How to grow cannabis in coco coir?
Coco coir is a versatile growth medium that makes an excellent option for all growers. Coco coir comes in loose and compressed brick form comfortable for transport-store-use. Coir ensures superior water retention, aeration while being economical, user-friendly.
Coco coir is an essential grow medium and soil amendment that helps cannabis to grow to their fullest potential. Researches say that coir-based substrates are effective for cannabis during the vegetative and flowering stages of production.
It can be handled manually or automated hydroponic systems with real time sensors and regular monitoring. It is also resistant to fungal-bacteria-molds, provides sturdy substrate for all kinds of cannabis like indica, sativa, hybrid and ruderalis.
Coco coir are commercially available as bagged loose coco coir and compresses blocks and also ready-to-use cultivation blocks .
The typical coco coir available on the market are pre-washed, buffered, hydrated and ready to use right out of the bag.
Coco coir are only usable when they are completely hydrated. It is preferential for a grower to place coir blocks within the larger containers such as air pots, plastic pots and fabric bags .
Fabric pots are ideal to start with cloners and new seedlings, it comes in different sizes of 1, 2, 3, 5 and 10 gallons. A 5 gallon fabric pot is best suited for a 5kg compressed coco block.
Complete Guide for Cannabis Grow
Preparing Grow Substrate
Even the coir is pre-buffered, light buffering is needed at the grower’s end. Coir has a natural high concentration of sodium and potassium, so it needs to be treated by soaking in Ca-Mg solution to leach out the excess salt content.
Higher concentration of potassium leads to calcium deficiency in grow medium used for marijuana plants.
Hydrate the compressed block with distilled water to note down the precise nutrient addition and balanced pH and EC. Once the brick is fluffed, completely damp prepare for the decent grow mix for cannabis.
Marijuana requires highest aeration compared to other weeds. Mixing grow supplements like perlite and vermiculture improves water intake and encourages strong root growth.
The most recommended coco-perlite mix of 70-30 , i.e, 70% of coco and 30% perlite at top layer. For a new cloner, the perlite mix of 50-50 helps the root to grow deeper, quicker providing easy water accessibility.
Cannabis potting mix needs 2-3 inch layers of clay pebble at the bottom to aid oxygenation and better drainage.
And flush the mix by pouring pure water with a pH of 6.5 until the run off is less than EC 100 (0.1). The flushing is essential to drain away residual EC from buffering that could burn sensitive cannabis.
Plant Nutrient Mix
Coco goes well with every kind nutrient supplement. Cannabis grows in a hydroponic system with coir as the medium demands some essential grow supplements like Cal-Mag and other plant grow nutrients .
No matter what nutrient schedule you use, make sure not to include nutrient at every watering. Otherwise you will burn your plant with excess nutrient buildup.
While using nutrient solution, test for pH of the solution, use wisely with the prescription provided at the back end of the nutrient pack.
Furnish other fertilizers and grow amendments to enrich the nutrient availability.
Caring for Cannabis
Stage- 1- Germinate (1-5 th days)
Cannabis can be grown commonly on general germination trays or the individual rooters and make sure to keep the bottom of the tray/rooter moist with a shallow pool of water.
At the early stages of growth, the relative humidity should be kept high (65-80%), pH 6.2 to 6.4 and room temperature should be maintained at 72-79F (22-26C) and measured for perfect Nutrient Element Ratio (NER).
Have the grow light turned-off (dark) during germination to protect the young roots from light heat and later after a day or two switch it with 18/6 lighting hours (16 hrs light-8 hrs dark).
Stage- 2- Seedling (6-12 th day)
In this stage where cotyledons sprout out, turn-on the CFL light to 24 hours (full day) and room temperature of 70-85 o F (20-30 o C), humidity 40-60%.
In this stage, the pH of water inflow should be between 5.6 to 6.5 inorder to improve calcium solubility.
The seedling in the coco/perlite substrate should be watered once or twice per day until 20% runoff from bottom. Coco must not be let to dry and be frequently wetted.
Lighting power of 15-25W of Fluorescent or LED (23 W of CFL) is required for the stage of true leaves to occur and the intensity of the light should be maintained properly by adjusting the height between lighting and seedling.
Place a thermometer or hygrometer to check for simultaneous change in temperature and air moisture.
In the first few of true leaves appear, start fertigation inflow with EC around 350-400 and strengthen the dose of Cal/Mag to its full potential and other nutrient schedules for better growth of cannabis.
Increase the EC of the solution by parts of 80-100 every time. At the end of seedling the nutrient solution must be of its full strength around 1000EC.
After the plant has 3 nodes, transplant to a bigger container.
Stage- 3- Transplant
Continue to water your plant till 10-30% runoff and maintain the water pH at 5.6 to 6.5. About 2 weeks later transplant your cannabis into a bigger new pot preferably, fabric pot . Let the EC of the new pot mix be lower than seedling substrate to avoid transplant shock.
Once the cannabis reaches half of its final desired size, start plant training.
Look for any color changes in the leaves, if the first few leaves have turned yellow then it means Nitrogen deficiency (sigh of reduced chlorophyll production), so make appropriate arrangements for proper nutrient management and do not go low or higher than optimal.
Considered as a regularly growing plant, cannabis are provided with 12-12 lighting duration (12 hrs light, 12 hrs darkness).
Keep close monitoring of the plant in this flowering phase as the chances of nutrient deficiency like lacking in Phosphorus that shows small, dark green leaves with purple veins and lack of Potassium turns leaves yellow, brown then die.
And importantly control the room temperature from 65-80 o F (18-26 o C) and humidity ranging 40-50%.
If possible tease(train) your plant by gently bending and stretching, but avoid training once the buds are formed.
Stage- 4- Harvest
Harvesting at the right time means a lot. Harvesting early, loses its potency; later will produce a sleep dosage.
Choose for the precise moment of harvest by observing through glittering trichomes under Magnifier.
Trichomes start head out clear and glassy- buds are not potent.
Trichomes heads turn milky white as it matures, these trichomes are full of potent with the highest level of THC and CBD that are used in Recreation- mental/psychoactive effect.
With some more time felt (after a week), white trichome head turns amber/golden that has less THC used for Relaxing- anti-anxiety effect.
Fail-Proof Cannabis Germination Method in Soil or Coco
We have a cannabis seedling germination page that includes everything you need to know about all the different germination methods, but this tutorial is different. In this tutorial, I’m going to share exactly how I do my seeds from beginning to end. Just follow these instructions and you’ll end up with healthy, fast-growing plants that germinate in just a few days. It’s basically fail-proof.
Turn your cannabis seeds…
This step-by-step tutorial will teach you how to germinate seeds and provide basic seedling care
Soon you’ll have healthy cannabis plants to admire
1.) Get Cannabis Seeds
There are a few different ways to get cannabis seeds, with the most common being ordering seeds online and growing seeds you find in weed that you buy. Learn how to research and find the right strain.
Here’s a picture showing several healthy and viable cannabis seeds
2.) Prepare Your Soil or Coco Containers
Before you start germinating your seeds, set up your soil or coco. It will still be a few days until your seedlings arrive, but you want to have everything ready before the seedlings need to be planted.
Get your containers ready before you start germinating
When it comes to new growers, it seems like the most fool-proof method (at least for me, and many of the new growers who write in) is the Paper Towel Method! It’s so simple, but there’s something about wet paper towels that a young seedling loves Learn About Other Ways to Germinate Seeds.
Paper Towel Method – Place your seeds inside a folded wet paper towel (Important: use cheap brand!)
This method is hard to mess up if you follow the instructions. Place your seeds inside a folded wet paper towel, and put that between two plates. The purpose of the plates is to prevent the seeds from drying out. Don’t let any part of a paper towel hang out the edges or it will wick away all the moisture and dry out. Keep everything totally contained between the plates.
Surprisingly, the really cheap paper towels work the best because the seeds and roots lay on top without getting stuck to anything. This is important. The more expensive “cloth-like” paper towels (like Viva brand) aren’t good for germination because the roots actually grow into them instead of laying on top.
Wet a paper towel (use the cheapest brand you can find). If growing multiple strains, you may want to label the paper towel so you know which is which. Place each seed on the wet paper towel next to their label.
Cover with another wet paper towel
Add another plate on top to keep the paper towels from drying out. Make sure now paper towel is sticking out the sides.
- Check on your seeds every 24 hours but try not to disturb them. When they’ve germinated, you’ll see the seeds have cracked and there are little white roots coming out.
- They should germinate in 1-4 days, though some seeds can take 7 days or longer (especially older and smaller seeds).
- Keep them warm if possible. Seeds germinate a little faster is to keep them in a warm place (75-80°F). Some people use a seedling heat mat but in most cases that’s unnecessary. I leave mine near a sunny window. I usually put a thermometer in the same place to make sure it’s not too hot or cold (or just check the plate with your hands)
Here are those seedlings about 2 days later. Be extra careful when removing the paper towels. Don’t let the seeds roll around or you won’t know which is which. This is when you’ll be glad you used cheap paper towels, as they are much easier to peel off without disturbing your seedlings.
You can see some of the seeds sprouted, but some of them haven’t yet. That’s totally normal! Each seed is different. If this happens to you, you have two choices. You could plant the ones that have already sprouted and let the other ones stay in the paper towels until they germinate. Or you could just put all the seeds in Rapid Rooters now, and hope for the best as far as the slow-sprouting ones. It’s up to you. Letting the unsprouted seeds stay in the paper towels longer improves the germination rate in my experience, but it’s simpler (easier) to move them all at once.
Seeds often germinate at different rates even if they get the exact same conditions
4.) Place Germinated Seed in a Rapid Rooter
Now it’s time to get your Rapid Rooters! Alternatively, you could place your sprouted seeds directly in the final growing medium (coco or soil). I think these help them get started, but I’ve grown many successful plants by just putting the germinated seed directly in its final home.
Rapid Rooters are nice, but not necessary
The Rapid Rooter should be cut open lengthwise. I use big scissors but you could also use a knife.
Gently place the germinated seed inside, root down. Place the seed close to the surface so it doesn’t have far to go.
If you have a root that is curved or bent, don’t try to straighten it out. Open the Rapid Rooter and lay the germinated seed down gently. It will naturally lay on its flattest side. When you slowly close the Rapid Rooter, the bent parts of the root will end up in the “crack” of the Rapid Rooter that you cut to split it open from the side.
Most seedling plugs will go back into place easily, and you’ll barely be able to tell it’s been opened. I love Rapid Rooters because their texture causes most seeds to stay in place and not “fall down” further into the hole once you’ve got the Rapid Rooter closed.
5.) Water the seedling in the Rapid Rooter until you see a root come out bottom, 1-2 days.
Make sure to always keep the Rapid Rooter moist but not soaking wet and give plain water.
Since your seed has already sprouted and been in placed into the right growing position, it’ll often pop its head out within just 12-24 hours! Sometimes you see just the leaves, but often you actually see the seedling push the shell above ground.
Don’t touch the shell if possible because a tiny tug in the wrong direction can pull the seedling out of the plug and break off the taproot.
Try to let the seedlings break free if possible. But if you have a seedling that’s stuck in a shell after a day or two, and doesn’t seem to be getting any better, you need to go in and help.
I’ve found that pointy tweezers are perfect to pry open a shell that’s stuck. Just close the tweezer, stick it inside between the shell halves, and let it slowly open to pull the shell apart without you ever touching the seedling.
Sometimes a “film” from inside the shell gets stuck on the leaves. If that happens, try putting a drop of water on the film a few times a day to soften it. If the seedling doesn’t push it off on its own, hold the stem between your fingers (so it doesn’t pull at the root) and use tweezers to gently tug at the membrane and release the leaves.
Don’t use a dome on seedlings unless it’s very dry where you live. If you do use a dome, consider keeping a vent open and watching the humidity. A young seedling doesn’t require as high humidity as clones (which are what the domes are designed for), and seedlings tend to get “wet feet” and stop growing as fast in constantly wet conditions.
Water your seeding in the Rapid Rooters until you see a root coming out the bottom. Keep Rapid Rooters moist but not wet. During this time, give seedlings bright filtered light. A CFL or LED light bulb kept several inches away works well. I’ve left mine on the kitchen table next to a sunny window, and that’s also worked fine for me as long as it doesn’t get too hot.
You should see a root come out the bottom in just a day or two!
After you see your first root, it’s time to…
6.) Put Seedling in its New Home
You are about to water your seedlings for the first time, so prepare your water now.
- Coco – Prepare water with seedling-strength nutrients, and make sure to pH your water to 5.5-6.5 right before giving it to plants. Unlike soil, coco does not naturally contain any nutrients so you must provide nutrients in the water from the first watering.
- Soil – Prepare plain water at 6-7 pH. You don’t need to add nutrients for the first 3 weeks or so because your plants will live off what’s in the soil. Adding extra nutrients at this point might overload and burn the seedlings.
Now that your water is ready, dig a hole that’s a little smaller than the Rapid Rooter, and place your seedling plug inside. The idea is to let the Rapid Rooter stick up above the soil a little to help the roots get more oxygen. It’s okay if the plug goes in flat with the soil, but don’t bury the stem as that can cause stem rot in some cases. Even if you’ve got a tall seedling, you usually won’t notice the extra length once the plant is bigger.
Gently pack the nearby soil/coco to hold the Rapid Rooter in place so the seedling is stable.
Your seedlings get a little extra oxygen if you let the Rapid Rooter stick up into the air slightly as opposed to burying it.
Example of cannabis seedlings growing in coco coir, about to get seedling-strength nutrient water. If they were in soil, I would give plain water for the first few weeks.
Water immediately in a small circle around your seedling. For most grow mediums and containers above 1 gallon, you can give 2 cups (500 ml) of water immediately without overloading your seedling. If the grow medium feels moist (for example coco that was recently re-hydrated), give 1 cup (250ml) of water this first watering.
Give 2 cups (500 ml) water in a circle around the seedling. If the grow medium is already wet, give just 1 cup (250 ml)
How to Water Seedlings in the Beginning
Two Main Goals
- Seedling roots never dry out (most important)
- Seedling roots aren’t staying soaking wet (roots need oxygen)
Seedlings “drown” and die due to lack of oxygen if they get too much water too often. To avoid this, try to provide an amount of water that lets you water seedlings every few days. Avoid giving so much water that the seedling roots are in a super wet grow medium for days as this causes “damping off” and root problems. Some grow styles like high-frequency fertigation call for watering more frequently. Just remember that the more often you water your plants, the less water you should give at a time. Also, keep in mind that a smaller container tends to dry out fast while a bigger container holds onto the water for longer
Try to maintain a schedule that lets you water your plants every few days without them looking droopy
- Water in a small circle around the base of the plant at first
- If the growing medium feels dry within 1 day, give more water next time. Otherwise, give the same amount again next time you water
- Repeat, until you can give enough water to get at least a little runoff, and have it dry in a few days
If the medium is drying in less than 2 days, it means you need to give more water to the plant at a time, or possibly transplant to a bigger container if the plant has outgrown its current one.
If your growing medium takes longer than 3 days for the top inch to dry, it means the soil is staying wet too long, and plant roots aren’t getting enough oxygen. It also puts your plants at risk of getting fungus gnats . Try giving less water at a time until the plant is drinking more. It’s possible you may have a problem with drainage in your medium ( what is good soil? ) or there are no drainage holes so extra water can’t come out the bottom of the container. Always remove any runoff water instead of letting the plant sit in it.
More seedling resources
Some growers like to put seedlings in solo cups and then into their final container. When done right this can increase the rate of growth by providing more oxygen to the plant’s roots. If you go that route, I recommend paper cups as they’re not as bad for the environment.
Autopsy: Why Aren’t My Marijuana Seeds Sprouting?
If your seeds still aren’t sprouting and growing properly, consider the following factors.
If there’s no germination at all…
- Temperature may be too hot or cold – aim for 75-80°F
- Too wet – seeds and seedling roots should always be moist, but should not be soaking wet
- Too dry – if a root dries out the seedling can die
- Bad seeds – It might not be you, it could be the seeds themselves. Even if you purchase from a good breeder, sometimes you still get duds. How can I tell if seeds are viable?
If seeds sprout, but then stop growing…
- Temperature is too hot or cold – aim for 75-80°F
- Too wet – new seedlings don’t like “wet feet” so make sure your Rapid Rooter or growing medium never looks shiny or muddy, as that means there’s too much water! For this reason, it’s also usually recommended to avoid using a humidity dome with seedlings unless your air is dry. Although clones love humidity domes (they need water from the air because they don’t have any roots to get water), seedlings like it a little drier or roots tend to get mushy.
- Too dry – less common unless you live in a very dry area, but sometimes your medium dries out too fast if you’ve got a heavy-drinking, fast-growing seedling!
- Too much light – if the seedlings get blasted with high levels of light right away, it can shock them. They may need some time to adjust to higher light levels. Simply starting your grow light a little further away than normal is usually enough. Think sunny window at first, and start ramping up after a week of healthy growth.
- Not enough light – if seedlings are growing long and stretchy without growing new sets of leaves, it means it wants more light.
- No light for more than a day – if the sprouted seed doesn’t get light within 24 hours after sprouting, it may die. Once seeds are sprouted, get them in a Rapid Rooter and under at least some amount of light as soon as possible!
- Roots damaged – If somehow your roots got damaged, it can sometimes stop the seedling from growing
Unfortunately, sometimes you will never know why certain seeds just don’t thrive. It’s all part of nature. But if you follow this tutorial you will get the best results possible.