autoflowering soil

Basics of Growing Autos in Soil from Seed to Harvest

An autoflower is a special type of cannabis created by mixing the genetics of the Ruderalis with Indica and Sativa.

Over the years, autoflowers have become stronger and sturdier enough to be grown by both commercial and home growers.

The biggest difference between autoflowering and photoperiod plants is that autoflowers begin to flower indepndent of the light cycle provided.

Therefore, an 18/6 light cycle from the very beginning until the end will work perfectly. Although autoflowers are easy to grow, it’s best to familiarize yourself with the basics before you start.

So, here’s a step-by-step guide to help you through the entire process of growing autoflowers in soil.

1. The Best Lights

When growing autoflowers indoors, even if you’re not growing in soil, light is a super important part of growing any kind of plant, including cannabis plants so it’s important you know what’s available and choose the best suited for your grow setup.


High-intensity light bulbs have been used since the beginning of cannabis growing indoors and are the most common light fixture used due to their low cost and effectiveness for home growers.

Light bulbs are essentially found in two types, Metal Halide (MH) and High-Pressure Sodium (HPS), each one of them is used in different stages of plant growth due to the spectrum emitted and the results are quite good.

A few years ago LEDs weren’t too good so growers didn’t even think about using them due to the high cost and because they weren’t as good as they’re nowadays.


LEDs have been in the market for a couple of years now, in the beginning, they weren’t worth it but they have evolved a lot, and nowadays are considered the best not only by home growers but also commercial growers.

These light fixtures can cost up to 10x more than light bulbs but emit a full-spectrum so, despite the high price, you can get better results and higher yields which ends up being worth it.

Obviously, there are several brands and qualities but most LEDs consume up to 60% of energy and growers say that their plants produce more trichomes, so depending on why you’re growing and if you can afford it, it’s definitely a good choice.

Lights When Growing Outdoors

If you’re growing autos outdoors you cannot choose a light fixture but lucky for you, the sun is the best light source so despite not having to worry about light intensity and spectrum, you have to make sure your plants are getting enough sunlight for them to develop properly and to allow the buds to fatten up nicely.ç

2. The Best Soil Mix

When growing autoflowers in soil, there are several mixes that can improve the medium in which roots grow, depending on the conditions you’re growing in, you may want to make your soil more oxygenated or provide more water drainage so you can find several additives that serve in different cases but all of them will end up improving your soil and consequently, plant growth.

Additive Advantages
Coco fiber Retains water and helps avoid soil compaction.
Perlite Helps dry the soil faster and increases oxygenation.
Vermiculite Improves soil quality and helps keeps soil moist.

We recommend a mix of soil, perlite, and coco fiber to provide enough water drainage and oxygenation, resulting in the best soil for autoflowers.

3. The Best Nutrients

Nutrients are another vital factor for cannabis growers, there are several brands of synthetic and organic nutrients that offer basically the same results but they work differently and you should choose the best one based on your grow setup.

Synthetic nutrients

Synthetic nutrients are basically manmade nutrients extracted from minerals, they contain a specific ratio of macro and micronutrients, making it easier to use them, you just have to mix and water.

But the way they work is completely different from organic nutrients, while organic nutrients focuses on maintaining a living soil, synthetic nutrients just feed the roots directly so despite being easy to use, it’s also easier to overfeed your plants and cause deficiencies.

Organic nutrients

On the other hand, organic nutrients are derived from living sources and focus on maintaining the beneficial microorganisms in soil alive so they develop a symbiotic relationship with your cannabis plant, this way your plant feeds them and in return get more water and nutrients available for them to absorbs when they need to.

Now, organic nutrients can be quite expensive but they’re fairly easy to make at home, it may take time and you will have to learn how to do it properly, but there are several ways to make your own organic nutrients that will not only save you money but you’ll also learn a lot about cannabis plants and the nutrients they need.

DIY Organic Nutrients

Super soil

Super soil is a technique used to make your own pre-amended soil that contains everything to feed your autoflower from seed to harvest, this method consists of only watering your plants to help the microorganisms break down the nutrients and make it available for your plants to absorb and grow.

Now, there’s no such thing as super soil for autoflowers, as long as you do it properly, you can use it to grow any kind of plant!


Composting is very similar to making super soil but it’s usually made with the food scraps you’re left with after cooking and basically consists of burying the leftover scraps in damp soil, this way you activate the microbial life and make the nutrients available for your plants, you can also add worms to accelerate the process, it’s a super-effective technique called vermicompost.


KNF is another way to get minerals found in plants and vegetables but unlike super soil and composting, it consists of fermenting the vegetation that contains the nutrients your plant needs for each stage.

In this technique, you end up with a couple of liquids suited for the vegetative stage, flowering stage, others that act as natural pesticides, and natural sources of Calcium and Magnesium that are used just like synthetic liquid fertilizers but completely organic.

So, to start growing autoflowers in soil you’ll need:

  • Good quality autoflowering Seeds
  • Potting soil containing equal proportions of peat moss or coco peat/coir, compost, perlite, vermiculite (optional), or a commercial potting mix
  • Use fabric pots containers that are at least 12 Liters.
  • Good quality light fixture like HPS or LED, or at least 12 hours of sunlight if you plan to grow outdoors. Use CFLs during the seedling stage
  • Nutrients for vegetative and blooming phases.

4. Germination

It’s pretty easy to germinate cannabis seeds. You can sow the seeds directly in the pot, but if you don’t have a lot of experience or are impatient like the rest of us, soak the seeds in plain water for 24 hours. It’s common to see a tiny taproot after a day of soaking but it’s alright if you don’t see them.

Many growers use nail files to gently scratch the surface of the seeds, but do not do this if you’re fairly new. A scratch on the seed coating allows water to penetrate the shell and the seed develops a taproot faster. Place the seeds in moist paper towels for 2-3 days until you see long tap roots. The next step is to plant seeds in their final containers and wait for them to push through the soil.

Here’s a quick video to help you with germination:

5. Week 1

The first week is extremely crucial for autoflowers. It’s important to NOT use any fertilizers in the seedling stage since the plants are very tender. You risk burning them, and a single mistake now might prove very costly later. The seedling will have two cotyledons (sometimes 3) that are almost round in shape when they just appear.

There are various products that can be used on seedlings, but they are not necessary because they will be fine even if they are left alone. At this point, you can use CFLs or fluorescent lights to ensure that the seedlings don’t burn under powerful lights.

However, many growers wing this by adjusting the distance between the lights and the seedlings so that a single LED light is used for the entire cycle from seed to harvest. Water the seedlings sparingly only when the pots are almost dry. Overwatering or under-watering seedlings can either stunt or kill them, so it’s recommended that you water only when the plant needs it.

The seedlings develop at least two leaves apart from the cotyledons at the end of week 1.

6. Week 2

You can use nutrients at quarter strength once the seedling is comfortable with at least two leaves. Continue using nutes at quarter strength at this point, but regulate the pH and maintain the range from 5.8 to 6.5 at all times. Some growers use half-strength but it depends on how big the plant has grown.

If you see more than 3 to 4 nodes on week 2, use nutes at half strength. Monitor the plants carefully to detect lockout or deficiencies. As always, water the plants only when the pot is almost dry. Shift the lights closer to the plant if it starts growing too lanky.

7. Week 3

Now that the plant is on week 3, use the nutes at full strength. Some plants like LSD-25, for example, need a lot of nutes whereas others may not require too much. “Less is more” when it comes to nutrients in autoflowers, so use nutrients at full strength only if the plants have responded positively until now.

Check out the basics and tips for growing Autoflowers in soil, from seed to harvest!