---
product_id: 317174410
title: "Redrock 4 inch Rockwool Cubes – 4\" x 4\" Stone Wool Starter Blocks with 42/40 Hole | 6-Pack | for Hydroponics & Indoor Growing | Includes Twin Canaries Chart"
brand: "twin canaries liquid volume conversion chart"
price: "€ 42.46"
currency: EUR
in_stock: true
reviews_count: 8
category: "Twin Canaries Liquid Volume Conversion Chart"
url: https://www.desertcart.hr/products/317174410-redrock-4-inch-rockwool-cubes-4-x-4-stone-wool
store_origin: HR
region: Croatia
---

# Optimized moisture retention 4" x 4" dense stone wool cube Pre-formed 42/40 mm planting hole Redrock 4 inch Rockwool Cubes – 4" x 4" Stone Wool Starter Blocks with 42/40 Hole | 6-Pack | for Hydroponics & Indoor Growing | Includes Twin Canaries Chart

**Brand:** twin canaries liquid volume conversion chart
**Price:** € 42.46
**Availability:** ✅ In Stock

## Summary

> 🌱 Elevate your indoor garden game with Redrock Rockwool – where roots meet perfection!

## Quick Answers

- **What is this?** Redrock 4 inch Rockwool Cubes – 4" x 4" Stone Wool Starter Blocks with 42/40 Hole | 6-Pack | for Hydroponics & Indoor Growing | Includes Twin Canaries Chart by twin canaries liquid volume conversion chart
- **How much does it cost?** € 42.46 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.hr](https://www.desertcart.hr/products/317174410-redrock-4-inch-rockwool-cubes-4-x-4-stone-wool)

## Best For

- twin canaries liquid volume conversion chart enthusiasts

## Why This Product

- Trusted twin canaries liquid volume conversion chart brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Moisture Mastery:** Balanced water retention and air exchange for thriving root zones every time.
- • **Plug & Play Planting:** Pre-formed 42/40 mm hole ensures seamless transplanting with rapid rooters and cuttings.
- • **Precision Propagation Power:** Engineered 4" x 4" cubes for flawless early-stage growth in hydroponics.
- • **Sterile & Sustainable Growth:** Inert, U.S.-sourced stone wool provides a clean, soil-free environment for organic success.
- • **Universal Hydroponic Compatibility:** Works effortlessly with ebb & flow, drip irrigation, and all major systems.

## Overview

Redrock 4 inch Rockwool Cubes are premium stone wool starter blocks designed for hydroponic and indoor growing. Each 4" x 4" cube features a precise 42/40 mm hole for easy transplanting, made from dense, inert U.S.-sourced rock wool that optimizes moisture retention and air flow. Compatible with all major hydroponic systems, these 6-pack cubes come with a Twin Canaries liquid volume chart, making them a top choice for professional growers seeking consistent, organic propagation success.

## Description

desertcart.com: Redrock 4 inch Rockwool Cubes – 4" x 4" Stone Wool Starter Blocks with 42/40 Hole | 6-Pack | for Hydroponics & Indoor Growing | Includes Twin Canaries Chart : Patio, Lawn & Garden

Review: Very good - Work good
Review: Great starter blocks not a ton of dust. - Nothing beats these for hydroponic growing. Center hole matches rapid rooters.

## Features

- Rockwool Cube for Hydroponics & Propagation – This 4” x 4” stone wool cube is engineered for early-stage growth and propagation in hydroponic systems, perfect for leafy greens, herbs, and fruiting crops.
- Pre-Formed 42/40 Planting Hole – Each block includes a standard 42/40 mm hole designed for clean and easy transplanting of starter plugs or cuttings.
- Inert Stone Wool Composition – Manufactured from dense, U.S.-sourced rock wool for a sterile, soil-free environment that supports consistent moisture and air balance.
- Efficient Moisture Retention – These rock wool planting cubes retain water evenly while allowing proper dry-back and air exchange, helping maintain healthy root zone conditions.
- Compatible with All Major Systems – Ideal for use in ebb & flow, drip irrigation, and other hydroponic setups—trusted by greenhouse operators, indoor growers, and commercial cultivators.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0949TQN76 |
| Best Sellers Rank | #51,386 in Patio, Lawn & Garden ( See Top 100 in Patio, Lawn & Garden ) #52 in Hydroponic Growing Media |
| Brand | Twin Canaries Liquid Volume Conversion Chart |
| Capacity | 384 Cubic Inches |
| Color | Red |
| Customer Reviews | 4.5 4.5 out of 5 stars (246) |
| Date First Available | May 11, 2021 |
| Finish Type | Unfinished |
| Included Components | Twin Canaries Chart |
| Indoor/Outdoor Usage | Indoor |
| Item Weight | 13.4 ounces |
| Manufacturer | Twin Canaries Liquid Volume Conversion Chart |
| Material | Stone Wool |
| Number of Levels | 1 |
| Number of Pieces | 6 |
| Planter Form | Plant Pot |
| Product Dimensions | 4"D x 4"W x 4"H |
| Set Name | 6-Pack |
| Shape | Rectangular |
| Size | 6 Blocks |
| Special Feature | organic |
| Style | Rustic |

## Product Details

- **Color:** Red
- **Material:** Stone Wool
- **Planter Form:** Plant Pot
- **Special Feature:** organic
- **Style:** Rustic

## Images

![Redrock 4 inch Rockwool Cubes – 4" x 4" Stone Wool Starter Blocks with 42/40 Hole | 6-Pack | for Hydroponics & Indoor Growing | Includes Twin Canaries Chart - Image 1](https://m.media-amazon.com/images/I/71L0ldvRKSL.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Very good
*by R***N on June 15, 2025*

Work good

### ⭐⭐⭐⭐⭐ Great starter blocks not a ton of dust.
*by A***R on October 12, 2025*

Nothing beats these for hydroponic growing. Center hole matches rapid rooters.

### ⭐⭐⭐⭐⭐ Works well. Fast shipment!
*by V***E on August 22, 2024*

Worked as described

## Frequently Bought Together

- Redrock Rockwool Cube – 4" x 4" PRO Stone Wool Starter Block with 42/40 Hole | Rockwool for Hydroponics and Indoor Growing | 6 Pack + Twin Canaries Chart
- Redrock Rockwool Cube – 6" x 6" PRO Stone Wool Planting Block with 42/40 Hole | Commercial Rockwool for Hydroponics | 4 Pack + Twin Canaries Chart
- VidaWool 1.5" Seed Starter Plugs-Hydroponic Pods- Stone Wool-Rock Wool Cubes for Hydroponics-Plant Starter Grow Pods-Hydroponics Growing System-Garden Supplies for Plant Propagation-50 Count Bag

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**Shop now:** [https://www.desertcart.hr/products/317174410-redrock-4-inch-rockwool-cubes-4-x-4-stone-wool](https://www.desertcart.hr/products/317174410-redrock-4-inch-rockwool-cubes-4-x-4-stone-wool)

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*Product available on Desertcart Croatia*
*Store origin: HR*
*Last updated: 2026-05-14*