The Essentials of Seed Germination: Moisture and Warmth
At the heart of seed germination are two critical factors: moisture and warmth. Seeds are dormant entities, and to awaken them, they need the right environment. Moisture initiates the breaking down of the seed’s outer shell, while warmth simulates the ideal conditions of spring, signaling to the seed that it’s time to grow. It’s crucial to understand this, especially for those who might attempt to germinate seeds in colder conditions. Cold temperatures can hinder or even halt the germination process.
Understanding the Two-Step Process:
Pre-soaking in Water (24 hours): This step ensures water penetrates the seed’s protective outer shell, initiating germination.
Damp Paper Towel Method (48-72 hours): This method provides continuous moisture without the risk of drowning the seed, allowing the germination process to complete.
Step 1: Pre-Soak Your Seeds In Water
Preparation: Use clean glasses, ensuring no soap residue. Fill with a small amount of either pH-adjusted tap water (5.8) or distilled water. Let the water reach room temperature.
Kelp Extract: For enhanced germination, especially for older seeds, add kelp extract (0.2 gram per gallon). Kelp contains gibberellic acid, aiding germination.
Aloe Vera Gel: Aloe vera is known for its rooting hormones and antibacterial properties. Adding a small amount of fresh aloe vera gel to the soaking water can further boost germination rates. It’s a natural and effective way to enhance the germination process, especially beneficial for seeds that might be a bit older or more stubborn.
Warmth: Place glasses on a heat mat with a towel underneath. Cover with another towel to trap warmth and block light.
After 24 hours: Carefully pour out the seeds and water. Transfer seeds to damp paper towels.
Step 2: Germination in Damp Paper Towels
After the pre-soak, the next stage is to provide a consistent moist environment for the seeds to continue the germination process. This method ensures the seeds remain damp but not waterlogged, and it’s a controlled way to monitor their progress.
Preparation: Fold paper towels into squares and moisten them with either pH-balanced tap water (5.8) or distilled water. The towels should be damp but not dripping. Excess water can be gently squeezed out.
Seeding: Place your pre-soaked seeds inside the damp paper towels. This environment will provide the continuous moisture they need to sprout fully.
Storing for Germination: Transfer the paper towels with the seeds into open plastic bags. This setup maintains the moisture while also allowing some air circulation.
Warmth: As with the pre-soak, warmth is essential. Fold the seed bags inside a tea towel and place them on a heat mat. This setup ensures the seeds remain at the ideal temperature of 20° – 26°C (68 – 78°F) for germination.
Monitoring and Transplanting: Regularly check your seeds every 12-24 hours. Once the tap roots are about 0.25” – 0.5”, (0.75 – 1.25 cm) in length, they’re ready for planting. This length is optimal as longer roots can be more delicate and prone to damage.
Prepare pots in advance so sprouts can be immediately transplanted once they are ready.
The ideal size pot for planting your seedlings is 4” size. Use 4” pots and not a larger size because a 4” size pot produces a plant with a tight root ball that is easy to transplant later. With a larger sized pot, you’ll get looser, more spread out roots, which are bad because they are prone to getting torn or damaged during transplant. Another benefit of 4″ pots is faster top growth. Small pots constrain plant roots which forces growth upwards. When their roots are allowed to expand their growth outwards a plants top growth is slower.
Pack pots with grow media. On the bottom of the pot, add a 1” layer of hydroton. Hydroton prevents water buildup on the bottom of the pot and creates air pockets so roots get access to air. Fill the rest of the pot with coco coir.
Pre-water the coco coir with distilled water, or tap water pH balanced to 5.8 prior to adding sprouts to the pots.
Planting Sprouts
To plant your sprouts, first make a hole in the coco coir to plant your sprout in. The end of a tube is a good tool for this. The hole should be deep enough that your sprout’s tap root fits all the way inside. Drop your sprout into the hole using your fingertips so its tail is positioned down. If you miss, and the tail isn’t pointing down, it’s usually better to leave it misaligned than keep poking at it and risking damage. The tail will naturally revert itself and point back down on its own as it grows longer.
Bury sprout 1 cm deep.
Gently backfill the indent with the coco coir until your sprout is completely covered. It shouldn’t be buried that deep, no more than 0.25” (0.635 cm) of medium on top.
Water & Nutrients For Seedlings
Water pots using a watering can with a wide distribution and slowly pour until water starts to drain out the bottom of the pot. When it starts to drain out the bottom you’ll know you’ve added enough water. Do not add water past the point it starts draining because an over saturated medium will suffocate sprouts.
Remember the weight of the pot when it is fully watered so later you can pick it up and judge if it needs more water or not by how heavy it feels. As a general guideline, plan to water every 2 days at first, then switch to every day when your seedlings get bigger. Never water past the point it starts to drain out the bottom.
For the initial watering use distilled water, or tap water pH balanced to 5.8. Once seedlings appear and their first two baby leaves begin to yellow, begin adding fertilizer at the following concentration:
Seedling:
350 – 500 TDS
0.7 – 1 EC
During the first week of growth extra phosphorus in fertilizer is beneficial for seedlings.
Adding 2 parts kelp extract / 5 parts humic acid will help enhance root growth.
Excessive chlorine can be harmful to roots. Remove chlorine using vitamin C (ascorbic acid) tablets or a water filter.
Add light after your sprouts emerge from the media. Lights for seedlings can be left on 16-24 hours per day.
Seedling:
100 PPFD
5,000 – 7,000 LUX
Delicate seedlings can be damaged by excessive light. Start with low light levels and raise it gradually.
Don’t allow the stems to become elongated and spindly. If you observe any stretching, increasing light intensity fixes this problem.
To encourage rooting, use a full spectrum light with emphasis on blue wavelengths. Red wavelengths are not ideal for seedlings because they promote stem elongation at the expense of root development.
LED or florecent Tube lighting is common for nurseries. The correct type of bulb is often labelled cool white.
The more branches there are on a plant, the more clones it will yield. Shorter, bushier plants with more branches make better mother plants than plants with long stems and fewer branches. To encourage more branch growth, transplant in 2” pot size increments as plants get bigger. For example, from a 4” pot to 6” pot, from 6” pot to 8” pot and so on. This technique constrains roots, which has the effect of forcing more branches to grow.
How To Know When It’s Time To Transplant
Without sufficient roots to hold it together, media will be loose and will fall apart during a transplant, causing unwanted root stress and damage. Before transplanting, check first to see if there are roots growing out of the drainage hole at the bottom of the pot. This is a good sign that roots are developed enough to handle a transplant. Another good sign your roots are mature enough is the diameter of the plant’s top canopy is wider than the diameter of the pot. The diameter of the canopy mirrors the diameter of the root ball, and a wide canopy suggests that the root system has developed to the outer perimeter of the pot.
Roots growing out bottom, and top canopy with a wider diameter than the pot are signs that plant is ready to be transplanted.
Setting Up A Fresh Pot For Transplant
The first step for preparing a new pot is adding a layer of hydroton to its bottom. For 6” – 8” pots, use 1” of hydroton. For 10” and wider pots, use 1.5” of hydroton. Hydroton is added to the bottom of pots because it creates air pockets that help with drainage and provide plant roots with air access.
Fill the new pot with coco coir, with the outgoing pot nested inside it. Pour a mix of 90% coco coir, 10% hydroton between the old and new pots, saturate it with treated water, then push it down with your fingers until it feels firm.
Add a mix of 90% coco coir, 10% hydroton.
Add water.
pack down.
Remove the old pot using a twisting motion. The coco coir in the new pot will have a convenient indent ready to receive a new rootball.
New pot is ready to receive transplant.
Performing A Transplant
Secure the stem of the plant you are transplanting between your fingers, and its base with your palm. Then flip the pot upside down. The plant might simply fall out into your palm. If it doesn’t, with your other hand push your finger into the drainage hole at the bottom of the pot to dislodge the rootball. The rootball should come out as one piece with little mess.
Hand position for transplanting rootball.
Once the plug is removed from the old pot, drop it into the indent in the media in the new pot. Perform the transplant quickly because roots shouldn’t be exposed for any length of time.
Add some additional coco coir to fill in any gaps. Pack the coco coir tightly around the rootball.
Finishing Up
After the plant has been successfully moved to the new pot, add 1” of sand on top. The sand helps prevent insects from getting into the coco coir and laying eggs.
Sand on top provides a protective barrier against pest infestation.
As a last step, lay down a layer of hydroton. Hydroton helps with even distribution of water and maintaining the integrity of the sand barrier. Without the hydroton, coco coir can float up over the sand during watering.
A mother plant should be a minimum of 3 1/2 months old before it is strong enough for a small harvest of clones.
If you want to keep a mother plant alive after taking clones from it, only remove clones from the bottom 1/3 of the plant. Only take what you need. Don’t cut off more of the branch than you have to. With modest removal, the plant will stay alive and regenerate afterwards. If you don’t plan to regenerate the mother, strip off the entire bottom 3/4 of the plant right to the stem. You can use the top 1/4 as well, but it will produce weaker, slower growing clones.
If you are planning to reuse the mother, at 3 1/2 months you should be able to take 6-9 clones, and at 4-6 months, 12-28 clones. These numbers are approximate. The exact number depends on a variety of factors, such as pruning techniques, transplanting techniques, and the genetics of the mother.
A mother plant can be re-used many times, repeatedly producing and regenerating clones again and again. After harvest, a mother will take 2-3 months to fully regenerate back to a state where more clones can be harvested.
For smaller mother plants, a 10″-12″ sized clay pot works well. For mothers that need to produce bigger clone yields, a 24″ pot will result in a much larger plant.
For small indoor farms, it’s easiest to work with smaller mother plants. Smaller mothers don’t take up as much room and offer the flexibility of maintaining several strains.
Mother plants must be kept in a perpetual state of vegetative growth to produce clones. Maintain daily light levels for 12 hours per day or higher, 16 is recommended.
Ideal light spectrum for a motherplant.
Use a full spectrum light with emphasis on blue wavelengths, 400 nm – 500 nm. Blue light discourages stem elongation and encourages root growth. A large root system will lead to greater branching that can be harvested for clones.
To feed motherplants use a standard mineral fertilizer intended for vegetative growth.
Motherplants benefit from enhanced uptake of minerals, especially calcium. Amino Acid opens up ion channels, dramatically increasing how much calcium mother plants are able to absorb. Calcium makes plant cell walls thicker with more stored energy. More stored energy make cuttings more resilient with faster rooting. Amino Acid is an excellent bio stimulant choice for motherplants.
A clone is a section of branch that gets cut off a mother plant and rooted, transforming it into a new plant. It’s called a clone because it is genetically identical to the mother.
Because clones are genetically identical to their mother plant they will all grow the same way. For example, their rate of growth, node spacing, and leaf shape will be the same.
A primary benefit of genetically identical plants is when they are grown together in a group their heights all stay the same, making it easier to light their canopy. When plants all grow at different rates, shorter sections of the canopy receive less light than the taller sections, resulting in underdeveloped buds on the parts of the canopy that don’t get enough light.
Clones also allow you to grow only the very best plants. Plants grown from seed are compared for positive attributes such as yield size and quality through a process called phenotyping. The best plants are chosen as mothers and their genetically identical children become production plants.
Genetically identical clones on flood and drain table at beginning of a cycle.
Preparation
Cuttings are especially vulnerable to bacteria, mold and viruses. A clean work environment and tools helps to prevent contaminations. Before taking cuttings, scrub down the entire work space with paper towels soaked in a solution of 10% bleach and 90% water. Disinfect scissors by wiping the ends with paper towels dipped in isopropyl alcohol. Wear a clean pair of plastic gloves while you are cleaning and while you are taking cuttings.
Disinfecting scissors.
Fill a freshly washed jug with clean water for temporarily holding cuttings during the process of extracting clones. Extracted clones can be held in a jug, just like fresh cut flowers in a vase. This prevents the ends from drying out during the extraction process.
Keeping ends of cuttings submerged in water prevents tissue damage.
Prepare for a cloning session by adding some root stimulant powder to a freshly washed small glass for dipping the stems of cuttings in.
Root stimulant powder is a commercially available product that contains chemicals that stimulate new roots to begin growing from a severed stem.
Never dip clones directly into the bulk supply container of root stimulant because the entire container could get contaminated. For same reason, after a cloning session don’t put unused power back into the bulk supply container. Throw it out.
Preparing Rockwool
Clones will have trouble rooting if pH is not within a specific range. Rockwool does not natively have the right pH balance and needs to be prepared in advanced by soaking it in dechlorinated and pH balanced water.
To prepare Rockwool, pH balance water to 5.5 using pH up and pH down solutions. pH up and down are very concentrated. A 3 ml dispensing syringe makes it easier to dispense it one drop at a time.
Dechlorinate water using a water filter or with Vitamin C (ascorbic acid).
After the water’s pH is adjusted to 5.5, soak rockwool cubes in it overnight. This will correct the pH of the rock wool.
Rockwool is made up of spun glass fibres that are not healthy to breath in. Use a dust mask when handling dry rockwool because the fibres can become airborne. Rockwool is safer to handle when it is wet.
Soak rockwool in water pH adjusted to 5.5.
Preparing Net Pots
Nest rockwool cubes inside 4” net pots filled with hydroton.
Rockwool cubes are slightly over saturated after soaking in solution overnight. Oversaturated cubes run a risk of rotting plant stems when they are inserted in the rockwool. After soaking, give rock wool cubes a light squeeze to eliminate a small amount of excess water before adding them to the net pots.
Removing Clones From Mother Plant
To take a clone, remove the top part of a branch by cutting just below a node. The cutting should have 3 nodes plus the top canopy.
A good cutting has 3 nodes + the top canopy.
Remove lower branches.
Trim all the shoots and leaves off the stem of the clone. Leave only the top growth intact.
Cut away all growth except top canopy.
Make an angular cut right under the 3rd node.
Stripping away the bark around the bottom node to expose the underlying tissue promotes more robust root growth.
Shave away the bark around the bottom node.
Bark has been shaved away. Cutting is now ready to be rooted.
Setting Cuttings In Net Pots
Dip the bottoms of the clones in the shot glass containing the root stimulation powder.
Push the plant stem into the rockwool cube after coating the ends with root stimulation powder.
To make it easier to insert the stem, make a slit in the rockwool first using the end of a pair of scissors.
Trim the leaf tips of the cuttings. If you don’t, the leaves tend to become rotten or mouldy during the rooting process. Trimming the ends also reduces the transpiration function of the clone, leaving it with more energy for growing new roots.
Cut off the leaf tips.
Rooting Cuttings
Cuttings are rooted and become clones inside a humidity dome. A humidity is like a life support system for your clones because it provides an environment with high humidity and temperature. Outside of the humidity dome, cuttings can die because they have no roots to draw up water. Inside the humidity dome, high humidity levels allows them to absorb water through their stem and leaves.
Clones root fastest with temperatures between 24° – 30°C (75 – 85°F), with the ideal temperature around 25°C (78°F). A large heat mat kept under the clone dome helps raise its temperature. If the heat mat is too powerful and the humidity dome gets too warm, set an electricity timer to switch the heat mat on and off automatically until the correct temperature is reached, or place a towel over the heat mat to dull the heat. Temperature is an important detail because the faster clones root, the higher their survival rate is.
To set up the humidity dome and net pots, add enough water to the bottom of the humidity dome so that the hydroton in the net pots is submerged in the water, but the rockwool cube is above the water line. The hydroton can draw water up using its wicking action to maintain the rockwool, keeping it moist.
Adding a bed of loose hydroton to the bottom of the humidity dome will help anchor the net pots in place and reduce light exposure to the clone’s roots once they emerge from the net pots.
The humidity dome should be kept as clean as possible to prevent fungi build up. Clones are very vulnerable to harm resulting from an unsanitary condition. Every week, empty all the water from the humidity dome and replace with fresh water. Changing over the water also has an affect of oxygenating the water which is beneficial for the clones.
For the first week, the water in the humidity dome doesn’t need any nutrients. pH balance the water to 5.5, dechlorinate it, and add sodium benzonate at a concentration of .13 gram / 100 litres to prevent fungi infections.
After the first week, prepare the water as above, and also add vegetative growth fertilizer at the following concentration:
Clone & Seedling:
350 – 500 TDS
0.7 – 1 EC
Foliar sprays are very beneficial for clones. Apply a foliar spray up to 3 times per day, spraying the canopy of the clones while avoiding drenching the rockwool cube. Clones can draw water and nutrients through their foliage and this is very helpful for them before their new roots have grown in.
Prepare a foliar spray with 5 parts humic acid to 2 parts kelp.
After you’ve taken clones from the mother plant there will be some sections of severed branches still attached to the stem. These branches can be further pruned to encourage faster mother plant regeneration.
New plant growth comes from nodes. Sections of branch still attached to the nodes get in the way of new growth and should be trimmed off.
Prune off excess lengths of branches from the mother plant.
Branches trimmed back to the nodes will regenerate new growth quickly.
