Outdoor growing during winter can be done! Some areas in Southern California have weather that will permit this.
I did this not only as a test, but as a necessity. Store bought cannabis can expensive, especially in San Diego!
Taxes of about 24% make it near impossible for many people to afford cannabis oil (aka Rick Simpson oil), especially for those that need it instead of costly prescriptions.
The weather app on my phone shows it can get as low as 32oF, but my digital never went below 36oF. So my plants were never exposed to weather colder than 36oF
Below are examples of how the flowers look during winter.
I harvested the CBD God Bud right after the image was taken. The plant could have used another couple weeks of growing. I was out of oil and didn't want to pay the huge taxes!
Lemon walker could also use more flowering time outside. It was raining when I took the picture (rain drops cover the flower). Again, I am out of oil, so I harvested this plant early.
I have noticed that the trichomes turn white much quicker than the normal growing season; usually a couple weeks before the flowers are done growing. The bud size is much smaller, but the trichomes tend to grow more on the leaves in this weather as well. This may be due to the lack of light during winter.
The plants will need to be started indoors under 18 or 24 hour lights. Bigger plants will tolerate the cold weather much better than small plants. Shorter phenotypes should be at least 18 inches tall before being placed outside in the cold. Tall Phenotypes may need to be 2-3 feet before going outside for flowering.
Cold Weather Problems
There are many problems trying to grow outside during winter. One of the first things to consider is when to put the plants outside. I watch my weather app, and wait for until there are a few nights that do not go below 40oF. I have not tried it colder than that. I wanted to give them a few days to acclimate to the cold before any freezing or frost-causing weather occurs.
Nights that go below 40oF, or when frost or freeze warnings show on the weather apps; the plant will need to be protected at night. I bring them under a covered patio close to the house when it gets dark. Plants left out in the open are more affected by frost than in a covered areas.
Expect to see the pistils to be wilted down. This image shows minor wilt, but they can get much worse than that. Pistils are really only needed for pollinating, and the flowers/trichomes will continue to grow even though the pistils are basically gone.
This Green Crack (by Humboldt Seed Organization) has drooped down after the cold night. This is typical during the first 2-3 weeks of being outside in the cold. After the slightly drooping plant has been out in the sunlight; and may take 6-8 hours for it to fully perk back up.
Fan leaves will get a little damaged as well. This Alpine OG (by Moxie) got a little cold damage, but that was the worst of it.
We need to consider a few things about protecting the roots. They are also prone to freezing damage. Mycorrhizae will help make the roots stronger. I use this once a week for the first 4 weeks while they are still under vegetative growth indoors.
The roots are also prone to cold damage if the soil gets too dried out. Don't over water it ether, saturated soil can also lead to more problems such as:
Pest problems during the winter are overall less of a problem, but there are a few that have messed with my plants in the cold weather.
Snails and slugs will eat small younger plants, but tend not to eat the flowering plants. They will leave a huge amounts of slime all over the plants which is difficult to wash off. Using a snail bait like Sluggo close by the plants will keep them away.
Aphids are less of a problem in winter, but I do get a few after a rain. They will need to be picked off, dead aphids can cause bud rot or mold.
Yellow sticky traps like this are very useful, especially indoors. Fungus gnats lay eggs in the soil, and the larvae eat the roots. Fan leaf damage is seen if the roots are too damaged. Gnats tend to be worse indoors. Severe infestations may need an insecticide.
This white area in the center of the leaf looks like possible powdery mildew. This is a huge risk while growing in cold and rainy weather. Be sure to inspect the plants often. This can be taken care of if its in an early stage like this.
The leaf image above is the same infected leaf. I sprayed Neem oil on the plant at night, and the next day the powdery mildew was gone. Neem oil is also useful for aphids, white flies, spider mites, and much more. Be sure not to spray the plants for 1 week before harvesting.
Be sure to also remove any leaves that touch any of the flowers. The moisture build up will also contribute to mold.
The last problem I have had to deal with is very strong winds. This is not isolated to winter, Southern California gets crazy winds during the Santa Ana's as well. The plants will have a harder time recovering during the winter.
We can stabilize the plants better by prepping them during vegetative growth. I use 5 gallon grow bags, but only fill it about half way after the small clones have been transplanted into the grow bag. While the plants are growing, remove the side branches to make the plant grow taller. Leave enough space to add more soil. Burying the main stem in more soil will help stabilize the plants. (see the video on the top of this web page for a visual)
Removing the fan leaves, especially on the top of the plant will reduce the drag the plants get from windy conditions.
Growing outside in winter can be difficult, but it can be done. I have not grown anything below 36oF, so I don't know how much colder the plants can tolerate.