Soil Analysis – how to read pH and nutrient levels
A soil test is the cheapest investment in the garden: a few euros and you know what is actually missing instead of guessing. The catch is that the result is a table of numbers with no context. This tool turns every parameter — pH, phosphorus, potassium, magnesium, calcium, organic matter and micronutrients — into a clear rating and a concrete recommendation.
What the tool evaluates
Enter your test results and the tool rates 13 soil parameters, assigning each a level: very low, low, optimal, high or very high. It adds a recommendation for each — for example "potassium fertilizing recommended" or "stop fertilizing and leach nutrients". The thresholds are based on agronomic ranges for vegetables.
| Parameter | Optimal range | Unit |
|---|---|---|
| pH | 6.0–7.0 | — |
| Phosphorus (P) | 15–25 | mg/100 g |
| Potassium (K) | 20–30 | mg/100 g |
| Magnesium (Mg) | 5–8 | mg/100 g |
| Calcium (Ca) | 150–300 | mg/100 g |
| Organic matter | 2.5–4.0 | % |
| Salinity (EC) | < 0.5 | mS/cm |
Soil pH and liming
pH decides whether plants can even take up the nutrients present in the soil. Most vegetables like pH 6.0–7.0. Below that the soil is acidic and needs lime; above it, iron, manganese and zinc become hard to absorb.
Rough liming rates
pH below 5.0 (very acidic): 3–5 t CaO/ha. pH 5.0–5.5 (acidic): 2–3 t CaO/ha. pH 6.0–7.0: no liming needed. On a small plot, scale that to your bed area — the tool does this together with choosing a calcium fertilizer.
Organic matter — the foundation of fertile soil
Organic matter stores water and nutrients and feeds soil life. Below 1.5% the soil is depleted and needs heavy organic feeding (30–40 t/ha of compost or manure). The 2.5–4.0% range is the sweet spot, maintained with organic matter every 2–3 years.
Salinity (EC) — the silent seedling killer
High salinity usually means mineral over-fertilizing. Above 2 mS/cm you must stop fertilizers and leach the salt with heavy watering. The symptoms — brown leaf margins and stunted growth — are easily mistaken for drought.
From result to action
The rating is only the first step. From it, the fertilizer calculator matches specific fertilizers to the deficiencies found and converts doses to your bed area, and you can log what you applied so you never fertilize the same shortage twice.
Frequently asked questions
What pH is best for vegetables?
For most vegetables the optimal pH is 6.0–7.0. Exceptions that prefer more acidic soil include potatoes and blueberries. Below 6.0 consider liming; above 7.5 consider acidifying.
How often should I test my soil?
Repeat a basic test (pH, P, K, Mg) every 2–3 years, or more often if you have growing problems. Take a sample from several spots in the bed, 15–20 cm deep.
When should I lime the soil?
Best in autumn or early spring, before the growing season. Do not combine liming with manure or nitrogen fertilizer — leave a few weeks between them.
Does this replace a lab test?
No — it is a result interpreter. You enter values from a lab test or a meter and the tool turns them into ratings and recommendations.
Soil Analysis – how to read pH and nutrient levels
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