Among other things, I have spent the last year studying optimal formulations for growing tomatoes in all types of environments. It has been very rewarding from both an analytic and personal standpoint. The results are applicable to nearly all annually grown herbaceous fruiting plants, including members of Solanaceae (tomatoes, peppers, potatoes, eggplants, ...), Cucurbitoids (melons, squash, cucumbers, ...), Beans (kidney bean, lima bean, ...); but not other legumes such as peas -- or for that matter cannabis.
Key point #1: There are presently no single-bottle, single-bag, or single-box solutions. Please don't ask where to buy it.
Many commercial growers have known some or all the formula for decades and if you wish you can go read about it at university agriculture extension web sites, and also at web sites of some commercial suppliers. The "mix" is not available in a single bag for historically practical reasons -- one of which is the difference in mineral content among farmers' water supplies. This is changing due to the increased use and lower prices of reverse-osmosis water filtering systems.
First let's look at the primary nutrients N, P, K. There are several scenarios:
1. Soil grown, determinate types, organic: 4-4-7
2. Soil grown, indeterminate types over a long season, organic: 4-2-7
3. Soil grown, determinate types, water-soluble: 11-12-21
4. Soil grown, indeterminate types, water-soluble: 11-6-21
5. Hydroponic, determinate types, liquid: 4-4-7
6. Hydroponic, determinate types, water-soluble: 11-12-21
Key point #2: All of these are applied during growth phases 1, 2, and 3 so that the concentration of K (potash) is respectively 150ppm, 200ppm, and 250ppm.
Now because my interest in obtaining a tomato food that is suitable for consumers and also acceptable by those interested in organic gardening principles, I am going to focus here on the lower concentration scenario. Why lower? Because it is not possible to have a higher concentration of nitrogen and satisfy USDA certified-organic requirements. I would also like a liquid solution so that the efficiency of fertilizer injection can be employed, both in soil-based and hydroponic applications.
Ok, so having stated all my caveats (
) here is the scenario for soil-grown:
4% N
4% P
7% K
0.43% S
0.85% Mg
1.70% Ca
0.1% Fe
0.005% Cu
0.02% Mn
0.01% Zn
0.02% B
0.0015% Co
0.0015% Mo
0.4% Alfalfa Extract
0.25% Barley Extract
0.4% Kelp Extract
0.4% Sugars
1.2% Humic Acid
For hydroponics, extra Sul-Cal-Mag is needed. The changes are:
0.9% S
1.75% Mg
3.50% Ca
So in future posts I will explore what it will take to get this mixture from available materials and what it will take to get it produced on a commercial scale.