Score: 3/5


The Formula 707 Growing Mix is marketed by Aurora as being “created for a special kind of gardener, those who want to control their own destiny.”

While it’s not exactly clear what’s meant by that statement, it is obvious that this soil is designed for large containers—or growers who want to minimize preparation and gardening time.

This soil is not just pre-mixed and ready to use straight out of the bag: Aurora states on its website that growers can punch holes at the bottom of the bag, cut off the top, and plant directly into the bag, using it as a container. This will certainly appeal to some customers—especially those with little growing experience.

Although the website requests customers to contact the company for pricing, it’s available elsewhere online for $34.99 for a bag that’s three cubic feet, which is reasonable.

The Formula 707 Growing Mix contains ingredients that are geared toward large-container growing. For example, there is more peat and less perlite than in the Aurora Original Potting Soil. This allows the soil to hold water for longer.

Although it contains multiple soil amendments, mineral additions, and microbes, the company recommends using an additional fertilizer to provide nutrients. This not only brings the overall growing cost up but also increases maintenance time.


Base and Composts

Most of this soil is made up of coarse peat moss. This helps improve aeration as the coarse texture means the soil is not tightly packed. Additionally, peat is able to retain up to 20 times its weight in water and hydrate plants as necessary over time. Peat moss also contains elements such as sulfur that encourage the plant to produce and express its natural terpenes.

Aurora also includes composted virgin forest material in this formula. This is a natural soil conditioner made from compost taken from a forest floor. It’s extremely effective as a natural fertilizer, as it holds nutrients that can help the plant’s growth. Unlike synthetic fertilizers, however, these nutrients are released over a period of time.

Composted virgin forest material also enhances the soil itself in a number of ways—mainly by helping water retention, drainage, and aeration. It also encourages the proliferation of soil organisms, which, in turn, provide the plant with nutrients. This ingredient is not often seen in pre-mixed marijuana soils, so it puts the Formula 707 above some similar products on the market.

Another natural ingredient that acts as a fertilizer is worm castings. Growers have found that worm castings protect plants from disease, increase the overall yield, and shorten the germination cycle, all without the use of any chemicals.

Aeration and Drainage

This soil contains a number of ingredients that improve water retention, drainage, and aeration. The main examples of this are perlite and pumice, which are coarse, pebble-like materials that have been ground and mixed into the soil.

Although a lot of companies choose either one or the other in their soil, as both have very similar qualities, Aurora has included a mix of both. Arguably, this enhances their effectiveness. Both perlite and pumice help to provide spacing between particles of soil, thereby aiding aeration and drainage. This helps minimize the risk of overwatering, meaning that neither the soil nor the roots will be susceptible to rot.

Aurora also includes coco fiber in this soil formula to loosen the soil and make it easier for nutrients to get to the roots. This, too, improves overall aeration and drainage. It’s great that Aurora has combined coco fiber and peat, as the former takes a lot longer to naturally break down than the latter. This combination means less maintenance overall as the soil doesn’t have to be replaced as quickly or as often. As an added bonus, this also helps keep the costs down.

Mineral Additions

Aurora has included a number of mineral additions in this soil’s formula. One is feather meal, which is not often seen in pre-mixed growing soils. Made from processed poultry feathers, it is a natural organic fertilizer that is known to improve soil structure and increase plant growth.

Another additive, soybean meal, is a fantastic organic, natural source of nitrogen that won’t harm the plant or its roots. Fish bone meal is a great source of phosphorus and calcium. Lastly, organic kelp meal is another good source of nutrients.

Greensand is another fantastic addition to this soil. It contains around 30 beneficial minerals, including magnesia, iron oxide, silica, phosphoric acid, and lime—all of which greatly contribute to overall plant health. Volcanic rock dust, which is also included in the Formula 707, has similar properties.

Soil Amendments

The Formula 707 Growing Mix also contains an excellent blend of natural soil amendments to help fertilize and deliver nutrients to plants. Some of these are relatively innovative and often overlooked by many soil companies in favor of those that are cheaper and more easily available.

One example is bat guano, which is essentially bat feces. It efficiently delivers to the plant nutrients and beneficial bacteria present in the guano as a result of the bats’ diet of fruit and insects. It is also an effective fungicide and inoculant. Overall, this is an excellent ingredient that makes a huge difference when growing marijuana—although it’s worth noting that the exact type of bat guano is not specified, which can affect the stage of the growth cycle that it should be used. However, as it is used in presumably small amounts as a general ingredient, it shouldn’t pose too much of a problem whenever it is used.

Aurora also includes an excellent mix of microbes in the Formula 707, all of which increase the biomass of the plant’s roots, enhance the uptake of nutrients, and help container-grown plants to resist stress. These are Funneliformis mosseae, Rhizophagus intraradices, and Septoglomus desertícola.

Quick Summary – Pros and Cons


  • Contains a great mixture of innovative ingredients to promote growth.
  • Contains a great mixture of innovative ingredients to help water retention, drainage, and aeration.
  • Ready to use—can even plant straight in the bag.
  • Reasonably priced.


  • The company recommends using an additional fertilizer.
  • Designed mainly for large container growing. Therefore, it may not suit everyone.