Grodan PRO Delta Gro-Blocks

Grodan PRO Delta Gro-Blocks


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Grodan Brand Product
$128.95 - $1,405.95

Lead time: Please call 888-815-9763 for regional availability and pricing


Grodan PRO Delta Gro-Blocks

Grodan PRO Delta Gro-Blocks come unwrapped and ready to go!

Grodan Delta is the basis for an easy to steer the propagation process, which results in uniform, good quality plants. Each block guarantees uniform water and nutrient distribution.

Grodan Delta scores high in saturation and firmness, which means it always performs well in highly mechanized propagation processes.

What is Rockwool?

Grodan Stonewool (rockwool) is made from molten rock spun into cotton candy-like fibers and then compressed into cubes, blocks, or slabs. Where other rockwool brand manufacturers cut all sizes from one batch of wool, Grodan is unique by making different types of fibers. The purpose is to support the requirement of the plant in the different plant stages. Grodan has a tremendous capacity for absorbing nutrient solution while retaining plenty of oxygen for rapid plant growth. Grodan comes in graduated sizes. Seedlings started in cubes are easily transferred to blocks and then onto slabs, if desired. Seedlings or cuttings started in the Grodan cubes can also be transplanted into more traditional planters and growing mediums.


Grodan Delta is a reliable propagation block for vegetable crops, and is used worldwide. The excellentwater distribution, degree of saturation and firmness safeguard the results under diverse growing conditions

Delta Technology

Delta Technology ensures uniform distribution of water and nutrients throughout the block. Newly transplanted plants benefit thanks to the good availability of water and nutrients, which encourages he roots to penetrate deeply into the substrate slab.

Delta Gro-Blocks are similar to a plant container. Need a 3 in. pot? Then choose a 3 in Gro-Block. Small plants can be fully grown in our larger Gro-Blocks. Holes are the perfect size for any 1.5 in starter plug.

Big Mama is Grodan's largest block ever produced! Big enough to grow a large plant for its entire life. More than twice the amount of wool as the Hugo Block.

Come in packs labeled with instructions.

  • Effortless start-up of propagation
  • Uniform WC and EC distribution
  • Easy WC management
  • Excellent root growth throughout the block
  • Greater firmness for better handling

Grodan PRO Delta Gro-Blocks Videos

Product Q&A

Grodan PRO Delta Gro-Blocks Questions & Answers

Q: What is stone wool?
A: Stone wool is a mineral wool made of volcanic rock. Stone wool consists of 5% solid material in the form of stone fibres. The remaining 95% is made up of pores.

Q: How is stone wool made?
A: The basic materials for our stone wool are basalt and limestone. These are melted to form lava in an oven with a temperature of 1,500°C. The lava is then poured over a number of fast-rotating discs. Thanks to the centrifugal force, the drops fly off the discs and lengthen to form fibres. The process can be compared with candy floss being made at a fair. The fibres are then compressed to form a sturdy mass, from which the slabs and blocks are then cut.

Q: Why is stone wool suited for growing vegetables?
A: Our stone wool growing media are designed for Precision Growing in a greenhouse. Precision Growing focuses on ‘root zone management’, or in other words, steering of the root environment. Everything that happens in the stone wool substrate has an impact on the functioning of the root environment and therefore the development of the plant. So, we continually investigate how our products, tools and user advice can respond perfectly to changing circumstances, so that the plant is given the very best care, without wasting resources.

Tech Specs