Grodan Stone Wool A-OK Plugs 1.5 inch X 1.5 inch

Grodan A-OK Starter Plugs for Leafy Greens, Herbs and Cuttings

Grodan built the A-OK 36/40 plug for lettuce, leafy greens and herbs in hydroponic systems, and it handles any seed or cutting too. Each plug measures 36 x 36 x 40 mm, which works out to 1.4 x 1.4 x 1.6 in. Ninety-eight square plugs sit joined at the top in a 7 x 14 sheet that drops into a standard 10 x 20 in tray. Here each sheet comes individually shrink wrapped, sold one at a time or as a carton of 30 sheets and 2,940 plugs. The stone wool has a uniform density, firmness and fibre structure from plug to plug. That uniformity spreads water, nutrients and pH evenly, so a whole tray germinates on the same schedule. Each plug tapers toward the base, which lets it separate cleanly from the sheet at transplant. Saturate the sheet in a balanced nutrient solution at an EC of at least 1.5 mS/cm and a pH between 5.5 and 6.5. Soak it for several minutes, or pass over it a few times with a coarse spray, then let it drain. Weighing a few sheets from different benches confirms they are evenly saturated.

1.5 Inch Rockwool Cubes From Sowing to Block

Once the sheet is wet, a seed or a cutting goes straight in. Cuttings want a humid space, and domes should be vented gradually as roots form. Record the starting tray weight, because lifting the tray is the quickest way to decide when to irrigate. Stone wool holds far more water than a young root can use, so overwatering stalls more starts than drought does. Keep irrigation light and frequent while roots are still inside the plug. When roots show at the base, tear the plug from the sheet and set it into a fully saturated block. Water generously for the first few days after the move so the plug never dries against the block. Rooted plugs for lettuce or herbs can also go straight into an NFT channel or a floating raft. The shrink wrap keeps each sheet clean and square until the day it is used. That makes a single sheet easy to store between sowings, and a carton easy to stack on a shelf.

Key Features

• 36/40 Format: Each stone wool plug measures 36 x 36 x 40 mm, 98 to a sheet.
• Shrink Wrapped Sheets: Each sheet stays clean and square until it is conditioned and sown.
• Fits a 10 x 20 Tray: The 7 x 14 sheet drops into a standard propagation flat.
• Uniform Density: Water, nutrients and pH spread evenly, so a tray germinates together.
• Tapered Base: Plugs separate cleanly from the sheet and seat firmly in a block.
• Built for Leafy Greens: Suited to lettuce, herbs and leafy greens in hydro, and to any seed or cutting.

Technical Specifications