Growing Marijuana outdoors is one of the best pleasures in life. The local climate plays a big part along with many other variables, below is a list of key points and tips to consider when growing Marijuana outdoors.
The location where you are growing marijuana seeds is a big player in the outcome of your yields. We have a clear overview on our website of which zone is most suitable for each outdoor strain and auto flowering strain. There are certain strains that are better suited for hot sunny climates and some that will perform just as well in colder climates like The Netherlands.
Tip: Each strain is clearly displayed with an A/B/C rating. Look at the flowering times and determine if your country can provide the sunlight that the strain needs to ripen and really hit its true potential.
Indica varieties will begin to show signs of pre-flowering and stretching earlier than varieties that are more Sativa dominant. Plants need certain light cycles to induce the hormone production that triggers flowering. A plant can be kept in a vegetative state as long as it receives more than 12 hours of light. In nature the daylight hours are at their longest during the months of June and July. As August gets closer, many varieties will display a burst of white pistil pre flowers whilst stretching, indicating that the blooming cycle has been induced. Sativa varieties can take longer to show initial signs of flowering and also naturally take longer to bloom and ripen. If you are growing Marijuana outdoors in a tropical environment that receives a lot of light, both Indica and Sativa varieties will start flowering around August. Indica varieties will finish their flowering cycle by mid September. Sativa varieties will take 12 weeks to finish flowering and fully ripen, these can usually be harvested towards the end of October.
Tip: A plant must receive at least 14 hours of daylight to grow, 12 hours to induce flowering and 9 hours to ripen. Plants produce hormones based on the environment they are in so respond to a diminishing photoperiod.
In the northern hemisphere, the sun will always set in the south, so if you can grow Marijuana outdoors in a south facing location you can ensure your plants receive the most light possible. The hottest part of the day will be from 12pm until 3pm, after this point you want the plant to receive as much light as it can. In the evening the light will be less intense than throughout the day, however an extra few hours of sunlight every day will make a huge difference over the upcoming months.
Tips: Before you place your pots for the remainder of the growing period, work out the difference in how the sun moves between April and August (in the northern hemisphere). By following the sun this way your plants will receive the most sunlight possible. In many countries there is publicly available data by government weather institutes that can help you figure this out (NOAA.gov for USA for instance). Once your pots are in place avoid moving them around and aim to keep the growing Marijuana plant in only one space.
If you are germinating Cannabis seeds directly into the soil or growing medium and begin to grow directly in the sun, this can be the perfect start in many ways. Firstly the soil is gently heated to an optimum temperature to promote root development. Another reason is that the amount of lumens the sun produces is the highest you can achieve. Therefore as long as the actual temperatures are not too cold or too hot, seedlings can be grown under direct sunshine in any of the zones indicated on our website.
Tips: Leaving your plants in the hot sun all day can sometimes have downsides. Growing Marijuana outdoors in hot, dry conditions like in Spain and elsewhere around the Mediterranean can make for huge plants, but these climates can also cause many heat issues when the plants are younger. Attempt to give the plants shade during the hottest part of the day in situations like this. There is still plenty of light available and it will allow the plant to transpire as it would like and the soil temperature to cool down to around 20 °C.
The temperature of the environment is a huge factor in root growth, plant growth, vigour and overall yield. When growing Marijuana indoors, the objective is to replicate the outdoor environment indoors. Therefore your daytime temperatures during the growing phase should be 22-25 °C and 17-19 °C at night.
Growing Marijuana outdoors can be more difficult depending on where you live. Temperature can strongly affect root growth if it is too high or too low. Avoid temperatures below 10 °C if you are in a colder climate, especially if the plant has just been watered. In hot climates, temperatures over 30 °C can cause serious stress and humidity issues and slow down plant growth. High temperatures can also encourage excess transpiration and can cause the plant to adapt to these dry conditions by slowing down its metabolism.
Tips: Invest in devices which will tell you the air temperature, soil temperature and humidity. Knowing how hot or cold your roots are getting will be very useful to eliminate any problems that may occur. A heating mat can go a long way to counter cold surfaces and cold roots. Other solutions are to cover the top of the soil with large white stones. This will facilitate heat absorption in the soil and improves the air to flow around the roots whilst protecting the soil from algae build up. If the soil is too cold, heating from the bottom can be also done with a heating cable coiled up on the floor under the pot, this replicates the effect of a heating mat. Adding more air holes to your pots works well against overheating and does a good job of ensuring the soil stays cool. When your soil is too warm covering it up with plastic paint bucket lids works well as these can sit on top of the soil without burning the medium. Plants need water from both their roots and the air, so understanding when too much or too little is available allows the growing Marijuana plants to be as healthy and happy as possible. For more information on watering you Cannabis plants please check out our guide on watering your Cannabis plants.
As spring approaches, it is a good idea to start your plants off indoors for the first week rather than planting directly outside. This is to give them the best possible start and to ensure they are protected from any insects or bugs that may want to harm the plant in this early stage. When growing Marijuana outdoors, there is nothing worse than discovering your freshly germinated seedlings have been eaten overnight. A good way to ensure that the young plants stay protected is to place large plastic cups over them during the night. This way you can sleep knowing that during this important time in the plant's life, there are no unnecessary setbacks caused by nature.
Tips: Using a simple fluorescent or even H.P.S. light will give your seedlings the perfect start. This will ensure a constant temperature and light source for the starting stage. Often plants can have a challenging start when planted directly outside.
If you are growing Marijuana in pots then selecting the final pot size can usually determine the final size of the plant once flowering. A good way to think about this is the bigger the pots and root ball size, the bigger the yield. It is a good idea to prepare a final medium you will transplant into for the flowering stage. Ensuring excellent drainage is a big part of forming healthy roots that can breathe inside the medium. Below is a list of all the potential growth media that can be incorporated when growing Marijuana outdoors.
Tips: Using soil is effective but adding perlite, vermiculite and coco for drainage works great. Worm castings are a rich source of nitrogen and humates and bat guano is very high in Phosphorus and Potassium.
Growing Marijuana outdoors means you will not be able to completely control the environment, which can cause your plants to grow into shapes and sizes that are not desirable for your current grow and may affect yield. Fortunately there are numerous methods to modify the appearance, growth pattern and yield of the plant, a list of these plant training techniques is provided below:
L.S.T: When tying down the plant, it is a great idea to use metal wire to anchor the plants down into the ground. The closer to the ground the plant is, the more room you have to play with. Many plants that grow taller should be pinned back down and spread out to grow openly.
Super Cropping: A good time to supercrop and snap the plant stem, is at the same time as the tying or pinning. Alternatively you can tie the plant to a support like a piece of bamboo or fence. Once the plant has a support, you can snap the stem and allow it to recover and form a thick knuckle over the breaking point of the stem.
Topping: This means reducing the plant height and promoting more lateral growth. The best time to pinch and top the plant is during the vegging phase. When growing Marijuana outdoors, this will refer to the stage from April to July.
Tip: Try to use all of the techniques listed above on a plant over a long period of time. Avoid these techniques once plants are flowering as this can have adverse effects on the yield. A plant grown with these techniques will have the support and framework to produce large yields. These different forms of training can be combined to optimize yields, one method that incorporates multiple training techniques is mainlining. For more information on mainlining please read our detailed blog article.
Something that is often overlooked when growing Marijuana outdoors as well as indoors is managing the root ball, air pruning is the way that existing roots grow new roots and create a large root mass. When a root detects there is low humidity, it will split similar to a plant forming a new shoot after topping. Root pruning is done naturally but using felt pots or any pot with a lot of holes in the side can really make a difference in terms of growing a heavy feeding plant. The roots will naturally be pruned as long as there is fresh air circulating in and around the pots.
Tip: A simple way to air prune roots is to take a plant pot and add a hole every inch of the pot. Air pruning should be done throughout the grow, from the start of the grow until the final pot.
Now that you have discovered the many techniques that can be used when growing Marijuana outdoors, the other big player is which genetics you will be growing. This is the part where you need to calculate which strains can finish flowering before the weather turns bad during autumn. When growing Marijuana outdoors, short flowering Indica strains will be best suited for people who have shorter summers whereas almost any strain can bide well in the generous climate around the Mediterranean.
Tip: Spend time to research the genetics of the strains you want to grow. Outdoor growing is a long term commitment and it is best to know everything about a strain before spending time and money, certainly considering the added risk factors compared to growing indoors. Everything you need is only a click away and it could not be easier to start your venture of growing Marijuana outdoors. Because Spliff Seeds is a Dutch company, we take pride in the fact that we have bred many different lines of Cannabis that are suitable to grow outdoors even in our suboptimal climate.
This is a Medical Kush x Dutch Automatic cross which has very strong resistance to mould and bud rot. Similar to the Medical Kush, this very reliable variety will smell pungent and have a powerful skunk and kush aroma. Expect yields of frosty kush buds in 10 weeks and a low profile plant of 60-80 cm tall. Yields of 40-60g per plant can be achieved with this medium difficulty strain in all three climate zones.
Gold Rush Outdoor is our top seller and is a cross of Purple Power x Polm Gold x Afghan. Similar to the Polm Gold, this variety is a rock hard producer that is ready to harvest between the start and the middle of September. This is one of the earliest flowering varieties we have made thanks to the notoriously early flowering Purple Power, expect the best traits from Polm Gold and Purple Power to come through. Gold Rush Outdoor grows to a height of 2m and has an earthy diesel aroma, it can be harvested early to mid September. Very high resistance to cold, mould and damp environments. Outdoor yields from this medium difficulty Sativa are 350-450g per plant with great results in zone: A/B/C. For more information read our growing marijuana guide.