Anybody with RAFFIA knawlege ?

It would probably work. I would only go 3 inches. That is what the Univ. of Florida recommends for mulch. Tree leaves would work too if they are not green.

Are you buying raffia? Last I checked it was usually unsustainably harvested from the tropics.

And, if you're buying it, why not just use cardboard? Or leaves? Or grass clippings? Or anything else that is free and can be used as mulch? The primary goal of mulch is to be biodegradable organic matter that acts as a barrier between your soil and the air/sun. The secondary goal is to promote biological activity within your soil by providing food for your soil to eat up and break down into further derivatives of organic matter. If you're mainly concerned about the primary goal, having 1 ingredient for your mulch will do. If you care at all about the secondary goal, you should look into having a mixture of ingredients for your mulch (browns/greens/various materials to provide sugars/proteins/nutrients/organic matter to your soil).

But yes, raffia would work, as far as trapping moisture goes.

Raffia, a fiber from a palm is a renewable resource used to make many useful items ranging from baskets to clothing. It may be much too expensive to use as mulch although it could be.There are more then likely other, more readily available, and less expensive materials to use as mulch.
How thick a mulch should be depends on many things but to 1. aid in "weed" control, 2. aid in soil moisture retention, and 3. help keep soil temperatures from getting too high the mulch needs to be thick enough to keep sunlight from reaching the soil. Newspaper, or cardboard, can help do that so the material covering that paper does not need to be 5 inches thick. But a coarse material, such as Raffia, may need to be to accomplish the smae thing.

Hi & welcome to Gardenweb.

In a container I would devote all available space to soil/roots, not mulch. It's good for plants to dry out, until they are "about to wilt," then to get enough fresh water that it flows out of the bottom holes. A potted plant, especially pepper plant, that is soggy all of the time will usually die. Outside containers often need water every day. If it's taking less than a day to dry out, there's just not enough soil in the pot.

While you do not want the soil to be so wet that it would cause root rot you also need to remember that plants cannot, and do not, uptake nutrients from the soil they are growing in in the absence of moisture, so allowing the soil to dry out to the point plants start to wilt would not be a good idea. That will alos stress the plants making them more susceptible to insect pests and maybe plant diseases.

I didn't say start to wilt, I said about to wilt.

purpleinopp, I agree that all, but a few plants(not aquatic plants)
need to dry out between watering.
I have sandy soil in my garden & with pine straw , because it is free here,(sorry TOO57) & I do not water every day so the soil can dry out. Dry out: not moist or without moisture in the top 1 inch/25mm.

It would be much easier to give specific advice about this plant if we could see a pictue, if that's something you'd want to do, TOOBUKUSAn57.

It would have to be a very big plant to be drying out daily in a 5-gallon bucket, but it may not have much soil in it.

Agree that actual wilting is not good for the plant, kimm, but it's unavoidable sometimes here for my plants in the ground. Occasional slight wilt has not seemed to hurt any of my pepper plants in the past.

As jolj points out, aquatic/bog plants would be an exception but it's generally not a good idea to keep a potted plant moist all the time. If the roots rot, it will die. If it starts to slightly droop, it's almost certain to recover after a thorough soaking.

If one allows their plant to slightly droop once, then pick up the pot, you will have a gauge upon which to base future watering decisions. When the pot feel like it's almost as light as it was when the plant started to wilt, one can pick it up and know if it is almost that lightweight again, time to water. That is one advantage of a potted plant that's small enough to pick up, or tip on its' side a bit.