Growing Media
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7Growing media is the thing your roots actually live in, and it decides more about how you grow than the nutrients do. It sets how often you water, how forgiving the system is, and which feed you can use. Pick the medium first, then build the feed around it.
Which medium should you use?
| Medium | Watering | Forgiveness | Best for |
|---|---|---|---|
| Soil | Every 2-3 days | High | First grows, organic feeding |
| Coco coir | Daily or more | Medium | Faster growth with mineral feed |
| Rockwool | Multiple times daily | Low | Precise hydroponic control |
| Clay pebbles | Continuous | Low | Flood and drain, DWC |
| Perlite | As an amendment | – | Adding air to soil or coco |
| Plugs and cubes | Kept damp | Medium | Seeds and cuttings |
The trade-off in one sentence
The more inert the medium, the faster the plant grows and the less room you have to make a mistake. Soil buffers everything and gives you days to notice a problem; rockwool buffers nothing and gives you hours. Coco sits in the middle and is where most people end up.
Coco is not soil
The most common and most expensive mistake. Coco holds calcium and magnesium and releases potassium, so a soil nutrient will leave you cal-mag deficient within a few weeks. Use a coco-specific feed, or add CalMag separately. Coco also needs feeding every watering – there is nothing in it to draw on.
Air is as important as water
Roots need oxygen. A medium that holds too much water suffocates them, which looks exactly like overfeeding and gets treated with less nutrient, which makes it worse. Adding 20-30% perlite to soil or coco is the cheapest improvement most growers can make.
What we stock
Coco from Canna, Plagron and Ugro; soils from Biobizz, Plant Magic and Plagron; Grodan rockwool; clay pebbles, perlite, vermiculite and propagation plugs. Match with nutrients and pots.
Growing media FAQs
Which is best for a beginner?
Soil. It is slower but it will forgive the mistakes you are going to make. Move to coco on your second grow.
Can I reuse it?
Coco and clay pebbles can be washed and reused. Rockwool should not be. Soil can be recycled if you amend it, but it is rarely worth the effort at small scale.
Do I need to buffer coco?
Most branded coco is pre-buffered. Cheap unbuffered coco needs a cal-mag soak first, and skipping it causes exactly the deficiency people blame on their nutrients.
Why buy growing media from The Hydro Bros?
We are a hydroponics shop in Croydon and we sell these by the pallet over the counter. Tell us your system and we will tell you which medium suits it and what feed it needs. Discreet UK and European delivery, and excellent customer reviews on Trustpilot.
