Most growers are familiar with the two main stages of a cannabis plant’s growth, the vegetative stage and the flowering stage. However, plants have a crucial period of growth before they enter the vegetative stage, and this is the seedling stage. Caring for seedlings properly is an essential first step in growing a healthy plant and maximizing yield.
Anytime you set up to grow cannabis seeds, the process always starts with germination. The seeds split open, and a taproot emerges. Shortly after, a tiny stem penetrates the surface of the soil and the first two leaves appear. These leaves are not true leaves, but are a part of the seed’s embryo and provide nutrition for the growing seedling until its first true leaves appear.
Between these first two leaves, called cotyledons, two more leaves will appear. They will have only two tips, unlike the seven-tipped leaves that are the hallmark of a marijuana plant. Once From the elbows of these two leaves, another set will appear with three tips and from those leaves will emerge leaves with five tips. The next sets of leaves will have seven tips, marking the end of the seedling stage. At this point, the tiny plant will be a few inches tall.
Caring for seedlings differs from caring for mature mmj seeds or purple haze feminized plants in several ways. Seedlings need to be protected from outside elements that would not normally bother a larger plant, as they are damaged easily. Growers should keep their seedlings inside of a protective container meant for housing young seedlings. Many containers are commercially available, however, a soda bottle that has been cut in half and placed over the seedling like a dome will work just as well.
There are many other things that growers must consider when planning how they will care for their cannabis seedlings. These include the following:
Germination is the process of activating a seed so that it sprouts a taproot and grows into a seedling. How growers care for seedlings will differ slightly depending on their method of germination. There are several methods growers can consider but the best results tend to come from using the paper towel method.
To germinate using the paper towel method, wet a folded paper towel with distilled water and place seeds inside of it. Place the paper towel in a container and keep it warm. Check it periodically to ensure the seeds stay moist. Seeds will germinate after two to three days, at which point growers must transplant the sprouted seeds, as leaving them in the paper towel too long could result in the taproot attaching to the paper towel or drowning in the water.
Depending on the strain of cannabis, growers must consider the container in which they will plant their seedlings. Traditional cannabis strains can be planted in smaller pots and transplanted into larger ones as they grow. However, autoflowering cannabis plants do best when planted in their final pots, as they develop too fast to allow for safe transplanting.
Seedlings have different water requirements than more mature plants do, even if the plants have only just entered the vegetative phase. While mature plants will need the soil to dry out slightly between waterings, seedlings need to stay moist consistently. However, they are still susceptible to overwatering.
Overwatering a cannabis seed deprives its developing root system of oxygen. Most often this is because the container is too large, so the tiny roots cannot absorb the amount of water they are given. If growing in a smaller container is not a possibility, growers can avoid overwatering by spraying their seedlings with water until the soil looks moist. It is important to direct the water at the base of the seedling and not spread it over the surface of the pot.
Underwatering should be a constant concern for growers, as cannabis seedlings will die quickly if left too dry. Seedlings’ roots must be able to access water at all times. Growers should watch their seedlings carefully to be sure they stay wet and provide them with adequate drainage to prevent overwatering.
Supplying cannabis plants with the nutrients they need to thrive during each stage is a major concern for growers. During any stage of growth, providing too many or not enough nutrients will harm the plant. Seedlings are especially sensitive to this, and cheap weed growers should be careful about the young plants’ nutrient levels to avoid future costly losses.
First, growers should make sure the soil they are using to grow their plants does not have any added fertilizer. Not only does this not support their plants’ needs, but it can lead to nutrient toxicity if they add their own fertilizer.
Providing nutrients to seedlings when they are too young is another major concern for seedling care. Seedlings get most of their nutrition from their cotyledons and do not need additional nutrients until they grow a bit larger. When using commercially available nutrients, growers should use half of the recommended amount to test how their i-49 seed bank plants respond.
Avoid nutrient deficiency by using high-quality soil without added fertilizers. Too much fertilizer can cause nutrient lockout, which prevents the cannabis plant’s roots from absorbing nutrients. Added fertilizers may also be too heavy in a nutrient that the young plant doesn’t need, which can upset their sensitive nutrient balance.
Signs of nutrient deficiency will appear on older growth first. Since seedlings are small with minimal growth, growers can see signs of this on the first true leaves they develop. If using a high-quality, fertilizer-free soil, growers can begin adding nutrients to the young plants every other time they water them.
Growers should also be mindful of their container size when addressing a nutrient deficiency in seedlings. Rootbound plants cannot absorb nutrients efficiently, so it may be time to transplant the plants.
Growers must monitor the temperature and humidity of the environment in which their seedlings are growing. Seedlings are more sensitive to changes in temperature and humidity, so growers must be vigilant in making sure the environment is stable.
The temperature should remain around 73-degrees Fahrenheit while the seedlings are growing. If they get too cold, it will stunt their growth. Fixing the issue can be as simple as moving the grow light closer to the top of the seedlings.
Seedlings that are grown in high temperatures will have leaves that curl upward. Growers can move the light away from their seedlings and check to make sure they are receiving enough water.
Humidity needs to be high for young seedlings to help them retain enough water to thrive. Growers should aim to keep the environment at about 70% humidity until they reach the vegetative stage. Once that happens, they can lower the humidity to prevent mold or fungus growth.
When working indoors, pot seeds do best when germinated under a fluorescent grow light, as they produce minimal heat, which will make it easier to control a seedling’s environment. These lights can be placed close to the tops of the seedlings, which prevents their stems from becoming leggy and weak.
At the minimum, cannabis seedlings will need a lighting schedule that is the same as it would be during their vegetative stage. Growers can give seedlings as much as 18 hours of light per day to boost their growth, but they should never receive less than 16 hours of light per day.
When germinating seeds outdoors, growers will need to monitor their seedlings to be sure they are getting enough light. If they are not, they can move them to an area with more direct sunlight, or supplement their light by bringing them indoors at the end of the day and using a grow light. Signs that a seedling is not getting enough light include white and elongated stems that cannot hold the weight of the new leaves.
While it is unlikely, seedlings can be given too much light and will grow more slowly as a result. If this happens, simply moving the light farther away from the plants will solve the problem.
Growers must keep a watchful eye on their seedlings for signs of certain insects that prefer these young plants. Insects will kill a seedling quickly, ruining a plant before it gets the chance to grow. The most common insects that attack cannabis seedlings are fungus gnats and cutworms.
Fungus gnats bore holes into the roots and stems of seedlings, cuttings, and young plants. Between feeding on the plant and creating entry points for infection, fungus gnats can present a significant threat to cannabis seedlings.
Cutworms are a breed of caterpillar that feed on seedlings until they develop between 6 and 8 nodes. It takes very little time for these pests to destroy seedlings, as they feed on the top of the plant’s stem, essentially cutting it off completely. It can take as little as one night for a cutworm to destroy a young auto flower or feminized plant, so growers must act fast.
Seedling care is often overlooked when planning how to grow cannabis plants. However, caring for seedlings properly can make a huge difference in whether the plant survives and how it grows when it is more mature. Growers who understand the needs of cannabis seedlings have the best chance at growing a robust, higher yielding plant.