How to grow cannabis in summer after a late start. Read our full guide on germinating cannabis seeds in July and growing cannabis in the summer. Growing marijuana outdoors produces a higher yield, gives your buds a unique flavor, and it's far less energy-intensive than using indoor grow lights. Outdoor cannabis plants can grow up to tall and produce of quality weed per plant–and… Dear Dan, I want to plant seeds directly in my outside location instead of germinating them inside. Is this unwise and can you give me any advice? –
Can I start seeds in July and harvest in October?
Yes you can! Although most growers would, perhaps correctly, point out that a July start is a little late if you are aiming for maximum yield. Many outdoor growers would hope to germinate their cannabis seeds a couple of months earlier than July in order to give their plants the best chance of reaching their true genetic potential.
That said, you can germinate your seeds in July and still get a good quality harvest. If you are interested in knowing more about how to grow cannabis in summer, even after a late start, we have some great tips and info.
“When is it too late to plant cannabis for summer?” is a common question from outdoor growers. The answer depends partly on your local climate and the type of cannabis seeds you are hoping to grow.
With some expert advice on the best type of seeds for your situation (autoflower seeds vs feminised seeds), growing cannabis in summer is very straightforward. Lots of people get great results and so can you!
Pros and cons of starting cannabis seeds in summer
The summer solstice (longest day) is June 21st (Northern Hemisphere) and December 21st (Southern Hemisphere). Regarding the summer solstice, cannabis is generally recommended to be planted outdoors before the solstice. This remains good advice, but for many growers it is also possible to plant your cannabis seeds after the summer solstice and still get a harvest in the autumn/fall.
Advantages of seeding cannabis in July for northern Hemisphere growers (or January for Southern Hemisphere growers):
- The warm summer weather has already arrived, your growing season is already here!
- No risk of losing your seedlings due to an unexpected late frost.
- Guerrilla growers will already have lots of wild plants growing rapidly, perfect to hide your cannabis plants behind!
- There is still time left for a harvest, even if it’s a slightly shorter remaining grow season.
- You can look forward to seeing your plants thrive outdoors immediately in the mid summer conditions.
The disadvantages of starting cannabis seeds in July also need consideration:
- In general, your soil will be drier for your seedlings. Root growth is more difficult in dry soil so watering needs to be more frequent while the plants are young and more vulnerable to the heat.
- Black plant containers can become extremely hot in direct sunlight. In the worst cases this will bake the root ball, dehydrating the soil and the plant. This can kill the plant within a day or two. Keep plant containers in the shade, perhaps wrapped in a reflective white cover. Avoid putting plant containers on hot tiled surfaces.
- Plants germinated late in the season will likely be smaller than they would have been with an earlier start. This will mean smaller yields.
- Young plants may not cope well with direct midday sun in the hottest part of summer. Consider living them some shelter/shade from the sun between midday until around 4-5pm in extreme conditions. Perhaps under a tarpaulin or similar.
- With a short vegetative period the root network of your plants won’t be as deep or extensive as it would have been with a long vegetative period. This means you will need to give extra consideration to watering your plant more regularly.
How to grow cannabis outdoors in summer
Look for a private area where you can plant your cannabis seeds and allow them to develop without risk of discovery. Outdoor cannabis growers often have several guerrilla grow locations, just in case one of them is discovered. Unused field corners, waste urban land, river banks, hillsides etc all make great potential locations.
If local soil quality is poor you can supplement it with supermarket soil, well-rotted manure, general fertiliser etc. You can easily make a cannabis organic summer soil mix by blending some quality compost with some slow release organic nutrients such as those from BioTabs. Or you could add your own ingredients to enrich local soil e.g. bone/fish/blood meal, seaweed, worm castings, bat guano etc. If you can grow cannabis on your own land, balcony or patio that makes it easier to monitor plant development.
“How often should you water outdoor cannabis plants during summer” is another common question. In times of hot weather it is normal to water both at morning and night. If you use a larger plant container the roots have a larger available root space of moist grow medium which will allow your plant to manage for longer periods with watering.
If you root your plant directly into the moist earth (without a container) it allows you more latitude, you may need to water less frequently since the roots can source their own water unless in severe drought. When growing in containers you can assess the remaining moisture levels by lifting the container (if possible) to assess the weight. Or you may prefer to use a hygrometer in your plant container to measure moisture level in the root zone.
Growers in extremely hot regions often ask whether will cannabis grow outdoors in summer, in the south with hot temperatures. Unless temperatures are regularly hitting 35-40ºC for prolonged periods then you should be able to get the plants through to harvest.
Planning your grow after a late outdoor season start
If you are aiming to plant cannabis seeds in the summer, most growers aim to get their plants outdoors as soon as the weather is suitable. For growers in northern Europe that can mean waiting until the last frost has passed.
- At Dutch latitudes, or similar, growers often put their plants outdoors around late May.
- At southern Mediterranean latitudes you might place your seedlings outdoors in March.
Obviously, an earlier start allows your photoperiod feminised outdoor strains a longer period of vegetative growth and therefore a larger final result. But that doesn’t mean that you can’t start your feminised seeds in July, and accept a somewhat smaller final result.
Autoflowering cannabis seeds are generally recognised as being the fastest, simplest and easiest way to grow cannabis. They can grow from seed to harvest in around 3 months.
Having a spare pack of autoflower seeds in the fridge is always a good idea for outdoor growers contemplating a last-minute summer grow. Check out the Dutch Passion Seed Sale for the latest special offers.
Choosing the best suited seeds for a summer cannabis grow
If you’re planting your cannabis seeds in June or July you need fast growing outdoor strains. Autoflower seeds are particularly recommended for outdoor growers thinking of a late start.
If you plant your auto seeds in June (or early July) you should have a crop around late September or early October. If you can pre-grow your auto seeds indoors for a couple of weeks (under 24 hours of daily light) before planting them out that will speed up your plant development and final size even more.
Choose the faster autoflower strains if you are up against the clock with a late season grow. Some longer blooming autos (e.g. Auto Ultimate, Auto Glueberry) can take a few weeks longer than average, such autoflower strains are probably best avoided if you are on a tight schedule.
Recommended fast/tough auto strains include Auto Mazar, Auto Blueberry and Auto Blackberry Kush. All will do well outdoors and are fast enough to deliver a harvest even if planted outdoors late in the year.
Photoperiod feminised strains are also a good choice for a late season outdoor grow. Dependable strains such as Frisian Dew, Think Fast and Durban Poison are all recommended.
However, it should be noted that photoperiod feminised outdoor cannabis seeds germinated in July will only have around a month of vegetative growth before starting bloom. This will have inevitable consequences on size and yield. Expect a small/medium sized result rather than a monster outdoor plant.
Watering and feeding schedule for outdoor cannabis in summer
Watering requirements when growing in the middle of summer can be high. Growers in Southern Europe may see heatwave temperatures in excess of 30ºC for long stretches. This can mean watering your plant at morning and night. Some growers leave some water/nutrient solution in a tray underneath their plant container.
This can help the plant from completely drying out. Some growers remove their plant from direct sunlight in the middle of the day, or place the plant in shade to protect it from the worst of the midday heat.
Growers in cooler climates (e.g. Northern UK, Scandinavia) may still face hot temperatures though rarely as high and prolonged as those faced by growers with more Mediterranean climates. Watering and feeding schedules for growers in these regions will vary significantly.
Whether you are growing in a hot or a cool climate you will need to find the right watering schedule for your conditions. Even in the same grow location, outdoor conditions can vary significantly from one year to the next.
Flowering cannabis plants seeded in July
Autoflower seeds germinated in July (Northern Hemisphere) will probably start bloom during August and finish flowering in late September or early October. Many outdoor growers enjoy the often compact, squat and bushy nature of growing autoflowers outdoors. Autos can be easier to hide than 3-4 metre tall photoperiod monsters!
Autoflowering cannabis seeds also do very well in a greenhouse or polytunnel. As with feminised strains, a greenhouse helps protect your plants from the worst of the late-season weather. It’s something to consider if you have significant concerns about the October weather at your grow location/latitude.
Feminised strains planted in July will have a month (or less) before they show signs of bloom. That means it is more realistic to have modest expectations of the final plant size and yield. But even with a July start, you can still harvest some good quality buds in autumn/fall.
Cooling cannabis plants during summer
How to shade cannabis plants in summer? On the hottest days you may want to keep your plants out of the midday sun, if only for a few hours. Cooling cannabis plants during summer isn’t easy.
If grown in a container, move your plant to a shaded area. Some growers create shade for their plants with a tarpaulin, but this isn’t always easy when growing outdoors.
Avoid placing your plants on a hot tiled surface which can greatly increase temperatures in the root zone. Likewise, avoid black plant containers which will heat up in the sun and cook the root ball.
Even when a cannabis plant is badly dehydrated it can often recover after a few hours of cool conditions and plenty of water. After all, people have been growing cannabis in hot climates successfully for thousands of years.
The real issues happen if your plant is in mid bloom and hits a heatwave. Recovering from heat stress and dehydration is easier in vegetative growth then it is in bloom.
Professional growers do have a few options. Increasing CO2 content, for example in a greenhouse, allows plants to tolerate higher temperatures. Some greenhouse growers with blackout blinds equipped on their greenhouse have an easy way to shade their plants if temperatures reach dangerous levels.
Harvesting cannabis plants seeded in July
If all goes well, and it often does, your cannabis plants started in July will be ready to harvest around October. If the late season weather is poor, you may consider creating some kind of shelter/cover to keep torrential rain off your buds. With a little bit of luck you may see your plants grow steadily and supply you with some bonus winter buds.
For those growing in reasonable climates, it is also possible to get an early season auto harvest as well as a late season auto harvest. The following grow review from Denmark shows how even Scandinavian growers can get two successive autoflower harvests each year
Grow cannabis from seed to harvest in 3 months!
Even if you have left it late to plant your cannabis seeds this year you can still get a decent harvest with a short 3-4 month summer grow. Feminised seeds, and perhaps especially autoflower seeds, are great options for growing cannabis in summer even with a late start. If you are thinking about a late season outdoor grow remember it’s easy, secured and fast to buy cannabis seeds online!
How to Grow Cannabis Outdoors
This article was co-authored by Jamie Corroon, ND, MPH. Dr. Jamie Corroon, ND, MPH is the founder and Medical Director of the Center for Medical Cannabis Education. Dr. Corroon is a licensed Naturopathic Doctor and clinical researcher. In addition to clinical practice, Dr. Corroon advises dietary supplement and cannabis companies regarding science, regulation, and product development. He is well published in the peer-review literature, with recent publications that investigate the clinical and public health implications of the broadening acceptance of cannabis in society. He earned a Masters in Public Health (MPH) in Epidemiology from San Diego State University. He also earned a Doctor of Naturopathic Medicine degree from Bastyr University, subsequently completed two years of residency at the Bastyr Center for Natural Health, and is a former adjunct professor at Bastyr University California.
There are 20 references cited in this article, which can be found at the bottom of the page.
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Growing marijuana outdoors produces a higher yield, gives your buds a unique flavor, and it’s far less energy-intensive than using indoor grow lights. Outdoor cannabis plants can grow up to 14 feet (4.3 m) tall and produce 4–8 pounds (1.8–3.6 kg) of quality weed per plant–and it’s not rocket science to grow cannabis outdoors. We’ve put together a comprehensive guide to tell you everything you need to know about picking a location, germinating marijuana seeds, and maintaining your crop to get the highest possible cannabis yield.
Grow Q&A: Starting Pot Seeds Outdoors
It’s ideal to start your outdoor crop indoors but if for some reason it’s impossible, you absolutely can plant directly in your chosen location. Keep in mind that unless you’re using feminized seeds, you’ll still have to return at least once to remove the males before they mature. Also, remember that young seedlings can be easily damaged by exposure to the elements early on in life. On the plus side, any that survive are sure to be hardy and well acclimated to their location.
Plant more seeds that you expect to grow out fully and water them in well. Sounds to me like you can’t regularly visit your chosen location so be sure to bring water and organic fertilizer whenever you find the opportunity (and especially if there’s been no rain for over a week).
If you choose to start them indoors, the benefits are plenty. Seedlings can be started while it’s still winter outside and vegetated into nice-sized bushes before it’s warm enough for them to go out. Oscillating fans will recreate the wind to strengthen the young shoots and prepare them for life in the wild. Stronger plants mean bigger yields.