Germinate Weed Seeds In Light Or Dark

Most plants need light to grow and keep them healthy, but not all plants need light to germinate, and, as we shall see, some seeds find light a hindrance. Germinating marijuana seeds,how to germinate marijuana seeds,how to store marijuana seeds,germinating marijuana,how long to germinate,marijuana seeds,seedling cannabis,germinate marijuana seeds,how to germinate marijana seeds,germinating your cannabis seeds with paper towels,marijuana seedling stage,weed seedling stage

The Effect of Light on Germination and Seedlings

Do seeds need light to germinate? And how does light affect the germination of seeds? T&M’s former Technical Manager, David Batty, investigates these questions and discusses the question of whether seedlings need light. Some plants germinate well in darkness, some prefer continuous light, and others have no preference either way.

Apparently it was custom in Ancient Egypt, before finally sealing the tomb, to leave a little pile of moistened corn near the sarcophagus. One can imagine the seed germinating in the pitch darkness, stretching itself upward feeling for light which was not there and finally toppling over having exhausted its food reserves.

It is a fact of life that most plants need light to grow and keep them healthy, but not all plants need light to germinate, and, as we shall see, some seeds find light a hindrance. If we look at the matter from the gardener’s point of view, however, we can use the rule of thumb that most cultivated plants on sale in seed form prefer to germinate in the dark. There are some notable exceptions however, some greenhouse perennials, epiphytes, many grasses, and even tobacco all prefer light and a large number of seeds are not fussy either way.

The reason is that commercially produced seed is bred and selected for its ease of germination as well as other more obvious characteristics and so peculiarities such as light or dark requirements do not often occur. On the other hand seed which is obtained non-commercially, in small quantities from the home gardener, seed lists, or the more unusual items from seed merchants may prove to be much more fussy in its requirements. In fact, research has shown that with seeds other than cultivated forms there is a great deal of variation. We can divide seeds of this type into those which germinate only in the dark, those which germinate only in continuous light, those which germinate after being given only a brief amount of light and those which germinate just as happily in light or darkness.

As long ago as 1926 experiments were carried out by Kinzel to find out the light requirements of hundreds of plant species. He found about 270 species which germinated at or above 20°C (60°F) in light, and 114 species germinated at the same temperature in the dark. He also found 190 species which germinate in light after experiencing hard frosts and 81 species likewise germinated in the dark. Fifty-two species germinated in the light and 32 species in the dark after light frosting and finally there were 33 species which were unaffected by light or dark.

Unfortunately, as with all gardening matters, things are not quite this simple. Other factors, it seems, can also affect the seed’s light requirements, for example, with some species (e.g. Salvia pratensisand Saxifraga caespitosa) light requirement only exists immediately after harvesting whereas with Salvia verticillata and Apium graveolens (Celery) this lasts for a year and to confuse matters further other species develop a light requirement while in storage. Chemicals also, such as nitrates in the soil, can substitute for light in stimulating seeds to germinate so that some light requiring seeds will still germinate if covered with fertile soil. Still it all makes for interesting gardening doesn’t it?

For a fairly comprehensive list of the Light/Dark requirements of seeds we refer you to Thompson & Morgan’s booklet ‘The Seed Sowing Guide’, which they will be pleased to send you for only 99p if you drop them a line. This is a helpful general guide but it is worth remembering that not all seeds in the same genus behave in the same way. For example Primula ohconia needs light and Primula spectablis needs darkness for germination, so there is still a lot to learn, much of which can only be gained by personal experience and sharing that information gained with others.

The explanation of how light affects some seeds and causes them to be in a state of readiness for germination and yet prevents other seeds if necessary from germinating is highly complex. Suffice it to say that it is mainly the light’s effect upon a plant pigment called phytochrome within the seed. This relates to the type of light which the seed receives. As a generalisation, light in the red wave length usually promotes germination whereas blue light inhibits it.

In a practical vein the light requirements of a seed may relate to the habitat in which the seed parent usually grows, so as to ensure that those which fall in an area conducive to growth will germinate and those which fall in less salubrious circumstances bide their time. For example a seed requiring light to germinate might fall into the deep shade of another plant where growing conditions would be very poor, whereas a seed falling into an open, well lit space would germinate quickly and flourish. On the other hand, it may be essential for the establishment of the young seedling that part or all the seed needs to be covered with soil or in the shade, perhaps, to protect the young root.

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In such a case with a seed which required darkness, uncovered seed, which is exposed to light will not germinate. Sometimes only part of the seed is light sensitive. Phacelia is light sensitive at only two points on its surface and in a lettuce at only one. The micropyle where the water is absorbed, is light sensitive perhaps to ensure that only correctly oriented seed with the best chance of survival germinates.

Of course, the effect of light on seeds should not be over emphasised, no real hard and fast rules can be laid down, as other factors interact with light. To the gardener, the two questions he needs to have answered are ‘How deep should I sow my seed?’ and ‘Should I cover the seed tray to exclude light or not?’

In answer to the first question, depth of sowing depends a lot upon the size of the seed. Very tiny seed should normally be sown and left uncovered. Small seed which needs light will usually receive it even if you cover it with a light sprinkling of compost or vermiculite because light does travel a short distance through the soil and with some seeds exposure does not need to be long or continuous. For example tobacco seed receives all the light it needs to germinate, after it has taken up water, in 0.01 seconds of sunlight and even moonlight will do!

It is not just the very tiny seeds which sometimes need light to germinate, an average seed like Impatiens is light sensitive too and should be covered with a fine sprinkling of vermiculite after sowing and left in diffused light, placed in polythene to provide a high humidity until germination which usually takes 10-14 days at 21-42°C (70-75°F).

Medium sized seeds and upward, unless they have a light requirements (and we do not know of any really large seeds which do) should generally be sown just below the surface, enclosed in a polythene bag or cling film and placed in diffused light.

Some, but not all, popular seeds which prefer light for germination are:

Providing artificial light should not normally be necessary for seeds sown in greenhouses, well lit propagators etc. but if light is a problem or, more importantly, if you want to ensure rapid, healthy growth of your seedlings after germination then some form of additional light may be necessary. This would particularly be the case in raising seeds early in the season and quite a number of flower and vegetable seedlings respond to supplementary light. For example, tomatoes and cucumbers where vigour and earliness have been improved, also Antirrhinum, Stocks, Gerbera, Gloxinia and Gesnaria have all responded with a higher growth rate when given extra light in the winter months.

Tuberous begonias when sown in late winter must have supplementary lighting if they are to develop properly. They are sensitive to day length and when this is less than 12 hours they form tubers instead of making vegetative growth. In order, therefore to produce healthy young plants lighting must be given to extended the day lengths to more than 12 hours.

To provide this light, fluorescent tubes of the Gro-Lux type, to give light something akin to sunlight should be used, suspended around 2 feet (60cm) above the seedlings. As there will be so much moisture about use only approved horticultural fittings when installing the lights and fit a time clock if possible so that the lights can be on for 12 hours each day.

David Batty is a former Technical Manager at Thompson and Morgan Seeds, where he looked after the seed-testing laboratories.

Source of article
Growing From Seed – Spring 1989 Vol. 3 Number 2
Copyright: The Seed Raising Journal from Thompson & Morgan

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Step Two: Germinating Marijuana Seeds and The Seedling Stage

December 31, 2018

Germinating marijuana seeds means “activating” the seed,. which is the first step to start growing your weed (or technically the second step after building your grow room ). The seed contains not just the embryo, but also the food that plant will use during its very early stages of life. When exposed to moisture and warmth, the seed will naturally “activate,” and begin using its stored food to develop a taproot and push up from the grow medium. In order to achieve successful germination and rapid early growth, it is crucial to maintain ideal conditions for your germinating seeds.

If you are new to growing cannabis, and would like some extra help germinating your cannabis seeds. Then check out this awesome video from Percys Grow Room . It will take you step by step through the germination process.

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Where to get your cannabis seeds from? (Seed Banks That Ship to USA)

Marijuana seed can be obtained from many sources (online and offline), the quality and the and genetic diversity can vary based on where you’re getting cannabis seeds from. Online seed banks are your best bet if you’re not located in a region with recreational legalization established.

There are many reliable outlets sell high quality seeds, here is a list of The Best Online Seed Bank for Feminized Seeds that ship to the USA, in the industry. These seed banks have strong reputations and are known for providing high quality genetics.

If it’s your first time growing, it also pays to get feminized seeds. Dealing with identification and removal of males is an additional complication that inexperienced growers can avoid simply by purchasing feminized seeds.

The choice is always up to the grower, but I strongly believe feminized seeds are a justified expensive and recommend them for any new grower.

Mature Cannabis Seeds, This Is What You Need to Do

Once you get your marijuana seeds, you will want to check if they’re matured. If you use a good seed bank, like the ones in the list above, then you will most likely receive quality seeds that are ready to be germinated.

Matured marijuana seeds shell tends to be very hard, darker brown or deep tan, with lighter accents (stripes). If they look fresh and green, it means they didn’t reach full maturity, they’re pretty much useless .

How to Germinate Marijuana Seeds

Before you plant the seeds, you need to germinate your cannabis seeds, and to do so, you will need three main things; water, heat, and air, like every living being on earth. There are a few common methods for germinating seeds, and some seed banks provide detailed instructions for how to germinate the seeds you purchase from them. Some banks also provide a guarantee on germination rates, and will provide replacements or refunds, but only when their instructions have been followed.

Although we recognize a number of methods as being successful means to achieve germination, always follow your provider’s instructions when applicable, particularly so that you may take advantage of any guarantees included with your purchase.

Now, how to germinate marijuana seeds ; the following method (paper towel germination) is the most common, and one of the most simple. Here is what you need:

  • Clean plate, and another one to be used as a cover (optional)
  • Paper towels
  • Marijuana Seeds

And here is the method:

  1. Soak 6 paper towels sheets in a distilled water.
  2. Take 3 of the soaked sheets and put them on the plate.
  3. Put the marijuana seeds on the soaked sheets, each seed should be an inch or more apart from the one next to it.
  4. Cover the marijuana seeds with the remaining 3 of the soaked sheets.
  5. Now, if you need to create a dark environment for the seeds, you can take another plate (the same size) and flip it over to cover the seeds/paper towel sandwich. This is not necessary if you have a dark place to put the seeds, such as a cabinet, drawer, closet, etc.
  6. Finally, as for how long to germinate marijuana seeds in paper towel: just give it some time. The germination period is different from one seed to another. Some seeds germinate quickly, others can take up to a week.

Check your germinating marijuana seeds at least once a day. You will probably need to add more distilled water as they begin to dry out. You don’t need to completely drenched the paper towel, but it should always be damp to the touch. Once the seeds split, you will see a single taproot coming out (see the picture below). You will know that your beloved cannabis seeds are successfully germinated.

Once the tap root is approximately 0.25-0.75 inches (0.6-2.0 cm) it’s time to move them into a starter medium (rockwool cube, peat moss plug, etc.) or soil and straight to your grow room.

Important tips to ensure successful germination for the marijuana seeds:

  • Keep the seeds in a warm environment, between 70-77°F. High humidity is also preferable; germination rates tend to be higher at around 70-80% RH.
  • Make sure to keep the paper towels sheets soaked all the time. If them seem like they’re getting dry, simply add some distilled water to keep the sheets saturated.
  • Open the plate’s only once a day to check the progress.
  • As the seeds begin to split, do not, I repeat, DO NOT touch the seeds or the tap root. It’s very important to keep this area clean and sterile.When you are ready to transplant them to the medium, use sterilized tweezers if possible.

Moving Your Germinated Seed to A Pot

Due to the limited root system the germinated seeds have, best practice is to plant the germinated seeds in small containers. This will increase the plants’ accessibility to oxygen and nutrients by avoiding overwatering.

When plants are initially placed in large pots, they cannot use all of the water and nutrients around them very quickly. This results in damp conditions that facilitate the growth of mold and certain pests. Thus, we prefer to start our seedlings in small containers like solo cups, then transport them to a bigger container when they start developing a larger root system (once they hit the seedling stage).

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Here is what you need to do:

  • Acquire a small 2 inch pot (or solo cup) for each germinated seed
  • The soil you will be putting in the pot shouldn’t be dense. It has to be rather loose and airy. You generally want a mixture of potting soil and perlite, roughly 70:30 to 50:50.
  • Dig a hole approximately 0.5 inches, or one knuckle deep, in the middle of the pot using a pen, and drop the germinated seed in it ( tap root faces down ). Make sure to transfer the germinated seed gently and carefully, I usually avoid using my hands to move the seeds; a pair of tweezers would do the job.
  • Lightly cover the hole/seed with soil (enough to block the light without obstructing the seedling when it emerges).
  • Now, add a little bit of water. Make sure the soil still covers the seed after watering it. Not much water is necessary, and you shouldn’t need to water again until after the seedling emerges.

Final Steps – Marijuana Plant Seedling Stage

Place the small pot(s) in your grow room, and turn the lights on. The seeds technically don’t need the light at this point, but they immediately do once they pop out of the soil. Having the light on and waiting for the plant will assist the young plant to develop better and faster. You can leave a fluorescent light close to the surface (a couple of inches away) from the plant since fluorescent lights don’t emit a lot of heat, but HID or LED should be at least 24 inches away, if not further. Refer to the light manufacturer’s instructions to see if they provide a recommendation for distance from the canopy at various stages of growth.

Here are a few other things to keep in mind for germinating your seeds:

  • The temperature should be around 73 F at all times . Warmer temps will not cause any problems, at least until closer to 90 F. Cooler temps, however, can stunt growth in early stages.
  • Humidity should be around 60-70% RH.
  • When you water the pots where you planted your seeds, you want to make sure giving them just the right amount of water without over saturating the soil, which may cause suffocating the sprouts and kill it. Using a spray bottle can do the job; they do not need much water early on..
  • Make sure your pots have holes in the bottom to allow water to drain.
  • Do not overwater! It is really easy to overwater and cause severe stunting or even kill the seedlings. If you can feel any moisture at all when you touch the soil, they do not need water yet.
  • In 3 to 7 days, you should start seeing the first signs of your newly born cannabis plant.
  • Once you see the first sprouts; have your fluorescent lamp running 18 hours on, 6hours off in 24 hour intervals.
  • In 3 to 4 weeks, the cannabis plant should be around 4 inches high, which is big enough to be moved to a bigger pot; this is the true start of The Vegetative Stage ! If you are using a solo cup, the plant’s fan leaves should now be stretching over the edges of the cup. This is a good indicator that you are ready to move up to a larger pot.

If you have any questions, and you would like more help with starting your cannabis grow, then join the cannabis growers forum over at Percys Grow Room. They have over 1 thousand members, waiting to help you with your grow.

Percys Grow Room also have competitions, grow diaries , Guides on fixing cannabis plant deficiencies, and much more. If you’re a new grower it would really benefit your grow if you signed up.

Just click here , it will take less than a minute, its free, and your plants will thank you for it.

Here is our complete Step by Step Beginners Guide to grow marijuana Indoors

  • Step One:Choose the right strain/seeds. Here are the Best Marijuana Seed Banks
  • Step Two:How to Build the Perfect Indoor Grow Room (For up to 6 Plants)
  • Step Three:Germinating Your Marijuana Seeds and The Seedling Stage
  • Step Four:Marijuana Vegetative Stage
  • Step Five:Flowering Stage
  • Step Six:Harvesting and Drying
  • Step Seven:Curing and Trimming

Editor’s Note: This post was originally published in Jan 2018 and has been revamped and updated as needed for accuracy and comprehensiveness.

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