Soil Amendments & Conditioners

It changes the physical or biological behavior of the soil it is mixed into. Depending on the product, that can mean better drainage in heavy ground, more water held in sandy ground, more air at the root zone in a container, more organic matter and biological activity, or improved structure in soil that has been compacted by equipment or foot traffic. Amendments are about how the soil works, which is different from fertilizer, which is about what the plant is fed.

A fertilizer supplies nutrients directly to the plant. An amendment changes the growing environment so the plant can use nutrients, water, and air more effectively. Some amendments carry incidental nutrient value, particularly composts, but the reason you specify one is the physical and biological effect, not the nutrient number. Most successful programs use both.

Perlite for maximum aeration at the lowest weight and cost, especially in short-cycle container production. Pumice for long-cycle crops, specimen material, and mixes that need durability and ballast, since it does not break down or float the way perlite can. Both are covered in more detail in the comparison section above.

Raw wood fiber can, because the microbes decomposing it pull nitrogen from the surrounding soil while they work. Treated and composted wood products are processed to reduce or eliminate that effect. If you are incorporating wood fiber into a root zone, use a treated or composted grade or adjust your feed program. If you are applying it to the surface, the effect is much smaller. Tell us the application and we will recommend the right form.

For general soil improvement, incorporating a layer of two to three inches of organic amendment into the top six to eight inches of soil is a common starting point, which works out to roughly one cubic yard per 100 to 160 square feet depending on depth. Heavier clay and badly depleted sites take more. For a specific spec, tell us the site conditions and what you are planting.

You can, and many growers do use a light compost layer as a topdressing. It will feed the soil as it works down. It will not do the other jobs a mulch does nearly as well, though: it suppresses weeds poorly, it breaks down quickly, and it can grow its own weeds if left on the surface. For a surface layer, a bark or mulch product is the better tool.

Our green compost is OMRI certified. If you are producing under organic certification and need to confirm which of our other inputs qualify or need documentation for your certifier, raise it at the quote stage and we will tell you exactly what we can supply.

Parboiled rice hulls are a lightweight organic aggregate used much like perlite, to open a mix and improve drainage while adding very little weight. Composted rice hulls have been milled, treated, and composted, which changes them from an aeration aggregate into an organic amendment that contributes structure and organic matter to a blend without the nitrogen drawdown of raw fiber.

It matters less than it does in a mulch, where color and weathering behavior are visible, but there are differences. Redwood is naturally fibrous and rot-resistant, so redwood-based fines persist longer in a blend. Fir products are widely available in a broad range of grades and are the more common volume component. For most blending applications, particle size and whether the material is raw or composted will affect performance more than species does.

Yes. Most of our customers buy finished blends rather than components, and custom blending to customer specification is core to what we do. If you have a formulation you want run, or a media you want matched, send us the details. See our soils and growing media page for our standard blends.

We deliver in bulk throughout Southern California and the Central Valley, with in-yard pickup, bagged, and palletized options available.

Keep material covered, off bare ground, and out of standing water. Peat and fine fibrous products are the ones to watch, since they are difficult to rewet evenly once they dry out completely. Perlite should be kept contained, as it is light enough to blow. Composts are best used within the current season, and should not be stacked so deep that the pile goes anaerobic.