




🧱 Grow smarter, not harder—rock your roots with Grodan!
Grodan Rockwool Delta GRO Blocks are premium 4-inch hydroponic grow cubes designed for seamless seed starting and full-cycle plant growth. Featuring pre-formed holes for starter plugs and engineered fibers for balanced moisture and aeration, these natural, organic blocks support robust root development and efficient nutrient uptake—perfect for indoor gardeners seeking clean, container-free cultivation.










| ASIN | B0812XYTKN |
| Best Sellers Rank | #34,600 in Patio, Lawn & Garden ( See Top 100 in Patio, Lawn & Garden ) #209 in Plant Cages & Supports #919 in Garden Fertilizers |
| Brand | Twin Canaries Liquid Volume Conversion Chart |
| Color | Brown |
| Customer Reviews | 4.7 4.7 out of 5 stars (438) |
| Indoor/Outdoor Usage | Indoor |
| Item Weight | 13.4 ounces |
| Manufacturer | Twin Canaries Liquid Volume Conversion Chart |
| Material Feature | Natural |
| Moisture Needs | Moderate Watering |
| Number of Pieces | 6 |
| Package Dimensions | 11.81 x 7.83 x 3.98 inches |
| Product Care Instructions | Water |
| Soil Type | Sandy Soil |
| Special Feature | organic |
| Sunlight Exposure | Partial Sun |
| Unit Count | 6.0 Count |
T**S
Great
Perfect
J**S
Grodan is top quality rockwool
These cubes came packaged well in a plastic wrap. These are genuine Grodam rockwool cubes and are very high quality!
D**R
Great for the price
Not much to say, works great for the price. Only needed 4 so used one of the extras to create a plug for the center.
D**E
A must if you want double yeilds.
I use these in a 4.4 gallon auto pot with coco and let me tell you. If you want to grow some bricks, use these cubes inside your pot with your grow media. Give a little extra time to veg maybe 2 months with some root inoculant and you will have some plants growing with bark on the stalks. I have done comparison without using the cubes and the harvest is 3x less not using the cubes. Roots look like ropes within pot they are so large. I grew Barney Runtz Muffin as my test. With cubes average 1 plant 6-8 oz dry without cubes about 2-3 oz dry.
D**N
They work. The plastic packing around it keeps it as a cube unlike cheap alternatives
These work just about as well as the peat moss plugs but they last a lot longer. The wrapping around each one keeps it as a cube and keeps it the right shape. The cheap ones that don't have plastic wrapping are worthless. These are worth paying for I guess.
B**O
Easy use medium
Wash well before use
D**Y
what can you say it worked like advertised
shipping was free
T**R
Perfect size for larger plants
Quality perfect for larger plants. Seeds germinated quickly and cubes held structure
Trustpilot
3 weeks ago
3 days ago