Tips For Perfect Seed Germination And Propagation Of Clones
At Holland Horticulture, we know from our customers just how important it is to get that Christmas harvest and with just 94 sleeps to go until the festive day, if you haven’t done so already, now is the time to get your seeds germinated or your clones rooted, so you’ll be safe in the knowledge that your crop will be ready before this crucial deadline.
We’re often asked what is the best way to start seeds or cuttings, a quick search on the internet will reveal various methods, some right, some wrong, some indifferent, but ultimately it is down to personal choice, as what works for one person, may not work for the next. Therefore this article is to help highlight some of the key areas to give you all the tools you’ll need for a high success rate at the propagation stage of your grow.
For those of you starting off from seed indoors, it's not as straight forward as outside by simply preparing your plant bed, sprinkling a healthy amount of seeds on to it, covering them with soil, then waiting while nature takes it course. Indoors, it’s an entirely different ball game, especially if you want to germinate those ultra hot rare chilli seeds you’ve been storing for that special occasion. That’s why we’ve put this article together, as all the staff at Holland Hydroponics have tried different methods, from soaking the seeds in water for 12-48 hours, placing them between damp paper towels, or putting them straight into soil or propagation plugs, such as Root Riots and Rockwool.
All of these techniques will work and depending what your final grow medium will be, can determine which method you use. For example, if growing in hydroponics, Rockwool would be the medium of choice, it wouldn’t be wise to start them off directly in a small pot of soil. This seems like an obvious statement to make, but believe us when we say, both novice and experienced growers alike have been known to do this.
Straight Into Soil
If the final medium is soil, or at push coco or a coco/soil mix, one of the most straightforward and successful methods is to place the seed straight into a small pot. The jury is still out as to whether its best to pre-soak the seeds in room temperature water; we personally recommend you give them a short soak of around 6-12 hours and certainly no more than 24. This part though is entirely up to the grower as some prefer to bypass the pre-soaking stage entirely.
The size of the first pot is also crucial, the smaller the better, its pointless placing a tiny seed into a giant 20 litre pot because as the seedling grows, it’ll be difficult to get a wet/dry feeding cycle started with a small plant in such a large pot. It simply won’t have time to dry out, which could also bring about mould issues within the soil or in a worst-case scenario, root rot before they’ve had time to develop properly.
Start them off in around 0.5-litre pots and certainly no bigger than 1 litre, fill them with a light fertilised soil, such as BioBizz Light-Mix or a dedicated seedling/cutting compost, fill the pots, pre-wet it with room temperature water using a spray bottle until the medium is moist but not soaking. Leave them for around 5-10mins to allow the water to disperse throughout the medium, if you feel it’s not quite wet enough, apply more water. Once happy, make a small hole with a pencil, or similar object, about 1/2" deep, place the seed in the hole, cover with some fresh soil, apply a touch more water, then place into a propagator and under a suitable light source.
Germination times can vary, some plants can show signs of growth in as little 24 hours, while others can take 3-4 days, sometimes longer. The most important thing is to leave them be, don’t go prodding around to see if there are any signs of germination, just make sure that the medium stays moist, humidity is high, temperatures stable and most of all, be patient.
Straight Into Propagation Plugs
This technique is similar to the above and the ideal choice if the growing media is coco or hydro. Again, we recommend that not only are the seeds pre-soaked, but also the propagation plugs, whether its Rockwool, Root Riots or similar, for approximately 15-20 minutes prior to placing the seed. The water should be room temperature, not straight from the cold tap, you can also add a touch of a seedling feed such as Formulex or a root stimulant, like Shogun’s Katana Roots, to help encourage germination and do not squeeze the plugs as this will expel any oxygen.
Growth Technology Formulex | Shogun Katana Roots
Once the seed is placed into the propagation plug, as with soil, these should then be placed in a propagator with the temperature maintained at around 20°C with a high humidity of around 80-100 RH. Again, like in soil, the seeds will crack and start to form a taproot in around 24-48 hours, but this can be plant dependent so don’t be worried if after 2 days there’s no sign, just be patient.
Although this is a technique we don’t recommend, high success rates are reported. Our concern, especially with the novice grower, is that the newly sprouted seed is very delicate and needs a steady, yet gentle hand to transplant it into the grow medium. Also, if the paper towel used is thin or doesn’t retain water very well, the paper fibres can become tangled around the taproot.
The key to germinating this way is to use good quality paper towel that doesn’t break up easily and holds a reasonable amount of water. Temperature also needs to be warm, around 20°C. It’s also quite common to place the damp paper towels into a zip lock plastic bag to help retain the warmth and moisture. This should then be placed into a dark or light proof location, for example an airing cupboard.
One advantage of germinating this way is that you can actually see with your own eyes how things are coming along, rather than having to wait patiently for the seed to start popping its head above the media. But leave the seed in too long once the first tap root has formed, issues such as mould can start to arise, so it’s important to get the seed into the first grow medium as early as possible.
A lot of growers prefer to use cuttings (also known as clones) over seeds, this way, they know exactly what to expect as the cutting, in identical environmental conditions, will grow very similar, if not exactly the same, as the plant it was originally taken from.
Taking & Preparing Cuttings
The cutting should come from a mother plant that is in the vegetative stage, not flowering, and be at least 2 months old. It also helps if the plant is watered prior to any cuttings being taken. The choice of where to take the cutting, although not pivotal, can help speed up the rooting process. We recommend taking them from nearer the top of the plant, as there will be a greater concentration of growth hormones compared to those lower down. That said, the Bible (Integral Hydroponics) states that clones should be taken lower down on the plant as the cambium (growth) layer is further developed, meaning it will root quicker. Which ever method you use, the preparation is still crucial as where to take a cutting can be down to personal preference, previous success rates or if a particular area of growth looks a perfect candidate.
The cutting should be taken with sharp scissors or scalpel and the blades should also be sterilised by applying rubbing alcohol or immersing in boiling water prior to use. This helps stop infection spreading into what is effectively an open wound.
The clone should ideally be around 75-130mm (3-5”) in length with a stem approximately 4-8mm in diameter. Cut the clone off the mother plant, this should be at a 45° angle, alternatively once cut from the plant, trim the end of the stem to the required 45°.
Now trim off any unwanted fan leaves and while any that are kept, cut in half as this will reduce transpiration (water loss). Then with a scalpel, carefully scrape the last 25mm (1”) of the stem, similar to peeling a carrot, as this will allow the rooting hormone to be absorbed quicker and encourage roots to develop faster.
Once the cutting is prepared, generously cover the cut, stem along with any exposed nodes with a rooting hormone such as Clonex. To avoid unknowingly contaminating the entire bottle, pour a small amount in a glass or container, then dip the cutting in that, do not dip straight into the bottle. Place the cutting into the rooting medium, gently pack it around the stem to keep it upright and place into a propagator keeping humidity high and temperatures stable.
As with germinating seeds, cuttings can be rooted in various mediums, our preferred method is Rockwool or propagation plugs such as Root Riots. These should be pre-soaked in room temperature water for around 15-20mins, which should also contain a light seedling feed such as Formulex or root stimulator like Katana Roots. The cubes or plugs should also be shaken to remove any excess solution and not squeezed, as this will expel oxygen. The rule of thumb is the medium should be moist, but not soggy.
Clones can also be rooted in a light-mix soil. The technique of taking and preparing the cutting is exactly the same, the medium, as when germinating seeds, should be pre-wetted so its moist, but not soaking and a hole should be made deep enough to support the clone. Once placed into the soil, it should be gently packed for support and then placed in a propagator and under a suitable light source.
PROPAGATORS AND LIGHT
To get the most out of your seedlings and cuttings, it’s important to give them the right environment with a warm temperature (approximately 20°C) and high humidity level (80-100 RH), as well as using the correct light; too strong, the young, delicate plants will crisp up and die, too weak and not enough light will be emitted to encourage root development.
There are various propagators on the market, so the choice is dependent to what’s suited to your grow room or environment. The time of year can also determine this, as during the winter months, to help achieve the required warm temperatures and high humidity levels, a heated propagator might be needed. Aeroponic Propagators should also be seriously considered as they deliver amazing results by misting the exposed stem to a mixture of nutrient solution, such as Clonex, and oxygen.
To help keep humidity and moisture levels high in propagators, its good practice to mist the inside of the lid. We also recommend leaving the lid off for around 15mins per day during propagation, this allows fresh air to circulate around young stomata and help encourage photosynthesis, along with healthy root and plant growth.
Which Light & What Schedule Should Be Used?
We recommend either dedicated Blue Spectrum CFL (Compact Fluorescent Lamp), T5 Propagation Lamp. These give off the spectrum of light required to encourage root development and vegetative growth but with a low heat output, you can position them close to the tops of the plants to help maximise the amount of light they receive and also keep the plants squat by limiting stretch. For example, the T5’s, PS1’s and 125w CFL’s can be a matter of inches away, while the 250-300w CFL’s should be a little further, around 8-10” (20-26cm) away.
Although we don’t recommend it, HPS and MH lamps can be used, but should be positioned far enough away so they don’t generate too much heat and burn the young plants, and also allows the plant to have an initial stretch as it reaches for the light source. For better results, we recommend using a dedicated T5, PS1 or CFL.
The lighting schedule initially should be set to 24 hours on. As the plant starts to develop roots and heads into the vegetative stage, the propagator can be removed and the light reduced to 18 hours on and 6 off. Its also around this time, you can switch from using a propagation lamp to a dedicated Metal Halide (MH) or High Pressure Sodium (HPS) to help get the most out of the vegetative phase before the plant heads into flower.
This guide isn’t definitive, it’s just to help give you the do’s and don’ts when germinating seeds or rooting out clones and to recap, below are some rules of thumb you should follow:
- Humidity should be around 80-100 RH
- Temperatures should be a stable 20°C
- T5, PS1 or CFL propagation lamps should be used instead of HPS or MH lamps
- The use of a propagator to help maintain high humidity levels
- Pre-soak Rockwool or rooting plugs prior to placing the cutting or seed
- Use a light feed like Formulex or root stimulant such as Katana Roots
- Clones should be cut at 45° and placed in a rooting hormone such as Clonex
- Misting the lid of the propagator can help keep high humidity levels
- Remove propagator lid for 15mins a day to allow fresh air to circulate
We hope this helps you get your seeds germinated or clones rooted and happy growing from all at Holland Hydroponics.