Seeds
Growing seeds for reproduction takes knowledge, attention and experience, and the Dutch agricultural sector has all of this in-house. During the growing season, the NAK acts as the supervising partner. We check that the seed crop grows well and meets the legal requirements.
Our seed laboratory adds another layer of quality control. It is certified according to ISTA-standards (International Seed Testing Association). This means the laboratory works according to internationally accepted methods. It is authorized to issue an ISTA-certificate with your sample.
Available tests
We offer the following laboratory tests:Moisture
The moisture content of a sample is determined using two methods: the furnace method and an electronic method based on NIR technology (Near-Infrared technology).
Cleaning
Our laboratory has its own cleaning department. Here, we clean small batches of seed using miniature cleaning machines, such as the clipper and the trieur. The clipper uses an upper sieve, a ground sieve and air (wind) to remove different types of impurities from the seed batch. The trieur removes impurities, such as sand and weed seeds, from the clean seed.
Before cleaning, we rub fescue and meadow-grass seeds to separate double seeds. During the cleaning process, the upper sieve catches the coarse parts of the sample, often pieces of straw. The ground sieve catches the finer parts, which are often heavier, such as sand or soil. The wind then blows away the light chaff. The trieur removes the remaining round parts, often sand and weed seeds, leaving clean seed behind.
Purity
Before the purity test, a working sample is prepared in the laboratory. This working sample is divided into four fractions: pure seed, harmless impurities (chaff, seed residues, sand and fungal structures), culture seeds and weed seeds.
The other seeds are identified by their scientific Latin name. Each fraction is then weighed, and the percentage of the total sample is calculated.
Count of other species
According to ISTA- and NAK-regulations, we take a larger working sample for the count of other species.
1,000 kernel weight
We determine the 1,000 kernel weight in one of two ways: using the entire purity sample, or using 8 groups of 100 seeds from the purified sample. A purity sample is the part of a seed sample that contains only pure seed, without other material such as chaff or weed seeds. Based on this sample, we calculate the weight of 1,000 seeds.
Variety testing
For variety testing, we use different methods depending on the crop. For oats, we use UV light. For wheat, we use a NaOH test (sodium hydroxide solution). Both methods help us check that the variety is genuine and meets the required standards.
Germination
The germination test is always carried out on pure seed. This means we first purify the sample in our laboratory.
Germination is measured under optimal conditions for each seed type, using ISTA-methods. The number of normal seedlings determines the germination rate.
The test includes several counts. The first count gives an early indication of the germination rate. The last count gives the final result. The number of counts depends on the seed type.
The result of the germination test falls into one of the following categories:
- Normal seedlings
- Abnormal seedlings
- Healthy seeds that have not sprouted
- Rotten seeds
- Hard seeds
We offer the following options for germination testing:
- Test with 400 seeds: ISTA-method
- Test with 300 seeds: NAK-certification method
- Test on disinfected seeds: we disinfect the seeds ourselves
Special germination
The special germination test determines the viability of the embryos in the seed. It gives an indication of whether the seed is viable and therefore has the possibility to grow into a seedling.
Seed health
Seed health research tests your seed samples on fungi that may occur on the seed. These germ fungi can have a negative influence on the germination of the seed.
Test results
After all requested tests are completed, you receive the results. You will always receive a NAK-result. If requested, you can also receive an ISTA-certificate. This certificate is available in two versions: orange and blue.
For the orange ISTA-certificate, the sample must be tested according to ISTA-methodology, and you must have requested a germination test on 400 seeds.
For the blue ISTA-certificate, you may submit your own sample.
Process time
| Process | Lead time* | Remark |
|---|---|---|
| Sample receipt | Within 2 working days | All necessary data must have been submitted correctly. |
| Moisture | Within 1 working day after the sample has been received | |
| Cleaning | Within 5 working days after the sample has been received | |
| Purity | Within 5 working days after the sample has been received | Unless the sample has to be cleaned before testing |
| 1000 kernel weight | Within 5 working days after the sample has been received | Unless the sample has to be cleaned before testing |
| Variety testing | Within 5 working days after the sample has been received | |
| Start getermination testing | Within 7 working days after the sample has been received | Unless cleaning is needed before testing |
| Determine germination | Depending on the method, differs per type of seed | 4 subsamples of 50 tubers |
| Start seed health testing | Within 5 working days after the sample has been received | |
| Determine seed health | Depending on the method, differs per type of seed |
Appeal
If you question the results of the moisture content, the purity percentage or the germination rate, you can request an appeal research. You can request the appeal within one month after we send you the test results.Sample weight
Seed samples sent to the NAK must meet a minimum weight. This weight depends on the type of seed. The minimum weights are set out in Table 2C, Chapter 2 of the ISTA-rules:
Germination and purity tests
| Species | Minimum weight (grams) |
|---|---|
| Cereals, peas, beans and sunflower | 1,000 |
| Seeds the size of a wheat grain, or larger | 1,000 |
| Seeds smaller than a wheat grain | 500 |
| Linseed | 500 |
Moisture samples
The minimum sample weight for a moisture test is 100 grams.
Packaging and logistics
- Samples must be packaged so that they cannot mix with other samples. The outside of the package must be free of chemicals and seeds.
- You must submit an application form together with your sample. If you want to submit a sample for research, you can download the form “Application for analysis” and the document “Instructions for application for analysis“. You can find both documents on the NAK forms page.
- We recommend that you pack your sample(s) in an air-permeable bag. This helps protect the quality of the sample. If you submit a moisture sample, the package must be vapour-proof. Pack moisture samples separately from samples for other types of examination.
- You can order sample bags from the NAK Logistics department. You may also use your own sample bag, as long as it meets the requirements above.
- We cannot accept improperly packaged samples or samples without an application form. These samples will be destroyed or returned at your expense.
- If your sample requires import documents for customs, make sure these are included. The sender’s name must be clearly visible on the package.
Fees seed testing 2026-2027
| Description | Price | Notes |
|---|---|---|
| Administration | ||
| Administration costs | € 26,20 | per sample |
| ISTA-certificate or copy ISTA certificate | € 3,20 | per certificate |
| Afterwards supply ISTA-certificate | € 12,60 | per certificate |
| Take-over of results from previous test | € 11,70 | per sample |
| Moisture test | € 21,25 | per sample |
| Purity test | ||
| Large grasses (Lolium spp, Festuca pratensis and Festuca arundinacea) | € 53,15 | per sample |
| Fine grasses (all other species) | € 70,80 | per sample |
| Poa spp (including test for indistinguishable species) | € 94,40 | per sample |
| Cereals, Mays, peas, Vicia spp, beans and Lupinus spp | € 21,50 | per sample |
| Other species | € 70,10 | per sample |
| Count of other species | ||
| Testing for other crop and weed seeds in the 10th time purity amount | ||
| When only weed or only crop seeds have to be examined, the price will be reduced with 40%. | ||
| – Fine grasses | €189,15 | per sample |
| – Large grasses and other species | €113,65 | per sample |
| – Other species | €113,65 | per sample |
| 1000 kernel weight | € 14,30 | Per sample |
| Count of other species in cereals | € 14.30 | per sample |
| Variety testing (NaOH) | € 14.30 | Per sample |
| Variety testing peas | € 37,75 | per sample |
| Variety testing Vicia faba (hilum colouring) | € 25,35 | per sample |
| Variety testing Triticum aestivum (Phenol) | €147,90 | per sample |
| Germination test | ||
| ISTA-method | ||
| – Cereals, Mays, Peas, Vicia spp, beans and Lupinus spp | € 47,30 | per sample |
| – Grasses and other species | € 69,80 | per sample |
| NAK-method | ||
| – Cereals, Mays, Peas, Vicia spp, beans and Lupinus spp | € 37,90 | per sample |
| – Grasses and other species | € 55,85 | per sample |
| Special germination tests | ||
| – Viability test (Tetrazolium) | €131,35 | per sample |
| Mixtures | ||
| (With mixtures all components are determined and each component is taken into account. Clearing the samples will also be taken into account.) | ||
| To clear the samples: | ||
| – One component | € 30,90 | per sample |
| – Two components | € 54,20 | per sample |
| – Three components | €147,55 | per sample |
| – Four components | €194,20 | per sample |
| Seed health test | ||
| Seed health test on Linum usitatissimum (agar method) | € 51,35 | per sample |
| Seed health test on peas and beans (agar method) | € 76,55 | per sample |
| Tilletia spp. (Bunt) | €234,95 | per sample |
| Testing Blind seed disease in grasses | € 65,75 | per sample |
| Anguina spp., Ditylenchus spp in grasses | €162,45 | per sample |
| Cleaning | €100,70 | per sample |
Advice and support
For specific questions about tests, samples, analysis, or logistics, contact our Customer Service Department at +31 (0)527-635350 or nak@nak.nl.
The NAK’s standard terms and conditions for the supply of goods and services apply to all our activities.