Coco Coir Guide: Choosing, Feeding and Reusing Coco
Coco coir is the growing medium most indoor growers move to after soil. It holds water and air at the same time, it carries almost no food of its own, and it's forgiving once you know its few rules. This guide covers what coco is, the mixes we sell, how it compares with clay pebbles and rockwool, and how to feed it.
What coco coir is
Coir is the fibre and pith from coconut husks, a by-product of the coconut industry. For growing it is rinsed and buffered - treated so it doesn't hold on to the calcium and magnesium in your feed - which is why you should buy coco made for growing rather than raw coir.
Coco is inert: it gives the plant almost nothing to eat, so you are in full control of the feed. That's its strength, and it's why coco needs a feed made for it.
The coco and coco mixes we sell
| Product | What it is | Good to know |
|---|---|---|
| Canna Coco Professional Plus | 100% coco flakes, rinsed and buffered | 73% water / 27% air; meets RHP quality standards; free of harmful viruses and soil diseases, Canna say |
| Jiffy Pro7 Coco 100% Coir | Pure coir, 50 L | For growers who want plain coco |
| Jiffy Pro7 70/30 Coco Perlite | 70% buffered coco, 30% perlite, 50 L | Lighter and more free-draining than plain coco |
| Ugro XL Rhiza | Buffered coco with mycorrhizae, 70 L | Beneficial fungi added; pre-buffered |
| Gold Label Hydro/Coco 60/40 | 60% clay pebbles, 40% coco, 45 L | For flood and drain, drippers and even Autopots |
Coco, clay pebbles or rockwool?
| Medium | Holds water | Best for |
|---|---|---|
| Coco | Well, with plenty of air | Hand watering or drippers, in pots |
| Clay pebbles | Very little - free-draining | Automated, recirculating systems (flood and drain, drip-recirculating). Also a drainage layer at the bottom of soil and coco pots |
| Rockwool slabs | A lot, evenly | Drip systems on slabs; sterile, so a clean start every run |
| Coco / clay mix | In between | Systems that flood or drip but where you want some water held |
Canna say clay pebbles on their own only suit automated, recirculating systems because they drain so freely - hand-water a pot of pebbles and it dries out fast. More on systems in our hydroponics guide.
Feeding coco
- Use a coco feed. Coco needs nutrients made for it: Canna Coco A & B (see the Canna Coco feed chart), Advanced Nutrients Sensi Coco, Plant Magic Coco A & B (chart), or Biobizz's Coco·Mix schedule in the Biobizz feed chart.
- Feed little and often. Advanced Nutrients' coco chart says coco works best fed at least once a day with plenty of run-off. Never let coco dry right out.
- Calcium and magnesium. With soft tap water or RO water, coco growers usually add a cal-mag product such as Canna CALMAG Agent.
- pH. Athena's chart gives 5.8-6.2 for coco; House & Garden's 5.8-6.3. See our pH and EC guide.
- Pre-soak. Athena pre-soak coco at pH 5.5-5.8 and EC 3.5-4.0 before planting.
Reusing coco
Coco can be used for more than one run. Canna's schedule doubles the CANNAZYM dose (to 50 ml per 10 litres) when the substrate is reused - the enzymes break down the old roots. Start with fresh coco if the last crop had root problems or pests.
Quick answers
Can I use coco in an Autopot?
Not on its own in the plastic Autopot pots - we recommend soil, or coco mixed with soil. The Gold Label 60/40 mix says it suits Autopots. See our Autopot guide.
Do I need perlite with coco?
No, but a 70/30 coco and perlite mix drains faster and holds more air, which some growers prefer, especially when hand watering.
Why do my coco plants go pale?
Often calcium or magnesium running short, or a pH out of range. Check pH first, then think about a cal-mag product.
More Growers' Guides
- Canna Coco feed chart
- pH and EC meters
- Fabric, Air-Pot or plastic pots?
- Hydroponics: the systems explained
Not sure what you need? Call the shop on 0117 971 3000 or pop in to the Bristol store and we'll help you pick.