---
product_id: 356049738
title: "Redrock Rockwool Cubes – 6\" x 6\" Stone Wool Starter Blocks with 42/40 Hole | 4-Pack | for Hydroponics & Indoor Growing | Includes Twin Canaries Chart"
brand: "twin canaries liquid volume conversion chart"
price: "236 zł"
currency: PLN
in_stock: true
reviews_count: 8
category: "Twin Canaries Liquid Volume Conversion Chart"
url: https://www.desertcart.pl/products/356049738-redrock-rockwool-cubes-6-x-6-stone-wool-starter-blocks
store_origin: PL
region: Poland
---

# high moisture retention with balanced drainage 6" x 6" commercial-grade block 42/40 mm precision planting hole Redrock Rockwool Cubes – 6" x 6" Stone Wool Starter Blocks with 42/40 Hole | 4-Pack | for Hydroponics & Indoor Growing | Includes Twin Canaries Chart

**Brand:** twin canaries liquid volume conversion chart
**Price:** 236 zł
**Availability:** ✅ In Stock

## Summary

> 🌱 Grow smarter, not harder — elevate your hydroponics game with Redrock Rockwool!

## Quick Answers

- **What is this?** Redrock Rockwool Cubes – 6" x 6" Stone Wool Starter Blocks with 42/40 Hole | 4-Pack | for Hydroponics & Indoor Growing | Includes Twin Canaries Chart by twin canaries liquid volume conversion chart
- **How much does it cost?** 236 zł with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.pl](https://www.desertcart.pl/products/356049738-redrock-rockwool-cubes-6-x-6-stone-wool-starter-blocks)

## 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

- • **Precision 42/40 mm Hole:** Fits most starter plugs for seamless transplanting.
- • **Robust 6" x 6" Stone Wool Block:** Supports larger root systems for vigorous vegetative growth.
- • **Optimal Moisture & Oxygen Balance:** High water retention paired with effective dry-back to maximize root health.
- • **Sterile, U.S.-Sourced Mineral Wool:** Ensures a clean, contaminant-free environment for controlled indoor growing.
- • **Versatile Hydroponic Compatibility:** Perfect for leafy greens, peppers, tomatoes, and herbs across drip, ebb & flow, and other systems.

## Overview

Redrock Rockwool Cubes are premium 6" x 6" stone wool starter blocks featuring a precision 42/40 mm hole, designed for hydroponic and indoor growing. Made from sterile, U.S.-sourced mineral wool, these cubes offer superior moisture retention and balanced drainage to support healthy root development. Ideal for a variety of crops and compatible with multiple hydroponic systems, they come in a convenient 4-pack with a Twin Canaries chart to optimize your growing strategy.

## Description

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

Review: Good product - I liked this product for its convenience it's easy to use and works great if you know how to use it and it is reasonably priced in just over a month my plants have grown 2' high and are Very healthy So far it has done its job very well (For Best Results maintain a very low humidity level to keep it on a more drying out side/ Higher humidity for a slower drying out period)
Review: No issues - Works great soaked in my nutes for few hours then put 2 inch into this 6 inch and plants are already grown a foot in 8 days.

## Features

- Premium Rockwool Cube for Hydroponics – This 6” x 6” commercial-grade grow block is ideal for growers using rockwool for hydroponics, designed to support larger root systems during vegetative growth.
- Stone Wool Construction with 42/40 Planting Hole – Manufactured from dense stone wool (rock wool), this grow block includes a precision-cut 42/40 mm hole to fit most starter plugs for clean transplants.
- High Retention, Balanced Drainage – RedRock rock wool planting cubes offer excellent moisture-holding capacity while allowing effective dry-back for optimal oxygenation.
- Made from U.S.-Sourced Rock Wool – Produced from high-quality mineral wool, these sterile rockwool cubes provide a clean and inert growing environment, free from contaminants and ideal for controlled systems.
- Versatile for Hydroponic Crop Types – Commonly used in greenhouses and indoor grows for leafy greens, peppers, tomatoes, and herbs—compatible with drip irrigation, ebb & flow, and other hydroponic systems.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B08C9DR6MN |
| Best Sellers Rank | #152,990 in Patio, Lawn & Garden ( See Top 100 in Patio, Lawn & Garden ) #3,065 in Garden Fertilizers |
| Brand | Twin Canaries Liquid Volume Conversion Chart |
| Color | Redrock |
| Date First Available | October 10, 2021 |
| Indoor/Outdoor Usage | Indoor |
| Item Weight | 2.03 pounds |
| Manufacturer | Twin Canaries Liquid Volume Conversion Chart |
| Material Feature | Natural |
| Moisture Needs | Moderate Watering |
| Number of Items | 4 |
| Number of Pieces | 4 |
| Package Dimensions | 12.76 x 12.17 x 5.59 inches |
| Product Care Instructions | Water |
| Soil Type | Sandy Soil |
| Special Feature | organic |
| Sunlight Exposure | Full Sun |
| Unit Count | 1 Count |

## Product Details

- **Brand:** Twin Canaries Liquid Volume Conversion Chart
- **Color:** Redrock
- **Indoor/Outdoor Usage:** Indoor
- **Item Weight:** 0.92 Kilograms
- **Material Feature:** Natural
- **Product Care Instructions:** Water
- **Soil Type:** Sandy Soil
- **Special Feature:** organic
- **Sunlight Exposure:** Full Sun
- **Unit Count:** 1 Count

## Images

![Redrock Rockwool Cubes – 6" x 6" Stone Wool Starter Blocks with 42/40 Hole | 4-Pack | for Hydroponics & Indoor Growing | Includes Twin Canaries Chart - Image 1](https://m.media-amazon.com/images/I/61i9UZNrCTL.jpg)

## Available Options

This product comes in different **Size** options.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Good product
*by D***N on March 20, 2022*

I liked this product for its convenience it's easy to use and works great if you know how to use it and it is reasonably priced in just over a month my plants have grown 2' high and are Very healthy So far it has done its job very well (For Best Results maintain a very low humidity level to keep it on a more drying out side/ Higher humidity for a slower drying out period)

### ⭐⭐⭐⭐⭐ No issues
*by Z***R on March 22, 2023*

Works great soaked in my nutes for few hours then put 2 inch into this 6 inch and plants are already grown a foot in 8 days.

### ⭐⭐⭐⭐⭐ Great
*by L***G on February 4, 2024*

Great product

## Frequently Bought Together

- 6 inch Redrock Rockwool PRO Grow Block for Hydroponics | 4 Pack + Twin Canaries Chart
- Grodan Rockwool Delta GRO Blocks | 4" Cube - Pack of 6 | + Twin Canaries Chart
- Grodan RW108004 Rockwool, 50-Pack Macro Plant Plugs, Green

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*Product available on Desertcart Poland*
*Store origin: PL*
*Last updated: 2026-04-22*