You don't need a wetting agent. Both the bark and the peat become hydrophobic around 30% moisture content. As long as they are not allowed to dry to this point they will readily absorb water.

In a SWC application it's very unlikely either would every dry to that point.

If you did want to use a wetting agent have you thought of trying Safer Soap at say 1 tbs per gal.? I have never done this because I don't like peat moss in any of my soil mixes. Good luck, Jack

The only time I've had difficulty is when I don't use a cover; I have a few containers that do not. I don't always fill the water holding area for various reasons (such as I am growing something that doesn't like being as damp as most mixes keep the container) so it can get dry on the top several inches before I'm ready to add water again. Because of the sunshine, it's really dry and the water can just roll right off. I do have a wetting agent I use at times for this, but it doesn't really happen often. Either Cocowet or EarthJuice Assist (I think I have the name right, it's not in front of me) work in these rare cases.

As JaG said, I don't have problems when I am keeping the container filled with water, as it wicks to the top and the mix only may get a bit dry on the top inch or less (if not covered - if covered, it doesn't dry out at all).

Thanks all for the suggestions. I will experiment with a bale of Sphagnum Peat Moss over the Winter and see how it absorbs moisture and wicks. Pro-Mix BX is made up of 82% Sphagnum Peat Moss and they don't list a wetting agent on the Ingredients label, so perhaps they don't use any. In any event, I appreciate all of your responses.

Raybo

A wetting agent is a surfactant. My favorite is the organic dishwashing liquid named Method Go Naked. You will find it at Target stores on the same shelf with other dish washing products. Inexpensive and double strength compared to similar products. Use one half tablespoon per gallon. Also excellent used as a 'sticker' in sprays at the same rate. Give it a try when washing windows, too. Excellent product for garden and home use.

I do use peat in some of my propagation mixes. I store it in 33 gallon plastic garbage containers with a lock down lid. When I break up a bale of peat and fill the garbage container I add water as I fill it. When you need to use the peat it is a real pain to have to get past the hydrophobic stage when you need to make a mix. By keeping the peat always damp it is a lot easier to use. Al

Yeah, as mentioned, a few drops of any soap will act as a wetting agent.

nandina,

I picked up a bottle of Method Go Naked liquid soap, and will give that a try. As Calistoga said, I will also let it soak in the mix for several days to thoroughly wet.

Raybo

Old thread - but a question:

Does adding the soap have a permanent or semi-permanent affect on the soil/media?

Meaning, once it's "in there" does it become easier to wet, or, do you have to add it to the water any time it becomes too dry?

Many years later...if I may join in..I always rehydrate my sphagnum peat, aka Canadian peat; been doing it for 30 years. I mix my own potting soil for my smallish nursery and for amending new beds. If you don't rehydrate, the peat will not mix well and may never rehydrate on its own. I've seen ribbons of it in beds years later that are still dry while the other soil is moist. YOU MUST BREAK THAT SURFACE TENSION.

I break a 3 cu ft brick of peat into six standard-sized, black cement-mixing tubs. I use only 4 for the smaller 2.2 cu ft brick. Break up any large clods of peat and spread evenly in tubs. Then apply ordinary dish soap (nothing fancy with additives.) I use Dawn, Brillo, Ajax, or Palmolive. Squeeze the soap out in an even pattern over each tub. Fill tubs with water. (You'll just have to develop a feel for how much - I count very slowly to 4). Then I let them sit for several days, sometimes a week.

Then I'm on my knees, kneading the peat to accept any water it hasn't yet absorbed. Often "rubbing' it in as you might in cooking or baking. Once fully blended, I stack the tubs and start mixing my soil - peat/top soil/perlite/ TM fertilizer.

I do this throughout late January-February-into early March - about 10 batches, yielding abt 80-90 five-gallon TidyCat buckets of potting mix. If using the peat in beds, I till first and then shovel-fold the peat and other amendments in before tilling again.

Dishsoaps are a phytotoxic brew of ingredients, most if not all of which are poisonous to plants and should not be used on foliage, incorporated into grow media, or allowed to become a small fraction of the soil solution. The question isn't whether or not these harsh surfactants will cause damage, it's 'how much damage will they cause'. 'Dawn' contains at least 11 phytotoxic ingredients.

Dishsoaps and other household cleaning products can destroy cuticular waxes in leaves, which compromises leaves' protective barrier against biotic pathogens and insect herbivory while also leaving the plant vulnerable to excessive water loss. Detergent solutions that make their way into the grow medium where they come in contact with root cells can quickly dissolve the lipid membrane surrounding cells, killing the cells and inhibiting water/ nutrient uptake. Hair cells growing as appendages off larger roots do the lion’s share of assimilating water and nutrients, and these very delicate cells would be the first casualty of any detergent in the root zone.

When establishing new plantings with media containing dry bark/peat, measure out the volume of medium required to fill the pot. Put half of it in a bucket or tub, wet thoroughly, stir, add the dry fraction, mix well, wait 15 minutes. Water and free water vapor from the wet soil will quickly diffuse into the dry soil particles, 'breaking' any tendency of the dry particles toward hydrophobicity well within the span of 15 minutes, leaving the grower with a pot full of grow medium which is evenly moistened and ready to receive plants.

Al