Marijuana grow guide

At Amsterdam Marijuana Seeds, we have been breeding, growing cannabis, and selling cannabis seeds for over 25 years. If you would combine the years of experience of our experts, support team, growers, and master breeders, we have over 150 years of experience. We have gathered all that knowledge and made it into this guide to help you get started with growing cannabis. This is our labor of love; we will share it with the community for free, as that is what we do in this community. Our guide can benefit the beginner as well as the more experienced growers. If you have visited our site, you know we like to give tips, share our tricks, and more.

• Types of cannabis and their effects
• Kinds of seeds
• The life cycle of the cannabis plant
• How to germinate your seed
• Soil and containers include transplanting information
• Water and pH levels
• Light and lamps
• Temperature, humidity, and ventilation
• Nutrients needed for each life phase
• Pruning, topping, super-cropping
• Harvesting
• Download grow guide

Types of cannabis and their effects

Originally there are three species of the genus cannabis; Cannabis Indica, Cannabis Sativa, and Cannabis Ruderalis. Since the 60s, people have started to blend these types, and while doing so, creating a new type of cannabis, the Hybrid. You can read more about Hybrids seeds on our hybrid page. Technically, all autoflowers are a hybrid strain because they have a parent from at least two of the three species. Because of the wide variety of hybrids, it's impossible to map their trades and effects individually as they are a mix. So we will elaborate on the original three types. They all belong to the group of plants that have psychoactive properties. However, their effects on the user and how they look different.

Cannabis Sativa

Cannabis Sativa grows the tallest of the three. Their buds are airy, and they have thin pointed leaves. When you see the signature picture of a cannabis leaf, it is usually the Sativa dominant leaf. Since they grow the biggest, they normally also have the largest yields. The effects you can expect from consuming a Sativa dominant strain are energizing, uplifting, increased creativity, cerebral head buzz, increased focus, promotes a general feeling of wellness, and reduced nausea.

Cannabis Indica

Cannabis Indica can be recognized for its short, bushy, and stocky stature. Their leaves are fan-like, and the fingers of the leaves are broad. They normally have good genetics to grow thick, dense buds. Indica strains are known to have higher CBD content than Sativas.

Cannabis ruderalis

The Cannabis ruderalis is the smallest of the three and has narrow palmate-shaped leaves. What sets cannabis ruderalis apart is that it switches automatically from the vegetative stage to the flowering stage with age instead of needing the schedule of 12 hours of light and 12 hours of darkness. Another advantage is that it has a shorter growth period for quicker and more yearly harvests. This makes it popular with beginners and those without an ideal climate or grow space. Ruderalis does not have a psychoactive effect in itself.

It has been interbred with Sativa and Indica plants to take on their psychoactive traits but remains autoflowering after crossbreeding. Even though these three species, Sativa, Indica, and Ruderalis, come from distinct, separate families, some growers think that Ruderalis is not even an "official" Cannabis. Still, these three can be blended and have, as most strains today are hybrid strains.

Summary:

There are 3 main types of cannabis; Indica, Sativa and Ruderalis. Indica has a more relaxing effect better suited for evening/nighttime usage. Sativa is well known for giving you a more uplifting effect, focus, and with a bit of luck, creativity. Pure Ruderalis is low in THC and will not do much; it's primarily used for creating hybrids as it autoflowers and has a shorter flowering time. Hybrids are new strains that mix at least two of the three original types. They can have any trait of the parent in a dominant or submissive amount.

Kinds of seeds

A. Feminized cannabis seeds

The most popular are feminized seeds, for a good reason, only female plants will grow and produce cannabis buds. Feminized seeds are, as the name suggests, specifically bred to exclude males. Many growers choose feminized, as you won't have the risk of any males stepping out of line and pollinating your precious females. Buying feminized seeds will take the guesswork out of sexing your plant and save you a lot of time and space. It is a terrible disappointment when you spend weeks nurturing a plant that ends up being male.

B. Regular Seeds

Regular seeds are a mix of male and female seeds. Naturally, cannabis plants produce a ratio of 50% male to female seeds. There is no way of telling if the plant will be male or female before the flowering phase. Male plants are mostly useful to breeders who like to create new hybrids.

C. Autoflowering seeds

Autoflowering feminized seeds are female seeds with the genetics of cannabis ruderalis to make the plants flower automatically with age. With auto-fem seeds, you get the benefit of feminized strains along with the benefits of ruderalis plants. Autoflowering cannabis plants are easier to grow, have a short growth period, and are great for stealthy growing due to their small size. Their size, however, may also be a drawback since they will produce smaller yields.

Summary

There are three kinds of seeds: Regular, Feminized, and autoflowering. Regular seeds have male and female seeds, which, if they pollinate, will not grow weeds. Feminized strains are specifically bred to be only female. Autoflowering cannabis seeds will start flowering by themselves.

The life cycle of the cannabis plant

The cannabis plant goes through four main stages, from seed until harvest. These are:

• germination stage
• seedling stage
• vegetative stage
• flowering stage

A. Germination

The cannabis plant life cycle begins with high-quality seeds. The seed of the cannabis plant is dormant and needs water to bring it to life. This process is called germination and can start anywhere from 24 hours, take up to 7 days, and sometimes even more. The wet seed will then sprout its taproot and can then be placed in a growing medium. The taproot will grow down into the growing medium as the stem grows upwards, and then two cotyledon leaves will grow from the stem. The cotyledon leaves will take in the sunlight allowing the roots to develop along with the first fan leaves. Now your plant is considered a seedling.

B. Seedling stage

Specific traits define a seedling; it must have developed a stable root system and true leaves, which means it has leaves that look like the iconic marijuana leaves we can all recognize. During this stage, a seedling will grow from 4 to 8 leaves. A cannabis plant can stay in the seedling stage for a broad range of time but normally around three weeks. A healthy seedling will be short with dense vegetation; the leaves should look bright and green. Take good care of your plant in this stage, as any stress or defects it will experience will take its toll. A healthy seedling will become a healthy plant!

C. Vegetative stage

This stage is when the marijuana plant begins to take off when it hits puberty. This is when plants grow big jagged leaves and produce much more foliage since they absorb and process much more nutrients and carbon dioxide. The growth of the marijuana plant will mainly depend upon the rate at which its leaves can gather sunlight and undergo photosynthesis. This is why you will need to give your plant about 18 hours of light during the vegetative stage if it’s grown indoors. You can begin topping and training the marijuana plants at this stage.

D. Flowering stage

The flowering stage is the final stage of the marijuana plant. The stage every grower anticipates the most, as it will show your cannabis crops coming to completion. The trichomes on the buds will let you know when the marijuana plant has fully matured. And when that does, you can begin the harvest.

Every stage of the marijuana plant has its unique characteristics. Knowing the stages will allow you to give your plant the right nutrients along with an environment that will allow it to flourish.

Summary

There are four stages in the lifecycle of the plant; seed germination, seedling, vegetative stage, and flowering stage. For optimal growth, create the right environment for every stage. The needs of the plant change with its growth.

How to germinate your seed

There are various ways for cannabis seed germination, but we recommend the paper towel method to our customers. You only need items that are custom around the kitchen. So it's cheap, easy, and successful.

For indoor growers, it's possible to skip step 5 and place your seedling directly in the main pot. Indoors are fewer threats that might hurt the seedling.

You will need the following materials:

• 2 plates
• Paper towels
• Distilled water (if your tap water is not drinkable)
• Good soil
• Tiny planting pots
• Lighting

Germination instructions:

Firstly, dampen a paper towel with distilled water and put it on a plate. Be careful not to soak the paper towel, as this will prevent the seed from getting oxygen and ultimately rot. Carefully spread the seeds out on the paper towel, cover them with another dampened paper towel, and cover them with the other plate. It would be best to put the plates with the seeds in a warm, dark place. The most favorable temperature to germinate seeds is 22 to 25°C (72 to 78°F).

You can open the plates once daily to check if the taproots are starting to emerge from the seed. Take notice that some seeds will sprout rather quickly while others need a week or even a bit longer to germinate. Every three days or so, spray some more distilled water on top of the paper towel starts to feel a bit dry. When the taproots are 1-2cm long (not more), it is time to transplant them into the little pots filled with soil.

Make a tiny hole in the soil a few centimeters into the ground. You can plant the cannabis seed with the taproot going down into the soil. It would be best if you were sure to plant your seed correctly, or it will not survive. Cover the hole with a little soil and give it some water. Make sure the seed remains covered after the water is added.

Be sure to put your plants where there is plenty of sunlight or use fluorescent lights. Be sure the plants do not dry out and avoid over-watering. Within 3-7 days, the little marijuana seedling will emerge from the soil. After that, your plant will reach a height of about 4 inches in 3-4 weeks. At this size, you can transfer the plant to a larger pot.

Summary

For seed germination, we advise the paper towel germination method because it is simple and requires no special equipment.

Soil and containers include transplanting information

Your grow medium is another important part of growing cannabis plans. We would advise using airy organic soil as your soil needs to drain well, and the roots can grow freely. You can even add some perlite or sponge rock to increase drainage.

Don’t use one full of nutrients as your seedling will need different nutrients than when it is an adult. Instead, add the nutrients to cater to the plant's needs perfectly. Use the pH tester to ensure that the soil’s pH remains between 6-7.

Start Your Plant In A Small Pot

It is important to transplant your marijuana from smaller plant pots to larger ones when it's seedling! Please consider that root expansion is the biggest limitation of its overall development. For your plant to reach its full potential, its roots will need to be able to expand fully.

Summary

For starting growers, we advise using organic soil with no added nutrients, as you will provide these yourself. Use different amounts per growing stage of the plant. Change pot sizes accordingly because the rest won't grow when the plant's roots can't grow.

Water and pH levels

Water plays a vital role in the life of your cannabis plant. High-quality water can take your plants to a higher level since it is the foundation of successful growth. Not enough water, too much water, and poor quality water will slow the growth and can even cause the death of your plant, so it is important to know what is in your water and what your plant’s water needs are.

Water quality varies according to your source and where you live. Water contains minerals and other components that will directly affect the pH of the plant's environment because of the nutrients it receives.

Water your plant correctly

When you water your plant, be sure to be thorough. Pour water evenly around the soil, making sure that the water gets to the deepest roots. If the bottom roots do not receive water, they will turn upwards to get to the water. Another important thing to note about watering your plants is that you need to ensure that the pot you use has holes in the bottom so the water can drain properly.

Your plants' pH is important

Measuring the pH of the runoff water will tell you how alkaline or acidic the plant’s environment is. A grower can purchase special tester drops or a digital pH pen. Cannabis plants like a pH between 6-7. If you can get it around a 6.5, that is best.

How to fix an incorrect pH

If you find that your pH is too high or too low, it can easily be corrected. There are many pH “up” and pH “down” solutions on the market that you can use to correct your pH value.

Growing with hydroponic systems

Hydroponic growing is a different ballgame, becoming increasingly popular. There are many benefits like

• you don't need any soil as water will be your growing medium
• Saves on water usage
• Utilizes space

The downside is that waterborne diseases spread quickly. So if you can provide a safe, clean grow space, a hydroponic system is an option. But this might be a bridge too far when you have just started growing and are still learning to grow cannabis.

Summary

Water is the giver of life. Your plant will need an increasing amount during its growth cycle. Water your plants at the right time, keep the soil moist, not soaked, and keep a close eye on the pH Value. Keep it between 6 and 7.

Light and lamps

Some people prefer indoor growing, others outdoors. Either way, cannabis plants require a lot of light/sunlight for their growth. Outdoors, the sun provides the light; for indoor growth, you must mimic this as closely as possible. Which grow light you may choose, make sure it can light up your grow space like the sun and make sure that all your plants can bathe in the light. No cutting corners! Get the right wattage, and make the height adjustable.

When creating your setup, invest in good reflective foil, and cover all the walls and ceiling if you want to get the most out of the light. When your plant goes into vegetative growth, leaves and branches will grow hard and fast, becoming a forest. Every extra ray of light reaching your plant will give it energy for growing weeds. In the Dam, many growers say, wattage = kilo. With three 600-watt HID lamps combined 1800-watt, you should be able to harvest 1800 grams (63 ounces).

Types of grow lights

The two most commonly used lamps to grow indoors are:

• High-Intensity Discharge (HID)
• Light Emitting Diode (LED)

HID lamps have been around for a while and have seen some great improvements making them more efficient.

LED grow lights are the latest trend in providing growing lights to indoor cannabis plants. Most growers like their effectiveness and the ability to give relatively higher yields than even the pertinent HID lights.

Light Spectrum

Your cannabis plant reacts better when the light spectrum matches its growth stage. For example, in the vegetative stage, blue light. In this case, 460nm is the optimum spectrum. This will create strong leaves. In outdoor growth settings, cannabis plants can get blue wavelengths during the summer. When the cannabis plants get planted indoors, some lamps that can give blue light comprise T5/T8 and Compact Fluorescent Lamps. In the flowering phase, the light spectrum required should make the plants give rise to potent and huge buds. A red light should be used at this stage and give spectrum levels of 660nm on average.

Distance of lamps from plants

Keeping lamps at the right length can greatly help get potent plants and enhance their yield. The emphasis is on giving sufficient light to your cannabis plants without making them prone to light burn. So make sure your growing space has enough height. The top parts of the cannabis plant can light up to 20 cm. The heat output is, under most circumstances, manageable since it rarely surpasses 600W. The plants get sufficient light when a small-scale grower uses a 250W lamp per square meter. Invest in adjustable light fixtures (fairly easy to find), which can help shift the height following the plant's growth. Providing optimal lighting conditions will make all the difference when growing marijuana!

Summary

All plants need light to grow; the lighter, the better. If you grow outside, choose the right cannabis garden spot with the most sun-hours and minimum shade. Indoor growers have to mimic this, use a strong lamp with the right spread, and use reflective foil so there is a minimum amount of shade.

Temperature, humidity, and ventilation

Following the light and lamps are the temperature, humidity, and ventilation. Purposely done so because lights can also provide heat, so you have to manage that too, when growing marijuana indoors.

Temperature

Cannabis plants tend to be choosy on the optimum room growth temperatures. Depending on the cannabis strains planted, the best temperature ranges at almost every phase of the cannabis life cycle need to range between 20° C and 30° C during the day. During the night, cooler temperatures like 20° C or slightly less work incredibly well.

Humidity

The right Humidity in your grow room helps to grow healthy plants, too much fluctuation will cause stress, and too high can give room for mildew to grow. So keep it steady and just right between 40 and 45%.

Ventilation

When growing weed indoors, fresh air does wonders!

You can use it to boost or lower the humidity levels, and seeing your plants waving at you will bring a smile to your face! Be sure your intake can provide enough airflow for the whole room.

Especially in the flowering stage as the plants are all full-grown and the space is filled with leaves and great-looking tops. A nice breeze will help your plant to grow strong leaves and provide some cooling while doing so. 

Summary

The right balance of temperature, humidity, and fresh air gives little to no stress. This is the right environment for a healthy plant to grow!

Nutrients needed for each life phase

Like humans, cannabis plants need specific nutrients to live a healthy, fruitful life. Different nutrients help the plant perform specific tasks like growing roots or buds. When you buy fertilizer, you will see on the packaging the N-P-K ratio. These are the macronutrients that stand for Nitrogen, phosphorus, and potassium. These are vital in every plant's life so that they can flourish. Most organic soil will take care of the micronutrients your plants will need.

N-P-K Nutrients

Nitrogen is especially important during the vegetative phase of the plant’s life as it is largely responsible for a plant’s development. It aids in producing chlorophyll; without it, the plant can’t create food from sunlight.

Phosphorus is a mobile nutrient within all plants, including marijuana; it’s truly a primary nutrient for the plant. It helps with cell division, transporting amino acids throughout the plant, new tissue growth, and general health and energy.

Potassium, like the other two, have several jobs. It helps strengthen the plant’s immune system, it is needed for photosynthesis (how plants create food from sunlight), and potassium assists with osmoregulation. Osmoregulation is how the plant regulates the water in its cells.

Want to know a bit or two about Potassium Deficiency? Check out our video, where Mr. Sour will tell you everything about it:

Each life phase requires different nutrients

Marijuana plants need different amounts of these nutrients during each life phase. Very young marijuana seedlings that have just germinated do not need extra nutrients, and giving them fertilizer too soon in life can cause nutrient burn since they are so fragile. You can begin giving your plant low fertilizer levels when 3-4 sets of true leaves (not including the cotyledons) have grown. A good starter NPK ratio is 11-40-13. You can add more fertilizer when 6-7 bladed leaves have developed. When your plant is fully in its vegetative phase, it will need plenty of Nitrogen. An NPK ratio of 19-5-20 will provide enough of the right nutrients to support its robust growth during this time.

When your Cannabis plant starts the flowering stage, it will again need a different fertilizer ratio. Now your plants have finished building their support scaffolding. Less leaf and stem production will occur, and nitrogen stores will be built. Therefore, less Nitrogen needs to be added. Phosphorus should be increased to support the production of buds along with potassium. An NPK ratio of 15-6-30 will give your plant the right nutrients. During the cannabis plants' late bloom period, you should change the NPK ratio to 0-27-27 to support the plant's bud production. At 10-14 days before harvest, you should flush your plants using a few gallons of pure water with a pH of 6.0 to 6.8.

Summary

Every cannabis plant's growth cycle stage needs specific nutrients to generate optimal health. Check growing schedules matching your growing medium and plant type to determine the right nutrients and amounts. An EC meter is a handy tool!

Pruning, topping, super-cropping

When growing cannabis, there is little we growers won’t do to ensure that we get the best yields when harvesting our crops. Pruning means manipulating your cannabis plant by cutting, bending, or tieing it to grow in a specific way that will give you more and better buds. Indoor pruning should occur between 10 and 15 days before you force flowering. If you are growing outdoors, you should start pruning a few weeks before you expect your plant to flower. Tall plants can waste a lot of nutrients and energy, supplying water throughout a long stem. Instead of your plant wasting so much energy growing a long flimsy stalk, it could have put more energy into growing you a big fat bud. Don’t start just whacking off leaves and branches!

Topping

The topping method is cutting off the top shoot. Let your plant grow to at least five nodes and cut the stem just above the second true node. The node where the cotyledons (the first two baby leaves) attach does not count as a true node. It seems counter-effective to cut the top off of your plant that you are eager to grow, but it will divide its energy to create multiple colas for you.

As new shoots form after the main stem has been topped, you can repeatedly top new shoots as they form. This will turn two new tops into four, and then you can turn four into eight. Make sure to allow at least one internode to form with a set of leaves and cut just above that each time.

Super cropping

Another pruning technique to increase your yields is called super cropping. Unlike topping, it does not include cutting anything off of your plant. It consists of putting your plant through stress to increase the number of tops. It will push the lower growth higher and wider so that it will flower. Not only can this method be done on almost all plants, but it can be done several times during the vegetative process. The nutrients will work twice as hard to produce higher yields in otherwise weak areas.

Summary

It's possible to manipulate your plant to grow more tops and increase yield in several ways; pruning, topping, and super cropping. All of them do give the plant stress and can influence the plant's growth. So you must decide if you think it's worth the risk. Tip, you can do a few plants only and see, weigh in the end if it was worth it.

Harvesting

At the end of your cannabis flowering stage comes harvesting time, the moment we have all been waiting for. However, you're not yet completely there; there are two more hurdles to be taken;

• Trimming
• Drying or curing

Trimming

Trimming is an important aspect of harvesting because it can greatly impact the final bud's look, potency, and smoke. Well-trimmed buds will excite buyers if you plan on selling some of your weed. It will sell much more quickly because it is aesthetically pleasing and shows off the beauty of the bud. Badly trimmed bud does not give off a good first impression and brings down the entire quality of the bud. Poorly trimmed bud dilutes the overall potency of the flower as the less potent leaves are wrapping around the outside of the bud, and smoking it will feel harsher. If you are growing a few plants for your personal use, trim, or don’t trim, to your liking. Although, if you wanted to sell some bud to a local dispensary, then you should do a good job of trimming to make sure your bud looks like it belongs on the top shelf.

Trimming Methods

There are two methods to choose from when trimming cannabis. Many growers will swear on one method, and another grower will convince you their method is better.

• Wet trimming
• Dry trimming

Find out what works best for you!

For both methods, you will practically need the same equipment: good-quality pruning scissors, larger pruning shears, rubbing alcohol (to clean the sticky residue off your scissors), rubber gloves, a clean work area, and containers to organize the trimmed buds, untrimmed buds, and leaves or “trim”

Wet trimming

To begin your wet trim, you will use your large shears to cut the branches off the cannabis plant. You can hang your freshly cut buds on a line, so they don’t get squashed in the container near your workstation. You want first to remove the fan leaves starting at the base. The fan leaves will be normal leaves without trichomes on them. You can save these and the trimmings to make hashish with.

After the fan leaves are removed it’s time to get up close and personal and trim the smaller leaves with the trichomes on them with your scissors.  You will cut all around the bud to reveal the cannabis nugget; pay close attention to how you sculpt it, as this will be the look of your final product. It would be best if you did this over a baking tray or bowl to catch the small leaves and extra trim to save them for making edibles, topicals, or hash.

Now that the final product is revealed, you can cut the bud off the stalk and let it dry on a mesh rack or leave it on the branch and hang it to dry. Your drying environment should be dark and have some airflow, like from a fan. Avoid direct wind to your buds. You can put a dehumidifier in the room for a nice touch. Keep an eye on your harvest every day. After about 5 to 7 days, your harvest will be dry enough for curing.

Dry trimming

The dry trimming begins like wet trimming, so you will cut down the branches and remove the fan leaves. Now you will hang up the branches in a drying space that is dry, dark, and cool with nice airflow. Do not overcrowd this area, as that may cause mold or mildew to grow. After 5 to 7 days, you can check to see if they are ready for more trimming by bending the stalk. If the stalk snaps, then they are ready for the next step.

The leaves have dried and created a shell around the nugget. It would be best if you trimmed the leaves off over a baking tray to sculpt the bud into its final product. The trichomes will be delicate, so be careful with every cut. These buds can now be put into a jar for curing. Now you have a great supply of beautiful nuggets and a stash of little leftovers to make into edibles or tinctures.

Drying or curing

By the time you are ready to harvest your bud, you have already gone through an incredible journey taking care of your cannabis plant. You have raised them well, but you are not done yet. You are the last step away from lighting up and reaping the rewards of your crop.

How to dry your buds

Although removing leaves and stems during harvest speeds up the drying process, moisture content becomes uneven. Quick-drying methods also trap chlorophylls, starches, and nitrates inside the plant tissue, which affects the burn and taste.

Drying marijuana slowly is the way to go. This way, the moisture evaporates evenly into the air, and you get evenly drying buds with minimal THC decomposition. As the pigments break down, taste and aroma improve. Slow drying allows enough time for the pigments to deteriorate.

One of the best ways to allow this process is by hanging the entire plant upside down to dry. Prevent the plants from touching each other, increasing the chance of mold forming. The ideal situation to dry your plants is to keep a steady temperature of 18 to 24°C (65 to 75°F) and avoid putting fans directly on the plant, as that will cause it to dry unevenly. The humidity should be kept between 45% and 55%. Your drying room should be quite dark as direct sunlight degrades the THC. Your bud's drying time will depend on temperature, humidity, and density.

By the end of a week, you should be able to start curing your buds, but huge and dense buds might take a few days longer. You can tell if your buds are ready to be cured by squeezing them to check their moisture content. The bud should be dry but not brittle. Also, check the stem; bend it; if it breaks (not just bends), it is ready!

Curing is the way to enjoy the fruits of your labor. You want to prevent mold from standing a chance and ruining your crop, and of course, you want the maximum flavor and potency you can achieve.

In summary

Harvesting and curing are the last steps before you can finally sit back and smoke; don't be hasty now! These last steps influence the end product; whatever method of trimming and curing you choose, do it with love, care, and patience, and your buds will be AMS- Grade!

Download grow guide

The pdf version of our guide is available for free, which also contains the following extra chapters:

• Equipment needed for growing
• Grow light and lamps
• Mildew, pests, and diseases
• Growing with Hydroponic systems.