Two fertilizer bags sit side by side. Both say “NPK 20-20-20 with micronutrients.” One costs 40 percent more than the other. A buyer who only reads the front of the bag has no way to tell why, and usually picks the cheaper one. A buyer who knows how to read the full label and spec sheet can see exactly what the price difference buys, and whether it is worth paying.
This guide is for that second buyer. It covers what the numbers actually mean, what the important claims are, and what most labels quietly leave out.
The three numbers
Every fertilizer leads with three figures, like 20-20-20 or 15-5-30. They are always nitrogen (N), phosphorus (as P₂O₅), and potassium (as K₂O), in that order, expressed as a percentage of total weight.
A bag of 20-20-20 is 20 percent nitrogen, 20 percent phosphate, 20 percent potash, with the remaining 40 percent made up of carrier, binding agents, and whatever else the manufacturer included. The ratio matters more than the individual numbers, because different crop stages want different balances. A rooting product leads with phosphorus. A fruit-fill product leads with potassium. A vegetative-growth product leads with nitrogen. A label that only ever offers one ratio is not built for stage-based nutrition, which is the whole point of specialty fertilizers.
What “+TE” and “with micronutrients” really mean
The suffix +TE means “plus trace elements.” It signals that the product includes micronutrients like iron, zinc, manganese, copper, and boron alongside the main NPK. This is genuinely useful, since most soils run short on at least one micronutrient.
The catch is that “with micronutrients” on the front of a bag tells you nothing about quantity or form. A trustworthy product lists each micronutrient with its exact percentage. A vague claim with no breakdown is a small red flag.
Chelated versus non-chelated
This is where cheap and premium micronutrient products separate. A chelate is a molecule that wraps around a metal nutrient and keeps it soluble and available to the plant, especially in alkaline soils where raw metals lock up fast.
| Chelate type | Best pH range | Notes |
|---|---|---|
| EDTA | Up to about 6.5 | Cheap, common, fails in alkaline soil |
| DTPA | Up to about 7.5 | Mid-range, good for slightly alkaline conditions |
| EDDHA | Up to about 9.0+ | Premium, stays available in highly alkaline soil |
If your soil or irrigation water is alkaline, an EDTA-chelated iron product is mostly wasted money, because the iron precipitates before the plant can use it. This single distinction explains why two “chelated iron” products can perform completely differently in the same field. Dragon’s chelated micronutrient line is formulated to stay available across the pH ranges that real irrigated soils produce.
What the label does not tell you
Here is the part most buyers miss. The front of the bag advertises what is in the product. It rarely advertises what is in there that you do not want.
- Chloride. Many cheap potassium sources are potassium chloride. Chloride accumulates in soil and damages chloride-sensitive crops like citrus, avocado, grape, and blueberry over several seasons.
- Sodium. Builds soil salinity, especially under irrigation.
- Heavy metals. Lower-grade phosphate rock can carry cadmium and other contaminants that matter for export-market residue limits.
A serious manufacturer publishes a full analysis that states these are absent or below detection. Dragon Paste, for example, is produced free of chloride, sodium, and heavy metals, and that is stated openly rather than hidden. If a spec sheet is silent on chloride and sodium, assume they are present.
A quick red-flag checklist
When you compare two products, be cautious if a label shows any of these:
- Only one NPK ratio offered for every crop and stage
- “Contains micronutrients” with no percentages or chelate form listed
- No solubility figure for a product sold as water-soluble
- No mention of chloride, sodium, or heavy-metal content
- No pH or EC guidance for fertigation use
None of these are automatically disqualifying, but each one is a question worth asking your supplier before you buy.
Why this matters for your program
Reading a label well is the foundation for everything else: the return-on-investment case for specialty inputs, the foliar program you build, and the way you manage difficult irrigation water. A buyer who can decode a spec sheet stops overpaying for vague products and stops underpaying for the contaminants that show up three seasons later.
Dragon publishes full specifications for every product, and the quality systems behind them are ISO certified. To request a spec sheet or talk through a product comparison, the team is reachable through the contact page, and the full product catalog lists every line.
Frequently asked questions
What do the three NPK numbers on a fertilizer bag mean?
They are the percentages by weight of nitrogen, phosphate (P₂O₅), and potash (K₂O), always in that order. A 20-20-20 product is 20 percent of each. The ratio between them tells you what crop stage the product is designed for: phosphorus-led for rooting, nitrogen-led for vegetative growth, potassium-led for fruit fill.
Why does chelate type matter when buying micronutrients?
The chelate keeps the metal nutrient available to the plant. EDTA chelates break down in alkaline soil, so an EDTA iron product fails where soil or water pH is high. EDDHA chelates stay stable in alkaline conditions. If your water is hard or your soil is calcareous, the chelate form is the most important spec on the label.
How do I know if a fertilizer contains chloride?
Check the full analysis or spec sheet, not the front of the bag. If chloride and sodium content are not stated, assume they are present, since most low-cost potassium sources are potassium chloride. A manufacturer that produces chloride-free product will say so explicitly because it is a selling point.
Is a higher NPK total always better value?
No. A higher total just means more concentrated nutrients per kilogram. It says nothing about solubility, contamination, micronutrient inclusion, or whether the ratio fits your crop. A clean, fully soluble 20-20-20 can outperform a contaminated 30-10-10 for a given crop stage.