How-to guide · Sap & Tissue sampling

The better the samples, the more consistent the results.

One sample, two results. Collect the youngest fully mature leaf, pack it securely, and send it in. We'll handle the rest. Follow these seven steps for an accurate reading.

Start the walkthrough ↓Jump to checklist

7:30–10:00

The morning window to sample

90–120

Leaves per sample (150–300 g)

1 sample

The lab analyses SAP + TISSUE

Where to sample

Location of sampling

Where you walk decides what the report represents. Sample the crop that represents the block, not its edges or its outliers.

Skip the outermost rows, and the first and last 10 steps of each row.

Pick only healthy leaves that reflect the average condition of the crop.

Sample from the same side of the plant (sunny or shady) the whole way through.

Got problem areas? Sample and label them separately, never mixed in.

When to sample

Best time for sampling

Sample between 7:30 and 10:00am. This is when the plant is fully hydrated and actively absorbing, giving a stable, repeatable reading. Stick to the same window every time so your results stay comparable.

5:00

Before the window

Hold off until 7:30. The plant isn't fully hydrated this early.

7:30

Optimal · 7:30–10:00

The plant is fully hydrated and actively absorbing, giving a stable, repeatable reading. Sample in this window every time.

10:00

Sap shifts · after 10:00 or 28°C

Transpiration speeds up and sap concentration shifts, so results reflect the plant under heat stress, not its normal balance.

14:00+

Which part

Which part of the plant to sample

Take the youngest fully mature leaf from the top of the shoot, not the newest emerging leaf, and not an older leaf further down. Sampling the same leaf position every time is what makes results comparable across samples and seasons, so you can track what's actually changing.

The ruleThe better the sample, the more consistent the results.

Remove the petiole, the short stem connecting leaf to plant, before packing.

Why it mattersOnce removed, the petiole keeps drawing sap from the leaf, diluting the sample and skewing your reading. The lab doesn't test the petiole itself, so take it off before packing.

Pear tree with marker 1 pointing to the fruiting shoots at the top of the plant

Hands removing the petiole from a young pepper leaf in the field

1 · Youngest fully mature leaf, top of shoot · 2 · Removing the petiole before packing

How much

Sample size: how many leaves?

90–120

leaves per sample

150–300 g

total weight

90–120 leaves (150–300 g) gives the lab enough material for both analyses. Larger-leafed crops need fewer; smaller leaves need more. If you're unsure for your crop, contact us for guidance.

One sampleThe lab splits your one sample into SAP and TISSUE, so there's nothing for you to separate. Just collect enough for both.

Represent the blockWalk the specific block and collect from multiple plants, not just the ones nearest to you or along the edges. A representative sample gives a representative result.

Pack & store

Packing and storing samples

✓ Do this

✓Pat wet leaves dry with a tissue before packing.

✓Stack leaves neatly in a zip-lock bag, fold large leaves to fit.

✓Squeeze all air out to prevent evaporation and degradation.

✓Keep samples cool in a cooler box or insulated bag in the field.

✓A fridge is fine for short-term storage before shipping.

✕ Never do this

✕Store wet leaves in the bag.

✕Leave samples in a hot car or under direct sun.

✕Mix healthy leaves with problem-area samples.

✕Freeze samples or rest them on ice packs, freezing ruptures cell walls and ruins the sap analysis.

Gloved hand stacking leaves neatly into a zip-lock sample bag — Stack leaves neatly, then press the air out.

Sealing a labelled sample bag while collecting in the field — Seal and label each bag as you go.

Ship it

Sending the samples

Prepare for shipment

Remove all air from zip-lock bags before sealing.

Hold at a stable temperature, not too hot, not too cold.

Storing before shipping? Use a fridge or air-conditioned room. Never freeze the samples.

Ship in a cooler box, away from UV light and temperature swings.

Where to send · overnight courier

South Africa · Intertek

Intertek Lab
Portion 113, Farm Elandsfontein, District Bapsfontein 412JR, 1510, Gauteng

East & Central Africa · Cropnuts

Cropnuts Lab
Crop Nutrition Laboratory Services, Limuru, off Limuru Road, P.O. Box 66437-00800, Nairobi, Kenya

Label your bag correctly first ↓

Insulated CROPNUTS cooler bag packed on shipping boxes, ready to send

Before you close the box

Quick sampling checklist

Correct part: youngest, fully mature leaf.

Petiole removed before packing.

Enough leaves collected (90–120).

Leaves dry before sealing the bag.

All air removed from the zip-lock bag.

Stored in a cooler bag while collecting.

Intake sheet matches the labeled bags.

Shipped as soon as possible for accuracy.

The one thing people get wrong

How you label the bag decides what we can read.

Every bag you send has to match its line on the intake sheet, exactly. If the label doesn't match, we can't trace the sample to your block, and the report is wrong or can't be issued. Two minutes of careful labeling protects the whole analysis.

A correctly filled label

DRIS SAMPLE LABELBatch #____

Client name

A. Green Farming

Farm name

Elandsfontein

Block name

Block 4 East

Crop / variety

Pear · Forelle

Sampling date

03 / 07 / 2026

Planting date

2019

One sample per blockThe lab analyses both sap and tissue. You send one labelled bag.

Write on the bag itself, or on a waterproof tag inside a second bag. Never on paper that can get wet.

Get these right, every bag

1Fill in every field, and copy it word-for-word onto the matching line of the intake sheet.

2Send one bag per block. The lab splits it into sap and tissue, so there's no SAP or TISSUE for you to mark.

3Problem areas get their own label, never mixed into a healthy-block bag.

4Write legibly in waterproof ink, cold bags sweat and smudge ballpoint.

If it's wrongA bag we can't match to the intake sheet is a sample we can't trust. In the best case it delays your report, in the worst case it can't be analysed at all.

Sample intake sheet

Ready to send your sample?

Log your batch on the DRIS portal before you ship. Capturing every sample online is what lets us match each bag to your block, so the label on the bag must match what you enter.

Submit online at the portal →

It's the same intake sheet, online: enter your details and every sample, and we'll email a confirmation and notify the lab. Then ship your bags to the lab below.

South Africa · ship overnight to

Intertek Lab
Portion 113, Farm Elandsfontein, District Bapsfontein 412JR, 1510, Gauteng, South Africa

East & Central Africa · ship to Cropnuts

Cropnuts Lab
Crop Nutrition Laboratory Services, Limuru, off Limuru Road, P.O. Box 66437-00800, Nairobi, Kenya

Curious what you get back? Good sampling in, precise nutrient-balance indices out.

See a DRIS sap report