How to Grow Big Autoflowers Indoors
by Tony – Dutch Passion Seed Company
These days more people than ever are growing their cannabis with autoflower seeds, and indoor growers as well as outdoor growers are having great success. The best auto genetics grow quickly and deliver THC levels which are equivalent to the best photoperiod varieties. So, how do you make the most of your indoor autoflower grow, maximizing both the final harvest as well as the quality level? Here are some of our top tips to get the most from our auto seeds.
Autoflowers Love Airpots
Anyone growing in coco fiber or soil should try growing their auto seeds in air pots. Air pots are available from most grow shops – they have a dimpled surface on the sides which prevents the roots from circling around the sides and bottoms of the container. The numerous air holes allow good levels of root oxygenation which allows your auto to grow rapidly. Air pots encourage roots to maximize the use of the grow medium and produce a strong, healthy root mass which utilizes all the available root space. Experienced cannabis growers know that the foundation of a healthy plant is a healthy root system. Using air pots for soil or coco growing helps you to grow cannabis plants with great root systems.
LED and CMH (Ceramic metal halide) Grow Lights
Autoflowers grow well under HPS light, but many growers find that they get better growth and potency with the more modern LED grow lights or CMH lights. A 315W ceramic light will give similar performance to a 600W HPS, using less energy, and many growers feel that they are worth the price premium. The most demanding growers prefer to use LED growlights, as these offer adjustable spectrum and adjustable power. LED can deliver a blue dominant spectrum for the first 3 weeks when the plant is growing, and the red portion of the spectrum can be increased as the plant starts to bloom. Many of the professional USA cannabis growers prefer to grow with LED because THC levels are often up to 25% greater than HPS, allowing them to charge more for their crop. Many home growers love LED simply because they use less energy to produce better quality cannabis than HPS. Also, HPS produces large amounts of heat, and heat stress is something which restricts cannabis from reaching full potency. If you can afford it, LED is the best grow light option for growing large autoflowers indoors.
Use 20 Hours of Daily Light from Seed to Harvest
Some people grow their autos under 16 or 18 hours of daily light. The best growth and biggest harvests usually come from plants grown under 20 hours of daily light from seed to harvest. Some growers like to grow their autos under 24 hours of daily light from seed to harvest, but this can cause nutrient deficiencies which can be challenging to correct. Growing the auto seeds on 20 hours of daily light is the best way to a fast and heavy harvest. Don’t worry if the leaves start to turn yellow towards the end, that’s perfectly normal and indicates that the plants are putting all the resources into growing THC-rich buds.
Don’t Be Afraid to Use Low Stress Training
Auto flowers are tough. Don’t be afraid to tie down branches using string to open up the plant structure and allow better light penetration to the lower branches. Many autoflower growers achieve XL harvests by using low stress training. By tying down branches it is possible to get all the blooms equidistant from the light. This allows the grower to keep all the blooms in the optical sweet spot, not too near the light and not too far away. This allows all the blooms to swell in ideal light intensities, and helps you get the maximum harvest from your autoflower plants. Often the tallest bloom on an autoflower is the central bloom – if that gets too tall it can simply be bent over by 90º, this will allow you to keep your light close to the canopy of buds.
Understand Nutrient Management
One of the most damaging events for an autoflower is to get nutrient burn early in their life. Nutrient burn is seen when the cannabis plant is given nutrient concentrations that are too high. The excessive mineral concentrations can’t be tolerated by the plants, the roots are damaged and brown crispy leaf tips are seen. Often, growth is permanently reduced and the final harvest quantity can be substantially reduced. Remember that the average autoflower only has around 75 days to complete the life cycle. The plant can’t afford to spend a couple of weeks recovering from nutrient burn when it is only alive for 10-11 weeks. Over-feeding an autoflower plant causes a lot of stress and simply reduces your final harvest quality and quantity. Try to increase your nutrient levels slowly as the plant gets older, avoid sudden increases to nutrients. Use an EC meter to monitor nutrient concentration, and use a pH meter to control the acidity/alkalinity levels of your feed solution.
Try Advanced Grow Methods When You Are Ready
Many growers learn how to grow their auto flowers in soil/compost. This is perhaps the easiest way to start growing autos. Growing in air pots of coco fiber will allow faster growth than soil, but perhaps you will also need more working knowledge of nutrient management to grow successfully in coco fiber. The fastest growth rates of all are often seen in hydroponic systems such as NFT (Nutrient Film Technique), DWC (Deep Water Culture) and other similar systems. However, to really master the challenge of growing in hydroponics you need to have plenty of experience in nutrient management. This means you will need to understand the nutritional needs of your autoflower plants at different stages of their lives and be able to apply the nutrients accordingly. Growing in hydroponics isn’t easy, but if you can do it well you will find it easy to grow monster autoflower plants indoors.
Become an Expert in Autoflower Genetics
The more you grow auto flowers, the more confident and capable you become growing them. Many of the best auto growers specialize in genetics from a single seed company, or even concentrate on a single variety. Once you have grown a few autoflower varieties you will start to get used to their growth cycle, noticing how tall they grow, and when the maximum amount of pre-flower stretch is underway. By understanding the growth cycle you start to become familiar with the needs and requirements of your plants. The more you understand the way your plants will grow, the better you will become at catering for their needs. The most experienced auto growers routinely achieve several hundred grams per plant from hydroponic systems. One of the main advantages of auto flowers is that they are able to bloom under 20 hours of daily light, putting all that energy into bud production and resin. Photoperiod plants have to make do with just 12 hours of light in bloom, this gives autos a serious advantage in terms of yield potential. Many of the best auto growers simply can’t achieve the same harvests in the same time with traditional photoperiods varieties – that’s why so many self-sufficient cannabis growers prefer to grow auto varieties.
Source: WeedWorld Magazine Issue 134
What temperature should the autoflower plants be kept at? This more applies if they were to be grown in the winter time.