Skip to content


OrganiCalc Pro is an online form that converts your Logan Labs soil test report into a list of recommended amendments designed to balance the mineral reserves in your soil. When you subscribe, you get access to OrganiCalc Pro, OrganiCalc for Vegetables and ORganiCalc Pro for Water on our website (they’re under the OrganiCalc menu).

  • Unlimited access for one year
  • OrganiCalc Pro works with Logan Labs Standard Test,  Standard with Extras, AA8.2 Test and AA8.2 with Extras
  • All of the mineral amendments may be modified.
  • Up to 6 carbon-based N-P-K amendments may be added (such as composts) or the standard amendments may be used.
  • Access to OrganiCalc Pro for Water is included for analysis of your irrigation water test
  • OrganiCalc uses calculation methods from the great agronomists in the biological, organic and regenerative world
  • Eliminates math errors
  • Trusted by soil analysts worldwide
  • Check out our testimonials


Which OrganiCalc Shall I Choose?

OrganiCalc for VegetablesOrganiCalc Pro
Designed for Logan Labs std soil test reports - Std M3, AA, AA8.2, extras, BFA Ag-dyn3
Analyze as many soil test reports as you care to
Trusted algorithm for choosing amendments
Recommendations for vegetablesDefault
Recommendations for only OMRI organic amendmentsDefault
Error checks for typos
Adjusts for sample depths other than 6"
Adjusts for area to be amended
Adjusts for depth to dig in amendments
Choice of US or metric units
Choice of Nitrogen target
Choice of 2 N-P-K fertilizers with "best fit" N-P-K hint
One custom N-P-K fertilizer
Choice of cation targets for sand, clay or loamDefault
Edit Ca, Mg, K and Na % saturation targets
Enter up to 6 custom carbon-based N-P-K fertilizers
C:N ratio of amendments calculated
Choice of P, S, B, Fe, Mn, Cu and Zn targets
All mineral amendments may be customized
Form remembers last entries
Includes OrganiCalc Pro for Irrigation Water
Required for commercial customers
Access to Soil Analyst forum


I have a soil test report from XYZ Lab, not Logan Labs. Can I use OrganiCalc with it?

Lab tests are not all the same. Other labs use different testing methodologies, even if they do a Mehlich 3 or AA test. OrganiCalc works best with Logan Labs soil testsThere is also a converter for Spectrum Analytic soil test reports.

You can order Logan Labs soil tests on our website, here.

When shouldn’t I use OrganiCalc?

OrganiCalc is designed to be an aid in growing nutrient dense food, however it is not applicable for certain circumstances.

Acid soil loving crops

If you are growing blueberries, rhododendrons, potatoes or other such plants, the recommendations are good, as long as the pH is low enough. OrganiCalc Pro allows you to set a target pH and will avoid adding lime or manganese. In OrganiCalc for Vegetables, don’t add the lime or manganese to acid loving crops.


These recommendations are for growing nutrient dense food, not for pasture. Aside from the expense of bringing large areas up to these levels, herbivores are very sensitive to changes in taste. Mineral application limits are much lower for pastures. Consult an analyst experienced in pasture management. Contact, and we will share what we have learned about pasture management.

Your soil is already balanced

Usually this happens after a few years of soil mineralization. Your soil settles to a point where the plants are growing very well. You don’t want to disturb this equilibrium, or lose valuable (cation) nutrients. You want to add only enough of the anion nutrients to grow a good crop: nitrogen, sulfate-sulfur and boron.

When your soil is mineral-balanced, it’s time to really focus on the biology.  5% organic matter is a nice number where summer is hot; 8 to 9 % is a good number where summers are coolish, such as in the Maritime northwest. Organic matter over 30% is more than enough.

Finally, if your soil is otherwise balanced and you have excess Ca, don’t try to fix it; leave it alone.

Can I use OrganiCalc for something besides vegetables?

Yes. OrganiCalc for Vegetables allows you to adjust the nitrogen target. OrganiCalc Pro allows you to adjust all of the mineral targets in order to tailor the report for any crop.

I have a bag of XYZ amendment. Can I use it?

OrganiCalc Pro allows you to change the list of amendments it selects from, and remembers the changes until the form is reset.  Alternatively you can use this form to convert a single amendment.

*Note that OrganiCalc is designed to prevent excesses of any nutrient in the soil and will not recommend an amendment containing a element that is already sufficient in the soil. So if your bag of XYZ contains magnesium and your soil already has sufficient magnesium, OrganiCalc will not recommend it.

Can I use compost along with my OrganiCalc recommended amendments?

Yes, but it’s good to have an idea of how many nutrients are being supplied by the compost. This page helps explain how much compost to use.

Back To Top