NPK 16-16-16: read the label and compare it with 15-15-15

Summary: An okra grower asked how 15-15-15 differs from 16-16-16 and whether to add a “fruit fertilizer” after flowering and fruiting began. Start with crop details and the actual label—not bag colour or the word “fruit.” A grade alone does not establish what to apply, how much or when to switch. This page helps you gather the information needed to check the choice.

What do the 16-16-16 and 15-15-15 figures tell you?

If confirmed on the label, both grades state balanced N-P-K figures; 16-16-16 shows slightly higher numbers than 15-15-15 for all three components. Read the complete bag or product sheet, including the analysis basis and any additions. Do not turn that numerical difference directly into a claim about yield, rate, savings or suitability for a particular crop.

On the conventional fertilizer-grade basis N–P₂O₅–K₂O, an equal 50 kg net pack illustrates the difference: 15-15-15 represents 7.5 kg of each stated component; 16-16-16 represents 8 kg, or 0.5 kg more each of N, P₂O₅ and K₂O. P₂O₅ and K₂O are oxide equivalents on the label, not elemental P and K weights. This is label arithmetic only; check the actual pack analysis and net weight. It does not establish an application rate or crop suitability.

To compare two identified products, record the product name and full analysis, net pack weight, price for the exact pack, quote date and delivery charge. “Price per kilo of nutrients” is not a reliable substitute for comparing fertilizer programmes or agronomic fit.

Okra has started flowering and fruiting: do I switch grades?

One captured buyer asked whether okra that had started flowering and fruiting needed a “fruit fertilizer”. That is a decision question, not evidence for a general instruction to switch from 15-15-15 or 16-16-16.

The DOA field package for okra lists NPK 12:12:17:2 with chicken manure for most soil types, with applications at weeks 2, 6, 10 and 14 after planting ^[source]. Check soil-specific rates in the original schedule; this page does not prescribe a rate for an individual farm. It is also a field programme, not proof that your bag of 16-16-16 should be replaced on the day flowers appear. Check the original schedule for your soil and system before changing the programme.

Replace the shorthand “fruit fertilizer” with the specific questions: what formula is on the label, for which crop and growing method, at which stage, and at what rate in a matching programme?

What details determine whether a programme fits?

Do not transfer advice between crops just because both bags show three NPK figures. Before choosing or switching, note the crop and variety, age or stage, field or container system, soil type if known, complete product label, what fertilizer was applied and when, and the programme you intend to follow. Rates and timing should come from guidance that names the relevant crop and conditions; if that is unavailable, ask the Department of Agriculture or a local crop adviser.

For field okra, the cited example is the DOA okra crop package. It names a formula and application weeks, while the soil-specific rate must be checked in the original table ^[source]. If you grow in containers or another system, do not assume that field programme applies unchanged.

Buying: request a quote you can compare

Separate the price of the product from its suitability for a crop. The price range cited here is a dated observation for a generic repack listing class, not today’s quote, an authenticated product or a delivered total ^[source]. For a current comparison, ask about a product you can identify: name as printed, full analysis, net weight, number of bags, quote date, delivery to your postcode and final total.

Ask for a photo of the actual label on the batch or pack to be supplied and a written quote. If the seller confirms availability but not the label or contents, mark that detail as unverified. The 16-16-16 price page separates dated asking observations by pack and date; compare a current quote separately.

Next step for the okra question

For a useful check, note whether okra is in a field or container, planting date or age, soil type if known, complete grade on the current bag, and the date/rate of its last application. Then compare with the DOA okra package and inspect the original soil table. If asking a seller about stock, send a label photo and request a quote; do not treat a seller’s supply confirmation as verification of dose or crop suitability.

Copyable message:

Hi, I grow okra in a ____ (field/container), planted on ____. It has started flowering and fruiting. Fertilizer used: ____; full label/analysis: ____; last applied on ____. Please confirm the name and label of the product you can supply, pack weight, dated price, delivery to postcode ____ and final total. I will check the rate against suitable okra guidance.

Ask about NPK supply

The GrowEasy NPK supplier route accepts enquiries; the available offer facts do not publish a price or SKU list ^[source]. You can send your crop, stage, a photo of the label you want, pack weight, quantity and postcode to ask about availability and a quote. This is a supply enquiry, not agronomic advice. Confirm product, net weight, dated price, delivery and written final total before paying. BETUL10 is mentioned in the CTA as a first-order offer; confirm eligibility for the exact item first.

Related: how to read an NPK label · 16-16-16 price observations · DOA okra package