Do You Need Grow Lights Before Germination? | Germination Tips Starting plants indoors from seed can be a rewarding way to get a head start before the main growing season or get started with an A good germination stage is decisive in obtaining shoots that develop rapidly and end up with powerful seedlings. Learn to germinate marijuana seeds fast.
Do You Need Grow Lights Before Germination? | Germination Tips
Starting plants indoors from seed can be a rewarding way to get a head start before the main growing season or get started with an indoor garden. However, germination (the process by which a plant begins to grow from a seed) can sometimes be spotty.
Some of your seeds might not germinate, or they might take too long to germinate. This can lead to gardeners seeking other ways to increase germination success, such as trying to add fertilizer after planting seeds, adding extra water, or putting them under grow lights to get them started.
You may have heard that grow lights can improve germination. That is not necessarily the case, but as always, there are exceptions.
Do You Need Grow Lights Before Germination?
In most cases, any source of light is unnecessary before germination, and grow lights in particular are not really useful at all for germination.
As explained below, light is not important for seed germination, with a few exceptions. However, grow lights are necessary for sprouted seedlings unless they are in a sunny window or otherwise getting direct sunlight.
The only benefit of grow lights before germination is that they can provide extra warmth which helps speed up germination. Germinating seeds at room temperature or slightly warmer is sufficient for most seeds, and some gardeners use a temperature-controlled seedling heat mat if they need extra heat.
Do Seeds Germinate Better in the Dark?
For most seeds, while they will still germinate with exposure to light, they germinate better in the dark. In some cases, such as with seeds in the onion family, light can actually inhibit germination.
If you think about it from an evolutionary standpoint, in nature, seeds with the most success will be those sitting on or in the soil. A sprout sitting on a rock or otherwise away from the soil would die even if it had the moisture and warmth to start the germination process.
Do Any Seeds Need Light Before They Sprout?
There are some seeds that actually need light before they sprout. These are mainly flowers, herbs, or vegetables with very tiny seeds.
These types of seeds can still germinate without light but sprout much better with light exposure. For example, celery is recommended to be surface-sown because the seeds are so tiny and germinate best with sunlight. Even lettuce seeds, which are less picky, sprout better with sunlight.
As a rule of thumb, you should plant seeds about two or three times deep as they are wide, so even if you bury tiny celery or lettuce seeds into the soil, about 1/4 inches deep is shallow enough to allow some light through. In nature, this is advantageous because small seeds don’t have enough stored energy to grow up through deep soil.
Does that mean you need a grow light to germinate these seeds? No. Ambient light from a room or next to a window will be enough.
If you are germinating seeds at home to grow and eat your own sprouts in a jar, it’s recommended to keep them out of indirect light.
SANSI LED grow lights over pepper and tomato plants.
When Should I Turn On My Grow Lights for Seedlings?
Seedlings should start getting light as soon as they appear. When you see the first sprouts emerge, you can turn on your grow lights.
If you leave your seedlings to grow without light, they will stretch and get leggy. This isn’t a problem for some vegetables like tomatoes, but most of the time it leads to weaker stems and more fragile seedlings when transplanting outdoors. If kept in complete darkness, seedlings will die.
The only exception is if you are growing microgreens. Often, microgreen growers will allow their sprouts to grow in the dark for a few days to become leggy on purpose. Then they will expose them to their grow lights, which perks up weak, yellow seedlings and turns them green. Leggy microgreens are much easier to harvest by cutting above the soil layer with a sharp knife or kitchen scissors.
Should Seedlings Get 24 Hours of Light?
In general, plants should not get 24 hours of light a day, and seedlings are no exception.
While it’s true that more light will lead to faster growth, and some plant species can be healthy with a 24-hour photoperiod, most plants need a period of darkness for plant metabolism.
For seedlings, you can keep them under 12 to 16 hours of light per day. Make sure to keep the lights close enough to the seedlings to keep them from getting leggy but far enough away to avoid overheating your seedlings (unless you like cooked sprouts).
What Kind of Grow Light Do I Need for Seedlings?
Unlike mature plants, seedlings can get away with much less powerful grow lights. Any kind of grow light, from LED grow lights to standard fluorescent lights.
If you already have T12 fluorescent lights, they can be used for starting seedlings, but seedlings will eventually outgrow the energy output of T12 bulbs. If you are buying a fluorescent grow light, T5 bulbs (especially T5 high-output bulbs) are brighter so they don’t have to be placed very close to the seedlings and can be used for larger seedlings.
LED grow lights are another option. The prices have gone down significantly over the years, and you can get full-spectrum white LED grow lights that are even better than the older pink/purple style of LED grow light that used to be more common. LED grow lights are energy efficient and can last for years, and you can get grow lights for under $100 that are strong enough to grow full-sized plants as well.
How to Germinate Cannabis Seeds Fast & Reliably
Like any early stage in the cultivation of marijuana, carrying out a good germination is decisive in obtaining shoots that develop rapidly and obtain powerful seedlings.
In this guide, we will discuss how to germinate your seeds so they sprout in good condition, and how to treat them when they do.
Before you start, make sure you have your growing environment ready and time available to spend. Once the growing process begins, the plant will not wait for you.
Introduction To The Cannabis Seed
If you germinate a seed the right way, it will swell until it breaks the shell. The first thing you will see sprouting is a small white dot called a radicle. This is where the root of your marijuana plant will develop, and will be responsible for absorbing water.
The radicle will grow and push the seed up. Next, the first “leaves” called cotyledons will sprout, and these will finish breaking the seed until it can fully open. At this point, you should already have the plant in a medium where it can grow.
Next, the first characteristic marijuana leaves will emerge — the cotyledons are not really leaves, and they eventually dry out and fall off — as the root begins to develop.
Congratulations! Your plant has been formed correctly.
How Do I Know if a Seed is Healthy?
It is possible to germinate marijuana seeds found in a joint you got on the street. But the best way to ensure you have healthy seeds is to buy them from banks with a good reputation and history, and choose varieties of marijuana seeds for the type of crop you desire.
In general, any seed that is dark and does not break easily is a healthy seed that will germinate well. If the seed is white or pale green, it is likely that it will not germinate.
Obviously, it is always better to do the test before deciding to discard it: If a plant is born, it was a healthy seed.
How Do I Know If It’s Female or Male?
There is no physical difference. If you don’t know where the seed came from, it will be impossible to know the gender of the plant.
You will have to wait for the plant to grow and begin its flowering stage to know if it is male or female.
To ensure that the plant will be female, you can buy feminized seeds from a bank. If you don’t want to buy online, you can get seeds from a growshop in your city, which resell seeds from these same banks. In countries where legalization is more complicated, you will need to resort to donations. You can search for phone numbers for cannabis organizations or try Facebook groups.
I also wrote a guide about types of seeds.
What Does A Seed Need To Germinate?
– Moisture is the first thing the seed needs to activate; the radicle will break the shell in search of more moisture.
– Heat (just enough), the ideal temperature is between 70ºF to 75ºF (21ºC to 24ºC), which emulate spring conditions.
– Leave it alone while you wait for the radicle to appear.
– Be careful when you touch or move it. It is very fragile and can break.
– Oxygen is necessary for the plant to be able to breathe, not to be flooded with water.
– Darkness is not totally necessary, but it is good for the radicle to not have direct light.
Overall, humidity and temperature are the most important factors for a healthy plant.
Water is essential for seeds. You must always keep the germination medium moist — without flooding. If the plant dries out after activating, it will die. On the other hand, if you drown it, the plant won’t be able to breathe properly.
The plant will germinate better if you keep it warm. You can put a “normal” bulb close to it to give it heat — but remember that the root should not receive light. Even better, put the germination medium on top of the power supply of your Play, Xbox, laptop or the like you have. I do not recommend using 3DS, PS Vita or Nintendo Switch
The plant can develop in as quickly as 12 hours, or it can take up to two or four days. If more time passes, it will not germinate. In any case, do not underestimate the speed of seed growth. Have your growing environment ready and check the seeds a few times a day — without fiddling with them.
Marijuana Germination Methods
There are several methods to germinate seeds that are very simple and work perfectly. In the following section we will examine three of the most popular:
Activate them in Water
Letting the seeds soak in water overnight is one of the most widely-used methods by marijuana growers. Simply fill a glass with lukewarm water — between 70ºF to 75ºF (21ºC and 24ºC) — and drop the seeds inside.
Let them rest quietly until they open and the radicle comes out, at which time you will take them out of the water, taking care not to touch the radicle with your fingers, and plant them.
Some seeds take longer to sprout than others, but after 24 hours they could drown. If time passes and the seed has not sprouted, I advise you to transfer it to another germination medium and leave it near a heat source.
The following video on germinating with peat tablets (which I explain in the next section) explains the process of activating seeds by submerging them in water.
The most popular method, and the one I use most frequently, is to allow your seeds to sprout on kitchen paper:
- Put several layers of paper on a plate or a Tupper,
- Dampen the entire paper with a sprayer,
- Important! Drain the excess water in case there is too much; you do not want water to accumulate on the plate,
- Deposit the seeds on the paper, leaving a few centimeters of separation between them,
- Cover them with several other layers of paper and moisten again, and
- Cover them with another plate or lid and secure them so they don’t separate.
When everything is complete, place it on a warm surface. A good trick is to deposit it on a power supply like that of a laptop or a PlayStation as mentioned above. It should not be something that will be moving in the coming days.
If you can’t find a power supply, you can heat the paper up by bringing it “normal” lamps, and putting them on top of the refrigerator or anything that emits a little heat.
Now is the time to leave the seeds alone for a few days. Separate the papers only a few times a day to make sure you keep the paper damp, and to monitor when they begin to sprout.
Once the root has emerged from the seed and is beginning to open, it is time to transplant it into the growth medium.
Dehydrated Peat Pellets
If you don’t like crafts, one of the best methods is to use peat pellets or “germination pills” — they can be bought in nurseries, grow shops, etc.
Peat pellets are specific to start seeds of all kinds; they are very easy to use and will give the seeds the perfect condition to germinate.
- Activate the seeds by immersing them in water, which can be beneficial for using peat tablets,
- Once activated, the tablets are immersed in water — in a different container — to hydrate them for about five minutes so they take shape,
- Then make a hole in the pill and bury the seed, taking care that the root is down and the top is not buried more than 5 millimeters.
Transplanting Marijuana Sprouts To Soil Once Germinated
If you germinated on kitchen paper or a similar method, or activated the seeds in water, it is time to transplant them into a growth medium once the radicle expands. They are still very delicate, so this transplant should not be the only one, but the first.
Small pots or disposable plastic cups are a good option for growing the sprouts. I don’t recommend that you plant the seeds directly into soil or a pot because it will be more difficult to maintain the conditions you need to finish the process properly. A small medium will help you to regulate humidity and temperature.
You will need to get a good substrate, airy and loose. If you use soil from your garden, which is not the best medium, make sure that it does not form mud when it is wet and that it does not remain hard when it has dried either.
Transplanting Step by Step
- Fill your pots or cups with substrate.
- It is important to make holes in the cups for excess water to drain,
- Moisten the substrate without soaking it. Using a sprayer makes things easier,
- Make a hole in the substrate with a pencil or pen deep enough for the radicle to enter completely, but for the top to be barely buried at about 5mm,
- To transfer the sprout, take it gently and insert it into the hole with the radicle down,
- Cover the hole gently with a little soil so it can come out smoothly, and
- Moisten the top of the soil a little.
When planting the seed/sprout, try to use small tweezers so you don’t have to touch them with your hands. If you don’t have any, be very careful when handling it and do not touch the radicle with your fingers.
If you germinated the seeds in peat tablets, you can transplant the whole tablet into the glass or small pot. As for humidity, the same rules apply, moisten without soaking.
Make sure the substrate is always wet as time passes. The top will dry quickly, so stay alert and keep it moist, but be careful not to water it if it’s still wet.
Light: Now It’s Time!
This is when you must give them light. When the plants are outside, they open their cotyledons quickly to make way for their first leaves. Or you can put them indoors if you are growing that way.
If you are growing your plants outdoors, make sure the sun is not too strong; if the pot or glass heats up too much, the plants will burn. Put them where they receive sun indirectly, in a window, for example.
It may take a few hours or a few days, but in a short time the seedling will come out of the substrate looking for light. If after ten days it still has not left, it is likely that it will never do so.
Before moving to the final growth medium, wait until the seedlings are stable and have at least 4 leaves so that they can withstand the last transplant without too much stress.
The good thing about plastic cups is that you can cut them out, which makes it easier to transplant.
Common Germinating Mistakes You Should Avoid
Looking at them too much
Constantly uncovering the seeds to see how they’re coming along can stop the whole germinating process. You must be patient with marijuana and let nature do its work in peace.
If the growing environment is not warm, the seed will know that it’s not the right time to sprout. As mentioned above, the ideal temperature for the seed to grow is between 70ºF and 75ºF (21ºC and 24ºC).
Touching them with your Hands
Putting your finger in the radicle can cost you the crop. It is very fragile and easily separates from the seed. Always grab it by the part of the shell or, failing that, the cotyledons, and always do it delicately.
Too few water
I never tire of mentioning that marijuana seeds must be in a humid and moist environment 24 hours a day for it to grow. If you let the environment dry, the seed will die.
Too much water
Once the seed is open, it needs oxygen to live – if you don’t let it breathe it will die. If you use a water sprayer it will be easier for you to avoid going overboard. You should also always make sure to drain the excess.
Hard pipe water
Some cities have water that is loaded with salt or lime. In these cases, it’s better to use bottled water (and if you plan to irrigate your crop with this water you should find ways to clean it as it will also affect the growth of the plant).
The plant does not need fertilizers or stimulants during its first weeks of life. Compost soil could burn it. So, a quality growing soil will be necessary.
Planting them too deep
The seed must be buried deep enough so that it is barely covered and can easily break through. The ideal height is about five millimeters.
Using Moisture Domes?
According to the Mandala Seeds bank, it is not recommended to prevent ventilation using domes because it can quickly cause fungi in the germination medium.
On the other hand, Sensi Seeds bank does recommend them but you should take care not to use them for a long time. It also mentions the importance of ventilation.
Thank you for reading
Any of the methods listed in this guide will achieve a germination percentage close to 100%. But remember, there will always be seeds that do not germinate; even the most prestigious banks cannot guarantee that all their seeds will sprout.
The interesting thing is that although some will be unsuccessful and others may take longer, some will open quickly and grow strong. This will tell you from the beginning which are the most vigorous plants, and they are probably the ones you will choose if you want to have mother plants to make clones or your own seeds.
Now that you know how to germinate and transplant the seedlings, the next thing to study is how to take care of your plants in their first weeks of life. Everything has to do with the growing environment you have prepared before starting to germinate, or you will not have enough time to treat your seedlings properly.
In a short time, I will write guides on preparing your growing environment — whether you are going to grow outdoors or indoors — and on the treatments for the first week of vegetative growth. If you want to be alerted when they’re published, sign up for my mailing list below.