The summer sun is the biggest and most inexpensive grow light in the solar system, but outdoor and indoor growers know that summer is a time of opportunity and peril.
Although cannabis plants can survive in almost any kind of climate, they don’t thrive in every kind of climate.
Researchers have found that cannabis grows best in moderate temperatures, between 72 and 82?F (22-28?C). Cannabis leaves are the plant’s “lungs.” They need a moderate range of temperature and humidity so they can take in and give out vapors and gasses. If humidity is above 50%, the moisture in the air inhibits the leaf’s ability to transpire, which can adversely affect growth rates and floral development.
High temperatures, even in the absence of high humidity, can have the same effect, although not for exactly the same reasons. Although it is obvious that high temperatures and powerful lighting can cause a plant to struggle to maintain its necessary fluid percentages, those conditions also cause it to need more nutrients, and to direct energy and nutrients away from floral production and vigor. The plant instead has to run through a lot of water and nutrients just to defend itself against the heat and radiation.
Indoor growers can control such factors much easier than outdoor growers can. Many indoor gardeners install or maintain a room air conditioner in their grow room. The air conditioner functions as a dehumidifier to keep humidity levels low, and is also useful for sucking stale air out of the room and replacing it with fresh air.
Marijuana plants have respiratory needs that inversely mirror human needs. We need oxygen, which is what they produce, and they breathe in carbon dioxide (CO2), which is what comes out of our mouths. The symbiotic breathing relationship between plants and people is yet another reason why growing marijuana is a life-affirming occupation.
To increase the affirmation, indoor growers stimulate vigor and yield by adding CO2 to their room environments. This augmentation must be carefully evaluated. CO2 is usually procured by purchasing or renting CO2 tanks and regulators. It can also be manufactured in grow rooms by CO2 production devices that are relatively portable, affordable and easy to use.
CO2 augmentation can result in faster crop cycles and increased yield, especially when combined with warmer-than-ideal room temperatures, extra nutrients, and extra water.
The downside of CO2 augmentation, other than the cost and bulk of the equipment needed to provide it, is that some plants stretch when they get such augmentation, adding height and internode distance rather than compact, floral-oriented growth.
Mid-summer outdoor growing concerns are part of the continuum that began several weeks or months earlier.
A successful expert grower who calls himself “Hopper” lives in the American Southeast. He shared some of his grow procedures with us when we told him we were doing a grow article that would first hit the magazine stores during the hottest part of summer.
Hopper has a 40-acre wooded parcel on a remote road in a county that doesn’t spend much time on marijuana eradication. There are a few helicopter patrols in late summer, but Hopper has become so confident that he grows about 40 plants in containers in open sun every year, and he has not been busted so far.
Every year in March, Hopper starts to make choices from his collection of specialty seeds. Some of them come from Marc Emery Direct; others are Hopper’s own creations that date back nearly 15 years. He is most proud of an Oaxacan-Indica cross and a Nigerian strain. In recent years he has imported DJ Short genetics, as well as classic Dutch strains and even Ruderalis genetics, into his genetic menu.
Hopper plants his seeds in Pro-Mix, which he favors because of its texture, cleanliness, aeration, and nutrient value. Pro-Mix comes in bales, which Hopper opens and reworks to free up compacted particles.
The soil becomes silky as he mixes; it pours like water. He fills one gallon buckets with the soil mix, making sure to pack the soil tightly ? but not too tight. Then he soaks the soil and inserts one seed in a half-inch deep hole in each bucket. He covers the buckets with chicken cages, to prevent critters from overturning them or nibbling sprouts.
This planting is done in March before all danger of frost has passed, but Hopper says marijuana seeds are resilient in soil and will sprout when they are ready to sprout. Some of his seeds, especially ones with genetics that originate in warm climates, lie dormant for weeks and sprout only when soil temperature has risen to a trigger point known only to the seed.
By mid-April, most of Hopper’s seeds have sprouted. He says he is fascinated, but somewhat frustrated, by a lack of stability and uniformity in some strains.
“If you look at 10 sprouts that are all supposed to be the same, and they have differentiated leaves and growth patterns, you know that these weren’t stabilized genetics,” he says. “That means you have to deal with different growth patterns, flowering times, and pest and mold resistance. I like to grow different varieties, so I would have to deal with some of that anyway, but when you buy 10 seeds of one variety, and you get three different types of plants, that’s a problem you don’t want or expect.”
Two weeks after sprouting, most of Hopper’s plants are short, thick-stemmed, and deep green. When I asked him why they were so short, he responded by pulling the entire soil ball out of the bucket to show me a thick constellation of roots that permeated the entire area. The little sprout had two sets of true leaves and was about three inches high, but it sure had developed a massive root system.
“They aren’t putting much effort into top growth right now,” he says. “They are setting themselves up with adequate root structure so they can thrive later on when it is boiling hot out here.”
Where Hopper lives, spring has wildly variable temperatures. A week of balmy, sunny weather can be abruptly followed by sub-freezing night temperatures, light snow, and sleet.
“Last year, we had a freeze in early May,” he says. “The plants turned black and purple. They looked like they would die off. I gave them some water and nutrients, and the sun came back out. They rejuvenated themselves, thickened up, and kept on going. Then came a hailstorm that perforated the leaves and knocked a few of the taller plants flat on the ground. Most of them came back. Marijuana is amazingly resilient.”
By July, daytime temperatures for Hopper’s plants are in the 85-98?F (29-37?C) range, humidity is around 80%, and the sun is so strong that even dark-skinned people get a sunburn if they are out in it.
Hopper makes sure his plants have adequate water, but he tries to duplicate nature’s drought and rainwater delivery timing by soaking the plant’s root balls every two or three days, then letting them dry out a bit, then resoaking before the plants wilt. He also transplants his crop into progressively bigger containers until some of the larger plants are in 25 gallon pots.
“I go through about 20 bales of Pro-Mix in a season,” he says. “When you grow outdoors in soil, you have to give them a lot of soil, a lot of room for the roots. I use Peter’s 20-20-20 plant food, in reduced dosages, during the vegetative season and shift to a bloom formula at the start of flowering. I stop fertilizing about two weeks before harvest.”
On extremely hot days, Hopper sprays his plant’s leaves with water, and sweats a lot moving them in and out of the shade.
“Plants can only handle so much, and they can get sunburned too,” he said. “People who start plants indoors and then bring them outside often see that those plants can’t handle the sun because they were not hardened to it early on. If you want to start indoors, fine, but you have to get your plants into real sunlight as early as possible, or else they will be wimps and will get fried by something stronger than an indoor light.”
In late July and the month of August, Hopper starts manipulating light cycles to induce early flowering. Some of his plants are Sativa-dominant, and would probably never naturally flower in Hopper’s area because they are used to equatorial day lengths.
To induce flowering, Hopper gives his plants 12 hours of daylight; then he moves them inside a totally darkened barn interior for 12 hours. He ends up with huge, sticky buds in July and August, long before most outdoor growers are seeing their first true flowers.
Buds and bugs
“Once you know who your females are, everything gets tense because a lot of things want to defeat your flowering and harvest goals. You have to watch out for mold, and for bud worms and caterpillars,” warns Hopper. “If your buds are fat and dense, you can have problems inside them close to the stem and never know it until it has destroyed the whole bud. I use a non-toxic product called BT in early floral stages to kill the caterpillars and worms. It won’t kill them if the buds are in advanced growth and they have burrowed deep inside, but if you get them early enough, you can kill them and it leaves no dangerous residue on the bud.
“You can also put mothballs with camphor in them around the base of the plants,” continues Hopper. “You will often see insect eggs there, or you will see signs of a worm that bores into the main stem of the plant. Protecting your plants is not going to be done by using powders and poisons; it’s going to be by you examining them and tending to them closely every day.
“Another thing people should know,” adds Hopper, “is that excess nutrients can cause mold.”
Summer buds grown in areas with high humidity are very susceptible to mold. Hopper says that mold comes on its own due to moisture, and also feeds off of the defecation left behind by bud worms.
“It’s hard to prevent mold,” he laments. “I’ve found that when leaves start yellowing and dying, you have to remove them all the way down to the main stem because the rotting leaf stem can cause mold to start. That takes some careful on-the-plant manicuring. If you get a bud that is moldy, there’s nothing you can do but cut it off. I used to throw them away or put them in alcohol, which will extract all the cannabinoids while eliminating the mold, but last year I bought ice-hash bags, which will extract the resin glands while washing away the mold, and I prefer that because I like hash a lot better than alcohol.”
By early September, almost all of Hopper’s plants have been cut whole and hung upside down to dry and cure in a room with low humidity, low light, and an ambient temperature of about 76?F (24?C).
“Sometimes I will leave a plant out after harvesting it for rejuvenation, and see what it does,” he says. “Some years, they come back and produce another harvest in October. Other times, they sit dormant through the winter and then begin to regrow in spring.”
Hopper has grown outdoors in his current location for many seasons, and has yet to see a cop or copter around his property.
“The worst that ever happened is when I found some guy in my patch trying to rip me off,” Hopper says. “I tied him to a tree, and left him there to spend the night enjoying the local black bear, whose visits are a good time to be indoors.”
Indoor growers control their grow cycle and environment from start to finish, but summer provides challenges that mostly involve keeping grow room temperatures low enough for optimum plant transpiration.
Grower Ygar says his room air conditioner was maxing out some days last summer, so he installed a bigger unit. He was also concerned about the pot smell coming out of his air conditioner to the outside world.
He solved some heat problems by getting lights that had heat exhaust and reduction features built in. These features include a glass pane at the bottom of the light, as well as a fan and hose exhaust system that sucks heat away from the bulb and vents it outside. Some lighting systems are water-cooled, although these are very high-tech and can be difficult to operate.
Some growers claim that the glass pane can reduce the amount of ultraviolet light the plants receive. Higher levels of UV are supposed to help increase production of resins and cannabinoids, but Ygar says he hasn’t noticed any difference in potency and his plants appreciate the cooler temperature.
To reduce odor, Ygar put in-line charcoal filters on his air conditioner inside and out. He also got an industrial-strength ionizer that neutralized much odor, and moved toward growing varieties that did not have a strong smell.
Ygar says he is not so much worried about summer-specific problems as he is by problems with yield and vigor.
“My buds tend to be small and not dense enough,” he complains. “They don’t fill in like they should. They don’t look huge like the ones I see in your magazine. Some people tell me it’s because I am growing in soil. Others say I didn’t get enough light onto the plants early on.”
Ygar’s troubleshooting led him to replace his bulbs, which were nearly two years old and had impaired light output. He is also considering whether he should convert from soil to hydro and buy a pre-packaged grow chamber. He is buying several new strains that are specific for indoor conditions and high yields.
“I am taking a big risk, a felony, to grow this stuff, and even though I pay attention to detail and am running an 800 watt light in a small space, I am not happy with my female to male ratio, or with my yield per plant, which is only about an ounce per plant even though I am pruning them to make them bushier,” he says. “I thought it would be easy to grow pot when I first started out, but I was wrong. You have to study it, get the right genetics, work the plants every day, give them what they want, and pray.”
For Ygar, Hopper, and the thousands of other valiant ganja gardeners who supply the world with cannabis, summer is a time of opportunity, sweat, and hard work.
Come harvest time, when the kind is fresh-cured and the harvest parties are in full swing, all the sweat and effort pay off as the sweet smoke is inhaled.
Then, the love and care of the grower combines with the plant’s dreams of light and oxygen, to become part of peoples’ physiological and spiritual universe.