Best Soil for Autoflowers: A Complete Guide

Autoflowers have a way shorter lifecycle than their photoperiod counterparts, but the soil basics are the same. 

The ideal soil should provide excellent drainage, retain adequate moisture, and contain a rich mix of nutrients to support vigorous growth. 

In this article, we'll show you how to mix the perfect soil for autoflowering seeds. We’ll also share a few popular brands of ready-to-use soil for some fuss-free cultivation! 

Key Takeaways 

1. A basic DIY soil recipe ideal for an autoflower seed can be made by mixing 80% organic soil with coco coir, perlite, compost, and seasoned manure.  
2. Advanced mixtures often include other supplements such as seaweed, biochar, bat guano, fish/blood/bone nutrients, dolomite, and worm castings. 
3. If you don’t want to mix your own soil, Fox Farm Ocean Forest and Roots Organic Formula 707 are popular options hailed in many growers' communities for their suitability with auto-flowering plants. 
4. Healthy soil for autoflowering cannabis seeds should be free-draining, light, airy, and with an open texture.

Why Pay Attention to the Soil You Use for Autoflowers?

First, auto-flowering strains have a shorter growing cycle than their photoperiod counterparts, which means that any nutrient imbalance will be felt greater. 

Also, autoflowers tend to be more sensitive to synthetic ionic nutrients than photoperiods. So, seasoned organic matter, microbes, organic feeds and salt based nutrients are better for keeping the plants healthy.

What are the Best Ready-to-use Soil For Autoflowers?

Before moving into soil mix recipes, note that mixing your soil can be cost-effective on a large scale, but buying bagged soil might be cheaper for smaller grows.

Ready-to-use soil is also perfect if you want to skip the mixing and get straight to planting. Several reputable brands offer high-quality soils perfect for auto-flowering cannabis seeds. 

Here are some popular options you can find on the market and what we think about them based on feedback from growers in our community:

1. FoxFarm Happy Frog Potting Soil

When your plants are seedlings, FoxFarm’s Happy Frog is one of the best soils around. It is pH-adjusted to allow for maximum nutrient uptake and gentle on the little ones. 

Once your seedlings have grown, you can switch out the soil to FoxFarm’s regular mix, the Ocean Forest which is more nutrient-dense. 

Ingredients: 

It is made of 50-60% aged forest products, sphagnum peat moss, perlite and fertilizer.

1. Composted forest humus
2. Sphagnum peat moss
3. Perlite
4. Earthworm castings
5. Bat guano
6. Humic acid (derived from Leonardite)
7. Oyster shell
8. Dolomite lime (for pH adjustment).

The soil also contains mycorrhizal fungi, which support nutrient uptake without overwhelming plants.  The microbe activity remains active for the next 2 years from the manufacturer’s stamped date.

It’s also well-aerated, with a mix that allows for healthy root growth and proper drainage although some growers recommend adding an extra 20% perlite for better results. 

Here are the nutrients it supplies: 

2. Coast of Maine Stonington Blend

This is another popular soil blend among many autoflower growers. Ingredients include:  

1. Mycorrhizal fungi
2. Peat moss
3. Coco fiber
4. Perlite
5. Kelp
6. Fishbone
7. Alfalfa meal
8. Worm castings

The Stonington Blend is an easy-to-use soil containing all you need to grow autoflowers. The nutrients it supplies are derived from composted poultry manure, fish bone meal, lobster & crab shell, kelp meal, earthworm castings, and alfalfa meal.

The nutrients the soil contains include:  

How To Make Your Own Soil Mix For Autoflowers

If mixing your soil for autoflower seeds sounds more rewarding because you know exactly what's in it, you have options. You can create a basic well-draining mix that requires fertilizing as the plant grows or make soil mix that will take your plant from seed to harvest with minimal extra effort.

For a well-draining mix, blend 80% organic soil with 10% coco and 10% perlite. You can easily mix this by hand in a bucket.

As for a soil mix, here’s a simple recipe that you can use. 

This recipe will result in roughly 0.841 cubic feet., but you can increase the amounts of each if you need more. 

Simply mix all ingredients in a container big enough, preferably with a lid, and allow to sit for up to two weeks. During the resting period, microorganisms multiply, actively breaking down the organic matter. 

Before planting your seeds, germinate them using our favorite method, the paper towel to dramatically increase your chances of success!

How To Tell If Your Soil Is Healthy for Growing Autoflowers

If you make your soil with a trusted recipe, you can always be confident it's healthy. Similarly, sticking to a specific brand of pre-mixed soil can give you confidence in producing healthy plants.

The best way to assess soil quality is to understand what it's made of. Healthy soil drains well, feels light and airy, and has an open texture.  Nutrient-deficient soils are often heavy, dense, and poorly draining. In such conditions, roots can struggle to thrive, especially if they are waterlogged and lack oxygen.

Final Thoughts

The potting soil is each grower’s deeply personal preference, but when growing cannabis, it is crucial to start with high-quality seeds.  

At HomeGrownCannabis, we're proud to be a leading online marketplace for high-quality autoflower cannabis seeds. Check out our extensive selection and have them delivered right to your door!