Germinating Cannabis Seeds In Coco

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. In this tutorial, we walk you through everything you need to know and do to grow cannabis seedlings in coco coir: pots, light, fertilizers, watering & more

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.

See also  Cannabis Seed Anatomy

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)

Vegetative phase

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.

Flowering phase

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%.

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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.

How To Grow Cannabis Seedlings in Coco Coir

The seedling stage is one of the most sensitive periods of a plant’s life. If managed well, seedlings develop into strong young plants that go on to be solid producers. However, if managed poorly, the plant can become stunted and never live up to its potential. Caring for seedlings in coco coir can be tricky, but we have you covered. In this tutorial, we walk you through everything you need to know and do to grow cannabis seedlings in coco coir. We cover how to prepare coco for seedlings, the best containers for seedlings in coco, relative humidity for cannabis seedlings, temperature for cannabis seedlings, light for cannabis seedlings, fertilizers for cannabis seedlings, how to water seedlings in coco coir, and how to treat seedlings with calcium deficiency.

This tutorial covers the roughly two-week period of the seedling stage. The seedling stage starts when the cotyledons (first round leaves) open, usually around 3-4 days after the seed gets wet. The seedling stage runs until the plant has three true nodes (sets of serrated leaves). Hence, this tutorial covers roughly days 3-15 from seed. For those crucial first 3 days, be sure to see our tutorial “Germinating Cannabis Seeds – a Step-by-Step Guide”.

As the plants start maturing during the seedling stage, it is time to work your way through a transplant strategy. We recommend that you always use a transplant regime and never start seedlings in final containers. For simple instructions and our explanation, be sure to see our tutorial, “Transplanting Cannabis Plants: Why, When & How”.

You will eventually get to final containers, so be sure to read our recommendations in “Pot Size and Type: The Best Containers for Cannabis in Coco” (Coming Soon). The end of the seedling stage is also when you should think about training your plants, so be sure to read our article, “Why You Should Train Cannabis Plants” and see our training tutorials.

How to Grow Cannabis Seedlings in Coco Coir

Coco Coir, CalMag and Seedlings

Before you use coco, it should be properly rinsed, buffered and mixed with perlite. Be sure to see our video and tutorial for “How to Prepare and Buffer Coco Coir”. The buffering process is crucial to prepare the coco for plants, and especially seedlings.

As I explain in the article, “Why You Need Cal/Mag in Coco”, the coco itself has cation exchange sites that need to be filled with calcium or magnesium. Buffering the coco allows you to satisfy the majority of the cation exchange sites. However, during the grow, more cation exchange sites are continuously exposed, which require additional CalMag. The coco will take its share of the calcium and magnesium before the plant has a chance, so if you do not provide enough, the plant will suffer.

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Calcium and magnesium deficiencies are common problems with plants grown in coco. It is especially difficult to deal with CalMag problems during the seedling stage. This is because the coco is taking the Ca and Mg from the nutrient solution. However, you cannot simply increase the dose. You are limited in the amount of CalMag that you can provide to seedlings because they cannot tolerate a solution with high Electrical Conductivity (EC). CalMag has a strong impact on EC so when seedlings do suffer Ca or Mg deficiencies, they can be tough to correct. If you do encounter problems with Ca or Mg deficiency during the seedling stage, we have suggestions for you below. However, it is best to avoid the problems in the first place by properly preparing your coco.

How to Prepare Coco for Seedlings

Buffering with a strong dose of CalMag prior to using the coco allows you to provide relatively little CalMag during the seedling stage of the grow. However, buffering solutions themselves have a high EC, and seedlings could be burned if they are placed in coco fresh from the buffering process. Therefore, it is important to reduce the residual EC in the coco before transplanting the seedlings.

When I begin a grow, I prepare and buffer enough coco for the final containers. I keep the bulk of the coco/perlite moist with CalMag Water in fabric pots until I need it. When it comes time to place seedlings into coco, I fill the seedling container with coco/perlite and then flush it by pouring pure water with a pH of 6.5 though the container until the run-off is less than EC 100 (0.1). This flush is important because otherwise the residual high EC from the buffering process could burn your sensitive seedlings.

Containers for Seedlings in Coco

We recommend growing sprouts first in a Rapid Rooter or Jiffy Pellet before transferring to coco. These peat-based media provide a more stable buffer for germinating seeds and sprouts. Be sure to see our tutorial, “Germinating Cannabis Seeds – a Step-by-Step Guide”.

When the root of the sprout grows through the Rapid Rooter or Jiffy Pellet, the little plant should be transplanted into the first container, where it will live out its seedling days. We advise strongly against placing small plants into large final containers. As I explain in our article, “Transplanting Cannabis Plants: Why, When & How”, there are significant benefits to starting plants in small containers.

When the root emerges, we recommend placing the plants into either fabric seedling bags or solo cups with prepared coco. The seedling bags create an ideal environment for young roots, however the solo cups are somewhat easier to transplant out of at the end of the seedling stage. If you use solo cups, be sure to cut numerous holes in the bottom of the cup to allow drainage.

Transplanting out of seedling containers can be tricky whether you use fabric seedling bags or plastic solo cups. For complete instructions and photos of the process be sure to see “Transplanting Cannabis Plants: Why, When & How”.