High Times is proud to present selections from Jorge Cervantes’ latest, most comprehensive opus, The Cannabis Encyclopedia. The book will be available worldwide on April 20, 2015. For more, check marijuanagrowing.com.
The following articles will outline three different gardens in three different locations: indoor, greenhouse, and outdoor. The examples show different planting and harvesting scenarios that use the natural advantages provided by each garden and the varieties grown. For more complete information about each type of garden, see chapters on Garden Rooms, Case Studies, Outdoors, and Medical Cannabis Varieties.
This is an excerpt from the Cannabis Encyclopedia, Chapter 4, Cannabis Life Cycle. It outlines the basic possibilities for a greenhouse cannabis gardener. Greenhouse growers in warmer climates can grow a total of four crops every year!
Greenhouse crops can be harvested two or more times a year, but most often greenhouses are planted in the spring and yield a single harvest in the fall. In cold climates, greenhouses must be heated. All greenhouses must be vented or cooled in warm weather. The basic harvest scenario below shows how to harvest three greenhouse crops every year.
This Mexican greenhouse needs shade cloth and supplemental lighting at night to keep plants in the flowering growth stage. The days and nights are between 11 and 13 hours long all year round. This is the perfect photoperiod for flowering in cannabis.
Greenhouse Spring Crop – 90 days
March 1 – Move bushy, well-rooted 1- to 2-foot-tall (30–60 cm) clones and seedlings into greenhouse.
March 1 – Long 12-hour nights and short 12-hour days in spring signal cannabis to flower.
March 15 – Remove any male plants. To distinguish plants, look for male pre-flowers.
March 15 – Transplant clones and female seedlings into large containers.
April 15 – Darken greenhouse after 12 hours of daylight, until harvest.
May 30 – Harvest: The less-intense sunlight will make for smaller buds than harvests later in the season.
Greenhouse Summer Crop – 90 days
June 1 – Move bushy, well-rooted 1- to 2-foot-tall (30–60 cm) clones and seedlings into greenhouse.
June 15 – Remove male plants; male pre-flowers distinguish male plants from females.
June 15 – Transplant clones and seedlings into larger containers.
July 1 – Induce flowering by blacking out (covering) greenhouse after 12 hours of light.
July 15 –Verify the gender of all plants. Remove any remaining males.
August 1 – Maintain flowering by covering greenhouse after 12 hours of light until harvest.
August 30 – Harvest a heavy crop of top-quality medical cannabis flower buds that have received maximum levels of sunlight.
Black plastic is alongside this light deprivation greenhouse. Every day the black plastic is pulled over the greenhouse to black it out and create a total of 12 hours’ darkness, which induces flowering in indica and sativa varieties of cannabis.
Greenhouse Autumn Crop – 75 days
September 1 – Move bushy, well-rooted 1- to 2-foot-tall (30–60 cm) clones and seedlings into greenhouse.
September 15 – Long nights and short days of autumn signal cannabis to start flowering.
October 15 – Medical cannabis flowers develop but low light levels limit growth.
November 15 – Harvest smaller buds that have received less-intense fall sunlight.
This small greenhouse protects flowering cannabis from regular rains and bad weather. It also keeps plants a little warmer at night. More regular irrigation is necessary when growing large plants in small containers.
Come back next week for Part 2 of this special series!