Once you have the amendments on hand, the is the question of how best to get them into the soil easily and effectively. This page is all about how to apply the amendments, including if you are practicing or planning no-till growing. We have a handy table of recommended application methods for each of the amendments below.
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 applied at the same time. But nitrogen and boron and sulfur (usually as gypsum) especially should be added to the soil just before planting. They are likely to leach over the winter.
For small area, like under an acre (although perhaps less than 3 acres) we apply the individual minerals separately, starting with the smallest amounts.
When applying small amounts of BioMin Copper or Copper Sulfate, Sodium Molybdate Dihydrate and Cobalt Sulfate we often use a sprayer. (These amendments are particularly difficult to handle; see the section below on cautions.) We dissolve the minerals in warm, good water (bicarbonates are less than 70 ppm). A lot of problems can be avoided by using reverse osmosis water in the tank. We have applied these minerals separately, but it may be possible to combine them in the same tank. Do a jar test to see if the sulfates cause precipitation. Check the bottom of the tank when finished, and if there is residue, add more warm RO water, and go over the area again. The amount of water applied is not important, just the weight of the minerals.
A small amount of humic or fulvic acid is a great addition to the tank. It will help to complex or lightly chelate the minerals. Read more about foliar applications here.
We find it easier to apply borax, manganese sulfate, gypsum, sulfur, N sources and most other minerals one at a time, just casting them by hand as evenly as we can.
If the area is large, or for other reasons you want to make just one trip through the field, all of the minerals may be blended with compost before applying. We purchased an “Odd Job” roll around concrete mixer for this – it will hold about a sack of concrete. Larger areas will require a larger mixer. 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. The disadvantage of this technique is now we have to be careful with the whole mix, not just one component.
Avoid mixing calcium sources like lime and gypsum with phosphate sources in the same hopper, so we do not tie up the phosphorus. The phosphorus sources especially need a bioactive soil in order to be available to plants. If you are making serious compost, it might be best to incorporate your P sources into that process. With phosphorus, it is not so much the amounts which matter, but the availability.
The advantage of no-till gardening is better biology and lower weed pressure. The disadvantage is stratification of the nutrients. At some point you will want to test the top 3″ and the 3″-6″ slice separately. Stratification can be a big issue; there are stories where nothing much would grow because of stratification.
The table on this page has information on which minerals will move in the soil profile, and which won’t. The table is for minerals in their elemental form; they are all mobile in their sulfate forms, especially when applied with water. So, if you need zinc (which is immobile in the soil), for example, you can dissolve it in water (as much as you can) and apply it during a rain event. It will penetrate to the depth of the water.
Phosphorus is very immobile in the soil. So, Fertoz or Calphos soft rock phosphate needs to be dug in. There is a way around this, which is to use a high P liquid fish every 7-10 days to feed the plants.
The same strategy of feed-the-plants rather than feed-the-soil will work for other nutrients. Zinc for instance, can be applied as a liquid and foliar (not just as a foliar – won’t be enough). This is lots of work compared to establishing a soil reserve for the plants to draw upon. You really need to evaluate the plants response to liquid minerals by maintaining a control area and presumably measuring the brix of the two areas.
In climates with moderate rainfall, the minerals will generally stabilize, and probably just the nitrate N, B, and S will need replenishing (for every crop). This is a great time to think about a no-till program.
Boron, Sulfur and Nitrate-N are anions and they leach. The boron and sulfate-sulfur can be surface applied, and they will make their way down when watered in. An N source, like feathermeal, requires a biological decomposition. If you leave it dry and on the surface, it will degrade/maybe vaporize until it finally gets wet and in contact with the soil. The same goes for surface-applied compost.
If you need to raise your pH with lime, there really isn’t another way other than digging it in.
If you are practicing or planning no-till, please see additional information here.
If this is a first time application, consider tilling or spading the amendments in to a depth of 6 inches (15 cm) to mix them thoroughly. Although tillage has a detrimental effect on soil biology, it is helpful to correct major nutrient deficiencies before beginning a no-till program.
OrganiCalc has a place to enter the depth you will be digging your amendments into. Normally this is 6 inches (15 cm), or the depth of your soil sample.
The first time you mineralize, apply the recommended amounts of Kelp or Azomite for the trace minerals we don’t test for. If you cannot afford the recommended amount, apply what you can afford. Quantities can be reduced/eliminated in subsequent years. Or, you may substitute foliar feeding with liquid kelp, about every 2 weeks.
In many cases cobalt can wait until the second year – there are often so many issues their effects are masked by other deficiencies or excesses.
Read the MSDS for all of the organically approved sulfates. These can be found by an internet search for “safety data sheet” and the name of the amendment. In general you will want to avoid touching or breathing or ingesting any of the materials.
Cobalt is especially hard to handle safely. Be sure to wear a dust mask or respirator and gloves as required. Store it in a locked cabinet. Or, better yet, spray any excess around the orchard or other areas. See a cobalt safety data sheet.
Boron has a relatively narrow range of appropriate levels in the soil. Too little means that plants won’t grow to their full potential. Too much and the result can be boron toxicity, until the boron is leached below the root zone. Until you get the hang of how much is just right, it’s a good idea to measure carefully.
Don’t breath any dust. If an amendment is dusty, wear a dust mask while working with it.
For best results apply all the recommendations. However, for large areas it may be necessary for cost reasons to triage the mineral applications. The Kelp/Azomite application is the first to go. It is a single large application to cover minerals we don’t test for.
Next, look at the bar graph at the end of the analysis. If the micronutrients are over 50% maybe there is enough there. These small measurements are difficult for the lab to make.
If your copper is over 2 ppm it is not deficient. We strive for 5 ppm so there is plenty there.
The amendments that will remedy the largest deficiencies are generally the most important. Although all the plant-essential nutrients are essential, some are more critical than others. The big three, nitrogen, phosphorus and potassium, are the ones that plants use the most of. A critical deficiency of any of these will usually cause serious setbacks.
|Amendments to add to the compost pile
|Azomite (for trace minerals)
|This is a clay. It is immobile in the soil. Clay is an excellent addition to the compost pile, better to use it there. It will do no harm if applied to the soil surface and will perhaps work its way down as a result of weeding and transplanting.
|Kelp (for trace minerals)
|Kelp or seaweed is a good source of trace minerals. Fresh seaweed needs to be rinsed with fresh water to remove salt before adding to the pile.
|Rock Phosphates (CalPhos, Fertoz)
|This is a clay and may be added to an active compost pile. Microbial activity will make the phosphorus more available.
|Biochar or bone char
|Both of these materials are the product of pyrolysis and need to be resupplied with nutrients before adding to soil, otherwise they can strip nutrients from the soil. These are excellent additions to the compost pile where they can take up excess nitrogen and other nutrients that may otherwise be lost.
|Basalt or granite rock dusts
|These are great additions to the compost pile where they can begin weathering and supply minerals.
|Amendments that must be dug in
|Ag Lime (Calcium Carbonate)
|If lime is needed in order to increase pH and calcium, it must be dug in.
|If dolomitic lime is needed in order to increase pH, calcium and magnesium, it must be dug in.
|Oyster Shell Flower
|Similar to lime, oyster shell flower will raise soil pH and needs to be dug in.
|Rock Phosphates (CalPhos, Fertoz)
|Rock phosphate is insoluble in water and phosphorus is immobile in the soil. It needs to be dug in. Microbial activity and organic acids will release it slowly over the span of years.
|Bone meal has phosphorus in a form similar to that of rock phosphate. It needs to be dug in.
|This is a mined rock and it has very low solubility. If you are going to use it. dig it in.
|This is a mined source of silicon that is insoluble in water. It needs to be dug in to begin weathering.
|Basalt or granite rock dusts
|Rock dusts are not soluble and need to be dug in.
|Amendments to scratch into the soil surface and watered in. These may be dug in too.
|Tiger-90 Elemental Sulfur
|This requires a type of microbe found in all mineral soils in order to lower pH and release plant-available sulfate. It must be in contact with moist soil. The microbes that break it down may not be present in a sterile growers mix. They are present in mineral soil.
|Gypsum (Solution grade)
|Gypsum is not very soluble, even as "solution grade" (which is just very finely ground gypsum). It needs a lot of water to dissolve and release calcium and sulfate into the soil. Once dissolved, the calcium part is not very mobile in the soil and will stay put. The sulfate part is very mobile in the soil and will leach with rain or irrigation.
|Soybean meal needs to be digested by microbes before it loses its phytotoxic effect and does not inhibit seed germination or burn transplants. Scratch it into the soil at least 2-3 weeks before seeding or transplanting.
|Microbial activity breaks down feather meal into plant available nitrogen. For this to happen it needs to be in contact with the soil and kept moist. Scratch it in and preferably cover with a light mulch. Apply close to transplanting or seeding. Usually it is also sidedressed a couple times during the season, or a liquid N is applied.
|Seabird Guano (0-11-0)
|This contains soluble phosphorus which needs water to dissolve. Scratch in and add enough water to moisten the top 6 inches, but not so much as to run off. Once in the soil the phosphorus will likely be immobilized by calcium and stay put.
|Composts as fertilizer or microbial innoculant
|See this page for advice on how much compost to apply to your soil. Get the compost in intimate contact with the soil for best effect.
|Amendments that can be dissolved in water or scratched in. These may be dug in too.
|All of these amendments dissolve easily in water. The dry powder may be spread evenly on the soil surface and watered in. Or they may be dissolved in enough water to spread or spray evenly onto moist soil surface, at least 1/4 gallon per 100 sq ft.
*Be sure to check the safety instructions before handling copper sulfate or cobalt sulfate.
|Magnesium Sulfate (Epsom Salts)
|K-mag, Langbienite, SulPoMag
|Sodium Molybdate Dihydrate
|Amendments to apply right before seeding or transplanting
|Scatter it thinly on the soil surface. It leaches very easily so do not water it in.
|Dissolve in enough water to cover the area evenly and spray or spread on.
|Nitrogen amendments except soybean meal
|Most nitrogen fertilizers have immediately available nitrogen. Nitrate-N leaches easily so do not overwater these. Plants may need a side dressing of N - see How Much Nitrogen Shall I Add?
|Liquid amendments to apply to the soil surface
|Mix with enough water to evenly cover the area and spray or spread on moist soil.
|Seabird Guano "tea"
|Soak 1-2 tbsp per gallon for 48 hours, agitating periodically. Spray or spread evenly on the soil.