Soil testing is one of the most important steps in growing giants, and if you dream of setting a record it is a must. Test results may be confusing at first but you can find someone to help you at no cost at several websites. Back Yard Giant Pumpkin Growers or Garden of Giants or at bigpumpkins
Some companies will give you recommendations on what and how much to use. Home test kits are worthless for the amount of information you need, tests should include results for pH, texture, soluble salts (ECe), Cation Exchange Capacity , percent lime, percent organic matter, nitrates, ammonium, phosphorus (alkaline soils – sodium bicarbonate extract, acid soils – Bray extract), potassium, calcium, magnesium, sodium, zinc, iron, manganese, copper, sulfates and
The Langley Soil Estimator allows you to see how adding a nutrient to your soil can change the balance between them. To help you learn how, do your own Langley estimate and compare it to the results from an experienced grower that is helping you. Many soil testing companies will recommend what nutrients you should add and it will give you accurate results without using the Langley calculator but it can fine tune it for you.
All soils will have a different amount of nutrients and texture, you strive to get the ratios correct not the amounts. If you start out by guessing what you need you could get one nutrient so high that you cant get the ratio of the others correct
The main page of the Langley Soil Estimator, the top information is entered in from your soil test, the lower section has common nutrients preloaded, you choose which you would like to use or you can add your own products to the list.
The examples in the two images below are from separate gardens and not related to each other
The above test is from Way Point Analytical Recommended test is S3M $16.50
Western laboratories will email your results like this. The top section is what you have, the bottom is their recommendations Atlantic Giant Pumpkin Soil test $55 .
We are using the recommendations from the westerns labs test in this example. This is for 1000sqft we will adjust it later to your garden size. The numbers to the left are in pounds on the right ounces are used. First you have to decide what type of products you will be using. Common fertilizers to use but not necessarily the best choices are
21-0-0 Ammonium Sulfate+24% sulfur
12-0-0 Blood meal is organic giving it a slow release N
45-0-0 Urea is a fast N source and can be lost quickly
11-52-0 MAP monoammonium phosphate + 18% sulfur
0-52-34 Monopotassium Phosphate no sulfur
0-0-50 Potassium sulfate +18% sulfur
Iron sulfate 20%
Zinc Sulfate Monohydrate — 35.5%
Manganese Sulfate Powder – 32%
99% pure copper sulfate is 25% copper
Magnesium (epsom salts) 11%
Boron – if using mule team borax 11%
When it comes to the math these results are simplified by the fact that you need close to 3 pounds of N-P-and K. If we use a slow release 20-20-20 fertilizer you can get all three pretty close.
You need 3.1 pounds of Phosphate the 20-20-20 is 20% Phosphate. Divide the amount needed 3.1 by the percentage of your product which is 20% 3.1 ÷ .20% = 15.5 pounds of 20-20-20 fertilizer is needed. This also gives you 3.1 pounds of Nitrogen and 3.1 pounds of Potash
Two more examples If you need 3.5 pounds of Nitrogen and you use 21-0-0 fertilizer divide 3.5 ÷ by.21% = 16.66 pounds of your fertilizer is needed.
If you used 12-0-0 Bloodmeal divide 3.5 ÷ .12% = 29.16 pounds of bloodmeal is needed.
Divide the pounds used by 1000 then multiple by the number of square feet of your garden.
If your garden is 852 sqft. Divide 29.16 pounds of blood meal by 1000— 29.16 ÷ 1000 = .02916 then multiple by 852 sqft. —.02916 x 852 = 24.84 pounds of blood meal for your garden