks, but some people choose to cure for as long as 6 months. This helps stop the loss of moisture and to preserve flavors and aromas.
The Complete Guide To Germinating Cannabis Seeds
Before you can be met with bountiful hauls of dank buds, there are several stages of cannabis growing that take precedence. Unless you can successfully germinate cannabis seeds, you won’t have a plant to harvest. Give your seeds the best possible start in life by reading our definitive guide to germination.
- The art of germinating cannabis seeds
- What to look out for in cannabis seeds
- Germination temperature plays a crucial role
- What is an expected germination time?
- Choosing your germination method
- Giving your seeds the best possible start in life
- Germination and beyond
The Art Of Germinating Cannabis Seeds
Often overlooked, it is all too easy to assume that the vegetative and flowering stages of cannabis growth are the most critical parts of the plant’s life cycle. However, with the chance of failure high unless you know what you’re doing, poor planning when it comes to germination can make or break your next grow. Giving your cannabis seeds the best possible start on their journey to bulging buds is a surefire way to encourage a healthy and robust plant.
Small, fragile, and in desperate need of a helping hand, there are several ways you can germinate your cannabis seeds. All methods have varying degrees of success, with both advantages and disadvantages. It is important to note that even with advanced growing expertise and top-of-the-line equipment, you may still end up with a few failed seeds. This is a natural part of dealing with a living organism. At Royal Queen Seeds, we provide a wide range of high-quality regular and feminized cannabis seeds. We label our genetics clearly, so you don’t have to worry about any unwanted surprises.
What To Look Out For In Cannabis Seeds
Regardless of where you get your seeds from, it is best to give them a slight (and delicate) inspection before planting. Most of the time, all seeds will germinate; however, poor-quality seeds will produce a weaker plant. Unfortunately, that is something you will not find out until well into the vegetative and flowering stages.
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.
Germination Temperature Plays A Crucial Role
Before we jump straight into the germination methods, there are a couple of germination golden rules. For the best results, we recommend staying within these guidelines, no matter how you choose to germinate. That being said, of all the factors to consider, temperature is one of the most critical. Seeds will always seek out even the smallest amount of moisture, but they use temperature as a sign that they need to do so.
- 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
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What Is An Expected Germination Time?
Three fundamental principles will trigger that first small taproot to appear: warmth, moisture, and darkness. With the promise of moisture, a single root will take shape before slowly developing into the cannabis plant we know and love. In the right conditions, seeds will begin to develop within 12–36 hours of moisture being introduced to them.
Timescales can vary, as it all depends on how ideal your germination environment is (see the golden rules above). Even the worst grower could make a seed germinate, but it may take a few weeks and, of course, increases the risk of a weaker plant.
Choosing Your Germination Method
Glass Of Water Approach
Arguably one of the least effective methods, but it is still viable. Incredibly simple to facilitate, beginner growers may opt to germinate their seeds in a glass of water. Half-fill a glass or bowl with water that is approximately 22°C (71°F).
After 3–5 days, the seeds will start to open, and you should see tiny white tips appear. Once these roots reach 2–3mm in length, use extreme care to transfer them from the water to pre-prepared soil pots.
The soil pots will need small holes (roughly 10–15mm deep) for the newly germinated seeds to be placed into. Once the seeds are secure, you will want to place a fluorescent light 13–15cm (5–6 inches) away to encourage growth. Finally, don’t risk overwatering your seeds at this early stage. Use a plant mister to make sure they stay damp but not soaking wet.
Wet Kitchen Towel Method
Probably one of the most common methods of germination. The kitchen towel method comes in several iterations. Some growers use cotton wool pads or absorbent pieces of paper. For this guide, we will be using kitchen towel as it is readily available and holds moisture relatively well.
Place one sheet of damp kitchen towel on a flat surface. Space your seeds a few centimetres apart before placing the second piece of kitchen towel over the top. You need to ensure both pieces are damp, not wet. Once again, when the white root tips reach 2–3mm, move the seeds (carefully) to soil pots. Use the same guidance found above for planting techniques.
Planting Directly Into Soil
Planting directly into your growing medium prevents having to move seeds when they are at their most fragile. That first root tip is covered with microscopic filaments that are easily damaged. Given that both a cup full of water and moist paper towels are more prone to temperature fluctuations from their environment, planting in soil is a much safer option.
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.
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.
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.
Using Stone Wool Blocks
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.
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.
The dome of the plastic container will create your seeds’ own mini tropical climate. If you then place all the components in a temperature-controlled cupboard, you will have created a self-perpetuating supply of moisture—no need to touch the seeds again until they are ready to be transferred to your final growing medium as a young seedling. Using the stone wool block method, your seeds should germinate in one to two days.
Two or three weeks after germination, your young seedlings should be ready for their new home. At this point you have two options; transplanting them into soil pots, or taking on the challenge of hydroponics. You’ll know when the seedlings are ready to be moved because the root system should start to poke out of the bottom of the wool blocks. As long as the roots haven’t begun to engulf the bottom half of the wool block, they will seek out water and nutrients in their new surroundings and continue to grow downwards.
RQS Soil Plugs
RQS Soil Plugs are another great option when it comes to germinating seeds. They are easy to use and contain a carefully crafted formula of ingredients designed to help seedlings thrive. Composed of the highest-quality peat and coir, they provide a superb balance of aeration and water retention. This ensures seeds don’t dry out, while also preventing fungal diseases that cause the dreaded damping off.
RQS Soil Plugs contain key micronutrients that seedlings require for optimal growth and development. The addition of active biologicals also helps to establish the root microbiome with beneficial organisms that fend off pathogens and assist in nutrient uptake and organic matter breakdown. Furthermore, the pH-balanced nature of these plugs means cannabis roots can easily absorb nutrients without the risk of lockout.
They’re super easy to handle and take any hassle out of transplanting. Once roots begin to appear, you can transplant seedlings directly into soil or hydroponic systems.
To use RQS Soil Plugs, place a single seed of your choice into each plug. Place your plugs into a propagation tray and mist them with water—just enough to get them moist. Use a clear-plastic lid to maintain humidity, and aim for the temperature and humidity conditions discussed above. Use a small hygrometer to keep track of these important figures.
Mastering The Cannabis Seedling Stage In Just 3 Steps
The seedling stage can be a looming challenge for novice growers. With these three simple steps, however, even inexperienced growers can manage their cannabis seedlings with confidence.
Cannabis cultivation, cannabis history, cannabis culture
Three simple steps to mastering the cannabis seedling stage.
Cannabis seedlings can be tricky to keep alive, especially for rookie growers. With a solid understanding of seedlings and their requirements, though, the all-important seedling stage can be a lot less threatening. Keep reading for three simple steps to growing healthy seedlings.
STEP 1: PICK THE RIGHT GENETICS, CONTAINERS, AND MEDIUM FOR YOUR SEEDLINGS
When sourcing your seeds, be sure to actively search out the right strain for you; your experience and skill as a grower, budget, grow equipment, preferences in taste and effect, and whether you’re growing indoors or outdoors will determine which strain will yield the best results for you.
As for the medium, we always recommend growing in a light, well-aerated, slightly acidic soil with a pH of 6.3–6.5. We recommend using between 20–50% perlite in your medium to aid with soil aeration and nutrient retention. The more nutrients you plan to give your plants, the more perlite you should add to your soil to help with drainage and prevent nutrient lockout.
Remember to water just around the stem of your seedlings, and only once the soil has completely dried out (see the section on over/underwatering below for more info). Also, keep in mind that seedlings (especially autoflowering varieties) are extremely sensitive to nutrients. Never plant them into hot (nutrient-rich) soil and don’t start feeding them until they’ve grown 3–4 sets of true leaves.
When it comes to picking pots, we recommend the following approaches for autoflowering and feminized seedlings.
THE RIGHT POTS FOR AUTOFLOWERING CANNABIS SEEDS
When growing autoflowers, we recommend planting them directly in their final pots. Because of their short life cycle, it’s best to avoid putting autoflowering strains through any kind of unnecessary stress, including transplanting. While the exact pot size you use will vary depending on the strain you’re growing and the size of your grow space, most auto growers use pots between 5–15l.
THE RIGHT POTS FOR FEMINIZED CANNABIS SEEDS
If you’re growing feminized seeds, transplanting isn’t as much of an issue since these plants have time to recover from the stress. Using Easy Start germination pots, you can support robust health right from the beginning. You’ll want to transplant your seedlings just before they start outgrowing their starter pots. We typically recommend transplanting once they’ve grown sets of true leaves that spread out to cover the full circumference of their current container.
From here, most indoor growers move their plants directly into 12l pots, but you can go above or below that to suit your particular strain and grow setup. Keep in mind that you can (and should) up-pot feminized photoperiod plants a few times to max-out development, meaning you don’t need to transplant your seedlings into a giant pot right away.
A NOTE ON CANNABIS POTS
From cheap nursery containers to sophisticated smart pots, growers are spoilt for choice when it comes to picking the right container for their cannabis plants. And while it’s possible to grow great weed in cheap plastic propagation containers, there are a couple of things you’ll want to keep in mind when choosing pots for your weed plants.
• Drainage holes
Make sure your pots drain well to protect your plants against fungal pathogens and root rot. If your pots don’t already contain holes (or some other kind of mesh to allow runoff), you’ll need to puncture them yourself.
One of the functions of a plant’s substrate is to serve as a site for air exchange between the roots and the environment. Smart pots like the RQS Fabric Pot help your plant’s roots respire by allowing more oxygen to reach them. This translates into faster, more vigorous growth, healthier plants, and a better harvest.
• Pot size
Keeping tiny seedlings in huge pots increases the risk of overwatering, as your plant’s roots won’t be big enough to extract all the water from their substrate. Any water that stays in the substrate will effectively drown the roots and attract pathogens and pests into your garden/grow room.
STEP 2: USE THE RIGHT GERMINATION TECHNIQUES
Cannabis seeds need four things in order to germinate: moisture, warmth, darkness, and time. To ensure you grow healthy seedlings, germinate your seeds using one of the following techniques.
• Paper towel method
Carefully place your cannabis seeds between a few moist pieces of paper towel, and place it all in a plastic container with a lid. Keep the container in a warm, dark place (temperatures between 20–25°C are ideal). Leave a slight crack in the lid to allow for some fresh air exchange.
• Glass of water method
Simply drop your seeds into a glass of water and let them sit in a cupboard for 24–48 hours at 20–25°C. Once you see the first signs of taproots sprouting from your seeds, they’re ready to plant. If your seeds don’t germinate after 48 hours in water, switch to the paper towel method. Don’t keep the seeds submerged for more than 48 hours or they’ll rot.
Your seeds are ready to plant once they’ve cracked open and released a small, white taproot. Plant your germinated seeds one knuckle (roughly 3–5 millimetres) deep with the taproot facing down. That way, your seedlings won’t have to reorient themselves.
• RQS Starter Kits
Alternatively, use the RQS Autoflowering or Feminized Starter Kits to provide your seeds with the perfect conditions from the get-go. This kit contains starter pots filled with perlite and beneficial bacteria, as well as a propagator and lights to breathe life into your seeds.
STEP 3: MASTERING THE SEEDLING STAGE
Now that your seedlings are in their soil, the real challenge begins. Cannabis seedlings are extremely fragile; armed with nothing but frail roots and a small set of cotyledons (that first set of small rectangular leaves), minor stressors can take down your seedlings in just a couple of hours. By taking the time to understand your seedlings and their specific needs, however, you’ll automatically know how to optimise their environment and help them grow into strong vegetative plants.
THE BASICS: OPTIMISING LIGHT, TEMPERATURE, AND HUMIDITY FOR CANNABIS SEEDLINGS
Seedlings have very particular needs when it comes to temperature, humidity, and lighting, and missing the mark in any of these areas can prove fatal for such small plants. For best results, we recommend growing seedlings in a propagator where you can easily create the perfect environment for them to flourish in.
Cannabis seedlings like daytime temperatures of 20–25°C and nighttime temperatures that are roughly 4–5°C cooler. High temperatures will stress your seedlings and stunt their growth, which, at such an early stage, can prove fatal. Dry leaves with curled up edges are a telltale sign of heat stress. With time, your seedlings might also develop other symptoms, including pale foliage and red or purple stems. Heat stress can also cause weak, wilting leaves with downward folding tips.
Cold temperatures, on the other hand, can freeze a seedling’s cells and affect its ability to transport and use nutrients, water, and oxygen. This will result in stunted growth and eventually death if not dealt with properly. Wilting foliage, slow growth, and poor plant turgor are some signs that the temperature in your grow room or propagator is too low.
While their roots are young and still developing, cannabis seedlings absorb water via osmosis in their leaves. To optimise this process, it’s super important to keep relative humidity levels at 40–60%.
Humidity levels below 20% will seriously stunt the growth of your seedlings and may cause them to develop symptoms similar to some nutrient deficiencies (yellow or spotted leaves). Humidity levels above 60%, on the other hand, will cause your plants to develop wet spots that can cause foliage to wilt or rot, as well as attract fungi and/or other pathogens and pests. Once your seedlings enter the vegetative phase, you should keep relative humidity at 50%.
Seedlings are sensitive to light and will burn under strong HID or LED bulbs. Like adult plants, seedlings will develop burnt, crinkled leaves when suffering from light stress. Alternatively, seedlings that don’t get enough light will grow tall and lanky and topple over.
For best results, we recommend growing your seedlings under an 18/6 light cycle using CFL bulbs with a blue light spectrum for the first 10–14 days. Once they’ve developed healthy true leaves and at least 2–3 nodes, you can move them under stronger HID or LED lights to start vegging.
GROWING SEEDLINGS OUTDOORS
Outdoor growers obviously don’t have the liberty of being able to change the temperature or humidity with the push of a button. If you’re an outdoor grower, you have three options on how to tackle the seedling stage:
- Most growers choose to keep their seedlings indoors under CFL lights for the first two weeks to protect them from elements.
- Alternatively, you can keep your seedlings outdoors during the day (as long as temperatures sit consistently between 20–25°C) and only move them indoors at night to protect them from the cold, rain, etc.
- Finally, you can keep your seedlings outdoors permanently in a propagator, greenhouse, or polytunnel to provide shelter and allow you to drive up humidity and manipulate the temperature.
UNDERSTANDING THE SEEDLING STAGE
Inside that dark, hard shell, cannabis seeds house all the necessary genetic information to sprout and grow into big, luscious plants. When exposed to humidity and warmth, seeds are able to absorb water from their environment. This process is known as imbibition, and it’s the key to life for all plants.
Once water enters a seed, it activates special enzymes that trigger the growth of the taproot (the small white root that pops out of seeds when germinated properly). This root starts to push deeper underground in search of more water while the seed sends a shoot up and out of the soil in search of light.
Cannabis seeds already contain two cotyledons (or embryonic leaves) that unravel and push the seed casing from the shoot. After the cotyledons emerge, cannabis plants will develop their first set of true leaves. These will grow out of the main stem and have just one finger.
During the early stages of their lives, cannabis seedlings get all their energy from stores inside the seed. As their roots develop, they can absorb water via their leaves. Once your plants have developed their first sets of true leaves (that is, leaves with at least 5–7 fingers), they are no longer considered seedlings and are officially vegging.
Remember, rapid growth and vibrant green foliage are telltale signs of healthy seedlings.
HOW TO WATER YOUR SEEDLINGS
There’s no universal schedule on how to water your cannabis seedlings. Instead, you’ll need to pay close attention to your plants and their medium. We recommend sticking your finger roughly 2.5cm (1 inch) into the soil and watering only when the soil is completely dry. Also, remember to water your plants close to the stem where you know their roots are. Finally, remember that your pots need to have drainage holes in the bottom so excess water can drain out.
Overwatering seedlings is one of the most common (and most fatal) mistakes rookie growers make. Unfortunately, it’s an easy crime to commit; scared to let their seedlings’ soil dry out, inexperienced growers often end up watering their plants too regularly. This essentially drowns a seedling’s tiny root system, starving the plant of oxygen and causing it to droop.
Overwatering can also occur when a plant’s container is too big or too small. When growing a small seedling in a big pot, the excess soil can hold water for days in areas untouched by the plant’s roots. What you’re left with is a big container filled with wet soil that’s not only robbing your plant of oxygen, but also creating a breeding ground for fungi, bacteria, and pests.
Similarly, under-potting can be just as detrimental to your plants. Plants that are root-bound take up water very quickly, encouraging you to water them more regularly than necessary, leading to overwatering.
While it’s not as common as overwatering, underwatering is definitely an issue for some beginner growers (especially those that have been warned about overwatering their plants).
Cannabis plants constantly lose moisture through their leaves in a process known as transpiration (which plays an essential role in a plant’s ability to transport water from its roots up through its stem). Hence, it’s super important they always have access to water from their soil. When a plant goes too long without water, a lot of its vital functions start to slow down. Any roots that dry out completely die off, stunting the plant’s growth or possibly killing it all together (if its root system is underdeveloped).
Unfortunately, the symptoms of underwatering are mostly the same as those of overwatering (drooping and wilting). However, you’ll be able to tell that your plants are underwatered if their soil is bone dry.
HOW TO PREVENT DAMPING OFF
We’ve all been there; your seedlings look perfectly healthy, then suddenly you find them slumped over the edge of their containers. Within 24 hours (or sometimes less), they’ve shriveled up and died.
This phenomenon, known colloquially as “damping off”, is caused by fungi like Pythium, Botrytis, and Fusarium. While these fungi can lie dormant in soil, they grow and thrive in overly wet conditions. Overwatering and high humidity, for example, are some of the most common causes of damping off.
Unfortunately, by the time your seedlings show the first signs of damping off (a limp and discoloured stem), there’s nothing you can do to save them. We just recommend removing the affected seedlings from your grow room or propagator ASAP to avoid spreading the fungi.
To prevent damping off, make sure to keep close tabs on the temperature and relative humidity in your grow space, and avoid overwatering your plants. Also, make sure both your soil and pots drain well.
Finally, to minimise the chance of a Pythium, Botrytis, or Fusarium infestation even further, be sure to always use new soil or sterilise your soil by baking it in the oven until it reaches a temperature of 85°C.
HOW TO AVOID NUTRIENT PROBLEMS
Healthy cannabis plants look vibrant and green, and any sort of discoloration on a plant’s leaves or stems can be a sign of nutrient stress.
Remember, cannabis seeds are jam-packed with nutrients to help get your seedlings through the first stage of their life. Once these nutrients run out, it’s time for you to step in and give your plants the added nutrients they need to veg and flower properly.
• Feeding seedlings
Cannabis seedlings are super fragile and can easily “burn” in nutrient-rich soil. In general, we don’t recommend feeding during the seedling phase. Instead, keep your seedlings chilling in their Easy Start pots until they’re ready to be transplanted and start vegging.
Most blogs and forums will tell you that your plants are ready to veg after two weeks, but that’s far from true; it usually takes about 3–4 weeks from germination for your seedling to use up all the energy stored in the seed, although some plants develop faster than others. But rather than going by time, we recommend you transplant and start vegging your seedlings once they’ve developed at least three nodes and 4–5 sets of true leaves.
• Transitioning to the vegetative stage
Once you’ve transplanted your seedlings into their new pots, give them 3–7 days to adjust. Remember, transplanting is a stressful process, and your plants will need some time to recover from it. Feed your plants too early after transplanting, and they likely won’t take up all their nutrients from their medium, which can cause problems (like nutrient lockout) further down the line.
Once you’re confident your plants have recovered from being transplanted, start feeding them with a mild nutrient solution. An NPK ratio of 4:2:3, for example, is a good starting point for plants just beginning to veg.
• Nutrient burn
Growers usually run into nutrient burn when they feed their seedlings too early or when they transition into the vegetative phase (either because they transplant their seedlings into hot soil or they start feeding with a fertiliser that’s too strong). The first signs of nutrient burn are dark green leaves with burnt tips. Left untreated, nutrient burn also causes leaves to curl upwards.
Luckily, unlike some of the other seedling issues we’ve mentioned in this post, it is possible to remedy nutrient burn. Simply lay off the nutrients for at least one week and water your plants with plain, pH-balanced water. Once your plant starts to grow more healthy, green foliage, slowly dial the fertiliser back in.
Whenever you start feeding your plants, we recommend giving them half the recommended dose of fertiliser during the first week of feeding. This gives the plants time to adjust to their new diet.
• Going organic
At RQS, we’re big fans of organic cannabis gardening. No amount of chemical nutrients could ever compare to the complex mix of microorganisms that exist in organic soil.
When growing organic, the focus is all about building a vibrant soil from the get-go, rather than growing in a stagnant medium and pumping it full of chemical nutrients once a week. While it’s a lot more hands-on, the taste of organic weed is hard to beat. Just remember that organically grown plants typically don’t provide the same yields as their non-organic siblings.
HOW TO PREVENT PESTS AND BUGS
Pests and plagues can destroy seedlings in less than a day. To prevent this from happening, it’s super important to keep the environment around your seedlings clean and at optimal temperatures and humidity levels. Avoid overwatering, and remember to read up on common cannabis pests so you can spot and treat them early. Some common pests to look out for include:
• Fungus gnats
These small, black, fly-like bugs feed off your plants and lay their larvae in wet topsoil.
• Spider mites
Black or red in colour, spider mites live on the underside of leaves and sometimes spin protective webs around healthy foliage. They love hot, dry conditions.
• Leaf miners
These small, slender, winged insects leave irregular snail-trail-like spots on healthy leaves.
• White powdery mildew
As the name suggests, white powdery mildew is a type of mould that forms as a white, flour-like powder on the leaves of your plants.
• Pythium and Fusarium
These fungi can be hard to spot, but white spots on wet topsoil can be an early sign of their presence.
Cannabis seedlings like warm, humid conditions. Unfortunately, pests and diseases also love these conditions. Keeping things extra clean and growing your seedlings in a propagator can help prevent an infestation.
HOW TO PREVENT STRETCHY SEEDLINGS
Seedlings stretch in order to get closer to their light source. To keep your seedlings from developing unnaturally long, flimsy stalks, grow them under blue spectrum CFLs located roughly 5cm from the top of the plants. Also, avoid keeping your seedlings in the dark for 24 hours after germination (a common piece of advice on grow forums), as the lack of light will force your seedlings to stretch abnormally.
KNOW WHEN AND HOW TO TRANSPLANT YOUR SEEDLINGS
Unfortunately, transplanting seedlings is far from an exact science; rather than following a strict calendar or schedule, it’s all about paying attention to your plant and knowing which cues to look out for.
As we mentioned earlier, a good rule of thumb is to transplant seedlings when their leaves fully cover the circumference of their container. After about one week, try checking on your seedlings’ roots. If you can completely remove a seedling and all its soil, it is ready to transplant.
Remember to be very gentle when handling your seedlings and transplanting them. Any minute damage to their roots can result in a ton of stress that, for such young and fragile plants, can take a while to recover from.
Now that you know the theory behind growing healthy cannabis seedlings, it’s time to get your hands dirty. Remember to invest in one of our Starter Kits for the best, most reliable results, and keep reading our blog for more tips on growing spectacular weed at home.