Can I grow cannabis outdoors in the UK?

by dope smoker on August 1, 2011

Yes you can!

An amazing amount of cannabis does grow without problem outside in the UK! And as we know weed that has been grown in the sun is always going to be better than weed grown using artificial lighting.

Guerilla growing (growing weed in the ‘wild’) is quite popular – costs are low and it can be done almost anywhere. The south of England is better, but plenty of fine weed has been grown outside in the north of England, Scotland and even Wales.

If you have a nice private back garden, all the better.

Strains proven to grow well in the UK are:

Passion Number One from Dutch Passion –  a simple to grow indica that thrives outside in the UK. The dutch have been apparently growing this outdoors since the 1980’s – in their cold climate.

Early Skunk from Sensi Seeds – an easy to grow very high yielding indica variety with body stone – ideal for beginners.

Frisian Dew also from Dutch Passion – This strain is half indica half sativa and again will thrive outside in the UK.

Purple Maroc from Female Seeds –  A sativa that produces lots of resin and finishes in mid July, does well in the UK.

Biddy Early from Serious Seeds –   Award winning early finishing plant.


Related: The Ultimate Guide to Growing Autoflowering Cannabis

Plants are normally started outside in in April – although recent arctic conditions would suggest this isn’t sensible. May perhaps! You could also start plants inside, as they don’t need big lights to start with – a simple florescent light can be used to start them.

Flowering generally begins in August or September, depending on the strain and can take several weeks at the least. Some plants will not finish until October – some strains such as Purple Maroc or autoflowering strains will finish much earlier, lessening the chances of mold affecting the buds, or hitting a frost.

Never plant seeds directly into the soil. It’s much better to grow the plant in a controlled environment for 4-8 weeks before slowly introducing them to an outdoor space by increasing their exposure by an hour each day before replanting or leaving them outside permanently.

Consider also that plants grown in pots will generally not grow as big as ones grown in the ground, so if you have to use pots consider using Smart Pots or similar. I have just tested these and found them to be amazing, indoors and outdoors.  They are what’s used in many big US grows though you’ll find them cheaper than on amazon. They allow for air pruning of the roots. I will never use a normal pot again after personally seeing the results of plants grown in these pots. They are known as aeration containers and the bigger the better. have the big ones at better prices. If you want to grow a kilo outdoors, this is the way to go. More info here.

J Arthur Bowers Multi-Purpose Compost with added John Innes‘ is a highly recommended compost.  Perlite is often added to compost to help it hold moisture.

Plant Magic Plus is also getting good reports.

The plants will need different types of fertilisers when they are in their different stages, flowering requires different nutrients to the initial vegetative stage. Some plants are also heavier feeders than others. You can buy organic fertilisers for this Bat shit (Guano) is also popular for the flowering period. Avoid chemical fertilisers. You may also want to investigate using molasses – specifically black strap molasses.  Some people only use molasses. You just put half a tablespoon into a small pot, add boiling water, let it dissolve a bit, stir in then add to your watering can or whatever.

Always use much smaller measures than suggested by the manufacturer. Often following manufacturers instructions leads to over feeding and burning. Do be very careful it’s an easy mistake to make. It may be better at first not to use any fertilisers as it’s so easy to cock it up – especially if you are using a soil with fertilisers already in it. Fish Mix is a great all round fertiliser that feeds the plant and is difficult to over use.

Another thing to bear in mind is that you can get a plant quite a long way on with just a fluorescent kitchen type light, then gradually introduce it outside for flowering (controlling the darkness ensuring 12 hours of total darkness each night) so this way it is possible to kind of do an indoor/outdoor grow and grow during winter. The (initial) vegetative stage is fine under a kitchen light. I did this recently with some Northern Lights and it worked fine.

Flowering requires powerful lights or the sun. This way you can grow whenever you like, but you do end up looking after the plants a lot, putting them to bed each night.

If you can’t be bothered with all that you can still start plants outdoors when it is not April. You could plant something in say August  and all that would happen is that it would go straight into flower if there is enough darkness. In effect seeds planted when we have long nights (12 hours dark or more) will ‘autoflower’ and should be fine as long as they don’t get too cold. Less than 15 degrees seems to be when they will start to become unhappy. You can protect plants from the cold with cloches, cold frames, a greenhouse or by bringing them inside for cold nights. Growing out of season yields are obviously not as big as normal, but certainly can be larger than some autoflowering plants. For many people the smaller size of plants grown like this can also be an advantage. Remember you can also ‘tie down’ plants that are getting too big, or ‘top’ them to keep them under a certain height. This normally leads to higher yields.

Autoflowering plants are becoming popular in the UK, with the possibility of two grow seasons in one summer.

There is a new class of Autos known as ‘Super Autos’. ‘Chaze‘ is particulaly good as an outdoor plant in the UK that yields significantly more than your normal  auto.  Magnums are also amazing for yield and high. Autoflowering plants can also be topped up.  You can keep an autoflower successfully under 24 hour light – many people have – so if the weather is crap you could bring an auto inside at night for more light – which would mean buying a light etc.

The water that you use to water your plants is hugely important, particularly if you are growing in pots. In the earth this tends to be less of an issue. Some people PH their water, some don’t. I did for a while and then noticed the plants seemed to love the rainwater which was around 8 as well – the same as tap.  Tap water in the UK contains calcium and other elements that can be good for weed. Outdoors you should be OK without messing around with this too much but if you notice discolouration on your plants it may be worth checking the ph of your water – Around 6 is good.  Lower the PH of water using ‘PH down’ if necessary.

UPDATE 10.12.2015

Since I first wrote this article, more autoflowering strains have come out, and I have discovered others which I must include:

Maxi Haze – These plants are very high yielding outdoors, up to 200g per plant. From Grassomatic, an expert Spanish company. Well worth a look.

Frisian Dew Auto – This is Dutch Passion’s autoflowering version of their very best outdoor plant. Ideal for the UK climate.

Super Skunk Automatic - The classic from Sensi in autoflowering format.

Magnum Autoflowering is a kick arse autoflowering variety. The highest yielding auto I have personally grown. Given plenty of room this plant really delivers. Reports of 250g+ if grown in the ground. The smoke is really nice – an upbeat, euphoric high that last as well as any photoperiod variety. Highly recommended.

Jack 47 Auto – this plant literally explodes. Difficult to get less than 2oz per plant I have found. High is good though I prefer Magnum overall.

Dinafem Cheese XXL Auto – High yielding cheese variety you can’t help but love. Outdoors it does great.

  • I’m growing PJs and they’ve sucked so far. Really bad genetics in the batch of seeds I got. Out of 10 seeds, only 3 have made it past the seedling stage and today the first of them showed sex – male! So all my hopes are pinned on the remaining two, which are now growing quite nicely on my patio (I move them to mini greenhouse overnight). A lot of the seedlings grew weirdly in one way or another but click here to see the strangest one:

    Love the blog, by the way.

  • That’s a buggar. I got 8/10 germinated with 7/10 female. Starting to show their purple bits slowly.

  • First time grower

    i found 3 seeds in my bag of herb, planted and all 3 grew !! my son knocked 1 over and it died :( the other 2 are now growing in the garden, and looking better by the day ! i smoke a fair bit of hydro grown stuff, im looking forward to the o’natural when it finally buds ;) i’ll keep you informed. Love the blog also :)

    First time grower

  • Best of luck with that! Nothing like buds grown in the sun..

  • Tidybo1

    Hi I have done the same thing and I am a first timer, how are yrs coming along and wot will you do with them when it starts to get cold?? I’m not sure how and when mine will flower they are about 350mm tall and have 7 blades on them

  • Bring them in at night when then the low drops below around 10 degrees. If you bring them in to a lit area you’ll be able to control when they flower. They need 12 hours of complete darkness to flower – if you ensure they are only getting 10 then they wont flower, they will just keep growing until you change the light. If you don’t do any of this they should start flowering once they’re big enough to – and that point is different for each plant.

  • Tidybo1

    So a quick update I flowered one of my plants by putting a bin over it to keep it dark so it’s getting 12/12 and it seems to be flowering quite nicely and the rest I have just left in the garden and have started flowering naturally that all seem to be coming on ok I just hope the weather stays ok and I can harvest before the frost comes this garden growing would be a lot easier out of the uk but more of an experiment this yr to see wot happens

  • Ah glad to hear you’re making progress. There’s nothing like experience. 

  • mrhaze

    the 12 hours rule is a general guide that covers all strains so that given 12 hours of darkness any strain will flower no matter what part of the globe it originated 
    many indica strains only need 9.5 to 10 hours of darkness to reach the critical darkness point and trigger flowering :) 

  • That’s interesting do you happen to know which ones?

  • JS

    when can i plant my passion 1 outside in the uk please and when can i plant my white berry outside ??? any advice would be great thanks

  • Not yet! I’d wait until the low is steadily above 9 or 10 degrees (a min/max thermometer is useful for this). And when they go out just a bit at a time each day is recommended so they can adjust properly.

  • Anonymous

    Hi cant tell you how glad i am to come across your piece above on outdoor growing, I have spent the last year trying to digest indoor growing just from bits here and there in different books. Indoor growing is great , nothing better than producing enough to keep you going for the next year in a three months , but with the hazzards of light heat/increase low energy usage/ odour control ya tend to spend the whole process with cross fingers. odour and lighting heat is ya major risk of gettin ya collar felt.

    Also with energy costs rising and the equiptment needed for indoor growing it still costs ya a few quid to run a complete process.

    Ive ordered the dutch passion , I dont wanna use soil, in the process of my research i come up with my own design of oxypot 6 pot system , which i now works absolutly amazing, that much so that im selling these kits i produce myself .

    Do you see any problems in me using this system outdoors that will have affect on the sucess of the plants,   and when do you suggest i put them out side, is there a paticular month or is it just when temp is above 9 degrees ? and i take it im best to get these as big as i can, is that on  continuous light untill outside growing day comences ?? or contoled reduction of timed light slowly braught down to the hours  daylight hours when there starting their outside growing

    And finally have you heard of size and yield increase from heat controled oxypot nutrient feeding  ?? , and also  the understanding that roots are lets say the  nerve centre of the plant, and thats where the growing can be manipulated  im thinking if im using the oxypot system outdoors with a heated oxygenated nutrient water tank would the plant above the roots be able to handle being out in cooler temperatures than 9deg

    Thankz .

  • Luckylorenzo123

    hi , i nead same advise, out side grow in the uk, can it be done, whats the best, plant to plant

  • I’m afraid I can’t answer individual growing questions, I will probably be wrong and it will take up too much time. Will update articles as I learn more. You could try the forums there are plenty of professional UK growers there with a lot more experience than me

  • Anonneh

    Why does no one ever give a good time to first put your plants out? but only the flowering dates? seriously its crazy hard to find some one stating a good time to start going outside. That would go rele well in this little guide .

  • I have made a small update to the article. Good luck.

  • Wow! this is such a great news that we can grow cannabis in outside of the UK. These are some valuable tips for growing cannabis in a better way. I am going to apply all these techniques for growing cannabis in my garden.

  • Nathaniel Wilky

    i am germinating 5 seed as wee speak and i was wondering if i planted them outside howlong will it take them to grow and can they grow at this time of year as its nippy out side

  • chris

    I got 2 bubba kush plants in my polytunnel in my garden they are now starting to smell strong 3 ft tall and looks like starting to flower, how can I contain the smell

  • Kelly Howell

    Hi guys… I need help… My partner was growing2 plants in the kitchen he then got sent to prison. Not know what to do with them as they got bigger I planted them in big pots out in my garden with my peas and
    My issue is there now about 4 foot tall and starting to Bud I think…. But I have no idea. I can’t ask him cos he is locked up. Please can someone tell me if there is anywhere I can sell the whole plant as I don’t want to kill it. But I don’t know what to do.

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