How to Apply Amendments

Before applying the amendments…

The first time you mineralize, apply the recommended amount of Kelp or Azomite for trace minerals. If you cannot afford the recommended amount, apply what you can afford. Quantities can be reduced in subsequent years. Or, you may substitute foliar feeding with liquid kelp, about every 2 weeks.

Many farmers prefer to lime in the fall, and add the other minerals in the spring. If this is not possible, all the minerals can be mixed together and applied at the same time. Nitrogen and boron especially should be added to the soil just before planting. They are likely to leach over the winter.

Blend all minerals with compost or humates before applying, if possible. Be sure to wear a dust mask and gloves for this. Mixing with compost is especially important for the sulfates which are usually applied in small quantities and are difficult to spread evenly. Check that the color of the mix is even everywhere before applying.

We especially recommend mixing phosphorus sources (rock phosphate and bone meal) and manganese with vermicompost, well-made active compost or humates (such as New Mexico leonardite) before applying. The phosphorus sources especially need a bioactive soil in order to be available to plants.

Humates are high CEC fossilized organic matter, high in carbon and very stable in the soil. They adsorb minerals onto their surface, and hold them so they are readily vailable to plants, a sort of chelation. Gently misting the humates before mixing with dry minerals encourages the minerals to connect with the humates. Humates are available as finely crushed rock or as micronized humates, for mixing with dry ingredients. Micronized humates are very fine particles which can also be applied with liquid fertilizers in a sprayer or through drip tape. It’s the humate’s surface area that counts, so a small package of very fine humates is as effective as a large bag of coarse material. Also, liquid humates are available which have been extracted with alkaline reagents. These are for mixing into liquid fertilizers.

Composted manure is a good source of phosphorus, potash, carbon, and sodium. It is a great substitute for rock phosphate and potassium sulfate, if your soil can stand the sodium that usually accompanying manures (we like to see sodium at 1% or less of total CEC). Compost is highly bio-active, and will provide a biological path for phosphorus assimilation when the ionic path is closed by high pH. Studies at Colorado State University show rock phosphate is ineffective at high pH, but that manure and manure based compost are effective. And (or), there is a high P fish fertilizer you may want to try if you have a high pH soil. Rock phosphate and bonemeal are especially unavailable to the plants if the pH is over 7.5. Instead, use composted manure, or mix rock phosphate or bonemeal or bone char into an active compost pile, then dig in the finished compost.

Unless your compost is tested for mineral levels (such a test costs in the $150 range), you won’t know how much to apply for P&K deficits. Make an educated guess, maybe spread a layer 1 inch thick, then re-test next year to see the compost’s contribution to P&K.

Applying the amendments…

OrganiCalc has a place to enter the depth you will be digging your amendments in to. Normally this is 6 inches (15 cm), or the depth of your soil sample.

Phosphorus is immobile. Mix well into the soil. Zinc is immobile. Mix well into the soil.

Spread the amendments evenly on the soil. If this is a first time application, consider tilling or spading them in to a depth of 6 inches (15 cm) to mix them thoroughly. Although tillage has a detrimental affect on soil biology, it is helpful to correct major nutrient deficiencies before beginning a no-till program.

When amendments cannot be dug in…

OrganiCalc assumes the minerals will be mixed evenly to the depth of your soil sample. If you cannot mix the minerals into the soil, as in an orchard, you can safely apply amendments at half the rate of the 6 inch (15 cm) recommendation, fertilizing to a 3 inch (7.5 cm) depth. (However, at least one very experienced analyst recommends applying the whole 6 inch amount.) In subsequent years gypsum will help carry the minerals downward to a certain extent, so it is best to plan on applying part of any calcium requirement the second or third year, as gypsum. If you can, apply a mulch to cover the minerals, and let the roots grow into the mulch.

If you can’t mix the minerals in, stratification will be an issue, especially if water is limited. Subsequent soil tests should be at different depths, from 1 to 6 inches.

After applying the amendments…

When transplanting, it’s nice to mix a tablespoon of bat guano with mycorrhiza into the soil immediately around the plant. This seems to make a big difference in our garden. Apply OMRI organic fish hydrosylate (E.B. Stone or equivalent) to young or leafy crops as needed. Do this about every 2 weeks when the soil is cold and doesn’t release enough N.

Many of the anions (N, S and B) leach readily and are used in large quantities by growing crops. If a second crop is planted, side-dress or dig-in feathermeal at 20 lbs /1000 sq ft (20 kg /1000 sq m). In cooler climates use feathermeal at 30 lbs/1000 sq ft (30 kg /1000 sq m). Sulfur and nitrogen work together, so blend up to 10 lbs/1000 sq ft of gypsum with the nitrogen. If you know your boron levels are low from an earlier soil test, you can carefully add a bit of boron too.

Sometimes we end up having much less zinc than phosphorus in the soil because of our application limit on zinc. Phosphorus could be blocking the plant’s uptake of zinc if available phosphorus is greater than 10x available zinc by weight. If you suspect a zinc deficiency you can try foliar feeding zinc sulfate (heptahydrate is more soluble than monohydrate) at 1 tbsp. /gallon to see if you get a response. Better yet, use chelated zinc as a foliar.

Retest next year…

You may want to retest next year at the same time of year, using the same lab, especially if your soil required fairly heavy applications of minerals or if you reached the application limits for any minerals. Once you get to the point where you know what to expect and your food is of excellent quality, you’ll realize that you don’t need to test as often.