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Cannabis growing in a greenhouse. 7 easy tips for a big home grown harvest


 Growing cannabis in a greenhouse or polytunnel is an easy way to become self sufficient in your cannabis needs, even if you only want to plant a small number of cannabis plants.  With a few basic rules and a few good quality cannabis seeds even a first time cannabis grower can get heavy harvests of top quality cannabis.  The greenhouse will protect the cannabis plants from the worst of the weather and allow you to grow monster cannabis plants which would be impossible to grow in a small indoor grow tent.  Whats more growing cannabis in a greenhouse or polytunnel is cheap and easy, you don’t need any experience, specialist equipment, lights or electricity supply.  

 shaman in greenhouse

Above, Dutch Passion Shaman gets too big for the greenhouse

Why choose a greenhouse?

A greenhouse protects your cannabis plants from the worst of the early and late season weather.  This allows the young cannabis seedlings the chance to establish themselves quickly, and take maximum advantage of the warm summer weather which will come later.  The greenhouse protects the maturing cannabis plants from torrential mid-summer storms which can sometimes damage outdoor crops in exposed locations.  The greenhouse also provides protection from the often cold and stormy autumn conditions which can damage the final harvest.  Temperatures inside a greenhouse or polytunnel are often a few degrees warmer than outdoors, allowing the cannabis plants to grow faster, larger and stronger.  

Above, AutoDurban Poison.  Automatics grow quickly and are easy to hide in the corner of a greenhouse

Expert Tips.  Greenhouse cannabis growing the easy way.


  • Clean the greenhouse at the start of the season.  Give the glass a wash and remove garden waste from inside the greenhouse.  The most successful greenhouse growers often produce a years supply of cannabis from an average family greenhouse, keep the greenhouse clean and it will provide great growing conditions for the cannabis plants.  Ensure that the greenhouse gets as much sunlight as possible

Above, Frisian Dew in a legal European greenhouse grow



  • Optimise the soil.  This can mean replacing all the soil with quality compost from the local garden centre.  Or you may just need to add some manure, organic fertilisers, bat guano etc.  In dry areas some people add water-absorbing crystals to the soil to allow the soil to hold more water than normal.  Many garden centres offer ‘Soil testing kits’ which allow you to determine soil quality, pH etc and will also suggest recommended soil improvers.  The most successful greenhouse cannabis growers know that a small amount of time spent optimising the soil conditions will encourage outstanding cannabis plants with heavy harvests of potent buds.



  • Make it difficult for neighbours to see the cannabis in the greenhouse.  You can do this with some garden fencing, some garden netting or a few well placed garden plants.  Some people prefer to ‘white wash’ the greenhouse with a white paint created to prevent greenhouses from over-heating in summer.  This is painted on the inside of the greenhouse at the start of the season, as well as protecting plants from the most intense summer heat the white-wash keeps the inside of your greenhouse totally private.  Another option is to plant some seeds of Frisian Duck, a Dutch Passion cannabis variety with spacial leaves bred to look nothing like traditional cannabis.


  • Choose whether you are planting in containers or directly into the ground.  Most greenhouse cannabis growers prefer to grow their cannabis directly in the soil, this allows unrestricted root growth and will allow you to grow massive cannabis plants which can be 2-3 metres high and just as wide.  These plants can often produce over 1 Kg of cannabis from a single plant.  However some cannabis growers prefer the flexibility of growing their plants on containers, this allows them to move the plants if required.  The biggest problem with growing in containers is the need to continually water/feed them.  Plants grown directly in the soil need hardly any attention, you can go away on a 2 week vacation and they will still be alive.  If you can, treat the plants to plenty of feed and water when its hot.  Cannabis is a plant that will grow well even when conditions are not great.  But if you are really wanting to get the best possible result then try to give the plants some feed and water when they need it most.  Many experienced greenhouse growers will add plant feed to the watering.  This will allow the plants extra minerals and nutrients to grow into the huge yielding cannabis plant that you have been dreaming about

Above.  Growing your own cannabis in a greenhouse.  Easy.


  • Protect the plants from slugs and snails.  Many greenhouse growers will use slug and snail pellets to protect the plants from attack.  Often copper rings (copper collars) around the base of the cannabis plant will help prevent your precious cannabis plants from being eaten by garden pests. 


  • Use autoflowering cannabis seeds to your advantage.  Many experienced greenhouse cannabis growers take advantage of the fast-growing auto varieties to produce multiple crops per year from their greenhouse.  Autofem varieties grow from seed to harvest in around 11 weeks, some greenhouse growers get 2-3 crops per year by using autos.  If you are doing this remember that autoflowering cannabis varieties do have their growth slowed down by cold weather.  If you have cold night time temperatures the plants can take an extra 2-3 weeks to finish.  Some greenhouse growers prefer to use automatic cannabis varieties alongside traditional photoperiod varieties in order to get a mid-summer harvest.  Most photoperiod cannabis varieties are ready to harvest around October in the northern hemisphere, or around April in the Southern Hemisphere.

Above, more Dutch Passion Frisian Dew in a mega greenhouse


  • Choose the best cannabis seeds you can get from a seed company you trust. Even the best cannabis seeds cost a few Euros/Dollars/Pounds each, the cost of them is insignificant when compared to the final harvest.  Dutch Passion have decades of experience with outdoor varieties which give exceptional results in a greenhouse.  Varieties like Frisian Dew, Frisian Duck, Passion #1, Durban Poison, Shaman, Hollands Hope, Forest Dream, Trance and Purple #1 are all well proven varieties .  Our range of autoflowering seeds are also well regarded and will also do extremely well in a greenhouse.  


Above, cannabis growing in a poytunnel is another easy way to grow

Millions of cannabis plants will be grown in greenhouses this year, and its easy to see why.  Its a simple way to grow your own medical or recreational cannabis, you don’t need to be experienced, you can grow 100% organically and the cannabis you grow will often be far superior quality to that which can be bought on the streets.  Its not too late to get a few cannabis seeds germinated this year for your greenhouse…..



Frisian Duck, with unusual shaped leaves, is a good cannabis variety to grow in a greenhouse next to the tomatoes





May 22nd 2015
Easy Indoor
Grow Guide

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Recent comments (4)

On 23 -05-2015 at 22:48 u Dominique van Gruisen wrote:
Well written article!

On 03 -09-2015 at 04:42 u Dj wrote:
i have a few question i need to ask you about out door weed i have ten growing right now in im lost in the timing of me grow but if i can link u some nice pics in you can tell me more about the plants

On 03 -05-2018 at 17:53 u Tracy latham wrote:
When my seeds arrive how do I plant them plz

On 04 -05-2018 at 10:03 u Eddy wrote:
Tracy, 3rd May. A good beginners guide is here https://www.dutch-passion.com/en/news-and-development/the-first-time-grower-greenhouses/ and here is an explanation to germinate your seeds https://www.dutch-passion.com/en/news-and-development/the-best-ways-to-germinate-cannabis-seeds/ good luck !

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Dutch Passion advise their customers to reassure themselves of local applicable laws and regulations before germination. Dutch Passion cannot be held responsible for the actions of those who act against laws and regulations that apply in their locality. Cannabis seeds should be kept as collectible souvenirs by anyone in an area where cultivation of cannabis is not legal.