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how big will a cannabis seed grow in 6 weeks

How Long To Veg From Seed

The vegetative phase is one of the most important stages of growing cannabis. It takes place before flowering and after seedling. There is a lot you should know about when you’re growing cannabis no matter it’s indoor or outdoor growing.

And, it’s important to know how long to veg from seed as well. Because the number of yields and how you can maximize the yields are dependent on knowing the ideal duration of every stage.

Chances are you are here to know the ins and outs of the vegetative stage and how you should treat your plants in this stage. Well, then you are in luck because today, we are going to share some information that every grower must know.

We will talk in detail about the seedling and vegetative stages of cannabis plants and share some additional tips that you will find helpful while growing cannabis. Also, there is an FAQ section to vanish your confusion regarding this topic.

Well, enough beating around the bush, let’s just get to the point.

Table of Contents

How Long to Veg From Seed

The one-worded answer is 3-6 weeks. Yes, the plant will be in the seedling anywhere between 3 and 6 weeks. Although it depends on which particular strain you cultivate and the environmental factors as well.

The seedling process will grow by destroying the seed coat. Meanwhile, the root systems at the plant’s base will start developing. Moreover, the leaves will start spreading out.

Your plants will step into their very first true growth cycle when new leaves grow. At this time, your plants will be growing until the flowering stage starts.


A healthy seed takes around 3-7 days to grow into a seedling. And, this stage will start only when the plants develop a stable root system as well as the beginning of growing ‘true leaves’ (true leaves are leaves that come with the same characteristics and forms of a mature cannabis leave).

Remember, you must pay attention to your plants all the time. Most importantly, the plants need much attention in the early stages of their growth and on the speed of developing foliage.

Your plants will transit into the vegetative stage once they start developing a stale root system and foliage. And, this is more important if you plan for transplantation. Because this is the right time to transfer your seedling to a new environment or container if you had been planning for it.

Some useful tips you should follow during the seedling stage:

  • Maintain proper humidity
  • Try to keep the temperature at 77°
  • Control the number of nutrients

Now, you may ask, what’s wrong with the nutrients? Well, for your kind information, nutrients may burn the seedlings of your cannabis. However, if you have to use fertilizers, use them in moderation. And, it’s a good idea to use fertilizers that contain Nitrogen.

Right after you notice the cotyledons, you need to set up white light for 18 hours a day. Try to keep the temperature somewhere between 68 and 77°. And, when it comes to humidity, it should be around 60%.

You can use CFL lights for your seedlings as they will not produce too much heat. You can keep 2 inches distance between the seedlings and the lights that will make sure of providing them plenty of light.

Amazon Grow Light

Vegetative Stage

And, now, your plants entered into the awaited vegetative stage when your plants come into their own and produce big leaves. In this stage, plants produce way more leaves since they absorb much more nutrients including Carbon Dioxide.

Not only the leaves but also the roots will keep expanding which will grow your plants taller. If you’re dealing with healthy plants, a single plant will grow up to 2” in a day.

In the primitive stage, you can control the vegetative stage by light exposure. And, if you are an outdoor grower, then, what part of the world you do live in will matter. If you are an indoor grower, you can keep the plants in the vegetative stage for as long as you want though generally, it lasts 1-2 months.

In this stage, there are a lot of happenings of the plants. For example, your plants will grow leaves and stalks. It creates a solid structure for supporting heavy buds. There will be adding new layers of leaves as well as the plants will grow larger and taller.

And, this is the time when you can recognize the cannabis varieties and notice the difference between them.

Hence, you should maintain the temperature properly by keeping them somewhere between 68 and 77° with the supply of white light (for 18 hours a day). And, make sure the humidity is around 50-70%. About the fertilizers, you should stick to the nitrogen-based ones.

The vegetative stage will last around 1-2 months.

How Vegetative Growth Time Affects the Yield

Does vegetative growth time affect your yield? If it does, then how?

Yes, two factors that increase yields are- veg time and light. So, yes, how long to veg from seed is an important question to ask. And, what about the brand of nutrients? Well, this is important as well, but we can keep it 5th on our list.

You may find it surprising that no matter, if it’s from seed or clone, doubling the veg time, can triple your yields. If you add 2 weeks to the veg time, you can get your double yield.

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Since there’s nothing come without drawbacks, so the increased veg time is. A longer vegetative time will take more time and lengthen the growing schedule, as well as there will be more time to make a mistake along the way.

Ultimately, the thing is, the longer the vegetative stage is, the bigger the yield will be.

And, the vegetative stage should last 1-2 months. So, if you ask now, is 4 weeks veg enough? We would say, you know the answer, my friend!

Light Cycle of The Vegetative Stage

As we said before, there are a lot of happenings in the vegetative stage, you need to know about the proper care for this stage.

Although it’s standard to keep the plants under grow lights for around 18 hours, if you want them to grow as big as possible, you can keep the plants 24 hours under the growing lights.

However, your plants will not start the flowering stage until they start getting 12 hours of constant darkness. Or, the plants will be remaining in the vegetative stage.

Indoor Vegetative Stage

When it is the vegetative stage, it’s not only light that grows large cannabis plants. And, when we’re talking about indoor vegetative stages, it’s also important to have a well-maintained grow room that comes with a high ceiling.

Something worth mentioning here, there are some strains such as Jack Harer and Northern Lights that can grow high-yielding crops without those manipulations.

Outdoor Vegetative Stage

Before you move the cannabis plants outside so that they grow under the sun, you would keep them indoors under lights. You can either start seeds or cut clones in March or April. Moreover, you would keep them under lights for 18-24 hours before you move the plants in May or June.

Therefore, if you want to grow the plants outside, it’s a good idea to keep them inside so that any kind of danger such as frost has passed. A big change in the environment like snowfall or a sudden fall in temperature may kill your plant outright.

However, once the risks are gone, your plants still will be in the vegetative stage outdoor. And, the duration is from spring to late summer.

Clone Vs Seed How Long to veg for better yield?

Although there are a lot of advantages of growing your cannabis from seeds, they require a longer period to reach harvest time compared to clones. It takes up to a week to show the very first signs of life from the soil.

And, do you know how long does it take for seedlings to mature? They take around 1-2 weeks. So yes, add another week more. You may not find it too long, however, speedy auto-flowering strains are way too popular.

On the other hand, clones save time because you don’t have to wait to think when a seed will germinate or grow into a fairly sized seedling. All you need to with a clone is to root your cutting, and your plant is totally ready to grow!

However, if you want to know whether seed or clone will provide you with better yields, then there are a few factors to talk about. Such as:

  • Seeds are really easy to access, but clones are a bit tough to access for home growers.
  • You can simply throw the seeds into the soil and they are okay with it. But you need to be very much careful while handing with the seeds.
  • There’s a risk whether seeds will germinate or not, with clones, it’s risk-free.
  • Clones save time whereas seeds take much time.

So, if you ask whether seeds or clones to choose, the answer is, it depends. We have pointed some factors here, now, you decide which one is the right fit for you.

Tips for Maximum Yields

Scheduling the light cycle properly can maximize your yield. If it’s indoor planning, during the vegetative stage, you should remain the plants under grow lights for 24/0 or 18/6. You should continue it for around 60 days which is the ideal time for growing more flowers.

And, if it’s outdoor planning, schedule your light cycle for cannabis for either 18/6 or 24/0. But the most important thing here is, you should keep the plants inside for a while and wait until the unfavorable conditions (e.g sudden drop in the temperature) have passed. Once passed, you can bring the plants out as well as let them grow under the fresh, open atmosphere.

When Do You Need to Re-Veg a Cannabis Plant?

There are some particular reasons why re-vegging a harvested plant. For example, in case, you think that you need to preserve an exact replica of a certain phenotype that may transition into its flowering stage, re-veg is the only option left.

If you need to reduce the vegetative period for any reason, you can re-veg the cannabis plant. Also, re-vegging offers bushier and more vigorous plants. So, you can also increase lant yields by re-vegging them.

Frequently Asked Questions

How Long Do I Veg For?

Most growers veg their plants somewhere between 2 weeks and 2 months. However, some growers don’t veg at all while some go longer.

How long does everyone veg?

It varies from growers to growers. However, the duration is around 4 weeks.

What’s the Average Grow Period for Cannabis?

Different strains have different growth periods. Such as Sativa strains’ growth period is 16 weeks, Indica’s 8-12 weeks, and hybrid’s 6-10 weeks.

How Long Do Seeds Last?

If you store seeds properly and they are in a good condition, your seeds will last a minimum of 1 year. However, depending on which plant you grow may last 2-5 years.

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Growing your own cannabis is not a big deal if you know how to do it properly. In every stage of it from seedling to flowering the plants, you need to know what to do and what not to do.

Knowing how long to veg from seed is one of the most important concerns. And, after reading the article, hopefully, you have no longer confusion in your mind regarding this topic. Also, we have shared some tips and tricks with you to maximize your yields.

Starting Vegetable Seeds Indoors

The easiest way to start any vegetable garden is direct seeding—wait until the weather warms and plant the seeds directly in the garden. Unfortunately, direct seeding is not practical for some crops. For example, tomatoes and peppers cannot be planted until after the last frost and after the soil has warmed. If seeded directly in the garden at that time, tomatoes and peppers require more than 100 days to produce the first fruit. In addition, newly emerged seedlings are very tender and easily killed by insects and disease or shaded by quicker growing weeds. Transplanting hardier young seedlings started indoors (transplants) allows an earlier start in the garden, which results in earlier yields of certain crops and makes better use of limited garden space. If a few simple guidelines are followed, transplants can be grown with a minimum of problems.

Potting Soil

Choosing the right potting soil is a very important part of starting seedlings indoors. The most convenient type to use is one of the commercial soilless mixes (Jiffy-Mix, Pro-Mix, Redi-Earth, etc.) that contain peat moss, perlite, vermiculite, and usually some fertilizer (see Table 1 for a mix recipe). These are specially formulated for starting seeds indoors. Soilless mixes are sterile and reduce the risk of losing seedlings to damping off, a fatal soilborne disease. Using soil directly from the garden is not recommended, because it may contain insects, weed seeds, or disease organisms that could damage or kill the young transplants. If garden soil is to be used, combine it with equal parts of sand and peat moss to improve drainage and structure. A teaspoon of ground limestone per quart of mix should also be added to obtain the proper pH. The mix must then be pasteurized to eliminate pests by heating to 180oF for 30 minutes. Heated soil gives off a strong smell, so consider doing it outdoors.

Getting Started

Containers, pots, flats, etc., are another essential component for starting transplants. When choosing a container to start your seedlings (Table 2), the most important factor is that the bottom have drainage holes. A lack of drainage can cause the soil to become saturated and can encourage root rot diseases in the transplants.

Before doing any planting, one word of caution: DON’T START PLANTS TOO EARLY. Plants that are started too early become elongated, pale green, and weak. The goal is to produce a stocky, moderately sized plant that will recover quickly when it is planted outdoors.

Table 3 lists how many weeks pass between seeding indoors and transplants are ready for planting in your garden. This period varies widely by crop, ranging from 2 to 12 weeks. Here is an example using Table 3. Suppose tomato is the crop to be grown. Table 3 indicates that tomatoes are a warm season crop, which means they cannot be planted until after the last frost. Assume May 15 is the last frost date for the garden. Because tomatoes take about 6 to 8 weeks from seeding to transplant, seeding indoors should take place between mid-March and April 1. If the crop to be planted were a cool season crop like lettuce, planting in the garden would occur in mid-April. That would mean seeding 5 to 6 weeks before that date, or roughly early to mid-March.

Crops are also listed as being warm or cold season. Warm season crops cannot be transplanted into the garden until all danger of frost is past. In New Jersey, this will range from April 20 in extreme southern New Jersey to June 1 in the colder northwest. Contact the county Rutgers Cooperative Extension office (listed under county government in the phonebook) for the last frost date in the area. Cool season crops withstand frost and may be planted outside much earlier, usually in mid to late April.

Next to each vegetable in Table 3 is listed the ability of that crop to transplant. Some are very easy to establish as transplants, such as tomatoes and lettuce. Others, however, do not do nearly as well. Those listed as poor, such as beans or corn, need great care and a minimum of handling. The roots of these plants are easily damaged. To start these indoors, use peat pots or pellets to minimize root damage. Some vegetables, like carrots and beets and peas, should always be seeded directly in the garden.

Place seeds in containers at the depths recommended in the chart. Plant one or two seeds per individual container or, if using flats, in rows that can be thinned or transplanted into individual containers following germination. Be sure to label the flats to avoid confusion, using a pencil or water resistant marker. Once the seeds are planted, the container should be bottom watered by placing it in a shallow pan of water and waiting until the surface of the mix is moist. This method avoids overhead sprinkling, which can carry away some smaller seeds. The pot should then be removed from the pan and allowed to drain.

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Germination is aided by maintaining high moisture levels in the mix and moderately high soil temperatures (Table 3). Sealing the container in a clear, plastic storage bag until seedlings emerge will keep the soil moist. Placing the starting containers in a warm place or on specially designed heating mats, available at some garden centers, can speed up germination. Once the seedlings emerge, remove the plastic bag and give the seedlings as much light as possible by placing them on a sunny window sill or 4 to 6 inches below a fluorescent light. Maintain room temperatures between 60 to 70oF. Higher temperatures or lack of light will promote unwanted, leggy growth. Seedlings can be lightly fertilized by watering with soluble fertilizers, such as Miracle-Gro or Peters, following the directions on the package.

When the seedlings develop their first true leaves, transplant those started in flats to individual containers. Dig the seedlings out of the mix with a small trowel or spoon. When transplanting, always handle the seedlings by the leaves, being careful not to damage the fragile seedling stem or root system.

One week before the seedlings are transplanted, they should be hardened off to better acclimate the transplants to outdoor conditions. Harden plants outdoors in an area protected from wind, and subject them to longer doses of sunlight each day, while cutting back on watering. One exception, harden tomatoes by reducing water only. Tomatoes exposed to cool temperatures may a develop a disorder called catfacing which causes the fruit to be misshapen.

After hardening, the seedlings are ready to be transplanted into the garden at the spacing indicated on the seed packet or the fact sheet Planning a Vegetable Garden FS129). Seedlings should be planted at the same depth at which they were growing indoors, except for tomatoes, which may be planted deeper. Firm the soil around the root ball, and water immediately with a solution of water and starter fertilizer. Try to transplant on a cloudy day to minimize wilting or transplant shock. If it’s sunny, provide the plants with some shade.

Table 1. Simple plant growing mix. a

Shredded sphagnum peat moss 10 gallons
No. 2, 3, or 4 domestic or African vermiculite b
(horticultural grade, dust screened)
10 gallons
Pulverized Limestone
Dolomitic Lime for mixes with domestic vermiculite
Calcitic Lime for mixes with African vermiculite
1 1/4 cups
3/4 cups
Superphosphate (20% P)
Triple superphosphate (46%)
1/2 cup
1/4 cup
Fertilizer (5-10-10) 10 gallons 1 cup

a This mix is used for germination. Supplemental fertilizer will be needed to grow plants to transplant size. Three weeks after seeding, apply soluble fertilizer like 20-20-20, 2 tsp/gallon of water. Apply weekly.

b Vermiculite should be pea size and free of dust. Final pH should be 6.0-6.5.

Table 2. Types of containers used for starting vegetable seedlings.

Types Comments
Peat Pots Made from compressed peat moss. These pots are filled with mix and seeded. The whole pot is then planted with the seedling. When planting outside, make sure the entire peat pot is covered with soil to avoid drying out.
Peat Pellets Compressed peat which expands when placed in water. Seeds are placed directly in the pellet after it has expanded. The entire pellet is placed in the soil and covered like peat pots. Peat pots and pellets are recommended for seedlings that transplant poorly since roots remain relatively undisturbed.
Plastic Pots and Flats These are filled with mix and seeded. When planting, carefully slide the seedling out of the container. Plastic flats can be reused if cleaned after use with a 1:10 solution of household bleach and water. Soak them in this solution for 10 minutes. Allow them to thoroughly dry before using. This will eliminate any disease problems
Table 3. Recommendations for starting vegetable seeds indoors.

Vegetable Ability to Transplant Weeks to Grow Depth of Seed (in.) Season a Optimum Soil Germination Temp. (°F)
Beans, snap poor b 2-3 1 warm 80
Broccoli good 6-7 1/4 cool 80
Brussels Sprouts good 6-7 1/4 cool 80
Cabbage good 6-7 1/4 cool 80
Cauliflower good 6-7 1/4 cool 80
Celery good 10-12 1/8 cool 70
Collards good 5-7 1/4 cool 80
Corn, sweet poor b 2-3 1/2 warm 90
Cucumbers moderate 2-3 1/2 warm 90
Eggplant good 8-10 1/4 warm 85
Kohlrabi good 6-7 1/4 cool 80
Kale good 4-6 1/4 cool 80
Leeks good 10-12 1/8 cool 75
Lettuce good 5-6 1/4 cool 75
Melons moderate 2-3 3/4 warm 90
Okra good 2-3 3/4 warm 90
Onions good 10-12 1/4 cool 75
Peppers good 8-10 1/4 warm 85
Pumpkins moderate 2-3 1 warm 90
Squash moderate 2-3 1 warm 90
Tomatoes good 6-8 1/4 warm 85

a Cool season refers to transplants that can tolerate frost. Warm season refers to plants that can not be transplanted until after all danger of frost and soil has warmed.

b To minimize root disturbance, start these seeds in peat pots or peat pellets.

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