Why Garden Soil Isn't Ideal for Containers
When selecting soil for pots and containers, it’s essential to recognize that garden soil taken directly from the landscape does not function effectively as a potting medium. This is because water and air behave differently in a container than in open ground.
In the landscape, water flows freely laterally and downward through the soil, allowing excess moisture to drain away and enabling air to fill the spaces between soil particles. In contrast, containers limit this natural drainage. When garden soil is placed in a pot, water accumulates, saturating the soil. This saturated condition significantly reduces air space, depriving plant roots of the oxygen they require. Roots lacking sufficient oxygen will quickly become unhealthy and may eventually perish.
Importance of Air-Water Balance in Container Gardening
The critical consideration in container gardening is maintaining a proper balance of air and water. Good potting mixes achieve this balance by incorporating components that create larger spaces between particles, allowing excess water to drain while still retaining sufficient moisture and air for healthy root growth.
Soilless Potting Mixes
This requirement has led to developing specialized potting mixes, commonly referred to as soilless mixes. These mixes typically contain components such as bark, peat moss, coconut coir, compost, sand, scoria, or sawdust. These materials have larger particles than regular garden soil, which enables better drainage and increased aeration.
Understanding Perched Water Tables
An additional factor to consider in container gardening is the perched water table, which is the layer of saturated soil that occurs naturally at the bottom of any container. Because containers limit downward water movement, water collects at the container’s base, creating this perched water table. The height of this saturated zone largely depends on the particle size of the mix—finer mixes hold more water and have a taller perched water table, while coarser mixes drain more freely, resulting in a lower perched water table.
Choosing Mixes for Different Container Sizes
Due to the perched water table, smaller containers are particularly prone to saturation, as the saturated zone occupies a larger proportion of the container volume. Consequently, smaller containers often require mixes with larger particles to ensure better drainage and adequate aeration. Conversely, larger containers have proportionally smaller perched water tables, allowing the use of mixes with slightly smaller particles that retain moisture more effectively without compromising root health.
Creating Customized Container Mixes
By thoughtfully selecting and combining these components, it’s possible to create mixes specifically tailored for various container sizes and plant types. A well-formulated container mix ensures an optimal environment, promoting strong root development and overall plant health.
American Flower Power ®
Flower Power was developed for the cannabis industry, but it has proven to be an excellent choice for general container growing and raised beds. Our goal in formulating Flower Power was to maximize growth in a balanced manner, yielding strong stems and large, dark green leaves. After conducting numerous field tests with various organic nutrient sources and structural matrices, we developed a mix that meets our criteria. Root development is also very healthy and well-distributed throughout containers of all sizes, from one gallon and larger. Flower Power works exceptionally well in large field containers.
Of all our blends, American Flower Power possesses the highest nutrient content and has become the preferred choice when rapid, robust growth is essential. Flower Power is a proprietary mixture of coconut coir pith and fibers that maximizes air space while providing excellent water-holding capacity. Additional ingredients include aged fir bark, scoria, worm castings, biochar, feather meal, poultry manure compost, gypsum, dolomite, and oyster shell.
How To Use
American Flower Power is designed for use in containers of 1 gallon size and larger. It also performs excellently in raised beds up to 24 inches tall. If the raised bed is placed on soil, create a transition zone between the Flower Power and the existing soil by loosening the soil to a depth of 6 inches or more and mixing in some Flower Power. This approach will encourage root growth into the subsoil.
We can also recommend using Flower Power as a soil amendment. If you are digging up some soil, adding Flower Power can enhance it and increase its fertility. Flower Power contains a wealth of plant nutrients and additives to provide a boost to any soil. For a 12-inch depth of soil, use a 4-inch layer of Flower Power to blend in.
Multipurpose™
Multipurpose™ is designed to handle a variety of tasks in the garden. It can be used as a potting mix, a soil for raised beds, or a soil amendment. Its universal nature justifies keeping a bag or two around for those times that you may need a potting mix or soil amendment.
As a potting mix
Multipurpose contains very little mineral soil. Instead, it contains scoria (red lava) and rice hulls, giving the mix an open structure with excellent drainage and a good balance between air and water retention—all essential requirements for a container mix. In addition, it has a nutrient content that works well with flowers, trees, and shrubs. It is an excellent choice for larger pots planted with flowers.
For raised beds
Multipurpose is also suitable for raised beds placed over existing soil or on top of an impermeable surface like concrete (add at least 8 inches). Its fertility is well-balanced for growing both perennial and annual flowers. While it does not possess the high nutrient content of Local Hero, our premium vegetable garden soil, adding some balanced organic fertilizer, will ensure a bountiful harvest of vegetables.
As a soil amendment
Multipurpose™ contains all the essential ingredients for an excellent soil conditioner. Compost, fir bark, scoria, and rice hulls work together to create loose and crumbly soils. Apply a 3 to 5-inch layer over your soil and mix it into the top eight inches; you will immediately notice the difference. Alternatively, you can incorporate some Multipurpose™ into the ground and leave the remainder on the surface. It offers a pleasing natural appearance that will blend seamlessly with your plantings.
Ultra Potting Mix ™
UltraPotting Mix™ is our most popular potting mix and has been in continuous production for more than 15 years. Its primary ingredient is coconut coir pith, a renewable byproduct of coconut fiber processing. Coir provides a dependable balance of air space and water-holding capacity, making the blend suitable for a diverse range of container-grown plants. It performs well with flowers, herbs, vegetables, roses, and many common nursery crops. We have also grown more demanding plants—such as succulents and terrestrial orchids—with excellent results, illustrating the mix’s versatility. The mineral component of the blend is scoria sand, which adds structure and air/water balance. As with any potting medium, adjust irrigation to the needs of each plant group.
UltraPotting Mix™ is also designed to minimize staining from drainage water. Potting mixes containing compost or organic fertilizers can release dark effluent that discolors patios and walkways. To avoid this, UltraPotting Mix™ relies on a slow-release mineral fertilizer rather than compost-based nutrition. This also gives us better control of its fertility and plant growth characteristics. Because the fertilizer charge is rated for roughly three months, we recommend avoiding additional fertilization for the first four weeks.
As with all of our soil blends, UltraPotting Mix™ undergoes growth tests about every six weeks as part of our quality control program. It performs consistently and serves as an experimental control when testing new or standard mixes.
What’s in Ultra Potting Mix
The primary ingredient in Ultra Potting Mix is coconut coir pith, commonly known as coir. (For more information about coir, see our soil amendments section.) In addition to coir, we incorporate fiber, scoria, and a balanced mineral blend.
Ultra Potting Mix is one of the few blends we make without compost. This design choice originated from a request for a potting mix that would not stain patios or decks. Mixes that contain compost and high levels of organic fertilizers often release pigmented water after watering, which can leave stains when it dries on surfaces. By using only coir and slow-release fertilizers, Ultra Potting Mix minimizes staining and reduces nutrient leaching, a major concern in container gardening.