Agra-wool - Speedgrow Sowing & Propagation Plugs

Basalt fibre plugs in a tray, for sowing and cuttings. Bonded with Ecose, a binder free of formaldehyde. Available in two cell densities, singly or by the box of eleven trays.

The one stone wool here you do not have to buffer

Ordinary stone wool asks for pre-treatment. Straight out of the packaging the material is not acidic, and without a soak at a set pH it pulls your solution upward over the first few days. Anyone working with stone wool blocks knows that step.

Speedgrow works differently. Agra-Wool state that these plugs need no buffering and that plain tap water is enough: wet them and use them. The difference lies in how the fibre is bonded. For a propagation tray that is worth more than it sounds, because a cutting with no roots cannot absorb a pH swing, nor does it have time to wait while you bring a tub up to value.

The binder also means the plug does not start at zero for conductivity but at a small value. Exactly how small is not documented anywhere by the manufacturer, so we give no figure and no period during which you supposedly need not feed.

Which cell density to choose

The choice is not about how many you can fit but about what you put in them. The roomier layout gives each plug more material to root into and more space between the stems, which suits thicker cuttings and seedlings you leave standing a while longer. The compact layout fits more into the same tray, which pays off for sowing in bulk and for thin cutting material that moves on to a larger medium quickly anyway.

Working at scale, it goes by the box of eleven trays.

Available sizes

Technical Specifications:

• Type: mineral fibre plugs for sowing and cuttings
• Manufacturer: Agra-Wool
• Material: Earthwool, fibre made from basalt
• Binder: Ecose, free of formaldehyde
• Cell density: 84 or 126 plugs per tray
• Packaging: single tray or box of 11 trays
• Preparation: wet with clean tap water, no buffering needed

Frequently asked questions

Do I really not need to pre-treat the plugs?
No. Agra-Wool state that wetting them with tap water is enough. That is the difference from ordinary stone wool blocks, which you do soak at a set pH.

When do I start feeding?
As soon as you see the first roots coming through the sides. Start light: a cutting that is not yet taking up has no use for a full solution.

What are the dimensions of a plug?
We do not state them. The measurements in circulation differ from the labelling on our own trays, and while that is unresolved we would rather name the cell count than a figure in millimetres.

Can I use them in any propagator?
The trays are a standard size and fit the common propagators. If in doubt, measure the internal dimensions of your lid.