How to Grow Weed: A Marijuana Beginner's Guide
Understand growing conditions for female and male cannabis.
Published on December 18, 2015

Without a doubt, female is the fairer of the marijuana sexes. Feminine cannabis is solely capable of developing the flowering buds, or colas, most of us think of when referring to weed. However, the average marijuana grower knows there are secrets to growing a higher ratio of females to males. Certain conditions can help the plant become feminized; everything from ambient temperatures to relative humidity are thought to push the plant towards choosing a certain sex. Most importantly, growing a healthy plant can help determine not only the sex of the plant, but also the quality of the flowers.

Let’s start with some of the plant’s basic characteristics: Marijuana plants grow in two main stages, vegetative growth and flowering growth. Plants generally don’t express their sex until they switch from vegetative growth to flowering growth, sometime in weeks 4-8. Females will express their sex by growing calyces and pistils, while males will grow little pollen sacs (they look like little marijuana testicles). Males can’t produce the desirable flowering buds, but if you’re in need of seeds, then allow your male plants to release their pollen sacs onto the females, which then will produce seeds along with their lovely bud. However, allowing male plants to pollinate the female plants will result in a less potent flowering bud than if the females are isolated from the males.

By isolating female cannabis plants from their male counterparts, females will produce more pollen. Females do this in order to increase their chances of becoming pollinated, since the females’ sticky pollen help to grab any male pollen that might be floating around in the air. So if you’re trying to grow potent marijuana – whether via an indoor grow box, or in your outdoor garden — you need to be a little cruel to your female plants by keeping them deprived of the male pollen that they’re trying to find. In a way, the female plant’s sexual frustration results in our pleasure in the form of a better flower and stronger high; think about that next time you light up.

A seed will either produce a male or female plant. If we consider a single seed, our seed has a particular chance, or probability, of being a male or female. Maintaining certain environmental factors early in growth can increase the plant’s probability to be female. According to the same article that has been shared numerous times, there are 5 hard and fast environmental conditions to grow by during our plant’s vegetative stage to maximize our seed’s probability of being female:

  1. High nitrogen, and low potassium levels
  2. High relative humidity (60-70%)
  3. Higher-frequency light (blue and purple)
  4. Low number of sun hours (14 hours light, 10 hours dark)
  5. Low temperatures (62-65 °F)

Weed got its name for a reason, despite the optimal growing conditions just mentioned, this plant is highly resilient to a number of adverse growing conditions. A recent study of male cannabis root growth in Italy showed just how resilient the little leafy plant is. The researchers in Italy wanted to know how well cannabis can hunt down water and nutrients in the soil. What they observed was that marijuana roots will grow quite deep, ~6.5 feet, in order to find what they need. According to a 2013 publication, corn only grows to ~5 feet in depth in optimal growing conditions. Considering that cannabis, grown in less than optimal conditions, grew 1.5 feet deeper than corn, grown in more ideal conditions, it’s no wonder we call it weed.

Peter Steele
Peter Steele is a freelance writer and geologist currently working on his PhD in sedimentology. Aside from academics, he enjoys taking brisk hikes, skiing, baking, drinking black coffee and watching television. He is a firm supporter of both recreational legalization and medical study of marijuana.
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