Rainbow Valley Compost

Soil Amendments and Fertilizers

Thriving sustainable agriculture is built on the ground of a healthy soil. In fact, organic certification requires a soil management plan. Do a soil test to determine your soil’s needs before embarking on a program of soil improvement. Check with your local Cooperative Extension for testing in your area, or consider our soil testing and recommendation service.

Soil amendments used with a program of crop rotation, composting and cover cropping can enhance fertility, improve soil tilth, promote disease resistance, support beneficial soil microorganisms, and even help restore balance to the garden and the world around it. Application rates vary depending on soil type and results of soil tests.

Fertilizers provide nitrogen and other nutrients in a form that is readily available to plants. Organic fertilizers can provide both an immediate boost and additional long-term fertility, feeding both the plants and the organisms that maintain soil health. We also offer soil amendments that have limited available plant nutrients but help to remineralize the soil, improve soil structure, or provide a long-term slow-release source of plant nutrients. Foliar sprays get nutrients directly to the leaves and can increase resistance to disease and to insect infestation.

Analyses provided here are those provided by the manufacturers, or, if none are available, from a Maine state lab test performed on our most recent lot: there is some variability in the nutritional analysis of natural fertilizers, so view these numbers as guides, not gospel. Fertilizers should be used as a supplement to, not a replacement for, the nutrients provided by healthy soil. Sustainability requires developing a long-term plan of cover-cropping, green manuring and composting.

Organic Certification

Inoculants, soil amendments, fertilizers, livestock supplies and pesticides are labeled as:
OMRI: Organic Materials Review Institute. Most state certifying agencies, including MOFGA, accept OMRI approval.
MOFGA: Approved for use by Maine Organic Farmers & Gardeners Association Certification Services. Check with your certifier.
WSDA: Listed by the Washington State Department of Agriculture’s Organic Certification division for use in organic agriculture in Washington State. MOFGA has indicated that they will accept products on this list for their certification program. Check with your certifier.
Nat’l List: One-ingredient products on the NOP* List of Allowed Substances (subpart G of the Organic Foods Production Act, sections 205.601-606). Check with your certifier.
AYC: Ask your certifier. Has not been reviewed by a certifier, but the active ingredient is allowed. Ask your certifier.
Not Allowed: A few of the products we list are not allowed for organic production but we think they have a place in sensible agriculture and can be used when certification is not an issue.

Items shipping from our growing supplies warehouse take 2-4 business days to process.