Peat vs Coco Coir?
By Nate Sawyer, Editor · Updated July 2026
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FoxFarm Ocean Forest Potting Soil
A rich, well-aerated premium container soil loaded with earthworm castings, bat guano and crab meal, feeding hungry container vegetables and transplants straight from the bag, with a pre-adjusted 6.3-6.8 pH. It is worth the premium for transplants but not everything: it costs more per cubic foot, its high nutrient load can burn seedlings, and it is not OMRI listed.
| Type | Premium container potting soil |
|---|---|
| Composition | Aged forest products, sphagnum peat, earthworm castings, bat guano, fish emulsion, crab meal, perlite |
| Organic | Uses natural/organic inputs (not OMRI listed) |
| With fertilizer | Yes (from natural amendments; pH 6.3-6.8) |
| Bag size | 1.5 cu ft (also 12 qt, 3 cu ft) |
| Best for | Nutrient-hungry container vegetables and transplants |
Compressed Coco Coir Brick (5 kg / 11 lb)
A space-saving, renewable peat alternative: one compact 5 kg brick expands to about 70-75 quarts of clean, near-neutral-pH medium that holds water yet still drains, and its sterile, weed-free texture suits seed starting and lightening mixes. Plan around its nature: it is nearly inert with no nutrients so add fertilizer, it must be soaked first, and cheap unbuffered blocks hold salts.
| Type | Compressed coconut coir growing medium / amendment |
|---|---|
| Composition | 100% coconut husk fiber and pith, triple-washed and buffered (low salt) |
| Organic | Natural peat alternative (many are OMRI listed) |
| With fertilizer | No (inert medium, add your own nutrients) |
| Bag size | 5 kg block, expands to ~70-75 quarts when hydrated |
| Best for | Seed starting, lightening mixes, and boosting water retention |
Our verdict
Both are the fluffy base of most growing media, but they behave differently. Peat (the backbone of mixes like FoxFarm Ocean Forest) is acidic at around pH 3.5-4.5, so mixes buffer it with lime, and it can be hard to re-wet once fully dry. Coco coir is near-neutral pH, rewets easily, holds a lot of water while still draining, and is a renewable coconut byproduct, though it is inert and unbuffered blocks can hold salts. For seed starting and eco-minded growers, coir is the easier, more sustainable choice. If you want a ready-fed, ready-to-plant blend, a peat-based mix like Ocean Forest wins out of the bag. Many gardeners simply use both, adding coir to lighten and rewet peat mixes.