Growing marijuana in a greenhouse

Because the popularity of growing marijuana is growing, in general, the amount of interest in using a greenhouse to grow marijuana is growing as well. There are plenty of advantages to growing weed in a greenhouse instead of a grow room, although it comes with its own fair share of drawbacks as well, of course.

In this article, we will cover some background information on greenhouses as well as the advantages and disadvantages of using a greenhouse to grow your marijuana.

Why you should consider growing in a greenhouse

The beauty of using a greenhouse to grow your marijuana plants includes the removal of the tricky complexities of an indoor grow room setup. It is also considered by many to be superior to growing outdoors, as it is more secure yet also more consistent and predictable than growing marijuana plants outdoors.

It takes the best parts of the natural elements and combines them with protection against the worst parts of the elements, making it the perfect situation, especially for growers that are located in northern areas.

growing weed in a greenhouse
Growing weed in a greenhouse

Although they heat themselves naturally to a certain extent, greenhouses can be heated further when necessary. If you are interested in having a marijuana growing operation to supply your recreational and/or medical marijuana needs, and a greenhouse is a feasible option for you, then you should definitely consider using it. Also consider the elements when you go from seedling stage to germination.

Tip: make sure to download my free Grow Bible for more information about advanced growing techniques

Marijuana that is grown in a greenhouse is particularly well-known for being more potent, so as long as you grow your marijuana from seed with strong genetics, you will find yourself with a very high-quality bud at the end of the growing season. This is precisely why more and more people are switching to greenhouse growing setups instead of indoor grow rooms or outdoor setups.

Outdoor or greenhouse?

It is sometimes difficult for growers to decide whether they would like to grow their marijuana plants in an outdoor setup or from within a greenhouse. This is especially the case for people who have been growing their plants outdoors with a relatively “hands off” kind of care schedule.

In other words, they let nature do its thing, and their marijuana plants generally are successful without too much grower interaction.

small greenhouse for growing cannabis
Wondering whether it is convenient to use a greenhouse? Start small!

For these growers, buying and using a greenhouse may seem like a major commitment. Why do that when you could simply let the plants practically grow themselves?

When considering this question, try and think about all the negatives that come with growing outdoors. Unexpected weather changes, exposure to pests and diseases, and the even more dangerous — human marijuana thieves — could all ruin your crop any year. Wouldn’t you like to ensure that your marijuana plants are successful this year?

When growing marijuana in a greenhouse, you are more likely to encounter pests like small insects rather than deer, rabbits, pets, and birds. This will already ensure the safety of your plants far more than if they were exposed outdoors.

using a greenhouse keeps animals away
Using a greenhouse will keep animals away

A greenhouse is also safer, using the “hiding in plain sight” logic. You can easily have a thriving garden of other plants while intermixing marijuana plants in with them — no one will suspect or see a thing.

If you are living in a more rural area, you could even get by with growing more than just a couple marijuana plants here and there among your “regular” plants. The key thing to think about in this situation is the smell, which will be stronger.

Greenhouse growing 101

Marijuana grown in a greenhouse can be set up in one of two ways. Either you will grow the plants in separate containers or pots, or you will plant them straight in the ground. There are pros and cons for both options, but ultimately it comes down to what fits best into your lifestyle.

Thinking about which seeds to grow in a greenhouse setup? Choose from my wide seed selection here.

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If you choose the container route, you will enjoy the fact that it makes it easier to move the growing plants whenever necessary. This is particularly handy if you are frequently visited by people (who you likely shouldn’t share your growing operation with), as you can simply move the plants elsewhere so as not to attract attention. Another reason to move your container-grown plants might include extreme weather coming in.

greenhouse grow with plants
Growing plants in a pot, easier to move

If you decide to plant your marijuana directly into the ground, on the other hand, they will fare much better when they are left alone for a longer period of time (such as a week). Of course, this is only if the soil they are planted in is high quality; if not, replace the old, poor quality soil with better quality soil.

Also read Hydroponic Marijuana Growing Indoors

A third option does exist for some particularly innovative greenhouse growers: hydroponics. People who have tried it in a greenhouse have had big success, making it a potentially good idea if it suits your lifestyle and experience.

The importance of genetics

No matter what you do with the following information, the most important piece of advice is this: buy high-quality marijuana seeds. It is worth the extra money to rest assured you are setting yourself up for a successful growing season.

If you buy cheap, poor quality seeds instead, then you simply cannot achieve the same level of success, no matter how much effort and time you put into caring for your plants.

high quality cannabis seeds produce the best grows
Buy high quality seeds to get best result

Additionally, be sure to plant these high-quality seeds in high-quality soil. This will give your plants the perfect boost at the very beginning of their lives to build a foundation for healthy growth up through the flowering phase. If you don’t have these two elements, your plant will never reach the monster size that greenhouse plants are well-known for.

The key is to think about each individual seed as an individual investment. Just a few seeds could actually feed your marijuana needs for an entire year if grown properly. When thinking about it like that, it provides the proper motivation to prioritize the needs and care of each seed as much as possible.

Maximizing your setup

Automated systems
One of the best things about really intricate greenhouse growing setups is the fact that it can be highly automated. In other words, it can be much easier for the grower because they don’t need to do as much day-to-day care for their plants. One such automated system is a watering system that delivers water to the plants automatically, or with little effort on the grower’s part.

automatic watering in the greenhouse
Automatic watering the greenhouse

You may want to consider installing some automated systems of your own if you are the type of person who enjoys planning such things ahead of time, if you have a high enough budget for it, and if you don’t enjoy the daily tasks of the marijuana plant care as much as the setting up process.


One good way to keep your marijuana plants safe from detection if the greenhouse is not located in an inconspicuous or private location is to paint the exterior with white shading paint. You can find this at a garden center, and it serves the dual purpose of preventing the greenhouse from getting far too hot on the warmest days during the summer. When you have a painted greenhouse, people will not be able to peer inside and identify what you are growing.

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An additional idea for people who just want to grow one or a couple marijuana plants is to actually grow tomato plants and use green plastic plant mesh so that they can have a secret one or two marijuana plants growing in the corner or amongst the tomato plants.

Start growing earlier in the season

To truly take advantage of growing your marijuana plants inside a greenhouse, try starting the growing season early this year. This is possible because greenhouses will get much warmer than the outside temperature once the sun comes out.

grow earlier with a greenhouse
More sun makes it possible to start growing earlier

When you start the growing season earlier, you have more time for the vegetation phase of your marijuana plants. When you have more time for the vegetation phase, your marijuana plants will be bigger and stronger for the flowering phase. As a result, your harvest in the end will be much better.

The key to doing this successfully is not to allow the greenhouse to get too cold at night during the early part of the season. You can do this by installing greenhouse heaters, found at your local garden center, to be run during cold nights.

This ability to lengthen the growing season for marijuana plants is one big reason why and an increasing number of marijuana growers are opting to grow their plants in a greenhouse instead of an indoor or outdoor setup. These plants have the opportunity to grow far greater in size than their outdoor counterparts, assuming the seed genetics, soil, and other care aspects are sound.

Believe it or not, some growers have even opted to grow just one big plant in their greenhouse setup — and that plant gave them hundreds of grams of high-quality buds at the end of it. If the plant starts getting too out of control, it could actually start growing out through any open windows that might be in your greenhouse, and therefore steps need to be taken to “tame” the plant. This is best done via tying techniques.

one big marijuana plant
One big plant in a greenhouse

It is a good problem to have, but growing gigantic marijuana plants is not necessarily an easy thing to deal with. Properly grown, fully maximized marijuana plants cultivated in a greenhouse will be tall and extremely bushy. This is particularly true if you have been giving your plants huge amount of space in the soil for their roots, good quality soil to begin with, land lots of sun. Make sure you are prepared for the “worst.”

Using a darkening system

Many greenhouse growers will opt to use what is known as a “darkening” system which, when set up correctly, should be dark enough that there is a complete blackout within the greenhouse — even during the middle of a sunny afternoon. The point of installing a darkening system is to simulate shorter days and longer uninterrupted nights, thus spurring your marijuana plants into an early flowering phase.

Maximizing your marijuana greenhouse setup
Maximizing your marijuana greenhouse setup

This is an expensive addition, but it will certainly ensure that you acquire your weed much faster than if you waited for the natural sunlight conditions to change over the course of the season. The way to “trick” your plants into entering the flowering season early is to have 12 hours of uninterrupted darkness and 12 hours of sunlight every day without fail.

The darkness is the most important part of this process — you must not allow any light in at any point, even for an instant. After a couple weeks of this, you should start seeing signs of flowering.

Extending the end of the growing season

A greenhouse can also be the perfect environment for manipulating the length of the end of your marijuana plants’ growing season. Many growers choose to use this to their advantage and lengthen the end of the growing season.

High yield while growing in a greenhouse
High yield while growing in a greenhouse

The main reason why a greenhouse is beneficial in this way is that it keeps the air around the plants (in other words, the air inside the greenhouse) toasty warm when it is sunny while the colder temperatures of the fall are creeping in.

General good care for long term success

If you are just looking to do your best with your marijuana plants, you are going to need to remember a few pieces of advice that will lead to happier and healthier marijuana plants year after year.

First of all, make sure to add new, healthy, high-quality soil every new year of growing. Buying it once and reusing it over and over simply will not do.

Use good and fresh soil when you start growing
Use good and fresh soil when you start growing

Just like if you were growing in an indoor setup, make sure you keep your greenhouse as tidy as possible at all times. This will help keep things like pests and diseases at bay in case they do come in contact with your marijuana plants.

For the safety and security of both you and your plants, you could try using fencing that has been placed in strategic locations (keeping it as inconspicuous as possible) to keep people who shouldn’t be there away from your greenhouse. It will additionally help anyone discovering it accidentally simply by looking at or into your greenhouse, and that means better security for you.

If you are buying the greenhouse now, you can make a strategic decision about which type of greenhouse to purchase. Some of the newer polycarbonate greenhouses, for instance, are already opaque and often come with doors that have locks on them. This will keep both people and eyes away from your precious marijuana plants. You can buy any size or shape of greenhouse you like, and you will luckily find that they are relatively inexpensive.

Polycarbonate greenhouse cannabis
Polycarbonate greenhouse cannabis

If you are growing more than one or two marijuana plants, you are going to need to deal with the potent smell. It will be stronger with many marijuana plants packed into a greenhouse, and unlike an indoor marijuana setup, you cannot simply use a carbon filter to get rid of the smell because the humidity will be so much higher here. If it is really a problem, the only way to get rid of the smell will be to extract it via an in-line ozone generator.

If you’ve made up your mind into greenhouse growing, the next step would be choosing seeds. Get high-quality marijuana seeds from my seed bank to get the best results.

High-quality marijuana seeds

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Which type of greenhouse should you buy?

If you have decided on a greenhouse but aren’t sure where to go from there, rest assured that the next step is simple. You simply need to choose the type that you would like to invest in.

Is cheaper better?

The short answer is no. When it comes to greenhouses, cheaper is not better. If you pay very little for a greenhouse that is inexpensive, flimsy, and portable, you will not have the best results you could.

If the wind picks up, the greenhouse could actually fly away. If the heat on a summer afternoon is too much, it will absolutely roast your marijuana plants. Don’t try cutting costs in this way.

Attached greenhouses

The most common type of attached greenhouses are lean-to greenhouses. Just like their name implies, lean-to greenhouses are greenhouses that lean up against the outside of your house or another building. These greenhouses are particularly efficient because they get any of the heat that leaks through the wall of your house, keeping your plants even warmer without any extra effort, and they are half the size of a normal greenhouse.

Lean-to cannabis greenhouse
Lean-to cannabis greenhouse

Lean-to greenhouses could be perfect for someone who does not have the lawn space for a full-sized free-standing greenhouse, or if you only want to grow a couple plants. They also have lower materials costs because one wall of the greenhouse already exists. One downfall with attached greenhouses is that they are limited in their position to where the wall of the structure is that they will be leaned up against.

Freestanding greenhouses

Greenhouses that stand on their own generally come in the shape of an apex (such as a house). Their frames are often made of wood or aluminum, which brings up an important point: remember that the sun cannot shine through wood or aluminum, and therefore shade will be created.

If the frame is particularly thick, there will be more shade in your greenhouse. More shade means less sunlight for many of your plants, so avoid really thick frames if you buy a free standing greenhouse.

Freestanding cannabis greenhouses
Freestanding cannabis greenhouse

Freestanding greenhouses, also known as detached greenhouses, have the major advantage of being able to be placed just about anywhere. They are not limited by a permanent structure like attached greenhouses are, meaning you can position them for optimal conditions. You will often hear free standing greenhouses referred to as A-frames or even-spans, given the fact that those designs are most often found on the market.

Connected greenhouses

A connected greenhouse is one that includes multiple greenhouses that have been attached to each other. They work well for commercial operations so that one large space can be formed for many plants to grow. It maintains one controlled climate for temperature and other environmental elements, making the operation and energy as cost-efficient as possible.

Connected cannabis greenhouses
Connected cannabis greenhouses


Most commonly found in commercial farming, polytunnels can also be bought in a smaller size more suitable for domestic uses. Their frame is curved and made of aluminum, with a stretch of a polythene sheet draped over it so it is a solid form.

Polytunnel to grow weed
Polytunnel to grow weed

This is one way of cutting the short-term costs of your greenhouse marijuana growing operation, as polytunnels are generally cheaper than other types of greenhouses. That being said, you will need to replace the polythene sheet once every three to five years.

Cold frames

Serving as one of the smaller and more temporary counterparts to the other types of greenhouses, cold frames are climate-controlled and inexpensive, often made at home by the grower. It is formed by using a cheap plastic or wooden structure that is then covered with clear plastic or glass.

Cold frames cannabis greenhouse
Cold frames greenhouse

If using glass, it should be thin plate glass; plastic should be thick so it doesn’t tear and can maintain the climate control. Cold frames are heated only by the sun — which makes them a worse choice for locations with unreliable or extreme weather.


If you add a heating system to a cold frame, it is now called a hotbed. Hotbeds, like cold frames, can be whatever size the grower wants them to be. Either it could be a large box that fits just one plant, or it could be a large structure that is big enough for the grower to walk and move around in.

If you are looking to have a large, climate-controlled structure, however, it is often better to choose one of the above, more permanent and reliable options instead.


The second thing you need to think about is what size greenhouse you would like to go for. Generally speaking, a good rule of thumb to remember is always to get a size of a greenhouse that is one size larger than the one you originally wanted to purchase.

Use a large greenhouse for growing more plants
Use a large greenhouse for growing more plants

It will help you have a little extra space to maneuver in, and it can be used to store equipment and other growing supplies if you have enough extra space.

Diffused or clear coverings or panels

Another aspect to consider when purchasing your greenhouse is whether to get one with diffused or semi-diffused coverings or panels or if you should opt for clear panels instead. It is usually a good idea to choose diffused or at least semi-diffused, despite what you might think is common sense.

Clear paneling allows more direct sunlight to hit your plants, a fact that is of particular importance in their earliest and most vulnerable stages of life. However, it will also keep your greenhouse a bit warmer than diffused paneling.

Semi-diffused greenhouse

Still, it is better to choose diffused or semi-diffused. This is because light that is being diffused is less likely to be competed for amongst the plants when they are older, and will keep any hot spots from starting to develop within your greenhouse. It will help even out the light that is hitting your plants, thus encouraging even growth, and will help your yield have a higher average yield.

Don’t forget: ventilation in the greenhouse

One of the toughest aspects of greenhouse marijuana growing is keeping the temperature at a steady and healthy level. This is especially true for those who have never done any type of greenhouse growing before, as the temperature is completely different from an indoor marijuana grow setup or an outdoor grow area.

The key is to keep your greenhouse warm when the weather is cool, and cooler when the weather is too warm. When you are deciding on a greenhouse, you should, therefore, think long and hard about ventilation. Essentially there need to be vents in the glazing if you want to keep a healthy growing environment for your marijuana plants.

Ventilation is very important in your greenhouse
Ventilation is very important in your greenhouse

Measure the vents and take the combined area of all of them. If this is not equal or greater than one-fifth of the area of the greenhouse floor, you are going to need to get more vents.

It is very important to maintain the entering and extraction of air in your greenhouse, or else your plants will be absolutely overheated during the hot days. An ideal greenhouse would include vents at the top (for air to leave the greenhouse) as well as at the bottom of the structure (for air to enter the greenhouse from outside).

You can have manually operated vents as well as automatic vent openers, the latter of which will provide you with a better growing experience. It is a relatively simple device with wax inside of it that expands in the heat and shrinks in the cold.

This causes the vent to open and close according to the appropriate temperatures. It will let you rest assured that your greenhouse will remain the proper temperature, even without you running back and forth to open and close all the vents.

Exhaust fans are also a possibility for certain types of greenhouses, allowing for an added layer of heat defense.

Know how to perfectly time your harvest so you can maximize your yield. Download our free mini harvesting guide

Choosing the right greenhouse location

There are plenty of environmental aspects you should consider when deciding where to place your greenhouse. In an optimum environment, your greenhouse will sit in a place that allows your plants to be hit with between five and seven hours of direct sunlight every day.

This is best achieved by facing the greenhouse southwards. Generally speaking, more direct sunlight equals a higher yield, so think about this part carefully.

Choosing the right greenhouse location
Choosing the right greenhouse location

Additionally, direct sunlight as early as possible in the morning has an added benefit: it helps prevent mold from developing. In the morning, dew can easily get trapped in your marijuana plants’ buds, causing a buildup and then the formation of mold over the course of several days or weeks.

If you have direct sunlight early in the morning, however, it will help keep these moisture levels down to a minimum — but of course, this needs to be combined with proper greenhouse ventilation.

Growing marijuana in a greenhouse: the basics

Now,  the actual growing part of the greenhouse marijuana setup. You will need to choose an appropriate strain, (depending on your location and climate), gather your top quality soil, and your setup is complete.

If you live in the Northern Hemisphere, your seeds will need to be sown in April. This allows them to be moved to your greenhouse by the middle of May. Begin growing them indoors with a propagation light, and move them outside for several hours per day to help get them used to direct sunlight.

Pick the best strains for growing in your greenhouse

This works similarly to a person tanning in preparation for a sunny vacation, or a mountaineer doing small, high-altitude hikes in preparation for climbing a mountain with minimal negative impact.

You can expect your plants to be in their vegetation stage throughout May and June, and will start entering the flowering phase after the longest day of the year has passed. This is because the sunlight will decrease every day, and when the plant “notices” this it begins to flower in an attempt to fertilize and produce seeds.

You can expect your marijuana plants to flower for eight or twelve weeks (unless you have applied a method of lengthening or shortening one of the lifecycle phases). In other words, the harvest time will roll around between the end of September or the beginning of October and the beginning of November.

Accounting for the weather

If you have a climate similar to England (less sunlight, more rain), then you may want to look into buying autoflowering marijuana seeds rather than regular photoperiod ones. In case you are not already familiar with autoflowering plants, they are the type that begins flowering after a certain amount of time has passed rather than once the light conditions change in a certain way.

Autoflowering marijuana plants for climates like these are particularly useful when grown in a greenhouse. Simply choose a time when the weather is warm enough, grow them for 60 or 90 days (depending on the variety you purchased), and rest assured that they will flower properly. That being said, you can expect smaller plants. But of course, with a tricky climate like that, you couldn’t expect monster buds in the end anyway.

Growing autoflower in greenhouse
Growing autoflower in greenhouse

An additional benefit of growing autoflowering marijuana plants in a greenhouse is that, due to their shorter life cycle, you could actually get in more than one harvest during a growing season. If timed correctly, you could harvest once mid-summer and once a the normal harvest season — or perhaps you are particularly ambitious and want to try for three harvests. In this way, your greater number of harvests can make up for the smaller plants and yield.

Adding extra lighting

Greenhouse lighting is considered any kind of lighting that comes from a source other than the sun. Generally speaking, this lighting is going to look similar to an indoor grow room setup. Your greenhouse may or may not need supplemental lighting, so it is important to understand the potential reasons for installing it.

First of all, extra lighting can prove useful if you need to have a longer period of sunlight for certain plants (i.e. seedlings or clones), or to keep a group of plants from flowering quite yet when the natural sunlight has gone down to a short enough time that it would naturally flower otherwise.

If you are adding extra lighting due to the former, you will also need to be able to create a partition between the plants you want to give the extra light to and the plants that are continuing with the natural sunlight growth.

Extra grow lights in greenhouse
Extra grow lights in greenhouse

Another reason to add extra lighting is if you are growing marijuana plants during the off-season when the natural light (such as the short winter sunlight) will not be adequate to complete a growing cycle. The more growing cycles you can get out of a year and a greenhouse, the more harvests you will get. And that, of course, means that your pricey investments (including the cost of the extra lights, not to mention the greenhouse itself) will pay off in a shorter amount of time.

If you want to add lighting to your greenhouse setup, you should try hanging HID lights over your marijuana plants. When the sunlight has dropped below 10 hours per day, begin using the HID lights so that your marijuana plants can get their 12 total hours of light per day.

Because you are growing in a greenhouse, you are doing the more economical and efficient method of growing during the winter. This is because you are utilizing whatever sun does exist in the winter, and that means keeping your lights powered down for longer amounts of time every day. The less you use your lamps, the lower your energy costs (and bulb replacement costs) are going to be. Using that logic, it’s hard to understand why more people aren’t growing marijuana in greenhouses throughout the winter.

FAQ Growing marijuana in a greenhouse

Can you use a greenhouse in the winter?

Greenhouses can withstand winter temperatures down to zero outside while not freezing inside, providing a place to keep your plants away from winter damage. Besides sunshine, there are also a variety of methods that you can use to keep your crops warm enough to harvest well in the cold weather.

Does my greenhouse need ventilation?

Your greenhouse needs ventilation to allow fresh air to move in. It is one of the most important components of a successful greenhouse. Without proper ventilation, the greenhouses and their plants become prone to a lot of problems. There are many reasons to use ventilation — Aside from keeping the greenhouse from getting too hot, it helps replenish carbon dioxide and remove moisture. Also, proper ventilation prevents pest infestation and promotes essential pollination within the greenhouse.

How do you keep a greenhouse warm without electricity?

There are many ways to heat a greenhouse without electricity. Aside from taking advantage of the sun and using solar panels, natural thermal masses such as water barrels or dark stones, compost, paraffin heaters, and even chickens can also be used.

Thanks for reading. Please leave comments or questions below and don’t forget to download my free grow bible. For any grow related question please visit the marijuana support page.

We want you to be successful in your marijuana grow journey! Choose the best marijuana seeds from our seed shop so you’re in for a great start.


Avatar for Robert Bergman

Mr Robert Bergman PhD


Robert Bergman is an Amsterdam-based marijuana grow expert who has years of experience from small grows to massive operations ... See profile

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62 comments on “Growing marijuana in a greenhouse”

  1. I want go get a greenhouse but I want to use a grow tent kit inside it that has all the extras that I will need such as vent, fan, light , order control etc. My question is can the grow tent survive in the greenhouse

  2. I want to veg under light and hothouse to flower can you give me some tips your seed choices ect everything you feel I might need to know I’ve got over a hundred seeds from you guys already an love your products thanks
    ,regards Jimma

  3. I soo’ beds a greehouse. On im65 yrs have tried and tried to grow a good plant. I have prescription for marijuana but $10 a day is beyond my reach. Love your advise and in going to try again. You have given me hope.

  4. Thx for info got good idee what to do I’m in south Africa and now I know what my problem was not enough ventilation plants overheating thx

  5. just bought a small green house for a couple plants thanks and ill be getting some seed soon if i have the proper temp can i grow in the winter?

  6. What about building a small tube geo thermal system to warn and cool a greenhouse? I have seen them in videos with 4” tubes that direct the air by having wired a thermostat to tun on and off tube fans.
    When greenhouse is too hot the fan sucking up from a pipe In the ground pushes cold air into the greenhouse.

  7. So, we have been successful growing in our greenhouse and now that they 3 plants are growing we need to know how to take care of them…… female vs male and trimming, if any….etc. They are growing pretty tall. Any advice or direction to an article or a YouTube would be helpful. Please and thank you.

  8. Robert is it possible on auto plants to employ us lights on the plants using a light rail the last 2 weeks of flower and boost the thc by as much as 28%

  9. Hi, I am setting up a 10×12 greenhouse in zone 5b. Can I leave the protective white film on the poly wall and roof panels? I am interested in privacy and sunlight control. thank you!

  10. For two plants. try a Migro 100. I use the 200W version with a six-plant DWC with a 600 x 1200mm grow tent.

  11. Hey Robert, tha you so much for your spe Marijuana Growing Information ! I read your whole ar about gro marijuana in defere cli.
    I am pla to move in Big Island of Hawaii nect next couple of Years .
    And would like to kmow anout growing Marijuana in Big Island of Hawaii, David from Alaska !

  12. Hey Robert, tha you so much for your spe Marijuana Growing Information ! I read your whole ar about gro marijuana in defere cli.
    I am pla to move in Big Island of Hawaii nect next couple of Years .
    And would like to kmow anout growing Marijuana in Big Island of Hawaii, David from Alaska !

  13. Great article on greenhouse for me at this time more tips on closet growing such as optimum LED wattage for two plants

  14. I lives in jamaica wanted to do some green house farming in marijuana ii wish y co be here to educate me more of the tec and get some huge turnover

  15. ol’Gerbs, It all depends on yout amount of daylight versus night. Too much darkness will cause autos to grow smaller due to early flowering. Personally; I would grow feminized for a much larger yield. Autos may be OK during the longest days of you year.

  16. Thanx. most interesting. i am building a 3mx3m greenhouse. i intend to grow Autoflowering all year long (plant a pair of seeds every month) do you believe that to be possible?
    pS. i live in johannesburg sA.

  17. This article says to not re-use dirt. That’s an expensive waste. Old dirt is still dirt. You just add some compost, some bone meal, a LITTLE blood meal, a little calcium, and some organic 3-3-3, worm castings, rice hulls. mix it in a tub or a tarp on the ground and you’ve got great growing ahead. Check the net for recipies. Will save you lots of dollars, and lugging heavy bags around.

  18. Hi
    I’m from australia I’ve just stated to build a greenhouse i already brought my seeds off ILGM im hopping to start growing in argust . The information i just read was very interesting and helpful thanks ILGM
    Cheers Les

  19. james staples,

    I advise you to go into our seed shop and read about the characteristics of each strain in order to decide which best suits you and the climate in Fla. That is the best way to decide. I also advise that you compost chickenshit before adding it to your plants. Fresh manure of any kind is too hot for plants and can harm them.

    On another note; you should start heater when the tmeps get below 50 f because, that is when cell damage starts to occur.

    Happy growing 🙂

  20. helo Robert…got a small farm deep in the woods with no one near on the Florida panhandle. Have built a small 12′ x 12′ greenhouse to grow some weed for myself/wife and sickly friend. We average maybe 10 hours of daylight and have cold spells occasionally. I have a heater that fends off the cold that I use when it’s below 40 degrees. At this time there are 6 babies growing that were planted in pots Nov. 1st that seem to be doing well. The seeds were not bought but came from some Mexican I’ve grown here outdoors. There’s room for a few more plants and I’m hoping you can tell me what seeds to buy for here that would be best. I’ve put a quart +/- of chickenshit into each of the containers also………James

  21. I’ve been growing marijuana Outdoors for the past 12 years I live in Massachusetts where weed finally became legal recreationally last year before then it was legal only medically so this year I decided to build a greenhouse I’ve been in the construction trade my whole life so built I chose to build it myself the structure is used to build is 20 x 20 with a 12 pitch meaning a 45-degree roof instead of having to deal with opening up the existing ground around the structure I chose to firstbuild a 20 x 20 raised bed garden that is 18 in in depth I achieved this by using 6 X 6 pressure treated beams stacked one on top of another and then drilled every six feet and the five foot piece of rebar sunk into the ground all the way around the 20×20. Area and then filled that box with my own super soil that I’ve refined over the years I chose to use clear polycarbonate Roofing and instead of closing in the walls I chose to use chain link fencing because I that the plants get stronger when they are blown around by the winds that we get and that comes in handy come flowering time when the branches getting weighed down the bud load this year I’m growing Super Skunk which I purchased from ILMG this past March I germinated seeds late March germinating seeds indoors and which went into the greenhouse early in May I planted the total of 7 because in Massachusetts you’re allowed to grow up to six plants for personal use and the plants are growing at such a high rate that I’m starting to worry they might grow bigger van the height that I have before purchasing the super skunk strain I did some research into plant height and the super skunk strain normally averages around 6 feet in some cases a little bigger my plants at this moment are getting close to being 9 ft tall with a circumference at least eight feet we still have around 6 or 8 weeks of vegetation before flowering starts and at the rate they have been growing they could get as big as 14 foot tall is my estimation my question is has anyone known the super skunk strain to ever get this big I’m very interested to see what the final result is and if all my hard work will pay off in the end let me know what you guys think if anyone needs or is interested in how I built my Greenhouse just let me know

  22. Marcel,

    As a commercial greenhouse grower, I can tell you that we prefer 6mil 4 year poly. We use a double poly system in order to somewhat climatize the house. If you have climate control, you should use 1 layer of 4 year 6mil UV plastic, and underneath that use a 6mil 4 year IR poly.

    If you have no climate control and only worry about heat; You can stick with cheap 6 mil poly, or at least place the UV 6 mil over your house to protect against harmful UV rays and sun scald.

    Happy growing 🙂

  23. I am doing a greenhouse grow in southern California currently but using 6mil clear plastic, should I invest in something else? I was also considering LED lights over HID, opinions on that?

  24. Ken,

    I t would be hard to address all your questions in this blog format. I suggest you join our forum and post a tropic. tag me @latewood for more help. Our members will probably chime in immediately. I will beed a link to the starter kit in question.

    Happy growing 🙂

  25. You should cut 1 opening on each gable end. On one end put in a small exhaust fan on the other put in a wire mesh screen. If you can place a sponge type material over the mesh and let your hose moisten the sponge every hour or so. You can do this with a water timer. The pulling of air over the wet mesh will lower the temp in the house substantially more than 2 degrees

  26. I have been looking for an article on greenhouses and here it is! I am not a big grower it’s just me so a large scale thing would be way to big. I got a mini greenhouse and I am so totally impressed. The girls are always toasty and warm. If it’s a warm day I will take them outside for a day of sun, then put them back in the evening. We just had a freeze and I worried all night, got up and there they were in their steamy little jungle none the worse for wear!

  27. Hello ILGM Team.
    I understand that in any growing environment, genetics and soil are two of the most important components. Im’ pleased to tell you in an article I read recently ILGM seeds were rated in the top 5. And I love the concept of auto flower. I live in Nova Scotia Canada and have 3 16′ x 50′ greenhouses at my disposal this year. I like auto flower for the reason it’s not so much light schedule involved. But would you not agree, one should get bigger yields from a auto flower in a green house than in a basement? I guess I’m getting to what do you recommend for that space, it is a diffused canopy. 1. do you recommend auto flower in this instance? 2. in that space allotted, give me a conservative number of plants I could grow in that space times three. 3. Your auto flower full complete kit of white widow, is that enough nutrients in the package to grow all 20 seeds? Thanks and will be purchasing soon,

  28. Just a random question. I was 2 days away from harvesting, flush my plants and noticed a small section of white powdery mold. I quickly removed the infected area and harvested straight away. Everything looks good while it hangs answer drys. Is there anything I’m missing or did I do the right thing and catch it in time?

  29. Lynn,

    That is a vague question, of sorts. Do I assume you are outdoors? You can gorw Sativa from start to finish in a 12/12 photo period. Fro more guidance, come see us here:

  30. Good read ……I am 50 yrs old, a first time grower and I have built a small green house 4’x4’x7′ just big enough for one or two plants. My vents are more than 1/5 of the flooring you recommended but will that be a problem even If i have coverings for them? Also what recommendations would you have for pest control with the vents being left open? Thank you

  31. TS,

    I would have to say; A Carbon Filter system, and companion plants that would help mask the odor. Happy growing. – I❤️GM

  32. What is the best way to get rid of potent smells in a polytunnels 4’x4′ green house with 6 plants?

  33. MEME,







  34. I’m interested in the greenhouse effect and would like more information about the size and widths. I f you can send me some prices.

  35. Commenting on this board, because I own a garden center. We are going out of business and have 25 green houses of various sizes for sale. In addition we have potting machines, irrigation systems, and everything else you may need. We are located in Wisconsin, but looking to bundle and sell things cheap if you are interested in getting your operation going. Email me for more information. [email protected]

  36. Kirk,

    By placing 50-60% shade cloyh over and around your hobby house; You can lower temps 15-20 degrees.

  37. I am not a fan of LED lighting, mostly due to the cost. I can set up an entire grow room with AC,for less a real good LED. We all use HID-(MH or HPS) lamps

  38. I know people out there that grow with LED lights. More and more people I know, especially growers with big indoor gardens, are incorporating LED lights into their gardens, or are going LED altogether.

  39. Kirk,

    Did you really think that you could close in plants in a greenhouse in 110f heat?

    Greenhouse manufacturers do have this solved as commercials growers grow inside greenhouse. We use what is called a “cool” wall”. You can find it at any major greenhouse company. Even commercial growers do not expect to grow between June and September. The summer is used to tear down and clean the greenhouse for the coming year. Greenhouses are meant to produce in the Fall to the beginning of Summer, a time when the majority of conventional growing is finished. Maybe you should do a little research on greenhouse growing. 🙂

    Happy growing everyone, lw

  40. Mr.Aaron Burdex Sr.,

    I am sorry Aaron. You will need to do research on builders and codee in your particular area. Most greenhouses can be bought and build by the owner with 1-2 helps. It is basically a big erector set. Once you get an idea of what you asre going to do; I suggest you join our free support forum at

  41. I bought a 6x8x8 Secure Grow greenhouse, and like all of the opaque-reinforced plastic sheeting greenhouses, none of the gables are removable. The “vent socks” that are installed in the gables are for vent fans, but a 435 cfm blower will only lower the temp about 2-degrees From 110- to 107. There’s no support from the manufacturer’s except to tell you that, “You’re the first person to ever complain about trapped heat”.
    So, I’m making 3-cuts in the gable fabric’s to drop the gable fabric down like a door. The I’ll have to install wire mesh over the open gables to keep the “security” aspect of the greenhouse intact. Bottom line, is that none of these reinforced poly-sheet green houses are cool enough to grow plants. Period. You’ll have to cut the gable material out, or wait for a responsible greenhouse manufacturer to solve the problem with new engineering that also involves the “sun” and the “heat” that the “sun” produces in a “greenhouse”.
    Start over manufacturers – and do it right.

  42. Hello, I live in the south west of Australia,ILGM site is just awesome,although I have been growing many years Iam always reading new information every day like I said just awesome.keep up the good work. Mark.

  43. Thank you for this network. Presently I own property in Atoka,Caddo,and Grady County Oklahoma.. Please reccomend builders, irrigation, and any logistics company’s in Oklahoma. Legalization of Medical M.J. will be on the ballot this year.Thanks.