Note: Once the plant is about 6 weeks old from seed, it will usually show signs of “pre-flowers” which will alert you to the gender before the beginning of the flowering stage. Pre Flowers usually reveal the gender around week 6 from seed, or you can wait until the plant switches to the flowering stage. After 2-3 weeks of the 12-12 light schedule, most marijuana plants will reveal the first signs of their gender (they either are a female plant and start growing buds, YAY! or they are a male plant and start growing balls, NO!).
What about plants that display both male and female parts? Only a female marijuana plant makes flowers/buds that contain a usable amount of THC. Male marijuana plants only make pollen sacs that they use to fertilize the females. Most growers will throw away any male plants that they encounter to keep them from fertilizing the female plants. If your female plants do get fertilized, they will use all their energy to produce seeds instead of making buds. This is good if you want seeds, but you will run into the same problem since half of the seeds will also be male. If you would like to start a breeding program to make your own hybrids, I recommend using a method that creates all-female (feminized) seeds so that you don’t waste time having to identify and throw out male plants. Getting clones of female marijuana plants or buying feminized seeds online from a seed bank are other ways you can ensure that all your marijuana plants are female.
If you don’t have a choice of seeds, and some of your seeds may be male (like if you just found seeds) than you will want to get your plants to reveal their gender right away so you don’t have to waste time and energy on male plants. For most marijuana strains, the male plants don’t produce usable amounts of THC, so most growers toss them on sight. Unfortunately, 50% of all regular seeds will become male plants. These male plants can also impregnate your female plants, which causes them not to produce as many buds, so unless you’re breeding, destroy male plants as soon as you notice them growing grape-like balls where their buds would normally be. A vigilant grower can carefully watch their plants and remove males when they develop the first signs of pollen sacs. How to identify female plants if starting out with regular bagseed? Below we’ll share two tactics growers use to identify gender in the vegetative stage. Tactic 1: Preflowers let you identify plants in week 3-6 from seed. Pre-Flowers reveal the gender of your plant by around week 6 from seed, and as early as 3 weeks from seed for some plants. In this area you’ll find pre-flowers nestled where the “joints” of the plant are. Tactic 2: Taking a clone and flowering it The following method can help you identify gender for plants that are taking a while to show their pre-flowers. If you’re just growing 1, 2, or 3 plants, it can be heartbreaking to find out all your plants are male, and you need to start over in order to make buds. When marijuana plants are seedlings (or when they’re just seeds), there’s no way to tell which plants are male and which plants are female. You have to “wait and see.” Male marijuana plants develop pollen sacs (look like little balls or nuts). Female marijuana plants start growing white hairs that develop into the marijuana buds (sensimilla) that contain THC and other cannabinoids. However, you may want to be more proactive and get rid of the male plants before they enter the flowering stage so you don’t have to waste the time and energy in caring for plants that you will eventually get rid of. If so, then you can use to following technique to identify and remove all the males from your grow. You can wait until your plants naturally show the first signs of their gender and then remove all the males, but that means you have to watch the plants closely. You also will waste time and energy growing plants only to find out that some or all are male and have to throw them away. If you want to be more proactive and get rid of all male plants right away, then use this technique. Take a clone from the unverified marijuana plant, label both the clone and the mother plant so you know which clone came from which corresponding mother. If you don’t label them clearly, then all your effort will go to waste! Once the clones have established roots, change just the clones into flowering mode by providing them with a light schedule of 12 hours on, 12 hours off.
The clones should start revealing their gender in a week or two. Males will start developing balls and females will start developing white hairs. Click on the pictures below to see some examples of male and female plants. Once you have determined the gender of your clones, you should make sure you throw away any corresponding male plants. Cannabis Pre-Flowers: Identify Sex of a Plant as Early as 3 Weeks Old (with pics!) Table of Contents. Leaf Sample Testing (Bonus) – Identify sex in just 1-3 weeks from germination Male Pre-Flower Pics – Appears 3-4 weeks from germination Female Pre-Flower Pics – Appears 4-6 weeks from germination. Variability of Plant Sex (How to Increase Ratio of Female Plants) Example of Male and Female Cannabis Pre-Flowers. Wispy white hairs are a sure sign that you’re looking at female pre-flowers.
How to Determine the Sex of a Young Cannabis Plant.