10 tips for bigger indoor autoflower harvests

Autoflower cannabis seeds now sell in roughly equal numbers as feminised seeds. Buy the best autoflower seeds and you can expect 25%+ THC levels, heavy harvests and terpene-soaked buds which are easily on a par with the best feminised strains. But you will also need to work hard to optimise your grow room conditions, equip it with the best grow light tech and ensure that your plants avoid the yield-limiting effects that come from under/over feeding and over/under watering. With a few expert tips, you too can soon be producing the same elite autoflower specimens produced by the top growers!

What is the average yield of autoflower cannabis seeds?

With so many ways to grow cannabis it’s difficult to define an ‘average yield’. Here are a few typical autoflower yield guidelines when grown in different methods from quality autoflower seeds:

•    Hydroponics. A seasoned hydroponic deep-water-culture pro equipped with LED will routinely pull 150g+ of dry buds from each autoflower, often much more.

•    Coco. Growing in a 20 litre airpot of coco fibre indoors could allow average harvests around 50-100g+ per plant, again assuming intense LED lights and a good grow environment.

•    Soil. Growing in a 15 litre airpot of soil might allow an average autoflower harvest around 30-70g.

Much depends on your choice of autoflower seed, your experience & grow conditions. Ensuring that your plants thrive in the nutrient and optical sweet spot from autoflower seed to harvest is a key essential which is, admittedly, easier said than done.

Best tips for bigger indoor autoflower harvests?

With one of the best autoflower seed collections currently available, Dutch Passion have benefited from seeing thousands of growers deliver exceptional results. Often the best auto growers routinely nail-down the most important parameters of their grow, allowing them to produce incredible harvests. Here are the top Dutch Passion tips which will allow you to replicate these XXL yields in your own grow room.

1) Pick your autoflower seeds wisely

The more experienced cannabis seed companies will be aware that some of their strains yield more heavily than others. Some will grow from autoflower seed to harvest in as little as 8-9 weeks (such as Auto Blueberry or Auto Blackberry Kush).

Others can take 12 weeks or longer, such as Auto Ultimate, Auto Glueberry OG and Auto Desfrán. Those strains with the longer grow cycles generally have higher chances of producing the heaviest harvests and may well be a preferred autoflower seed selection for those targeting the very heaviest yields.

2) Use a rich / healthy grow medium

No matter whether you grow in soil, coco fibre or hydroponics it is essential to meet the nutrient demands of your plants. Those trying to grow outdoors in sandy, poor-quality soil will struggle to produce heavy autoflower harvests. If growing indoors in soil, invest in a proven quality blend. If growing in coco opt for a high quality pre-washed & buffered blend. When shooting for maximum yield, it can pay to look after all the details.

3) Germinate seeds in their final pots

Most autoflower strains take around 75 days to grow from autoflower seed to harvest. Given the time-restricted life cycle many prefer to maximise grow-time by putting the autoflower seeds/seedlings straight into their final grow containers. This can save the plant the stress of being transplanted, which can amount to a few days of lost growth. This can add up to plenty of extra grams in the jars at harvest.

4) Preferably use fabric pots or air-pots

One other absolutely key recommendation to growers is to consider the use of large, aerated grow containers. Many of the most successful Dutch Passion autoflower growers can thank air pots and felt sacks (or similar) for at least some of their success. The extra levels of root oxygenation allow healthier, larger cannabis plants to grow.

If you can use large airpots/felt sacks e.g. 30-50 litres, you can allow a large root mass to form which will support a heavy yielding plant. Hydroponic growers find the more powerful air pumps often deliver better results than lower-volume air pumps.

5) Equip your room with LED grow lights and upgrade quality levels too

Another essential must-have for any aspiring and ambitious grower is to get a good quality LED grow light. Growers with a 1.2m x 1.2m (4ft x 4ft) tent often use around a 400-500W LED fixture. A 1.5m x 1.5m tent (5ft x 5ft) requires an LED of around 700-800W.

Without doubt, LED allows you the highest quality harvests - if you aim to produce branch-breaking yields they may as well be as potent as possible. LED helps you achieve this, especially if you are able to maintain your plants in the optical sweet spot from cannabis seed to harvest.

Supplemental UVA/UVB lights are also recommended, used for a couple of hours per day for the last 2-3 weeks they will juice-up your buds with extra terpenes as well as maximised cannabinoids.

6) Avoid changing your cannabis light schedule

Many indoor growers stick to the same 20/4 autoflower light cycle from autoflower seed to harvest. That means 20 hours of daily light followed by 4 hours of darkness. Many experienced autoflower growers stick to the light schedule with no changes whatsoever until harvest.

7) Keep your autoflowers in the nutrient sweet spot from seed to harvest

Avoiding the perils of over/under feeding your cannabis plants is one of the most important skills a grower can learn. Unfortunately, modern mineral nutrients have little grow latitude, meaning that numerous indoor growers will be familiar with the frustration of burning their plants with excessively strong nutrients and seeing brown-scorched leaf tips as a result.

Using slow-release organic nutrients (BioTabs are the market leaders and thoroughly recommended) offers probably the widest latitude grow method. Just mix the slow-release BioTabs nutrients into your soil (or coco fibre) and add nothing else but water for the rest of the grow. It really is that easy and has transformed the results of many growers. Especially those that were routinely punished with puny yields for misusing mineral nutrients.

8) Avoid underwatering / overwatering your plants

One of the key errors made by less experienced growers is the tendency to overwater their plants. Less common is the tendency to underwater. But both will stunt growth. Cannabis roots can’t grow in waterlogged soil which is inherently low in Oxygen (due to excess water).

Use of aerated grow containers such as air-pots or felt sacks can offer greater latitude against overwatering. Another option is to use soil moisture probes (tensiometers) such as those from Blumat. These give an accurate measure of soil moisture content and are useful for expert and rookie growers alike.

Home growers may be surprised to know that many professional growers use a soil moisture meter in every single grow container. If it works for the pros, it will certainly help the aspiring home grower.

9) Consider the Screen of Green (SCROG) method

The SCROG method involves systematically tying your autoflower branches and stem (using e.g. cable ties) to a horizontal screen. A metal screen with a 5cm square grid (available from DIY stores) is a great choice. Although the SCROG method does undeniably require effort, especially in early/mid growth, the results can be outstanding. The goal is to produce a canopy of blooms all emerging from the screen.

With a level canopy the LED grow light can be positioned at a height allowing all the blooms to bathe under optimised PPFD levels. This allows very heavy harvests, heavier than those which might have been achieved if the plant was allowed to grow in the natural way.

If the SCROG method seems too difficult, then consider some cannabis low stress training (LST) instead. Using some string or garden cord, systematically tie down the taller branches into a more horizontal growth format. This allows lots more light to illuminate the lower branches of your cannabis plant, producing chunky buds where only popcorn buds may have been possible before. Cannabis training is a particularly useful skill to acquire when chasing maximum yield.

10) High-stress training is possible for experienced autoflower growers

Experienced autoflower growers have the confidence to apply cannabis high stress training (HST) techniques to their plants. This can even include topping their autoflowers, a controversial technique used by some elite auto growers. This may delay the eventual harvest an extra week (or so). But yields are often improved when these high stress training techniques are applied well.

The same can be said about the use of cannabis low stress training (LST). The simple use of garden cord to tie down branches can significantly increase light penetration to lower branches, considerably boosting yields.

That said, less experienced autoflower growers should feel fully confident in allowing their plants to grow in the natural way, without training. Although yields may not be quite maximised, they will still be hefty if you have chosen a good strain. And you will have a much easier grow with less plant maintenance when growing the plant naturally, without training.

You’re geared up for monster autoflower harvests

One additional useful tip is to leave your plants for a week or two longer than normal before you harvest. Some phenotypes will continue to gain weight and resin when given extra time. If you’re chasing the heaviest possible harvest, you may want to wait until you are sure the buds have completely finished swelling.

Once you have chosen your autoflower seeds and got your grow room ready, you must let nature take her course. Outdoor autoflower growers have to hope for 3 months of sunny weather with no temperature extremes or storms. Indoor growers have to trust their own skills. and the preparations they have made.

One final tip is to gradually record data about your grow room and preferred autoflower seeds. Which nutrient regime is easier for you - slow release BioTabs or mineral nutrients? Which LED hanging height & light intensities work best at different stages of growth etc.

Slowly, but surely, you will fine-tune your grow room settings and gradually optimise all aspects of growth and grow-room control. These are the skills acquired by the best growers. Continual improvement is the mark of an ambitious, developing grower and gives them every chance of producing the type of XXL autoflower harvests that they could previously only dream about!