Metal Needle for 60CC Syringe

Sample Root-Zone Water Where a Surface Test Can't Reach

A pH or EC reading taken at the surface of a rockwool block or slab doesn't always reflect what's happening at the root zone, where drainage patterns and nutrient uptake can leave the deeper solution meaningfully different from the top layer. This Grodan metal needle attaches to a standard Luer-Lock 60cc syringe and reaches into the center of the block or slab, pulling a sample from the zone that actually matters for feed adjustments.

Sold as a single needle, it's built to attach and detach from a Luer-Lock syringe repeatedly across a monitoring routine without wearing out the fitting.

Key Features & Benefits

• Metal construction — holds up to repeated insertion into stonewool media better than a standard plastic needle.
• Fits any standard Luer-Lock syringe — attaches to any 60cc plastic syringe using the widely adopted Luer-Lock fitting.
• Reaches deep into blocks and slabs — pulls a sample from the root zone instead of only the surface layer.
• Supports accurate pH and EC monitoring — gives growers a reading that reflects actual root-zone conditions rather than surface runoff.
• Built for repeated professional use — designed to be reused across a monitoring schedule rather than treated as disposable.

Who Should Use This Sampling Needle

Commercial growers and serious hobbyists running a regular pH and EC monitoring routine on rockwool blocks or slabs are the fit for this needle, especially anyone who has noticed surface readings drifting from what plants are actually experiencing at the root zone.

About Grodan

Grodan pioneered engineered stone wool growing media in 1969 and is now part of the ROCKWOOL Group. Because so much of feed-solution monitoring happens directly inside its rockwool blocks and slabs, Grodan also supplies sampling accessories like this needle to support accurate root-zone testing.

Frequently Asked Questions

How does this needle attach to a syringe?

It uses a standard Luer-Lock fitting, the same twist-lock connection found on most 60cc plastic syringes used in hydroponic sampling. It threads on and off without tools, so it can be swapped between syringes as needed.

Why sample from inside the block instead of the surface?

Water and nutrient distribution inside a rockwool block or slab isn't always uniform, so a surface sample can read differently than the solution actually reaching the roots. Drawing from deeper in the media gives a reading that better reflects what the root zone is experiencing.

When should I take a root-zone sample?

Many growers check root-zone pH and EC on a regular schedule, such as weekly or after a feed change, to catch drift before it affects plant health. Sampling right before a scheduled feeding is a common approach, since it reflects conditions after the previous cycle has had time to settle.

Can this needle be reused across multiple samples?

Yes, it's built as a durable metal component intended for repeated insertion and use across a monitoring routine, not as a single-use item. Rinse it between samples if switching between different blocks or nutrient solutions to avoid cross-contamination of readings.

What syringe size does this needle require?

It's sized for a standard 60cc plastic syringe with a Luer-Lock fitting, which is the common size and connection type used for hydroponic root-zone sampling. Confirm your syringe uses a Luer-Lock connection before ordering, since a slip-tip syringe won't thread on securely.