If you’ve never attempted outdoor cannabis cultivation, you might not understand why it’s worth the painstaking effort of prepping your plants for the harsh outside environment.
But when you see monster plants growing the size of trees, with each one yielding several pounds or more of dried buds, you’ll quickly understand why so many growers opt to cultivate their cannabis outdoors.
One of the first questions growers ask is…
When should I transplant cannabis outdoors?
And the simple answer is, it depends.
For starters, you want to consider your local climate.
If you transplant your cannabis before all chances of frost have ended for the cold-weather season, your plants could be injured or killed by the extreme cold.
And just as important, you need to consider…
- The Photoperiod of Your Location
- Starting Plants To Maximize Summer Sun For Outdoor Cannabis Growing
- Hardening Off Cannabis Plants
- Hardening Cannabis Plants in Heat and Humidity
- Best Advanced Nutrients Products For Hardening & Transplanting Cannabis Outdoors
- Your Timing, Transplanting, and Hardening Recap
The Photoperiod of Your Location
Take into account your garden’s distance from the equator, and as a consequence, length of day.
Commonly known as the photoperiod, this is what triggers reproductive hormonal processes in your plants. If you put plants outdoors too early or too late, they won’t develop properly.
In the more southerly parts of the Northern Hemisphere, including the US southwest and southeast, the longest days of the year are rarely more than 14.5 hours, including dawn and twilight, when no direct sun hits your plants.
By contrast, in the Pacific Northwest, Seattle’s total maximal summer day length can be 16 hours, while that of Anchorage in Alaska can be as long as 20 hours in peak summer.
If you’re growing photoperiod cannabis plants outdoors, these day lengths aren’t always ideal.
Photoperiod cannabis thrives with 18 hours of grow-phase light and 12 hours of light during bloom phase.
If they only get 14 to 15 hours or less of light per day in grow phase, development will slow and the plants could begin flowering. The closer they get to having only 12 hours of light per day, the more likely it is that they’ll start flowering.
Let’s say you live in Southern California, Texas, or Florida, and want to grow outdoor cannabis this year. If you start your plants indoors and move them outside in the month of May, they’ll get about 13 hours of light per day. With many strains (especially those bred for more northerly outdoor locations), start flowering as soon as they move outdoors. Instead of gaining height like photoperiod grow-phase plants do under 18 hours of indoor light, the plants only gain their bloom-phase stretch, and often end up growing to be smaller than average.
To make matters worse, inadequate light hours at the wrong time triggers stress responses that can cause hermaphroditism, mutations and underwhelmingly small yields of low-potency buds.
So you can see why it’s so important to consider your location when growing cannabis outdoors.
Starting Plants To Maximize Summer Sun For Outdoor Cannabis Growing
The easiest and most foolproof practice for transplanting photoperiod cannabis plants outdoors is to start them indoors under 18 hours of light in mid-May. This way ,they’ve had four to five weeks in the indoor grow phase by the time the summer solstice rolls around in June.
When cultivating strains that you’re going to finish indoors, make sure the grow phase stays between three and five weeks.
Any longer and you’ll end up with massive plants too wide and tall for an indoor setting, unless your ceilings are upward of 12 feet high. Your plants may also run out of root space if you let them linger in grow phase too long.
When you’re planning to transplant cannabis outdoors, you can take full advantage of the boundless space available.
Unless you have a reason to grow short outdoor plants due to security concerns of living in a neighborhood with high population density, you want them to grow as big as possible.
For this reason, you can keep them in the grow phase indoors for far longer than you would if they grown completely indoors, putting them in very large pots and trimming them to create dense branching. Many cultivators will wait until the summer solstice to plant them in their outdoor setting.
Within a couple of months of the summer solstice, almost everywhere in North America (except for Alaska), total hours of light per day will be dropping to 12 to 14 hours per day. By that time, most strains will have started flowering and will finish by the end of November at the latest.
Hardening Off Cannabis Plants
No discussion of transitioning cannabis plants outdoors is complete without the important topic of hardening off cannabis plants so they’ll survive the move.
Most indoor grow lights lack the intensity and spectrum of the sun, especially that of the spring and summer sun. In fact, healthy seedlings happily growing indoors under 18 hours of HID or LED grow-light radiation can turn severely damaged when abruptly transported outdoors in full sun for even just a couple of hours a day.
To avoid that shock and damage, consider placing seedlings under shade that comes from trees or from a shade house, which is a miniature greenhouse enclosure with material that filters sunlight enough to protect young plants that aren’t yet accustomed to sunlight.
After a few days spent outdoors in shade and after the plants have at least five or more sets of true leaves, start moving them into full direct sun for short periods of time, but not during the peak sun intensity hours of 11 a.m. to 2 p.m.
Instead give them full sun during early morning or late afternoon, so they can gradually adjust to the strength of its rays.
Within one to four weeks using that strategy, and depending on the strain, your plants will be able to handle full and direct sunlight all day.
Hardening Cannabis Plants in Heat and Humidity
Hardening off cannabis also means getting plants that started indoors adjusted to outdoor heat and humidity levels.
The best way to protect your roots is by planting directly into the ground so that your plants’ root mass is covered by soil.
Plants grown in pots aboveground experience an unnatural condition of having the sun hit the roots almost directly, save for the thin layer of material the pot is made of. Black pots sitting aboveground in full sun are deadly for roots.
Many growers choose 100- to 400-gallon cloth pots that sit aboveground that are sturdy, reliable, and reusable.
Plus, cloth pots give you the added benefit of automatic root pruning and oxygenating airflow that hard-shell pots can’t provide. Now that we’ve discussed strategies to stop your root zone from frying, there’s still heat and humidity to deal with.
Let’s take a look at two opposite — but equally important — environmental conditions.
Growing in Hot and Dry Climates
The likes of Southern California, Arizona, Utah, Nevada and Texas have low humidity, intense sun, soil that is mostly sandy, and high temperatures. When it comes to outdoor cannabis cultivation, this is a recipe for plant disaster, unless you sufficiently water frequently enough.
The low humidity can suck the life right out of the plants during temperature spikes because they can’t draw water fast enough from the root zone to stay alive — or there might not even be enough water to draw.
Growing in Warm and Humid Climates
Conversely, in hot conditions that are also humid, the problems are the opposite. The root zone may become waterlogged if it’s been raining a lot, which decreases root function. Heavy, humid air deters leaf transpiration, which is a valuable function of the plants’ metabolic nutrient transport and photosynthesis. If you’ve done your research ahead of time and chosen strains best suited for the climate conditions of your outdoor grow, your plants have a better chance of surviving.
In some cases, if you have the infrastructure to do so (and this would unlikely be the case when it comes to a remote guerrilla-style grow), you can set up misters that cool your plants by producing chilled aerosolized fog. This approach has the added benefit of giving you the opportunity to use aerosolized natural pest control and feedants that fuel and protect your plants.
Best Advanced Nutrients Products For Hardening & Transplanting Cannabis Outdoors
In all cases, outdoor growers should take advantage of plant armoring products such as B-52®, a vitamin B complex that helps plants fight stress, and Rhino Skin®, the only potassium silicate hydroponic formula made for cannabis. Rhino Skin helps plants build sturdier cell walls and resin glands, setting a sturdy foundation to hold heavy bud weight.
You can also use the bloom booster Tasty Terpenes™, which boasts a myriad of natural substances that strengthen and protect stressed plants. Using cool water to hydrate plants during the hottest weather is also a smart move.
Your Timing, Transplanting, and Hardening Recap
Here’s a quick recap of the tactics for successfully transplanting cannabis outdoors are:
- Start the plants so they’ve had sufficient grow-phase development before placing them outside near the longest day of the year, the summer solstice of June 21.
- Choose strains most suited for your outdoor climate, security conditions and photoperiod length.
- Harden plants by giving them gradual sun exposure and protected root zones.
- If possible ,alter the outdoor environment of your plants by using chilled mist and sufficient water in the root zone.
- Plant your roots directly into the ground or in white cloth pots to avoid root damage from radiant heat transferring into the root zone.
- Feed your plants B-52, Nirvana and Rhino Skin to give them nutrients they can use to fight stress and build stronger plant tissues.
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