Re-Amendment Tips
How to Apply Amendments
For peat-based media, thoroughly incorporate amendments to the full volume of soil if possible. Recommendations are given in cubic yards for this reason.
Helpful tools:
If you are no-till, amendments should should be mixed with a small quantity of compost or mulch, topdressed, and watered in. Doing this in several applications is best if the amendment quantities are high.
For topsoil outdoors, incorporate minerals 6” deep if possible with a tiller, disc, or broadfork. If you plant to apply deeper than 6”, increase rates proportionally.
Micronutrients
All micronutrients (Iron sulfate, Manganese sulfate, Copper sulfate, Zinc sulfate, Solubor) should be applied in very small quantities. Dry applications should be avoided (Iron sulfate can sometimes be applied dry if the quantity recommended is high enough for even distribution).
The best way to apply these minerals is to dissolve them in water and spray or drench the soil for even distribution. Keep the solution well-agitated as you spray in case there is any settling. Alternatively, micronutrients can be dissolved in water and fertigated with good tank agitation.
Powdered vs Granular Products
Many of the amendments recommended such as gypsum, Potassium sulfate, langbeinite, and lime can be found in powdered OR granular forms. The only difference is the particle size of the product.
Powdered products = faster plant availability due to smaller particle size, and easier to apply through water.
Granular products = slower plant availability due to larger particle size, and easier to spread dry.
I generally recommend starting with powdered products because you can also use them mid-round for feeding your plants. They aren’t technically “soluble” but can be suspended in water and drenched on your soil.
After your soil is sufficient and balanced, incorporate more granular products for a slightly slower release rate in your soil.
Let the Soil “Cook”
If you apply a significant amount of nitrogen amendments, it’s important to let the amendments break down (aka “mineralize) for 2-3 weeks before planting.
This mineralization process converts nitrogen amendments from organic nitrogen to ammonium, and then to nitrate. If you plant early into a high-ammonium, low-oxygen soil, your plants will suffer.
Re-Test!
Several weeks after minerals are applied, perform another soil test to dial in nutrient levels even further.