Coco coir is made from the fibrous husk of coconuts. It holds water like a sponge but still drains well, and it is a renewable alternative to peat moss. These compressed bricks are cheap to ship and store, then expand into a big tub of growing medium once you add water.
What I’m testing
I want to know if coco coir can replace part of the bagged mix I use in containers, and how well it works for starting seeds. Specifically:
- Seed starting: germination and seedling health compared with a standard seed starting mix.
- Container mix: blending coco with Happy Frog potting soil and seeing how it affects watering frequency in grow bags.
- Feeding: coco has almost no nutrients, so I am pairing it with CALiMAGic and a regular feed to see what plants need.
- Value: how much usable mix one brick actually makes for the price.
How I’m prepping it
- Soak the brick in warm water in a large tub and break it apart as it expands.
- Rinse it to wash out excess salts.
- Squeeze out extra water until it is damp, not dripping.
- Mix it with other ingredients like rice hulls for drainage, or use it on its own for seed starting.
Results so far
Testing is in progress. I will update this page with photos and real results once plants have gone through a full cycle in it. Until then, treat this as my setup notes, not a final verdict.
Who it is for
Gardeners who want a peat-free option, hydroponic growers using drip or Dutch bucket systems, and anyone who wants to stretch their potting soil budget.
Common questions
How do you expand a coco coir brick?
Put the brick in a large tub, add warm water a little at a time, and break it apart as it softens. One brick expands to many times its compressed size.
Does coco coir have nutrients?
Very little. Plants grown in coco need regular feeding, and coco often benefits from added calcium and magnesium.
Is coco coir better than peat moss?
Coco is a renewable byproduct of coconut processing and rewets easily. Peat holds slightly more nutrients. Both work, which is part of what I am testing.
Want to test it alongside me?
Prices and availability change often, so check the current listing on Amazon.
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