Growing Cannabis Seeds Q & A


Have a question about growing cannabis seeds? There’s a good chance the answer is here! Browse through our helpful list of questions and answers, or search for your question in the search bar in the top right of the screen.

How much water does a plant require daily?

The amount of water your cannabis plant needs depends on a few different factors, like the humidity and temperature in the growing area, and the drainage. In the case of plants growing in pots of soil, water should be given when the top half-inch or so of the soil is dry. Then, water should be given until you can see it gathering in the base. A general rule of thumb: each watering should be approximately ¼ of the pot’s total volume. If your plants are growing outdoors, an exact amount of water is hard to state. Essentially, if the leaves begin to droop, the plant needs more water. You can still use the “dry topsoil” method to determine when to irrigate – water when the soil is dry to about 1-inch deep.

How many ounces can one plant produce?

The amount of flower you can get from one cannabis plant depends on the strain, the growing method, and the health of the plant, but the light source is a major factor. Most new gardeners will find their indoor plants can produce up to 1 oz per 100 watts. The number of plants doesn’t matter as much; in other words, if you have one 400-watt bulb, you should see about 4 oz of flower in total, whether you’re growing 4 or 10 plants. More watts = higher yield. If you’re growing outdoors, and the environment is ideal for cannabis growth, you could harvest more than 15 oz per plant. Some general research of the strain you’re planting should give you an idea of how much to expect in both indoor and outdoor environs.

What is the estimated growth period for a plant?

After a cannabis plant has germinated, it goes through a vegetative stage and a flowering stage. The length of the vegetative stage can be determined by the gardener: they may choose to extend this period – when the plant experiences about 80 percent of its growth – to allow more space for bud production, or keep it to a couple of weeks to shorten the time until harvest. (Auto-flowering seeds are the exception; they automatically move into the flowering stage after two or three weeks.)

In the flowering stage, the growing time depends on the strain, and can range from 40 to 90 days. Including the vegetative stage, the entire growing process of the cannabis plant generally takes between two and five months.

Do all feminized seeds becomes feminized plants?

All feminized cannabis seeds grow into female plants, which is to say they produce bud/flower, and cannot fertilize other plants. (This is a good thing, since male plants interfere with bud production in females.) If your end goal is to harvest a lot of useable product, feminized seeds are the best and easiest choice; you will not need to identify and weed out the male plants.

How much light is roughly required for a plant?

If you’re growing your cannabis plants indoors, you will want to provide them with 18-24 hours of light each day (plus 0-6 hours of dark) while they are in the vegetative stage. To encourage the plants to enter the flowering stage, change the lighting to an equal number of light and dark hours (12 on, 12 off).

If you want to grow your plants outdoors, it is often advisable to start them indoors, where you can give them all that excess light they need for the first few weeks of their life. Transfer them outdoors at a time of year when they are certain to get a good amount of light – ideally, the long days of summer.

Will my cannabis plants need fertilizer?

Generally speaking, your cannabis plants will almost certainly need to be given fertilizers during their life cycle. During the vegetative stage, plants usually need a combination of nitrogen, phosphorous, and potassium (N-P-K). Once they reach the flowering stage, you can turn down the nitrogen and turn up the phosphorous and potassium. Minimizing nitrogen hinders growth, so this step may even be taken during the vegetative stage if growing quarters are getting tight.

Be mindful that it is absolutely possible to give your plants too much of a good thing – in fact, it’s usually better to err on the side of fewer nutrients, rather than more. If the tips of the leaves begin turning yellow, your plants might be experiencing nutrient burn. Different nutrient deficiencies and excesses show up in different ways.

What indica cannabis strain is recommended for better sleep?

A high-indica strain such as Mazar is a great choice for inducing sleep and fighting insomnia. To avoid the traditional marijuana “high” a CBD strain like Critical Mass is another good option. Also keep in mind that the effects will last longer if you consume the medicine as an edible than if you smoke or vaporize.

How long can a cannabis plant live without sunlight and water before it dies?

This depends on how often you water, in the first place. While too dry is often better than too wet, like any living thing, cannabis plants need water to survive. It’s possible the plant will survive a week or more without water (and certainly longer in darkness than in light), but it could take some very gentle coaxing to get it back to health afterwards.

Without light, not only will your plants certainly not grow larger, but they will be stressed and you could face all the problems that come with that (such as hermaphrodite development). Since the vegetative stage calls for light as much as 24-hours of the day, lack of light is obviously much worse in the flowering stage of 12 hours on, 12 hours off.

Do all cannabis strains require the same time frame for growth?

No, different cannabis strains need different lengths of time to fully develop and produce the best possible yield. Strains like Northern Lights, Cinderella 99, and Jack Herer are known as “fast-flowering” strains, and have short flowering periods of 50-60 days. Other strains, like American and Super Silver Haze need up to 75 days in the flowering stage. Each of these time periods assumes an additional 2-3 weeks in the vegetative stage.

Will Cannabis seeds die in below room temperatures?

Ideally, your grow room should be at 70-75 degrees during the day and 50-60 degrees at night. During the flowering stage, less than 60 degrees can be problematic. Outdoors, some lower temperature nights are unavoidable and should not be too dangerous, but lengthy periods of 40 degrees or lower can cause irreparable damage. In the best case scenario, plants left in low temperatures will have drastically reduced growth.

Is it better to place your seeds in a darker room or near sunlight?

If you are planting your cannabis indoors, your seeds must be planted in a room that can be made completely light-tight. This is because the amount of light and darkness must be closely monitored during the life cycle of the plant. Once your plants have been placed in a room or space that can be completely blacked out, you can set up lamps that allow you to turn the “sunlight” on and off as needed.

After 2 weeks worth of growth with sunlight and water, how should a plant roughly look?

Two weeks after the sprout has peeked out from the soil or hydroponic medium, you cannabis plants have probably developed about three tiers of leaves (maybe 4 inches tall), and are beginning to move from the seedling stage to the official vegetative stage. That said, the appearance of your plants really depends on your growing method, and whether you are “topping” your plant (a practice of removing growth at the V between leaves, to encourage the plants to become fuller and bushier).

What is a good planting pot to use for cannabis seeds?

If you are simply planning to grow your cannabis plants indoors, in soil, a regular gardening pot with a hole in the bottom to allow for drainage (and a tray to catch it) will work fine. Pots that allow the soil to dry out on all sides (usually made of porous, sturdy fabric), and “air pots” that allow the water to run out all along the sides of the pot also work well. Essentially, any pot that allows your plant to get the essentials it needs – moisture, oxygen to the roots, nutients – is suitable for growing marijuana.

How many stages does a plant go through before it is ready to be harvested?

The short answer: 4 stages – germination, seedling, vegetative, flowering. Once your cannabis seeds have germinated (the seed has cracked open and the tiny sprout is visible), they are planted and can enter the seedling stage or the very early vegetative stage. Between three and six weeks later, your plants are probably ready to enter the flowering stage (this required a change in light and dark ratios). Depending on the strain, the plant will spend between 50 and 80 days in the flowering stage before it is ready for harvest.

Are there names for the phases cannabis plants go through?

Cannabis plants will go through four basic phases or stages during an average lifetime. The first stage is germination, wherein the seed is encouraged to crack open and sprout. Once this has occurred, the seed is planted; the first couple of weeks after it has broken through the soil are called the seedling stage. Once a little cannabis plant has emerged, the plant has entered the vegetative stage. After two to six weeks in the vegetative stage (when most of the growth occurs), the gardener can force the plant into the flowering stage by changing the daily light to dark ratio. The flowering stage lasts between 7 and 12 weeks, and ends with harvesting the flowers. In some cases, experienced growers may then let the plant “re-veg”.

What temperatures are best for outdoor season growing?

As long as you don’t plant your cannabis outdoors until the last frost has passed, it is unlikely that low temperatures will kill your plants – they may simply grow more slowly. If the temperature is consistantly below 50 degrees F (at night, for instance), the result will be smaller plants with smaller yields. The temperature of the ground is also an important consideration, as the roots require warmth as well. If the temperature falls below 40 degrees F, plant tissue damage can occur. If an unexpected cold snap blows in, try using a patio heater to keep your plants cozy at night.

For indoor cannabis gardening, what is the ideal temperature?

During lighted hours, try to keep the grow room between 68 and 75 degrees F. Adult plants in their flowering stage can handle temperatures as high as 80 degrees. During dark hours, the temperature can be a bit lower. As a general rule, the difference between light and dark temperatures should not be more than 10 degrees Celsius (Ie: if daytime temp is 75 F – 24 C – then nighttime temp can’t be less than 57 F or 14 C.)

Which will grow more quickly, a plant grown indoors, or outdoors?

While growth in height may not be different for indoor and outdoor plants, those grown indoors will be ready for harvest more quickly (but will not grow as large). The yield from indoor plants will generally be smaller than outdoor plants. However, also keep in mind that when growing indoors, the gardener has complete control over the plants, which can minimize potential problems. Outdoors, your plants are susceptible to pests, toxins and unpredictable temperatures.

Will outdoor plants get more sunlight than indoor plants?

The amount of direct sunlight an outdoor plant will receive depends on where you live, and the amount of sunny days your region experiences. That said, the plants do not differentiate between “real” sunlight and the light from the man-made light of the grow room. Indoors, cannabis plants can be grown under Fluorescent, HID, and LED lights with good results.

What is the flowering stage?

The flowering stage is the final step of the cannabis plant’s life cycle, which occurs before the plant is ready for harvest. During this time, the plant experiences minimal upward growth, because the water and nutrients are being used to grow the buds or flowers. The flowering stage is also the time when the little white hairs within the buds will become more noticible, and begin turning orange or amber. Crystallized resin will be secreted from the plant’s trichomes, and the buds will become dense and heavy. The flowering stage generally takes between 50 and 80 days. Learn more on our Flowering Stage article.

What factors can affect the potency of the cannabis flowers?

The strain you choose to grow will always have the most effect on the potency of your plant. In other words, if you plant a strain that has about 10% THC, it’s never going to be as potent as a strain that has about 20% THC. That said, there are some factors that could affect the potency of your harvest. Good amounts of essential nutrients like nitrogen, phosphorous, and potassium have been linked to higher potency. Where you are in the world may also affect the THC/CBD level of your plants (if growing outdoors). Bright light – either sunlight or man-made – will contribute to good cannabinoid production during the flowering stage.

What happens if my cannabis plant doesn’t get enough water?

Like humans, marijuana is largely made up of water. When growing inside, a lack of water can result in less photosynthesis. To conserve resources, the undernourished plant will close the pores on the leaves that allow water to evaporate, but when closed these pores also prevent water and CO2 from being absorbed. Nutrient deficiency will develop since the plant was getting nutrients through the water. Energy repurposed to deal with all these problems means your plant will not grow. Basically – don’t forget to water your plants!

Are CFL lights good for seeding?

CFLs are a great light choice for small indoor growing spaces. Compact fluorescent lights have a wide light spectrum that is well-suited to cannabis growth. That said, if you want to harvest a lot of plants or have a very high yield on each plant, CFLs are not the best choice. Opt instead for LED or HID lights.

After a month of growth (30 days) how my cannabis plants look?

Once your cannabis plants have hit the one-month mark, they should be between one and two feet tall, depending on the strain (indica or sativa) and whether or not you have been topping the plant. (Topping means the plant will likely have grown outward more than upward). This is probably around the time you want to transfer your plants to the flowering stage, if you haven’t already done so.

7 days after initial growth, will my plant start beginning to look like a seedling?

Yes, a week following the taproot sprouting from your cannabis seed, you should have a small plant with a couple of green leaves.

While watering my plant, is it better to use a measuring cup?

The water container size for watering your plants will depend on the size of the plant pot. When you water your plant, you should continue to pour until it has begun to gather in the tray below the pot. As a general rule of thumb, fill a container 1/4 the volume of the pot for each watering.

Can too much moisture cause fungus on cannabis seeds?

If you are following the water glass and paper towel method, your seeds will be soaking in water for 14-18 hours, so obviously they cannot be too wet during this time. But after the seeds have been placed in the paper towel, or into soil if you are planting them directly, too much water can drown the seed. It will also slow the growth of the taproot, because the root does not need to grow out in order to find the water it seeks.

If a cannabis seed is stored for too long, can it lose its growth efficiency?

If stored correctly, cannabis seeds can last for years. The longer the seeds have lain dormant, though, the longer they may take to germinate. If you are trying to germinate old cannabis seeds, consider scuffing or scoring the outside of the seed with sandpaper or a knife before planting/placing in water.

What sativa plant would you recommend?

There is no single best cannabis plant; the ideal strain is the one that best treats the condition you are medicating for, or that gives you the effect you want. For example, Tangerine Dream is one of the few sativa-dominant strains that offers muscle relaxation while still enabling you to be active and productive. Diesel is a good choice for reducing stress and anxiety.

Do indica strains have a shorter flowering time than sativa dominant strains?

In general, yes, indica-dominant strains have shorter flowering stages than sativas. On average, indicas require 8-12 weeks of flowering, while sativas need 10-16. That said, often indicas will be left in the vegetative stage longer, because this allows them to grow larger and support more flowers, so the total life cycle length might be the same. See our article on the topic, to learn more about the differences between indicas and sativas.

How much space does one plant need if it is grown indoors?

You don’t need more than a 5-gallon pail or pot in order to plant a single cannabis seed. Just make sure the pot is in a place that has relatively stable temperature and humidity, and is away from drafts.

What fertilizer should I use for my cannabis plants?

Your cannabis plants need three primary nutrients in order to flourish: potassium, nitrogen, and phosphorous. Find a fertilizer that has these nutrients. During the vegetative stage, your plants will need more nitrogen. Once the flowering stage begins, find a low-nitrogen fertilizer.

What are the qualities of a good cannabis seed?

Never assume a cannabis seed won’t germinate just based on how it looks. There’s no harm in attempting to germinate it. But the most viable seeds will usually be dark in color rather than light, seem a bit waxy, have a hard shell (a gentle squeeze doesn’t crush it), and be free of cracks.

Is it a good idea to manage your pH of your plant roots in case of nutrient problems?

Checking the soil for pH every once in awhile is a good way to make sure your plants stay healthy and don’t develop nutrient deficiencies. Sometimes, recognizing a problem with the pH can enable you to fix a problem before it affects your plants. If you are planting in soil, your pH should be between 6 and 7. If planting in a different medium, aim for a pH between 5.5 and 6.5.

How do I know when to stop fertilizing?

There are two reasons to stop fertilization of your cannabis plants: First, you may need to cut back on one type of nutrient if you notice the leaves appear burnt, or the plant is otherwise looking unhealthy. If you don’t know which nutrient is the problem, consider stopping all of them and slowly adding them back. Second, you might want to stop using fertilizer about a week before harvest. This is called “flushing” and can make your cannabis taste better.

In what soil should cannabis plants be grown?

Look for a soil that is light enough to allow good drainage, that retains enough water for your plants to slowly absorb. The soil should be dark and soft, without chunks of wood or rock in it. When it gets wet, the ideal soil will look like wet soil, not like mud (in other words, avoid a soil that looks like “dirt”.) Some things to add to your soil for the perfect mix: perlite, vermiculite, worm castings.

Does the ideal soil vary if the plant is being grown outdoors?

It is harder to control the qualities and potential contaminates of the soil if you are growing outdoors, in the ground. That said, a soil that is lightweight and dark, which does not turn into mud when watered, and is free of chunks of wood, rock, or other large items, is always the best choice. Indoors or out, you will need to make sure your soil and plant receive nitrogen, potassium, and phosphorous throughout the plant’s life cycle.

Are all cannabis plants green, or do they have mixtures of colors in them?

For the most part, cannabis plants are green. The appearance of a different color can signify a nutrient deficiency. If the tips of the leaves are beginning to turn yellow or brown, they may be lacking nitrogen or potassium. Dark-color leaves with visible purple veins and stems could mean too little phosphorous. It is possible that a perfectly healthy cannabis plant will be different shades of green throughout its life cycle.

If my first plant dies, should I use fresh soil and replant another seed or use the same soil?

If the first plant dies because it was forgotten about, then it is probably fine to reuse the soil it was planted in. But if the plant got sick and died, it is best to begin again with new soil, to avoid the possibility that whatever killed your first plant is still residing in the soil. If you’re at all uncertain the cause of your plant’s death, use new soil just to be safe.

What if my leaves start to burn on the ends?

The brown or yellow “burning” that can appear on the tips of your leaves is most likely indicative of too many nutrients. Try to catch the burn at its earliest stage, and cut back on the amount of nutrient solution you’re feeding your plants. If this method doesn’t solve the problem, it’s possible what you are actually seeing is a sign of potassium deficiency.

Should I keep my indoor cannabis plant in direct sunlight or at a distance from the window?

Most people who grow their cannabis plants indoors will use a grow room with a lighting set up, which allows them to monitor and control the amount of light their cannabis plants are receiving. If you are simply growing your cannabis plant like a house plant, definitely allow it to get as much sunlight as possible. Depending on the weather and the time of year, you may need to supplement the sunlight with a grow light.

Can I plant two cannabis seeds in one pot?

Unless you’re using a really big pot, it’s usually best to plant your seeds in separate containers. If your plants grow side by side, they will have to battle it out for enough water, light, and nutrients, and often one plant will win while the other will suffer. Planting too close together can also result in mold growth on the overlapping leaves.

Can I use Miracle Grow on my plants?

Miracle Gro is not recommended for cannabis plants. It contains a large amount of nitrogen that releases over time, which will be detrimental once the flowering stage begins. The mix is also a bit low on the other nutrients – potassium and phosphorous – which are essential to cannabis plant health.

Should I be wearing gloves while handling my cannabis plants?

As long as your hands are clean, working without gloves is unlikely to harm your plants. However, repeated exposure to cannabis plants has been seen to cause skin irritation. That, combined with nutrients and pesticides and other gardening products with which you may come in contact, could hurt your hands. Using gloves is a good way to avoid these problems.

How much distance do two plants need from each other while being grown indoors?

Aim for a foot or two between the stalk of each plant. This will prevent the leaves from overlapping and potentially developing mold. The exception here is the Screen of Green and Sea of Green growing methods. Spacing your plants needlessly far apart is not good either, however, as it will require you to install more grow lamps than you actually need.

How will I know if the plant is malnourished?

Watch for changes in the color of the leaves – brown or yellow “burning” around the edges, spots, overall yellowing; these are signs of nutrient deficiencies or overages. If the leaves are beginning to droop, this can indicate your plant is not receiving enough water, or is becoming root-bound. Essentially, keep a close eye on your plants so you can quickly notice any changes in their appearance.

Will the amount of water given to the plant change after a certain time, or should it consistently get the same amount of water?

When the plant is young, deliver small amounts of water at regular, short intervals. Check the soil – it should be dry on top, but still damp below the surface. As the plants become larger and hardier, they can be given larger amounts of water less frequently. As a general rule, watering of mature plants should occur every 2-3 days. Once the plant is flowering, water should be administered until it begins to run out the bottom of the pot.

Is it better to water my plant during the day or night?

Some growers believe watering plants while in sunlight (or during the hours the grow lights are on) is problematic because water droplets on the leaves can burn in the sun, and the light causes too much evaporation. This may not be a legitimate concern, as you should be watering your plants at the soil, not over the leaves. If you are concerned about evaporation, water your plants at night, but ultimately watering time does not appear to make a difference.

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