Autoflower vs Photoperiod Strains – How Do They Differ?

Cannabis cultivation has evolved for centuries as civilization continues to uncover the beneficial attributes of this remarkable plant. Ancient tribes and cultures grew cannabis for a wide range of purposes including food, fibre, textiles, and medicinal benefits. Modern discoveries, however, have elevated awareness from cannabis connoisseurs eager to learn more about the intricate nature of the plant. 

Coupled with advancements in science and technology, cannabis breeders are delving into defining specific traits with positive characteristics of unique strains. While interest has mainly focused on photoperiod plants, many breeders have recently turned their attention to developing new autoflower seed varieties.

What are the Differences Between Autoflowering VS Photoperiod Strains?

Light VS Time

Photoperiod cannabis strains have historically been the sole focus for most cultivators concentrating on efforts to produce big and beautiful plants. These types of cannabis plants grow through different life stages depending upon the amount of light available. Outdoor grown photosensitive plants are directed by hours of light from the sun to develop throughout their life cycle.

Indoor growers can change light cycles to initiate the transformation between vegetative growth to flowering mode. Typically, in the vegetative stage, lights are left on for 18 hours each day. This cycle promotes photosynthesis transferring energy into leaf and stem production.

By switching the light schedule to 12 hours on and 12 hours off in the grow room, this signals to the photoperiod cannabis plant that it is time to begin reproduction. The decrease in light hours sends the energy from leaf and branch growth to bud formation and flower development.

Autoflowering growth cycles, on the other hand, are not dependent upon light whatsoever. Instead, their ruderalis genetic makeup guides the growth cycles of a plant by a certain amount of time. Whereas photosensitive cultivars need several months to progress through their life cycle, autoflowering cannabis strains develop within a few weeks.

Size and Yield

Due to longer growth times, photoperiod seeds produce plants that can become quite large, ensuring a high yield of delectable buds. Autoflowering plants are relatively small in comparison due to their limited growth timeline. Seven to twelve weeks of development from germination severely reduces their ability to produce heavily.

However, newly refined genetics have created some impressive autoflowering strains, which, when properly trained, can produce favourable yields with high THC and CBD levels. As cannabis breeders continue to explore new possibilities, the popularity of autoflowering strains continues to grow rapidly.

The bottom line, of course, is yield. It is hard to compare a marijuana plant that will produce maybe an ounce or two with one that delivers several pounds. Photoperiod strains are notorious for their high yields if grown properly. Unlike the same varieties crossed with cannabis ruderalis, which only produce a fraction of the harvest, it is not hard to determine which type of plant is more lucrative for a grower.

Autoflower VS Photoperiod Growing Techniques

Photoperiod Cannabis Strains

Light sensitive cannabis plants require dedicated care during their life cycle. While they are not necessarily hard to grow, photoperiod marijuana plants do require attention as they transform through their different life stages.

As mentioned above, the change in light hours each day signals the marijuana plant to begin transforming into the flowering phase. At this same time, altering the nutrient formula will help the marijuana plant transition.

During vegetative growth, a cannabis plant takes up high amounts of nitrogen as it is building leaves, stems, and branches. Phosphorus and potassium are also essential elements during the growing stage but are readily taken up from the root system as the plant begins bud formation.

Photoperiod strains are vigorous feeders; they love their NPK. Depending on which grow medium you prefer, nutrient formulas will vary considerably. For instance, living soil amendment applications are much different from feminized marijuana plants grown in a soilless substrate.

Because of their abundant growth, light-sensitive cannabis plants often need training during the vegetative stage. Seasoned growers prune or bend marijuana plants to create a high-producing structure, allowing the plant to showcase a plethora of colas as it flowers. Often, photosensitive strains need staking or trellising to support the massive plant’s explosive growth.

Additionally, photoperiod marijuana plants are clonable to replicate the genetic makeup of a particular strain. Cuttings taken from a prized cannabis cultivar allows a grower to propagate additional plants from a mother plant to duplicate appealing genetics.

Autoflowering Cannabis Strains

Whereas photoperiod cannabis varieties require attentive care during their growth cycles, autoflowering plants are relatively easy to grow with minimal intervention. Auto’s are perfect for first-time growers wanting to learn how to grow marijuana.

Due to ruderalis strong nature, autoflowering cannabis strains do not rely on diligent care to progress through their growing cycles. They can be grown indoors or outside as the hardy stock is readily adaptable to most environments. Autoflowering strains can be cultivated at any time of the year in favourable conditions.

Autos prefer a light, airy growing medium that allows their root system to develop rapidly. They grow well in living soils that provide good drainage. Autoflowering cannabis plants also respond well to soilless substrates and hydroponic systems with proper nutrition.

Unlike their light-sensitive sisters, autoflowering strains are not heavy feeders. While autos do require NPK supplementation throughout their life stages, doses are a fraction of those administered to photoperiod strains.

A general rule of thumb is to start with low nutrient ratios, adjusting levels as the plant transitions through its growth cycles. Over-feeding a young autoflowering strain causes nutrient burning, stunting the growth of the plant. Because of their short life cycle, autoflowering genetics do not have time to rebound from trauma experienced in early growth development.

Any stress evoked during growth will have detrimental effects on an autoflowering marijuana plant’s outcome. Pruning or topping these fast-growing cultivars should be avoided, especially for beginner growers.

Instead, applying Low-Stress Training (LST) techniques to the autoflowering strain will encourage bud site development. Tall branches are bent down laterally using stakes or trellising, allowing the plant to expand out instead of up. LST methods applied during late veg and early pre-flowering stages provide a structure for the plant as it explodes in growth entering flowering time.

Contrary to photoperiod cultivars, successfully cloning autoflowering cannabis strains is complex. Since an auto’s life cycle is dependent upon time only, clones taken from a mother plant will exhibit the same short life span.

There is little time for a healthy root system to establish as the clone automatically progresses rapidly within a few weeks into the flowering phase. While it is not impossible to clone an auto, the resulting plant will produce minimal yield.

Learn more about growing autoflowering marijuana strains:

• Are Autoflowering Strains Potent?
• How to Increase Yield of an Autoflowering Cannabis Strain
• When to Harvest an Autoflower Strain
• What Are the Best Nutrients for Autoflowering Seeds?