Rockwool Cubes - Grodan Brand
$6.50 - $25.00$12.99 - $49.99
good to know
questions about the Rockwool Cubes - Grodan Brand
Quick answers before you buy. Still unsure? Our Sydney team is happy to help.
1 year warrantyIf anything goes wrong in the first year, we'll arrange a repair, replacement or refund.
see all FAQs
Overview
What would happen if you heated up basalt (a naturally occurring volcanic rock) to the point where it becomes liquid and decided to spin it like fairy floss? You would end up with an awesome hydroponic soilless substrate! These rockwool cubes are exactly that, with the outcome being a super light, and absorbent hydroponic growing substrate that maintains perfect aeration and moisture levels at all stages of plant growth.
Features
Rockwool is the ideal growing medium for germinating most types of seeds, propagating cuttings or even growing transplants. High success rates mean you spend less time struggling and more time growing!
- Contains no harmful chemicals, weeds, diseased soil or pests.
- Pathogen free.
These mats are made by Grodan, the market leader in rockwool. The substrates from Grodan are the only stone wool growing media awarded an EU Ecolabel. Rockwool from the market leader means consistent quality, peace of mind that what's in your rockwool is safe, and better growth!
Specifications
Dimensions of each regular cube: 40x25x25mm, large cubes are 40x40x40mm.
- Regular size are tapered to fit into netcups
- Small indents for cuttings and seeds.
- Can easily be broken up by hand or with scissors.
- Available in 24, 72, or 200 packs for incredible value.
Instructions
How to use rockwool cubes
To use these simply soak them in water for 10 minutes before planting two or three seeds (it's always good to have a backup) per rockwool cube. The cubes can be partially submerged in water, or bottom irrigated with a trickle of water to keep them moist. Note that they don't need much water as they're super absorbent!
When the roots start to grow out of the cubes, then you can place the cubes within another growth medium, soil, or directly in water and let them grow!
Want to know more? Read what rockwool is and how it compares in our guide to growing mediums. Ready to start? Browse our seeds and nutrients.
Why are my seeds not germinating in winter?
How do I stop algae growing in my hydroponic garden?
Why is there mould on my growing medium?
Warranty & returns
We offer change of mind returns on all products, and a 1 year warranty on all electrical goods. We're also so confident in your success, that we have a 60 day seed guarantee, and will replace any seeds that don't grow free of charge!
Buying with Gathera gives you access to our community and all our range of special resources to help you grow:
- Access to our community page.
- Horticulture experts on hand to help you out.
- You're buying into an ecosystem – need to replace a pump, light, netcup or other component? We have replacements available so that you don't have to ditch your whole system when one small thing breaks..
- We sell the stuff you need to feed your gardens - nutrients, seeds, growth mediums.
- Comprehensive FAQs.
S
This Rockwool product is great. Easy to use and I'm enjoying being able to propagate my aquarium plants with this fantastic product. Urban Plant Growers provide a great, fast service and delivery
M
These rock wool cubes work so well and if replaced each time you replant, they don’t go moudly. Best fit for the UPG trays.
D
There are many rock cubes out there but Urban Plant Growers cubes are of the highest quality and frankly, all my seeds grow better in these than anything else. Recommend you buy a large pack so save money and time.
M
This has transformed the way I grow seedling, never had a plant fail. I either leave them in the hydroponic bay or remove them with their little rock wool core intact and transfer them successfully to the garden.
R
Good but tends to go green after a while.
G
So Fast delivered in 48 hour’s
K
The cubes are mostly working but some get infiltrated with algae and go dark green. I also don't know what the little mites all over the plants are and how to get rid of them. I could attach some photos if there was an option to do so.
s
Cubes were a lot smaller than I thought they would be
F
Perfect. Great product.
L
How could you not love this product. Over 90% strike rate and so easy to transplant to the Gathera farm ( which I have had for years and she is still thriving and producing).
wow! thank you Lynne
M
They're good...except some of them break up into pieces but I'm sure that's with all rock wool cubes
Thank you for the review
m
My seeds went into my rock wool on 1/11/25. The basil and dill are grown well as is one coriander. However no parsley or chives have sprouted. Very disappointing
I don’t know why this should be.
A
Excellent product. Also useful for raising seeds in Eco Kitchen then planting rockwool seedlings directly in garden.
Thank you and we're glad to hear that you have found them to be an excellent product for both indoor and outdoor gardening. Happy growing!
S
haven't been able to use yet because I am waiting for rest of order.
Y
Took ages to arrive
D
Very convenient to use.
S
The little water pump in my grower isn’t working, any tips on fixing it please?
A
the rockwool cubes are a good product making it easy to use my gathera plant kit.to grow herbs that would normally go to seed in the garden.
S
They work as I expected.
m
Great product! Be sure to cut them into cubes rather than tear them as they tend to fall apart.
H
Have been using my indoor garden for over a year now, growing so many herbs I literally don't know what to do with them. Have so much tried thyme/basil/oregano etc from the surplus. Brings me a lot of joy!
S
I needed to order some replacement rockwool cubes : they arrived promptly and are now in use with my new batch of Basil! - thanks again
R
Rarely any issues, seeds sprout easily.
A
An affordable way to grow herbs at home. Perfect for apartment living!
M
Love these little rock wool cubes. So easy to use and to remove from the cups too.
H
These are easy and clean to use. I used these with a 12 pod unit for over 12 months and more recently with the Family Farm with 72 pods. There are quantity discounts that apply.
R
Communication from Urban Plant Growers was great. Delivery was prompt and I saved money by buying in bulk. And my plants are looking great!
K
I’ve had my eco kitchen for almost 6 months now and have used Rockwool every time with no complaints. Seeds always sprout and so easy to use.
A
I love the Rockwool Cubes they are great for germinating vegetable seeds.