After cannabis seeds sprout do they need light

Seed Starting, Part 2: What To Do After Germination

Check out our latest tutorial video below about what to do with your seeds after they have started to germinate (when they’ve started to grow). Then keep scrolling for some tips and links to help you out! If you missed the first video on How to Successfully Start Seeds, be sure to check that out first, as it will get you started on growing a great garden – whatever your skill level.

>> Download: When to Start Seeds Indoors

We also have for you an easy-to-follow written guide on when to start what.

1. Light

Your seedlings will need light, but they also need periods of rest (darkness) too. A good rule of thumb is to turn the grow lamps off when you go to sleep, and turn them on when you wake up (or use a timer). Read all about different types of grow lights here.

Seedlings need blue night and red light. Sunlight includes both. Red light stimulates the growth of leaves and flowers. Blue light regulates the growth/size of plants.

Don’t use incandescent light, use fluorescent. Full spectrum bulbs include both red and the blue light, or you could use one warm (red) light and one cool (blue) light.

The grow lamp should be about 2-4 inches above the seedlings, so adjustable lights are helpful. You can find the Tabletop Garden Starter® Grow Light Kit shown in the video (and in the photo above) from Gardener’s Supply.

Be sure you clean the lightbulbs, as dust and dirt can cut down on the amount of light emitted.

Hold your hand above the seedlings. If it feels warm, the light is too close.

2. Water

Water from below, not above, to ensure that you don’t squash the seedlings. Make sure your seedlings aren’t sitting in water, or you’ll have issues with rotting, fungus, and soil gnats.

Your seedlings might need to be watered if:

  • The soil looks lighter
  • The soil pulls away from the edge of the cell

Self-watering seed starting kits use capillary mats, but be sure to check the water levels on those as well.

3. Food

Seedlings need food when they get their “true leaves.” The first leaves that come up are typically embryonic leaves from the cotyledon (part of the seed) so look for the second (“true”) leaves to appear before you start fertilizing. Use fertilizer at a weaker strength than you would for full-sized plants.

There are several different options for how to fertilize your seedlings. The ones shown in the video are Sustane Compost Tea Bags and Alaska Fish Fertilizer 5-1-1 Concentrate 1 Quart

4. Airflow

Your seedlings will be healthier and more sturdy if air is flowing above and around them. A fan can be used – we recommend putting it on a timer, just like your grow lights.

5. Room to Grow

Most people put more seeds than are needed in each cell, so you’ll need to either (carefully) pull out the weaker ones from each cell, leaving one healthy one, or cut them off at the base. Monica demonstrates both methods in the video.

Be sure to check your seed packet to see how long it should take your seeds to germinate. If no seedling has appeared by a few days later than expected, sow some new seeds.

6. A Bigger Pot (optional)

It’s not needed, but if you’re not moving your seedlings into a garden for several weeks, you might want to transfer them to a larger container. If your plant is about two times the size of the container it’s in, or you can start to see roots below the cell, you might want to move it to give it more room to develop, access to more nutrients and more moisture, and the roots will have more space to grow. A 3 to 4″ pot should work well.

If you’re reusing pots, be sure you wash them well before you use them.

You can also use Eco-friendly Seed-starter Cowpots, which you eventually plant into the ground, adding nutrients and organic matter to the soil.

Use a potting mix (such as the Organic Potting Mix, 20 Qts. from Gardener’s Supply) when you transplant your seedlings. Make sure that it is adequately moist – if you grab a handful and squeeze it, it should hold together, but if you move your hand, it should fall apart (see the video at about the 23 minute mark for a demonstration of this).

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When transplanting, never grab a seedling by the stem, or you could damage or kill the plant. It’s better to try to push it up from the bottom of the cell, and try to take it out in one piece.

After transplanting, be sure to still water your seedling from below.

Important note: when you do move your seedlings outside, you need to do something called “hardening off,” which is slowly exposing them to the conditions they will encounter in your garden.

7. Label

Be sure to label your seedlings so you know what they are!

Ones shown in the video include ones similar to these seed markers. The garden stakes from Botanical Interests are currently sold out. One of our YouTube viewers also suggested using venetian blinds as labels. We thought that was a great idea!

What are you growing from seed this spring? Let us know in the comments below! And don’t forget to subscribe to our YouTube Channel.

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Disclaimer – All opinions expressed here are those of the author based on personal experience using the product.

Please note that the Amazon and Gardener’s Supply links (and only the Amazon and Gardener’s Supply links) above are affiliate links. Should you choose to purchase products through these links, GPReview will make a small commission (at no extra cost to you) that helps to support this website and our gardening product reviews. Thank you!

About The Author

Sarah, originally from Wisconsin, prefers to be outdoors whenever possible. She has been known to high-five trees on hikes, tests the limits of her balance on kayaks, and is re-discovering a love of cycling. She works behind-the-scenes at the Gardening Products Review, located in sunny Tucson, Arizona.

How to germinate cannabis seeds

So, you’ve decided to grow your own cannabis plants. You purchased a pack of seeds, assembled cultivation materials, cleared a space in your garden, and are ready to grow your first cannabis crop . With everything in hand, it’s time to begin the very first step of cannabis cultivation : germinating seeds.

What is germination?

Germination is the first stage of the cannabis growth cycle : the process that brings a cannabis seed out of its hibernation period and starts the cannabis growth process. After all, seeds in a bag don’t spontaneously start developing roots. Also known as “popping” seeds, seed germination begins when a seed receives environmental cues letting it know the setting is perfect to start growth.

Germination is the process that brings a cannabis seed out of its hibernation period and starts the cannabis growth process. Photo by: Gina Coleman/Weedmaps

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When a seed enters an environment with enough moisture, it will increase in size and slowly break out of its shell. A seedling or germ forms from which roots will emerge, helping the baby plant absorb nutrients from the soil. Seeds naturally develop roots facing down and stems stretching upward, allowing the young cannabis plant to simultaneously feed off light and earth.

It’s essential to acquire high-quality cannabis seeds for germination, as these will go on to become high-quality cannabis plants. Seeds that are fresh-feeling or too green indicate that they haven’t reached full maturity, while pale-green, white, or very dark cannabis seeds may have trouble sprouting. However, it’s tricky to know the outcome of a popped seed, so trying may be worthwhile. If you’re not ready to pop your seeds yet, store them in a dark, cool place until it’s time for germination.

Preparing to germinate cannabis seeds

Germination itself is a crucial aspect of cannabis cultivation. The seed germination process is the foundation of every marijuana plant, and steps can be taken to boost successful popping. For example, some cultivators improve germination attempts by soaking seeds in 1% hydrogen peroxide or a compost tea for 12 hours beforehand to kill any dangerous pests.

The environment in which seeds germinate also plays a role in the outcome. While there are several different germination methods, each requires proper moisture, minimal handling, and warm springtime temperatures between 68-72 degrees Fahrenheit.

How to germinate cannabis seeds

The best germination method depends on the cultivator’s choice. Here are some of the most common ways to pop your cannabis seeds.

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How to germinate seeds in soil

Soil is an easy, more natural method with which to germinate your cannabis seeds. The soil protects the fragile roots from any interference, and soil is, after all, where a cannabis plant would grow in the wild.

Soil is an easy, more natural method with which to germinate your cannabis seeds because the soil protects the fragile roots from any interference. Photo by: Gina Coleman/Weedmaps

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First, make sure you use the correct type of soil, either gently fertilized potting soil or a seed starter with a pH level of approximately six (6). The soil contains the right acidity and enough nutrients to strengthen your young cannabis plants for the first two weeks. Be careful not to add more nutrients, or you risk overfeeding and killing your seeds.

Place the soil in a small pot and use your finger or a pencil to push a small hole in the dirt, a bit more than half an inch deep. Insert the seed into the hole and bury it with soil. From this point on, don’t touch your seed. The young plant is fragile and knows how to position itself in the soil bed.

Gently water the soil with a spray bottle and situate your pots under a fluorescent lamp. Keep seeds away from the windowsill, as the temperature is too volatile for germination. In general, you’ll want to keep the temperature in the range of 70 to 80 degrees Fahrenheit.

Monitor your soil every day and keep it moist. Within four to seven days, you should see tiny stems sprouting from the soil.

When the seedling stems reach two to four inches in height, it’s time to transplant your cannabis into larger pots with more room for roots to spread down and out. After you’ve done this, you’ve successfully germinated your cannabis seeds into proper, young plants.

How to germinate seeds in water

You can also germinate your seeds by placing them in water. It’s slightly faster than the soil method, but you need to adjust your environmental factors accordingly. Remember, successfully germinating seeds requires a perfect balance of ideal growing conditions. When germinating in water, seeds need only 24-48 hours to pop their stems, though cultivators can keep them soaking for up to a week as needed. Water germination is faster because the seed gets all the moisture it needs immediately, and the shell softens and cracks more easily after soaking.

To employ water germination, fill a glass with tap water and let it sit until it reaches room temperature or around 65 degrees Fahrenheit. Add two to three plant seeds per cup and allow them to sit, watching for any changes. Change the water to fresh tap water every two days, making sure it stays at room temperature.

The seeds should start sprouting in about two days, though older seeds can take up to a week to sprout. You can remove them from the water and place them in the soil at any point once they’ve sprouted. Once the roots are about five millimeters long, they need to be planted.

The downside of water germination is that once they’ve popped, you’ll need to maneuver them into their growing medium manually. This is a delicate process, as germinating seeds are extra fragile, and any harm risks the development of your plants. Make sure to place the seed roots down in the soil when you transfer to a pot.

How to germinate seeds using paper towels

The paper towel method is also a common way cultivators pop their seeds. Some even use this method with cotton pads instead of paper towels, but the necessary steps are the same.

To germinate seeds this way, lay one paper towel on top of a countertop, place a few seeds, and cover them with a second paper towel.

Lay one paper towel on top of a countertop, place a few seeds, and cover them with a second paper towel. Photo by: Gina Coleman/Weedmaps

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Use a spray bottle to moisten the paper towels and then store the cushioned seeds between two plates, under a face-down bowl, or gently place them in a plastic bag. Maintain a temperature of about 72 degrees Fahrenheit, keeping the paper towel wrapped seeds in the dark and away from a windowsill. In two to five days, the seeds will pop inside the paper towel sandwich and emit tiny roots, ready to plant when they reach about five millimeters in length.

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Use a spray bottle to moisten the paper towels and then store the cushioned seeds between two plates, under a face-down bowl, or gently place them in a plastic bag. Photo by: Gina Coleman/Weedmaps

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The paper towel method also has its risk, as the fragile seedlings can be damaged during the potting process. The tiny roots can also get tangled in the paper towels, so make sure to move the seeds to potting soil before roots grow too long. Use your hands or tweezers to gently remove each seed from the paper towels and place them in a prepared growing medium.

How do you germinate seeds indoors?

Whether you’re planning an indoor cultivation or outdoor grow, it’s best to germinate your seeds indoors. It’s easier to maintain proper temperature, light exposure, and moisture inside, and you can protect your seeds from the elements. Indoor germination, whether using soil or paper towels, will ensure your cannabis seeds have the best chance for survival.

To germinate seeds indoors, use any of the methods described above. Within a few days, you’ll have popped seeds ready to transfer to a growing medium.

Do you need to germinate seeds before planting?

While many plants can be germinated in the ground, cannabis seeds are fragile enough that you should germinate them before planting.

Once your seeds have sprouted roots, they should be planted in soil, a soil-less medium, or in your hydroponic setup. Make sure not touch the root, caring for and navigating the seedling so that the roots face downward. Plant the seed about one inch deep in your growing medium, cover lightly, and allow for about a week for the seed to emerge from the soil. If the seed hasn’t poked through by day ten, it likely didn’t survive.

When can seedlings be put under lights or in the sun?

Not sure whether to grow your cannabis seeds in the sun or under lights? This article explains how much light you need, how to prevent your seedlings from falling over, and when to plant them outside.

“When can cannabis seedlings be put under lights or in the sun?” is a common and sensible question that is often asked by novice cannabis enthusiasts after germinating seeds indoors under lights.

For those who are growing indoors, cannabis seedlings may be put under lights as soon as they emerge from the soil or growing medium.

How much light for cannabis seedlings?

When using HID lighting (usually a metal halide lamp), young seedlings should be kept at least 50cm from the bulb.

With compact fluorescent lamps (usually 100w or more), a distance of around 15cm should be maintained between the top of the young seedlings and the bulb.

If using normal fluorescent tubes (18-36w), seedlings can be kept within a few centimetres of the light source.

Cannabis seedlings growing under lights should always be given a gentle breeze from an oscillating fan (a small household fan on the lowest setting is fine), as constant gentle movement will strengthen their stems significantly.

Are your cannabis seedlings falling over?

If cannabis seedlings grow tall and then fall over, this is almost always a result of growing in an environment with static air.

Seedlings intended for outdoor growing should be kept by a sunny window for the first week or two after emerging from the soil.

When they have grown their second or third set of serrated leaves (after the the round cotyledons that initially emerge from the seed) seedlings are usually hardy enough to flourish in direct sunlight.

When to plant your cannabis seedlings outside?

If outdoor temperatures are suitable, seedlings may be acclimatised to direct sunlight by giving them progressively longer daily exposure to outdoor conditions.

Starting with about three hours outside, at the sunniest time of day, seedlings can be given an extra hour of outside exposure each day, so that within about two weeks they can be left outdoors permanently.

Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.