If you're lookin' for some sweet tips for peat moss rehydration, you've come to the right place.

Here we're delving into info about the hydrophobic nature of peat moss. We'll also talk about what the heck you can do about it, so keep reading.


First, a quick note about the peat moss elephant in the room:

Gardeners really dig peat moss for its moisture retention ability. It fluffs up seed-starting mix and potting mix, and holds water like a sponge. I'd estimate that the vast majority of gardeners in the Western hemisphere likely rely on peat moss.

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That said, peat moss is the center of much environmental controversy because its sourcing is inherently unsustainable long-term.

This stuff accumulates in peat bogs at a ridiculously slow rate - we're talking 1mm per year at most.

Bogs are delicate ecosystems which formed over thousands of years.

You can imagine that digging them all up will have inevitable environmental consequences. They'll also eventually run out of peat and everyone will be force to switch to an alternative any way.

For this reason, many gardeners choose to make a proactive choice to jump ship before too many bogs are destroyed.

Recognizing the need for alternatives, one notable option is coco peat (coir). It's important to note, however, that coco peat also has environmental consequences. Increased transportation distance is required to source coco as compared to peat, for instance. That means more fuel burned to get it to you.

Whatever you choose, both peat moss and coco peat have very similar consistencies and moisture-retention properties. Both peat moss and coco peat are also similarly hydrophobic. For this reason, we'll use them interchangeably throughout this article.

coco peat rehydrated from brick in plastic tub red brown gardening
Coco peat (shown here) is often used as a more environmentally-friendly alternative to peat moss.

Just like peat moss, it is hydrophobic when dry and difficult to hydrate.

Dry Peat Moss Is Hydrophobic

Peat moss, when dry, exhibits hydrophobic properties. This makes dry peat moss challenging to get to absorb water.

If you pour a bunch of water onto a compressed peat moss block, it'll bead right up and drip off. It's very resistant to wetting when it's bone-dry.



This issue turns frustrating when using peat moss in seed trays. Trying to hydrate your seed trays when they're peat-heavy can be tedious and feel overly time-consuming. Here are some alternative methods to enhance rehydration:

Mix Peat Moss With Soil

The simplest solution to improve the rehydration process is to mix peat moss with soil or finished compost. This option is great if you're using peat to make a seed-starting mix anyway.

The compost will bind to the peat, and help hydrate it.

Feel free to mix in perlite, vermiculite, sand, and any other amendments and textural components to your own specifications.

You can experiment with a 50/50 ratio or a 2/3 seed mix to 1/3 peat moss. The goal is to ensure that there is sufficient soil in the mixture to counteract the hydrophobic nature of peat moss.

For ideas on seed-starting mix ratios, check out this article.

sphagnum peat moss compressed blocks premier 3 cubic ft
Blocks of Canadian peat moss (OMRI listed) at the local big box store

These are compressed, but not nearly as compressed as coco peat

Rehydrate Peat With Warm Water

Using warm water during the rehydration process can significantly aid in peat moss absorption. This method can be combined with the previous option by mixing warm water into the peat moss and seed mix combo.

I find that leaving peat moss in a plastic tub or tote with the lid on for a day allows the peat to really soak up the water.

Bonus points for putting the tub outside on a warm day, where the moisture has a chance to evaporate, condense on the lid, and precipitate back down onto the peat. A miniature hydrological cycle in a tub in the sun will do all the work of rehydrating your peat for you without any hassle.

shredded coco peat rehydrated for gardening
This coco peat was rehydrated in a tub of warm water just like peat moss

It started as a 10lb compressed block,
and filled most of a 20 gallon tote after hydration

Rehydrate Peat via Agitation

Another effective technique is to agitate the peat moss manually with water. Similar to the previous method, this approach involves mixing the peat moss and water by hand in a container before applying it to the seed trays.

The physical agitation helps break the hydrophobic tendencies of the peat moss, allowing it to soak up the water more readily.

Considerations on Using Surfactants

While some suggest using surfactants to aid in peat moss rehydration, I do not personally recommend it.

Surfactants often have a tendency to harm or kill various species of soft-bodied insect. This may be a benefit in sterile indoor environments (such as indoor hydroponics), but indiscriminately harming a broad swath of life is somewhat antithetical to the organic mindset.

That said, the negative affect of surfactants is diluted if you dilute your peat or coco as in a seed-starting mix recipe.



Pro Tip:

Be aware that some peat moss has a surfactant pre-applied, so it's worth reading the label to make sure what you're buying is just peat moss with nothing else added.

Final Thoughts...

Whether you use peat moss or coco peat for your gardening, you've now got the know-how to hydrate these notoriously hydrophobic mediums.

I hope you have a successful gardening season and get to enjoy spending time in your garden this year.

Got any tips or tricks that work for you? I would love to hear from you in the comment section below!