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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.

Contents:

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 only sell feminized cannabis seeds, so there is no need to worry about removing male plants.

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

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.

ROYAL QUEEN SEEDS FEMINIZED STARTER KIT

There is, of course, a far simpler way to germinate seeds. Ideal for beginners, the feminized starter kit by Royal Queen Seeds has everything you need to kick-start your next cannabis project.

The Royal Queen Seeds Feminized Starter Kit contains:

  • 3x RQS Critical feminized seeds
  • 20x Easy-Start seedling pots
  • 1x Propagator Pro
  • 1x pack of Bacto
  • 1x perlite
  • 1x fluorescent lights
  • 1x instruction manual
  • 4x AA batteries
  • 1x Royal Queen Seeds catalogue

*You will also need a measuring cup and a stirrer (not included in the kit).

1. Gently remove the foil from the back of the seed packet and place them carefully into a dry container.

2. You will need a shallow container that is large enough to accommodate the seed tray. Fill the container with one litre of lukewarm water (22–25°C/71–77°F). Pour in the packet of Bacto enzyme, allowing it to dissolve before setting the seed tray into the container to soak. The seed tray only needs to be immersed for 5–10 seconds. Do not discard the Bacto mixture after the seed tray has been soaked.

3. After removing the seed tray from your shallow container, poke a 10–15mm deep hole into the soil of each pot, and delicately transfer your seeds from their dry container into each hole. Remember, one seed per pot.

4. Using the supplied propagator, sprinkle a 15mm-thick layer of perlite into the bottom of the tray.

5. Place your seed tray into the propagator, adjust the walls, and position the lid. The lid comes with an on/off switch for the already-attached lights.

6. Check the water level in your reservoir once a day. Your aim is to maintain an even level. After 1–7 days, the seeds should have sprouted, with visible leaves appearing. Once the seedling is 3mm tall, transfer it to your final growing medium.

IF IN DOUBT, THINK SPRINGTIME CONDITIONS

No matter which method you choose, always think about what conditions would naturally be like in spring. In their natural environment, cannabis seeds would start to sprout in-line with the seasonal change from winter to spring. Moisture is still high, and temperatures will be naturally rising. Always ask yourself the question, “Does my germination setup replicate spring conditions”. If the answer is yes, there is a good chance germination will be a success.

GIVING YOUR SEEDS THE BEST POSSIBLE START IN LIFE

In most cases, germination will go off without a hitch. However, there are a few troubleshooting issues we can help with.

LIGHTING

The first is lighting. Your seed/young seedling will only need fluorescent or CFL grow lights, at least to begin with. While plants need light to thrive, too much of a good thing will damage cannabis in its first few weeks.

Position lights about 15cm from seeds. Once your seedling has developed its first proper leaves (they will have jagged edges), you can move the lights as close as 5cm. If you are concerned about damaging your seedling, place your hand between the leaves and your lights. If you cannot hold your hand in place for ten seconds without it being too hot, move the lights 2cm away. Repeat until you are comfortable with the temperature.

As young seedlings grow quite quickly, you will need to keep adjusting lights to get the best results. After two weeks under fluorescent lights, you will be able to switch to high-powered HPS or MH-style grow lights.

UPSIDE-DOWN SEEDS

Don’t panic, where possible roots will always grow downwards. It is not necessary to try and reposition the seed yourself. Disturbing the seed at this crucial time will do more damage than good. In most scenarios, what you are actually seeing is not a root protruding from the top of the seed, but the stem of a cannabis plant.

If you are ever unsure, always wait a few days for the first leaves (cotyledons) to appear. As long as a seed’s requirements have been met, the seedling should sort itself out. The best approach is not to panic; follow the golden rules and your young seedling will be ready to transfer to a larger pot in no time.

GERMINATION AND BEYOND

WHEN DO YOU START FEEDING?

It will depend on the growing medium you are using, but in most cases, you will not need to supply any nutrients for the first 2–3 weeks. There will be of plenty of nutrients available in the soil, and even coco will only need nutrients added after a week or so. If you do opt for coco or hydroponics, nutrients should be added at 0.25x their regular strength. Once the first set of leaves appear, increase this in increments of 0.25 per set of leaves. For beginners, we would always recommend using a soil medium. It allows you to get to know the intricacies of growing cannabis more efficiently, and can be the least punishing if you make mistakes.

An easy way to spot if more nutrients are needed is to observe the leaves. The serrated leaves will start to turn pale green as nutrient stores are depleted. Left long enough, leaves will eventually turn yellow. This is a definite sign that more nutrients are needed. Your plant will not die if the leaves turn yellow, but it is a timely reminder to feed your young seedling.

Nitrogen is the most commonly needed nutrient during periods of high growth. Once the seedling has been fed, the colour of the leaves will return to normal. Depending on how long you waited to take action, this can take a few hours or a whole day.

SIT BACK AND RELAX

The first few weeks of a seedling’s development require very little interference. Nutrients, as we have mentioned, will need minor tweaks, as will lighting. However, now that your seed has germinated, you have a few weeks of grace. Sit back, relax, and enjoy your cannabis plant taking shape.

Once those initial weeks have passed, you can treat your seedling like it is in the vegetative stage, and switch to strict lighting routines and full-intensity light. During germination, always remember the golden rules, and if in doubt, ask yourself if you have created “springtime conditions”. If you are confident everything is on track, all you need to do is observe and marvel at the creation of your very own cannabis plant.

Royal Queen Seeds Produces Some Of Europe’s Best Cannabis Seeds, Ensuring Hobby Growers Everywhere Have Access To The Finest Marijuana Strains Around.

Royal Queen Seeds Produces Some Of Europe’s Best Cannabis Seeds, Ensuring Hobby Growers Everywhere Have Access To The Finest Marijuana Strains Around.

Part. 2: The Vegetative Phase. The germinated seeds peak out above ground and immediately spring up.

Part. 3: The Cannabis Blooming Phase. Just another couple of months of blossoming we will be ready to get our sheers out of the cupboard.

Part. 4: The last weeks of flowering stage. After weeks of mounting excitement the long-awaited moment the harvest is finally within arm’s reach.

Part. 5: Harvest Time. Learn every step of the cannabis harvest and post-harvest process.

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?

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.

Three simple steps to mastering the cannabis seedling stage.

  • 1. Pick the right genetics, containers, and medium for your seedlings
  • 2. Use the right germination techniques
  • 3. Mastering the seedling stage
  • 3.a. The basics: Optimising light, temperature, and humidity for cannabis seedlings
  • 3.b. Growing seedlings outdoors
  • 3.c. Understanding the seedling stage
  • 3.d. How to water your seedlings
  • 3.e. How to prevent damping off
  • 3.f. How to prevent nutrient problems
  • 3.g. How to prevent pests and bugs
  • 3.h. How to prevent stretchy seedlings
  • 3.i. Know when and how to transplant your seedlings
  • 4. Get growing!
  • 1. Pick the right genetics, containers, and medium for your seedlings
  • 2. Use the right germination techniques
  • 3. Mastering the seedling stage
  • 3.a. The basics: Optimising light, temperature, and humidity for cannabis seedlings
  • 3.b. Growing seedlings outdoors
  • 3.c. Understanding the seedling stage
  • 3.d. How to water your seedlings
  • 3.e. How to prevent damping off
  • 3.f. How to prevent nutrient problems
  • 3.g. How to prevent pests and bugs
  • 3.h. How to prevent stretchy seedlings
  • 3.i. Know when and how to transplant your seedlings
  • 4. Get growing!

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.

• Aeration

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 Pothelp 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. carla

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.

• Temperature

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.

• Humidity

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%.

• Lights

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:

  1. Most growers choose to keep their seedlings indoors under CFL lights for the first two weeks to protect them from elements.
  2. 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.
  3. 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

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.

• Underwatering

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.

GET GROWING!

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.

Struggling with your cannabis seedlings? Click here for 3 simple steps to growing healthy seedlings, alongside tips for mastering the cannabis seedling phase.