Coco coir is one of the most popular growing media in greenhouses and hydroponic setups. It holds water and air at the same time, it is renewable, and it gives you a clean start that you control with your nutrient solution.
Why growers use coir
- Water and air together. Coir holds plenty of water but stays fluffy, so roots don't suffocate.
- A blank slate. Coir carries almost no nutrients of its own, so your feed decides what the plant gets.
- Forgiving. It is easier to manage than rockwool for beginners and doesn't dry out as fast as perlite on its own.
- Renewable. It is made from coconut husk, not mined or dug from peat bogs.
Pick your format
- Loose coir from bricks or 5 kg blocks for pots, buckets and beds. Many growers add perlite, often 70 parts coir to 30 parts perlite.
- Pre-filled grow bags that you just wet and plant. See our coir grow bags.
- Coir pellets for starting seeds and cuttings. Our 30 mm pellets fit standard 72-cell trays and hydroponic net cups.
Step 1: Expand and rinse
Soak the coir in warm water until it is fully expanded and fluffy. Kokkonut coir is washed to a low EC (0.5 mS/cm or less), so a quick rinse is all most growers need.
Step 2: Buffer with calcium and magnesium
Coir naturally holds on to calcium and magnesium and can release potassium and sodium in exchange. If you skip this step, young plants can show calcium or magnesium shortages in their first weeks. To avoid it:
- Mix a calcium-magnesium (cal-mag) supplement into water at the label rate.
- Soak the expanded coir in it for about 8 hours, or overnight.
- Drain, then plant.
Step 3: Feed with every watering
- Use a complete hydroponic or coir nutrient each time you water, rather than plain water.
- Keep the feed pH at about 5.8 to 6.2. That is the range most coir growers aim for.
- Water until about 10 to 20 percent runs out the bottom. This runoff carries away extra salts.
- Check the runoff now and then. If its EC is climbing well above your feed, water a little more each time to flush the salts.
Step 4: Never let it dry out
Coir is easy to re-wet, but roots growing in it get stressed if it dries out completely. Smaller, more frequent waterings work better than big soaks with long gaps between them, especially in a warm greenhouse.
Can I reuse coir?
Yes. After harvest, pull out the old root ball, rinse the coir with plain water to flush out old salts, and buffer it again before replanting. Many growers get two or three runs from the same coir.
Buying for a greenhouse or farm?
We supply coir by the case and pallet from Texas. See our wholesale page or use the coir calculator to work out how much you need.
