Can you grow autoflowering and feminised cannabis seeds together?

Close-up cannabis female plant flowering blooming cannabis plant grow room sizes
Close-up cannabis female plant flowering blooming cannabis plant grow room sizes

Even though autoflower strains and feminised cannabis strains can grow with radically different indoor light cycles, combining the two seed types can allow some useful benefits. Astute outdoor/greenhouse growers can also reap significant rewards when growing autoflower seeds alongside feminised seeds. This grow guide explains the advantages, and pitfalls, of growing autos and feminised seeds together.

Autoflower vs feminised cannabis light cycle
Key factors to consider before starting your seeds
Growing autoflowering and feminised seeds outdoors
Growing autoflowering and feminised seeds indoors

Autoflower vs feminised cannabis light cycle

harvesting feminised vs autoflower

Autoflowering cannabis seeds grow from seed to harvest typically with 20 hours of indoor light, often taking around 11 weeks. Autoflower genetics determine the point at which they start flowering automatically, usually around 4-5 weeks after seed germination.

No adjustments to the light cycle are necessary. Autoflower seeds have earned their reputation for being perhaps the easiest, fastest and most convenient way to grow cannabis.

Quality/potency levels of the best autoflower strains are definitely on the same level as the best photoperiod feminised strains.

Dutch Passion Auto Skywalker Haze with independent lab-confirmed 26% THC levels

Photoperiod feminised cannabis seeds grow vegetatively producing roots, leaves and branches (but no buds) under 18-24 hours of daily light. They only start to bloom when their daily light schedule is adjusted to a 12/12 (or similar) light cycle.

This means 12 hours of light followed by 12 hours of darkness in a 24-hour period. Depending on the cannabis genetics, the flowering period of a photoperiod feminised strain varies between 7-14 weeks, often around 9-10 weeks.

If you want a more detailed review of autoflower seeds vs feminised cannabis seeds the following explanation goes into more detail:

Autoflower seeds vs feminised seeds explained

Key factors to consider before starting your seeds

Dutch Passion cannabis seed finder

Despite the fundamental differences between the growth characteristics of autoflower seeds vs feminised cannabis seeds many growers have enjoyed significant benefits from growing the different seed types together.

When growing autoflower seeds alongside feminised seeds, be aware of the total time required for the auto growth cycle. Some auto strains such as Auto Blueberry or Auto Blackberry Kush may grow from autoflower seed to harvest in as little as 9 weeks.

That could be the perfect option to produce some buds while your SCROG screen of feminised strains is slowly filling (or while your fem strains are vegging in a non-SCROG setting).

On the other hand, some slower (but XXL yielding) autoflower strains such as Auto Ultimate may take up to 12-15 weeks to grow from autoflower seed to harvest. It’s worth taking some time to consider the various cannabis seed options before planning which auto/fem strains to grow together.

Growing autoflowering cannabis seeds and feminised seeds together outdoors

Think Fast Purple 1 Durban Poison Dutch Passion strains grown together from cannabis seeds

Many outdoor growers routinely plant a mix of carefully selected outdoor cannabis seeds  together with some autoflower seeds. You can use the same grow location, same nutrients and conditions.

The autoflower strains tend to be ready to harvest a month or two earlier than the photoperiod feminised strains. Perhaps much earlier if you germinate/start your autoflower seeds indoors at the very start of the grow season, planting out as soon as the weather is warm enough.

Whereas a feminised outdoor strain can take 5-6 months to complete the grow cycle (with yields potentially up-to/around a Kg) an auto is usually ready to harvest around 3 months after autoflower seed germination. This allows the outdoor growers a mid-summer harvest.

It also offers the outdoor grower some extra insurance against poor late-season conditions which could threaten the harvest from the photoperiod feminised strains.

Autoflower strains, with their shorter life cycle, tend to produce smaller yields. These are often around 50-100g per autoflower plant, but heavier dry yields (200-300g+) are certainly possible from the more experienced outdoor grower in optimised conditions.

For those that want some professional tips and advice about growing cannabis outdoors in borderline conditions the following UK outdoor grow guide is recommended reading.

Some outdoor cannabis growers with long, mild grow climates can get two, or even three, successive auto crops during each outdoor season. This offers flexibility and a predictable stream of autoflower harvests thought the year – an excellent way to complement the single end-of-season harvest from photoperiod feminised strains.

Growing autoflowering cannabis seeds and feminised seeds together indoors

Dutch Passion's Auto Blackbery Kush and Blueberry

Autoflower strains can be bloomed in 12/12 light conditions alongside your favourite feminised strains. Final auto yields will be compromised somewhat, but some growers germinate their autoflower seeds alongside their feminised seeds and grow them alongside each other with a 4-5 week period of veg conditions using e.g. 18-24 hours of daily light followed by a couple of months of 12/12 light.

The autos generally finish first, the last few weeks of 12/12 light are not optimised due to lack of daylight hours. Autoflower yields from a 12/12 bloom may be down 20-40% on those which you might have expected when bloomed under traditional 20/4 light cycles.

Growing autos and feminised strains together – the benefits of starting germinating your autoflower seeds earlier than your fem seeds

Some growers prefer to get their autoflowers growing for a month or two under a 20/4 light cycle before they germinate their feminised seeds and introduce them to the same tent with the same light cycle. When synchronised correctly, the autoflowers will be able to complete their ~75 day life cycle under 20/4 light while the feminised strains are just reaching the end of their vegetative growth cycle.

At this point the autos can be harvested and the feminised strains can be flipped immediately into bloom with a 12/12 light cycle. Around 9 weeks later the feminised strains can be harvested. For any grower seeking two fast, heavy harvests just 2 months apart, this is a great strategy.

How to grow autoflower seeds and feminised seed together. Squeezing an autoflower plant (or two) into a mother/cuttings room

To avoid compromising autoflower yields with 12/12 bloom conditions, many prefer to grow an auto or two in their grow room while their feminised strains are undergoing a prolonged period of vegetative growth under e.g. an 18/6 light cycle, or similar.

Those that use extended 10-12 week periods of veg conditions (e.g. for growing monster photoperiod plants or SCROG growing) will be comfortably able to harvest an autoflower plant in the same grow room conditions. But make sure you have adequate space, the best modern autoflower seeds can reach substantial proportions under intense light conditions.

How to grow cannabis indoors, master grow guide

Serious growers that maintain a dedicated mother room (often with 18-24 hours of daily light) also find that any unused space can be turned into highly productive real-estate simply by adding an autoflower seed or two. However, it’s important to note that the autoflower plants will benefit from higher PPFD (light intensities) than the mother plants/cuttings and will benefit from being closer to the grow light than e.g. fresh/small cuttings, especially when the auto is in bloom.

Some growers reduce the distance between the autoflower plants and the light (increasing light intensity) by sitting the autoflowers on a small stand, or giving them a dedicated light.

Without doubt, there are challenges and considerations when growing different strains of cannabis together. Different final strain heights, nutrient requirements and grow cycles will all vary. But with a small amount of planning and with accurate genetic info from your cannabis seed suppliers you should be able to manage. For those seeking some useful practical tips, the following guide may help.

Growing different strains of weed together

Growing autoflower seeds alongside feminised seeds is possible

And not just possible, growing autos alongside your feminised strains offers useful benefits and extra harvests! Whether you’re growing your marijuana seeds indoors, outdoors or in greenhouses and polytunnels, there are numerous good reasons to consider the advantages of using both types of cannabis seeds.

The best piece of advice is to research your choices of autoflower and feminised seeds carefully. Understand the likely length of the various strain grow cycles and plan ahead accordingly. With a little bit of upfront preparation/timing, you may be able to increase your yields with hardly any extra effort.

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