Quick reference

Seed, germination & grinding reference

The tables labs come back to: how to space and germinate each seed, which substrate to sow on, and which beads and speed to grind with for seed DNA.

Seed spacing & sowing distance by seed type

Seed type	Seed size	Spacing on tray	Sowing depth
Arabidopsis thaliana	0.3–0.5 mm	3–5 mm	Surface (needs light)
Lettuce	1–2 mm	8–10 mm	Surface (needs light)
Brassica & cabbage	1.5–2.5 mm	10 mm	5–10 mm
Onion	2–3 mm	8–12 mm	5–10 mm
Tomato & paprika	3–4 mm	12–15 mm	5 mm
Wheat	5–8 mm	15–20 mm	10–20 mm
Maize	8–12 mm	25–30 mm	20–30 mm

Substrate: paper vs sand/soil vs coconut coir

What to germinate seeds on. Paper is the ISTA workhorse for viability; sand/soil and coir suit larger or transplant-bound seed.

Property	Blot / germination paper	Sand / soil	Coconut coir
Reproducibility	✓ISTA-standard, uniform	✗Quality & pathogens vary	✓Consistent, inert
Observation & scoring	✓Roots & shoots visible	✗Seedlings hidden	✗Roots below surface
Cost & reuse	✗Single-use consumable	✓Sand reusable, low cost	✓Low cost, renewable
Contamination risk	✓Disposable, low carry-over	✗Soil-borne pathogens	✓Largely sterile & inert
Best for	✓Viability tests, 5–14 d	✓Large / treated seed, vigour	✓Transplant-ready seedlings

Germination conditions by crop

Crop	Temperature	First / final count	Light	Notes
Arabidopsis	20–22 °C	3 / 7 d	Light	Cold-stratify 3–4 d at 4 °C
Lettuce	20 °C	4 / 7 d	Light	Dormant above 25 °C
Brassica & cabbage	20 or 20/30 °C	3 / 7 d	—	Alternating temp aids
Onion	15–20 °C	6 / 12 d	—	Prechill if dormant
Tomato & paprika	20/30 °C alt.	5 / 14 d	—	Warmth speeds paprika
Wheat	20 °C	4 / 8 d	—	Prechill for dormancy
Maize	20/30 °C alt.	4 / 7 d	—	Paper or sand

Seed grinding: which beads for which seed

Sample	Bead / media	Container	Notes
Small fresh seed (Arabidopsis, lettuce, brassica)	3.0 mm zirconia + 2.8 mm steel	Tube / deep-well plate	1–2 beads per well
Medium seed (tomato, paprika)	One 4–6.3 mm steel or zirconia	2 mL tube / 4 mL vial	Dissect to ≤50 mg
Cereal & hard seed (wheat, maize)	3× 3.2 mm or 1× 6.3 mm chrome-steel	Reinforced vial	Pulverises in ~30 s
Very hard / oily (palm, sunflower)	Tungsten-carbide, or cryo-mill	Steel vial	Steel alone may lack energy
Leaf punch (genotyping)	One 4 mm steel or zirconia	96 deep-well plate	~5 punches, ≤50 mg

Homogenizing method & speed

Method	Typical speed	Beads / media	Best for
Oscillating bead mill (TissueLyser-type)	25–30 Hz (~1500–1800 osc/min), 30 s–2.5 min	Matched to sample	Plates & tubes; DNA, RNA, protein
Reciprocating grinder (Geno/Grinder-type)	~1500 rpm, 1–2 min	4 mm steel / zirconia balls	Seed & leaf DNA, high-throughput
Vortex + plate adapter	Max speed, 2–10 min	0.1–0.5 mm beads	Microbes, spores, soft tissue
Cryogenic mill	Liquid-N₂, dry grind	Steel / tungsten-carbide	Hard / oily seed; high-MW DNA

Dispensing vs. vacuum & manual

Why dispense instead of a vacuum seeder

Hand-placing seeds is slow and inconsistent, and vacuum seed systems struggle with small, light or irregular seeds and need a suction head and pump for every pattern. A mesh-plate dispenser drops a full 100-seed pattern in one pull, with no vacuum, no electricity and no seed damage. Swap the mesh plate to change seed type or container: it was developed to replace vacuum seed dispensers and inefficient robotic dispensers.

Formats

LabTIE seed dispensers, every format

Swap the mesh plate to match your container, from blot-paper germination trays to 96-well genotyping. Tap any format to view it on LabTIE.