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Learning how to feminize cannabis seeds is important in order to save time and money on your cannabis garden. When traditional fertilization methods are used to grow your cannabis plants, you have less control over the gender of future cannabis plants.
That is why many cannabis growers take extra steps to produce female cannabis plants when harvesting. We show you different ways you can feminize seeds before harvest.
What are Feminized Cannabis Seeds?
Feminized cannabis seeds produce only cannabinoid– and trichome-rich flower buds on female cannabis plants. Cannabinoids and terpenes are responsible for the potency, aroma, and flavor of cannabis. Male plants, on the other hand, do not produce buds and are mainly used for breeding purposes.
A cannabis garden that uses high-quality feminized seeds will produce a female-only crop without male plants, which can unintentionally pollinate your crop and potentially reduce your flower yield.
What are Regular Cannabis Seeds
Another common type of cannabis seed, a regular seed, results from natural pollination and the breeding of male and female seeds together without any chemical modification.
Cannabis growers working with regular seeds have a 50% chance of either yielding a female or male marijuana plant. The sex of the plant is determined by the genetics of the parent plants, and it is not possible to determine the sex of the plant from a regular cannabis seed before it is germinated and starts to grow.
Growing from regular seeds isn't the best option if you’re looking to strictly grow cannabis buds. While male plants serve their specific purpose of pollinating females, they don't produce the trichome-covered flowers that female plants do.
How Are Feminized Seeds Made?
Feminized cannabis seeds serve a major purpose for commercial and home growers. Feminized seeds can be made by inducing a regular female cannabis plant to grow male sex organs that contain pollen, also known as hermaphroditism. The hermaphroditic pollen will contain only the female X chromosome and no male Y chromosomes.
When used to pollinate a female cannabis plant, the seeds produced between the two plants will inherit two X chromosomes meaning that all future seeds will be feminized.
This method of seed production is widely used in the cannabis industry as it allows growers to produce high-quality buds with a higher yield. It also eliminates the need for growers to wait for the plant to reveal its sex, which can be a time-consuming process.
The Benefits of Growing Feminized Seeds
Growing feminized cannabis seeds has many benefits over regular seeds.
Save Time and Money
For one, growers don't have to hedge their bets hoping that the regular seeds will produce female plants. Instead of planting more regular strains than needed to get lucky and get enough females for your specific purpose, you can stick with a sure bet using feminized strains.
Ease of Cultivation
Male plants run the risk of pollinating female plants causing them to develop hermaphroditic structures and, ultimately, lower your plants’ yield compared to a grow without male plants.
Weeding out the male plants, however, takes time and energy. Male plants display their sexual organs when the photoperiod changes naturally or when indoor lighting environments change.
No Male Plants
Growers that don't want to spend the time monitoring the plant every day can use feminized seeds to ensure that their garden will grow flower buds.
Otherwise, growers will have to keep their eyes peeled for male plants and remove them from the grow immediately or else risk unintentionally pollinating female plants.
Feminized seeds are also known for producing plants that are more consistent in terms of their appearance, aroma, and effects. This can benefit growers looking to produce a specific type of cannabis strain.
No Need for Breeding
Finally, feminized seeds do not require breeding like regular seeds do, as feminized seeds will produce female plants regardless of the genetics of the parent plants. This can save you the time and effort required to breed your own seeds.
Male vs Female Marijuana Plants
Generally speaking, there is no way that you can determine the difference between male and female cannabis seeds in the initial stages of planting. In addition, you are also not able to change the gender of your cannabis seeds.
The differences between male and female marijuana plants can be subtle, but they can be distinguished by looking at the pre-flower stage, typically around 4-6 weeks after planting. Female plants will have a calyx, which is a small bulb-like structure at the base of the buds, while male plants will have small sacs called pollen sacs.
The purpose of using feminized marijuana seeds is to maximize the female seeds that will be part of your marijuana crop.
Why would you want female marijuana plants? Well, these are known to have a higher level of THC content. Male plants have reduced THC content, and for that reason, female plants take precedence over male plants.
With cannabis seed feminization, there are several pollination techniques that the marijuana grower can use for a favorable outcome.
Feminized Seeds vs. Autoflowering Seeds
Autoflowering seeds are seeds that have been bred to automatically switch from the vegetative stage to the flowering stage, regardless of the light cycle. This makes them ideal for growers who have limited space or want to have a quicker harvest.
However, it is important to note that autoflowering plants generally yield less than feminized plants, and their buds tend to be less potent.
Buying the Right Cannabis Seeds
When it comes to buying cannabis seeds, it's important to make sure you are purchasing feminized seeds if you want to ensure a high probability of growing only female plants. Many seed banks or dispensaries offer feminized seeds, and they can also be found online.
Female cannabis seeds are sold by various companies. So, you don’t have to wait to get your own. You can use the ones available to you, and by doing so, you will be sure that your outcome is a female marijuana plant with more THC content.
Be careful when buying marijuana seeds from companies online. Make sure this is a reputable company known for selling and delivering the right female marijuana seeds. Look for customer reviews or ask for recommendations from experienced growers.
Some “feminized” seeds may produce hermaphrodite plants if the seeds are of low quality. High-quality feminized cannabis seeds from reputable seed banks have been bred to not display hermaphroditic characteristics under optimal growing conditions. If you’re looking for a sure thing, carefully consider your cannabis seed source.
When you are choosing your feminized seeds, it's also a good idea to think about what strains will best suit your growing conditions and the desired end-product. Different strains of cannabis have different characteristics such as growth patterns, yield, and cannabinoid profiles, which can affect the outcome of your crop.
Alternative Methods to Feminizing Cannabis Plants
If you are going to do the feminization of marijuana seeds yourself, then there are methods that you can use, namely:
- Colloidal Silver
- Silver Thiosulfate Solution
Each of these methods should be successful if used in the right way to produce female marijuana plants. Let’s quickly look at each method briefly.
Pollinating Cannabis Plants
One of the simplest ways to produce feminized cannabis seeds is to pollinate your plants. Some cannabis strains can produce male flowers when the colas have reached late ripeness.
Side note: Ed Rosenthal, master grower and proud member of the CTU faculty, prefers to harvest plants around this time. Harvest the pollen by using a clean and small paint brush to transfer the pollen into a metal or glass container or in small amounts directly on the flowers.
Some outdoor-friendly cannabis strains may become stressed when grown indoors, which can increase the chance of producing hermaphrodite flowers. Indoor growing environments can stress plants with fluctuating light cycles and heat.
Stress training techniques are difficult to pull off, even for experienced cannabis growers. If you do happen to spot a hermaphrodite with pollen, collect the pollen and save it for later use when you feel comfortable using it.
Using Chemicals To Feminize Cannabis Seeds
Large-scale and home growers have harnessed the power of certain chemicals that can induce male flowers in female marijuana plants. These chemicals are used to hinder ethylene production.
Ethylene is a plant hormone that helps cannabis plants ripen and produce female flowers. When ethylene production is stalled, female flowers aren’t produced. Keep in mind, these chemicals must be directly applied to each branch that you want male flowers to grow.
The Silver Thiosulfate Method
The Silver Thiosulfate Solution, also known as STS, is one of the most common methods of generating female marijuana seeds. It is very effective in allowing female marijuana seeds to be available to marijuana growers. This method will feminize the seeds in the best way possible, making them more available on the market for growers.
The solution is made of a combined silver nitrate and sodium thiosulfate. The solution result is a hormonal response to stress found in the marijuana plant. Because of this, gender change is triggered. We recommend spraying a solution of 0.02-0.03% on your plants during this process.
You can do all of this yourself, but the marijuana plants have to be wisely chosen. You should only take female plants from a single cannabis strain that is almost mature. Then, separate the plant from the bunch and spray the plant with STS and change your light cycle to the flowering stage. Allow it to dry and then replace it, ensuring it sits alongside the other plants in the bunch.
Gibberellins are hormones that affect cannabis plants throughout their growth cycle. Some gibberellic acids such as GA3, 4, 5, and 7 can induce the growth of male cannabis flowers when sprayed directly on female plants before the flowering period.
Most growers use GA3, the most widely available and effective of the gibberellic acids. Use a solution of 0.1 grams of GA4 per liter of distilled water. Ed Rosenthal recommends spraying the top of plants for five days in a row and then changing the photoperiod to induce flowering.
The Colloidal Silver Method
With the colloidal or pure silver method, you also need distilled water. Use a spray bottle to apply this mixture to your female marijuana plants, but you must do it when the plants are flowering. Pollen sacs will be formed. The pollen has female genetics, allowing the marijuana seeds to produce female plants.
The Rodelization Method
The Rodelization method calls for the reaction of the female plants when they are stressed. Pollen sacs will grow when plants are stressed and not fertilized. Because the resulting marijuana seeds are exclusively derived from female genetics, it is likely that these will be female seeds and not male seeds.
How to Grow Cannabis from Feminized Seeds
Growing feminized cannabis seeds is easier than you think. If you want to have the best chance at harvesting high-quality cannabis buds, here are some factors to consider:
- New to growing weed? Explore our ultimate guide to growing weed from seed.
- Do you want to grow indoors or outdoors? Consider the pros and cons of indoor and outdoor cannabis cultivations.
- Do you want to skip the germination phase of cannabis seeds? Find out whether you want to start your garden with cannabis seeds or cannabis clones?
- Are you growing weed indoors? We help you choose the right indoor growing system.
As you learn to grow feminized seeds, you’ll face unexpected challenges, from preventing pest infestations to providing an optimal climate in your grow room.
How to Feminize Marijuana Seeds Summary
Breeders utilize a method called “feminizing” to make sure the resulting seeds will grow female plants, which are the ones that produce the desired flowers (buds) with higher THC concentrations. This procedure involves introducing female features into the plants' genetic makeup.
Here is a description of the “silver thiosulfate” (STS) process for feminizing marijuana seeds:
-Colloidal silver solution (often offered at a concentration of 20 ppm)
-Solution of sodium thiosulfate
Get the solutions ready:
In a 1:1 ratio, combine distilled water and the colloidal silver solution.
In a 1:1 ratio, combine the sodium thiosulfate solution with distilled water.
Female Plant Identification:
Pick female plants that are in the pre-flowering stage and are healthy and vigorous. These are the plants that will be used to make pollen.
Apply Silver Solution: Begin sprinkling the female plants' branches where you want the pollen to develop with colloidal silver solution. Typically, the fluid is sprayed directly onto the branch tips to accomplish this. Do this once daily, ideally during the plant's darkest part of the day.
Apply Sodium Thiosulfate Solution: Start applying sodium thiosulfate solution to additional branches on the same female plants a few weeks after applying colloidal silver. As a result, the treated branches won't be able to produce healthy pollen.
Gather Pollen: When the treated branches start to produce pollen sacs rather than blooms, let the pollen sacs develop. The small size and yellowish color of the pollen sacs make them easy to spot.
Transfer Pollen: When you want to feminize a separate female plant, carefully gather the mature pollen sacs and transfer the pollen to the blooms of that plant. Dust the pollen you've gathered over the pistils of the female flowers.
Isolate Pollinated Plant: To avoid unintentional cross-pollination, keep the pollinated female plant separate from other plants.
To gather seeds, let the fertilized female plant blossom until the seeds are ready to be harvested. When the seeds are ready, gently gather them and reserve them for later use.
It's vital to note that adopting this technique to feminize seeds necessitates close attention to detail and a solid grasp of plant biology.
The procedure can be lengthy, and the final product may differ depending on the original plants' quality, the success of the treatments, and the surrounding environment.
Additionally, be aware that using substances like colloidal silver and sodium thiosulfate may have an impact on your health and the environment. Always use caution when handling chemicals and abide by safety regulations.
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Can I make a cannabis seed female?
The conversion of a cannabis seed into a female plant is conceivable and is referred to as feminization. In order to develop female plants, which are the ones that produce the flowers (buds) with higher quantities of THC, feminization entails changing the genetics of the seeds.
What is the downside to feminized cannabis seeds?
Almost every plant cultivated from feminized cannabis seeds will be female and hence capable of producing the cannabinoid-rich blooms most producers are looking for. Feminized cannabis seeds are deliberately designed to exclude male chromosomes. Nevertheless, using feminized seeds may have certain drawbacks, such as:
No Male Plants for Breeding: Feminized seeds aren't the best option if you want to breed new strains or need male plants for other purposes. For conventional breeding, males are essential.
Risk of Hermaphrodites: Feminized plants may generate both male and female reproductive organs in response to stress (such as changes in the light cycle, food problems, or physical harm). These plants can pollinate both other females and themselves, producing seeds that you can collect.
Genetic Diversity: Restricting the use of feminized seeds from one particular lineage over time may lessen the genetic diversity of cannabis plants grown for use. Hardier plants, resistance to diseases and pests, and the possibility for new strains can all result from genetic variety.
Cost: Due to the additional steps and guarantee they provide of generating female plants, feminized seeds frequently cost more than ordinary seeds.
Naturalism: Some growers like to cultivate marijuana as naturally as they can, which involves utilizing ordinary seeds and letting plants grow unhindered.
Some growers believe that gendered plants have less vitality or are less robust than plants developed from ordinary seeds, though this opinion isn't shared by all.
It's important to note that not all growers share this belief, which is based on the idea that the stress involved in producing a feminized seed can affect the eventual plant.
Concerns concerning the ethics of changing plant genders exist, particularly in relation to extensive agricultural practices and potential effects on biodiversity.
Luis Cordova is a distinguished author, and renowned expert in cannabis cultivation, who possesses a Master's degree in Plant Biotechnology and Pharmaceutical Science. As a valued contributor to highly esteemed publications such as Cannabis Training University and Maximum Yield Magazine, Luis has emerged as a trusted source of guidance and knowledge in the cannabis industry. Having written thousands of informative articles, Luis is widely recognized for his comprehensive expertise on cultivating cannabis, both indoors and outdoors.