Peat vs Coco Coir?
By The DIYPicks Team · Updated July 2026
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FoxFarm Ocean Forest Potting Soil
A rich, well-aerated premium mix that feeds hungry container vegetables out of the bag. Worth the premium for transplants, but too hot for seed starting and pricier than basic mixes.
| 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 that rehydrates into a clean, water-retentive medium. Ideal for seed starting and lightening heavy mixes, but you supply the nutrients.
| 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.