Grodan Rockwool Delta Gro-Blocks - Hugo 6" x 6" x 5.8"

Grodan Hugo Grow Blocks are perfect for all phases of the grow cycle.  These 6 x 6 x 5.8-Inch rockwool cubes feature advances in fiber density to ensure plants get all the water, nutrients, and oxygen they need.  Root systems should grow to fill the block and a convenient 1.5-Inch hole at the top allows for easy planting, the transferring of clones, or inserting smaller cubes into a larger growing media.

Size: 6-Inch x 6-Inch x 5.8-Inch

Case Size: 48-Blocks

Ingredients: Molten rock spun into fibers

Advantages: Tremendous capacity for absorbing nutrient solutions and retaining oxygen, less messy and easier to use than alternative growing media

Price From: $2.75

* Required Fields

The Hydroponi Difference

1. Same-day/Next-day Shipping


2. Volume based discounts


3. No ordering minimums


4. Call for ordering assistance



Grodan Stonewool (Rockwool) Delta Gro-Blocks - Hugo 6" x 6" x 5.8" has quickly gained traction to become one of the premier choices of growing media for both indoor and outdoor growers.  Comprised of molten rock that is them spun into cotton-like fibers and compressed into blocks, cubes, and slabs, Grodan is the leader due to technological and qualitative advances not found in other competing brands of grow blocks.

Where other stonewool and rockwool manufacturers cut their blocks from one sample of spun rock, Grodan utilizes a proprietary process to infuse each block, cube, or slab, with different types, densities, and proportions, of fibers, thus ensuring every plant has exactly what it needs during the growing cycle.  Throughout the life of a plant, from clone or seed to maturity, it can be assured that Grodan offers a growing media that will properly soak, pass nutrients, and allow fresh air directly to the root zone.

Hugo grow blocks are one of the most popular sized blocks for several key reasons.  They offer a tremendous capacity for absorbing nutrient solutions while retaining plenty of oxygen for accelerated plant growth.  While smaller blocks support plant growth for part of the growth cycle, they will invariably need to be transferred into larger blocks or placed in additional growing media to see continued growth performance in the later stages of a plants life.  Hugo growing blocks are large enough to support a plant throughout its entire life without additional soil, coco, or other growing media. 

Another key advantage of using Grodan Delta blocks is that they are easy to move around, grow in, and discard.  There is no mess and no fuss.  Disposing of growing blocks is simple, they are thrown in a bag and thrown out.  Soil, coco, and other loose potting media require lots of clean-up and preparation.  With rockwool grow blocks half the work is done before a grower even starts.

Grodan Delta blocks are the most uniform blocks available.  They feature improved drainage grooves at the base of the block to allow water to easily seep out and oxygen to get in.  Sizes cover the gambit and ensure every plant can find an appropriately sized growing cube and/or slab.  

These blocks are used for direct sowing or "Blocking-on" of Macro and Multi-block raised plants.  AO 36/40 plugs fit snugly into the holes provided on the top of the blocks.  For even greater growing media requirements, Hugo grow blocks can be placed on top of grow slabs, adding even more volume, should the need arise.  Generally, under almost all conditions, Hugo grow blocks have enough growing media to support a plant throughout its life and placing it on top of a grow slab will not be required.

Proper handling of rockwool/stonewool grow blocks:

  • Use sharp tools when cutting plant holes in rockwool
  • If using mechanical cutting tools, a dust extractor should be used
  • Open boxes of blocks in a ventilated area
  • When filling containers or mixers with other products misting and dust extraction are recommended
  • To reduce dust wet floor before sweeping up
  • Place off cuts and any unused stone wool in bags

Shipping Weight: 30 lbs

Package Dimensions: 23.7" x 18.6" x 23.1" 

Units Per Case: 48-Blocks

Units Per Pallet: 12-Cases

Ingredients: Growth substrate material based on stone wool, high-alumina, low-silica (HT) wool

Storage: Blocks should be kept indoors to protect against adverse weather conditions including precipitation

Ecological Information: Stable product with no known adverse environmental effects

Disposal Considerations: Grodan Hugo Grow Blocks can typically be disposed of in an ordinary landfill although local regulations may apply.  Packing material is Polyethylene and can be supplied to PE manufacturers for recycling.

Soaking: It is recommended to soak blocks before the first use.  Video link: 

GRODAN Delta Benefits

1. Effortless start up of propagation 

GRODAN Delta is the perfect block for propagating young plants under a wide range of propagating conditions. The block is easy to saturate and water is distributed uniformly throughout the block, so reliable and vigorous plant growth is guaranteed. 

2. Uniform WC and EC distribution 

Based on the Delta Technology, the structure of the block and water distribution throughout the substrate have been improved. Newly transplanted plants will benefit thanks to the ready availability of water and the balanced nutrient solution (EC), encouraging the roots to penetrate deeply into the blocks.

3. Easy WC management 

The water content levels can be easily managed between 55% and 80%. This applies equally to low and high water content levels. If the moisture content level threatens to drop too low, it can be simply be restored to the desired level, for instance, 80%. Thanks to the variations in the small and large pores, the roots are always guaranteed a sufficient supply of air and water.

4. Excellent root growth throughout the block 

The Delta Technology ensures uniform distribution of water and nutrients throughout the block. Newly transplanted plants will benefit thanks to the ready availability of water and EC, encouraging the roots to penetrate deeply into the slabs

5. Greater firmness for better handling

As mechanization has been increasingly introduced into the propagation process over the years, the blocks must be able to withstand handling better during propagation. The stable firmness of GRODAN Delta becomes particularly important when the blocks are placed, spaced and picked up several times during propagation. An added advantage is greater protection for the roots during transport from the propagator to the grower.

Warning: The material in Grodan Grow Blocks has been known to irritate the skin.  High dust levels may irritate the throat and eyes.  For skin, should irritation occur, do not rub or scratch.  Wash off under running water prior to washing with mild soap and water.  For eyes, should irritation occur, do not rub the eyes.  Flush eyes with water and consult a physician if irritation persists.



Manufacturer Grodan