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The First Time Grower.  A beginners guide to greenhouses


Each year more and more people grow their own weed, if you have never grown marijuana before then one of the easiest and cheapest ways to start is in a greenhouse.  No complicated equipment  is needed and even complete beginners will get great results with good seeds and a few basic rules. 

This weeks blog will describe the basic principles of how to grow top quality weed quickly and easily in a greenhouse/polytunnel.  Although there is a lot of detail that we could go into, we will stick to the basic points.

Greenhouses offer the plants an environment which is often warmer, safer and a little more controlled than outdoor growing.  They effectively give a longer growing season by protecting against the worst of the wind and cold.  Greenhouse heaters protect against early/late season cold nights and are a way of keeping greenhouses warm in cooler climates.  Paraffin heaters can also be used, but may lead to extra condensation.  If you can, get a greenhouse with ventilation pane’s to help circulate air and prevent overheating on the hottest days.  Greenhouses come in a wide range of sizes and prices, some garden centres offer cheap second-hand ones.  The lowest cost plastic-covered ‘tent-style’ greenhouses start at ~ 30 €uro’s.  A 3-pack of quality feminized seeds is just over €20 for varieties such as Frisian Dew, Passion #1, Durban Poison etc.  So it is not at all expensive to get yourself prepared to harvest a great stash of quality weed this year.  Mediterranean growers have a growing season sunny enough and long enough to grow the widest choice of strains and can get 3 AutoFem crops in a year.  Polytunnels are more or less the same principle as a greenhouse, and are also popular with cannabis growers.

Selecting your seeds
.  You have 2 initial choices, traditional feminized seeds that will be ready to harvest normally around October in the northern hemisphere.  Or you can grow AutoFem seeds which will be ready to harvest 70 days after the seed sprouts.  Both will give you great weed, but normally you might expect a bigger harvest from a traditional feminized variety.  There is plenty of information about AutoFem’s on our website, they even grow well in places as cool as northern Russia.  For many people AutoFem’s have made it possible to grow outdoors or in greenhouses for the first time, for these people AutoFem’s have been a dream come true.  We have been working with AutoFem’s for five years and any initial disappointments we had with them have been replaced with some really impressive results we are seeing now.  The hard part is deciding which particular variety to grow, but that is also the fun part.  You can try Indica’s, Sativa’s, legendary varieties, just enjoy them and build a collection of your favourites. 

Planting your seeds.
  Growers in cooler climates often germinate their seeds indoors to give them a good start.  Plants are at their most vulnerable when young.  But many growers in warmer countries will simply start them in the greenhouse.  Greenhouse growers fall into 2 main categories.  Some growers plant their seeds in plant pots and others will root their plants directly into the greenhouse soil.  Marijuana will grow well in either situation.  Plants grown in containers have the advantage that they can be moved if there are unwelcome visitors or bad weather, but they will need regular watering.  Plants grown in the soil obviously can’t be moved but will be OK left on their own if you are away for a week.  Plants grown in soil also have the potential to grow very large.  We have seen a few occasions when the cannabis plant has outgrown the greenhouse, it’s a nice problem to have I guess.

Shaman, top quality skunk/purple hybrid. Mainly sativa,  potent  and great growth potential.  Here the grower had to remove the greenhouse panel.  The soil quality and warm greenhouse allowed Shaman to thrive

Preparing the soil. The best growers take their soil quality very seriously.  Poor quality soil can be easily dug out and replaced with good quality compost from the garden centre.  Or it can be enriched by digging in plenty of manure and fertilizer (blood/fish/bone-meal, guano etc) a few months before the plants are planted in it.  Whether you are growing in containers or growing directly into the ground it is important to get a good quality soil for dramatic improvements in your results.  Many growers add 25%, or more, of material such as Perlite or coco-fibre to help aerate the soil.  The main beginner’s error is over-watering and over-feeding.  We have seen thousands of self-sufficient home growers get absolutely superb results on their first grow, and you can too.  Many of the specialist ‘ready-mix’ grow soils can seem expensive but give great results and are the most convenient option for the new grower looking for a hassle-free first grow.

Cleanliness.  Greenhouses should be given a good clean every year; this will help keep the free of pests and diseases which could affect the plant. 

.  Modern polycarbonate greenhouses have a frosted, opaque appearance, allowing your crop to be private.  But other plants can be grown alongside to provide camouflage.  Or greenhouse ‘whitewash’ can be used.  Serious marijuana growers often build their greenhouse deliberately in a sunny spot which has been designed to be completely private.  For best results position the greenhouse to get as much sunlight as possible.

Once your plant is ready to crop it is chopped down, dried and cured in sealable containers.  Greenhouse grown pot is great tasting, and if you get quality seeds then you are in for a treat.  Just look after the soil and water them when they need it, avoid overwatering.  Consider liquid feeds later in flowering, you can get good quality products from companies like Canna, Plant Magic and others you will find on the internet or at your local hydro store.  For those growing in containers it is easy to make up a feed and pour it into the plant container.  For plants that are rooted in the ground larger volumes of feed mixture may need adding to ensure it reaches the majority of the root system.

The seeds are just a few euro’s each and greenhouses can also be bought for affordable prices.  Once you have made that investment you will have a satisfying new hobby and all the free pot you want for your recreational or medical purposes.  So if you have never grown your own pot before, growing in a greenhouse is an easy and great way to start.  Good luck in 2012!

Dutch Joe

February 3rd 2012
Easy Indoor
Grow Guide

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Recent comments (28)

On 03 -02-2012 at 15:53 u Juanma wrote:
Hello People of Dutch Passion. Thanks for this interesting blog. Which variety do you recommend for greenhouses? Thank You!

On 04 -02-2012 at 19:19 u DP Tony wrote:
Hi Juanma, it depends where you live. Passion#1 is always good in a greenhouse, highly recommended

On 09 -02-2012 at 21:46 u Weeds wrote:
Hi Dutch Passion! Can you please advise a strain for Ireland (54-55N) ? Regular strains are nearly impossible to grow without mold. Can you suggest an Autofem strain? It has to be able to handle very cold conditions, grey skies and not need much attention (guerilla grow). Thanks!

On 10 -02-2012 at 11:17 u DP Tony wrote:
Hi weeds, your best bet would be frisian dew or an auto. Frisian is one of the best rated traditional strains. In terms of auto's, they should all be OK in the summer, they only need 70 of the sunniest and warmest days you can give her. Tundra has proven outdoor Passion #1 genetics in her and could be a good choice for you, but I think any og them would do well in june/july/august

On 16 -02-2012 at 11:10 u Peter wrote:
When should I start to germinate indoors the Dutch passion feminised seeds?

On 17 -02-2012 at 12:51 u Tony | Dutch Passion wrote:
Hi Peter, If you are planning to eventually plant them outdoors then you might want to get the seeds germinating about 3 weeks before you plan on putting them outside. This gives them a good start and ensures that they are strong when they eventually out outside

On 17 -02-2012 at 22:24 u Jeeves wrote:
proper outdoors??

On 21 -02-2012 at 17:51 u Thib wrote:
Hi Dutch passion, i've just buy think different seeds, how this plant grow in outdoor? Is this plant massive? 9 weeks really? Thank you!:)

On 26 -02-2012 at 22:24 u I wrote:
Hey dutch passion:) i want some advise about guerrilla grow at mediteranian climates. I don't know which months to plant and if possible germinate outdoors.the only thing I am sure for is to pick an autoflower variety..which would you suggest for high yields? Thanks alot

On 29 -02-2012 at 16:30 u Tony Dutch Passion wrote:
I - you asked about autoflowers in mediterranean regions. You could probably start them around April or May and get good results. Start them in small pots at home before planting outdoors, and prepare the final position with good quality compost. Any of the Dutch Passion AutoFem's will give you good results and it takes only 9-10 weeks before you can harvest

On 29 -02-2012 at 17:03 u Tony | Dutch Passion wrote:
Hi Tracey, The Think Different will do best with a sunny place to grow and reasonable temperatures. We would recommend preparing the soil properly with quality compost and light fertilizers. You didn't say which part of Canada you are growing them in, but choose a reliably warm and sunny 10 week period for them and you should be fine.

On 12 -07-2012 at 04:28 u LAMWteOBqY wrote:
just get a lot of 5 gallon butecks and paint them black then fill them with water and stack them along the walls of the greenhouse below the plant shelves. Will accomplish the same thing and give you heat all night when you need it by soaking up the heat when you have too much and releasing it at night when you need it.Save the doors for a cold frame for next spring and sell Vegetable plants.

On 11 -09-2012 at 17:07 u Baph wrote:
hi, i have a couple Shaman outside and they causing me great torment. Four days ago (07/09) about 60% of the hairs are brown and the next day after a big storm they are all gone. now (11/09) again more brown than white and still they seem ready to me. im in canada and i saw the first signs of bloom on 30/07, and by the way none of them have any purple in them. please help i dont want to lose any potency if they are really ready thank you, Baph

On 20 -01-2013 at 00:35 u Mark wrote:
Hi dutch-passion was thinking of doin greenhouse grow in ireland i havedone in house grow b 4 just want 2 know if i feed them the same way with nutrients as in house ? r wat do i do ? THANKS

On 08 -07-2013 at 22:04 u Stupiddogbot wrote:
hi there ive just put 3 blueberry in 10ltr air pots in my green house, there about 8inch tall atm, Im feeding them on canna a and b, is there any advise you can give me, im in uk,, and hoping for a good yield, but im a little afraid ive left the season too late,. (first wk in july) do you think they will grow to there full potential? cheers,. :)

On 04 -08-2013 at 12:59 u Dave Step wrote:
Hi,I live in central spain and am considering a polly tunnel to grow some weeed,any views on this ,temps,watering etc,,many thanks

On 21 -12-2013 at 07:48 u PharmerKaren wrote:
How big of a greenhouse would you recommend for 10 average-sized plants?

On 26 -12-2014 at 21:00 u Rasdread wrote:
I live in the southern hemisphere, and I am growing in a greenhouse. My plants have started to produce trichomes, but no buds are forming. Is it because it is still too early for them to flower? Will this affect the overall yield of the plant negatively?

On 26 -12-2016 at 23:44 u Timothy Vagi wrote:
New to growing. Just started in solo cups, about 3"tall. Should i put a clear solo cup on top to have a little greenhouse effect. Tim

On 06 -05-2017 at 04:12 u Jamie wrote:
Love this site!

On 31 -05-2017 at 10:03 u Mick wrote:
Hi I was given some seeds by a friend in the Gambia, I have no idea what strain etc they are but they are now 5 t high and have reached the roof of the greenhouse. should i trim the tops?

On 31 -05-2017 at 11:47 u Mick wrote:
Hi I was given some seeds by a friend in the Gambia, I have no idea what strain etc they are but they are now 5 t high and have reached the roof of the greenhouse. should i trim the tops?

On 01 -06-2017 at 10:26 u Eddy wrote:
Mick, 31st May 2017. Yes, if the plants are getting too tall you can chop them back or tie them down. Good luck

On 12 -01-2018 at 21:27 u Ladybug Bill wrote:
Given optimal greenhouse conditions to grow mega big legal trees,(in Canada) what would be the optimal subsoil strata? If I'm digging down 5 feet for frost why not dig out the lot & replace everything with the best, but what with?

On 15 -01-2018 at 14:18 u Eddy wrote:
Ladybug Bill. 12th Jan 2018. Probably there is no single answer to your question. Some growers put a layer of decaying organic matter at the lowest levels, this could be fish or a similar nutrient rich layer (manure etc). The rest should be good quality nutritious top soil, if possible with added blood/bone/fish meal. You can buy soil from a garden supplier, or make your own from composting. Good luck!

On 12 -04-2018 at 01:26 u Gavin wrote:
I’m looking for a seed recommendation for a first time greenhouse grower in Ireland and do you discreetly package the seeds if I was to arrange for them to come to me in work? Thanks

On 16 -04-2018 at 08:30 u Eddy wrote:
Gavin, 12th April 2018. Yes, seeds arrive in a plain bubble envelope with no reference to Dutch Passion. Order away!

On 12 -08-2018 at 09:37 u Paul wrote:
best fertiiser for polytunne grows

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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.