A quick search on this subject, within this forum, comes up with several posts about this subject. It's not something that I would do, but others have.

Here is a link that might be useful: Click here for 'diaper talk'!

Zinnia, wouldn't you rather care for those plants that might need kept moist and those that don't appreciate that way by simply watering the plants as they need it.

To constantly keep moisture sitting at the roots is a very good way to, over time, keep the roots saturated with water they do not need and so, over time, the roots then begin to rot.
Once that begins, the plant is unable to take up further water....the plant above then shows what you have done.

Much better to water the plant as it needs it, water thoroughly so the roots get it, then the plant drains.
The saucer below then is dumped of that water.....so that the plant never sucks that water back up.

When you water, certain amounts of salts (from fertilizer) is also freed from the soil. By insisting the plant sits in that water, those salts are drawn back up.

Over time, this method of letting the water be given back to the plant again, results in poor plant health.

Much better to arrange for a way for the plant to drain water given. As the pot drains, it tells you the roots have sufficient...and the soil then gives up what it cant hold. When the plant dries, or you feel the plant needs more moisturizing, then you water......when the plant needs it.
By keeping moisture sitting in a diaper, you have no way knowing whether the diaper is dry or not and so, usually, you water when the plant doesn't need it.....or perhaps you have let the plant dry up too much.

Jeannie7,

While there may be some succulent/cacti that are highly sensitive to water in the soil, for most plants the amount of water around the roots doesn't matter as long as there is sufficient oxygen.

Hydroponic growing can be done by keeping roots in water 24x7 as long as the water is aerated.

It is lack of oxygen that favors root rot, not lots of water.

Self watering containers such as earthboxes also keep the potting mix constantly wet, but they use an aeration screen to allow oxygen to enter the mix as well and root rot doesn't occur.

Having said all that I don't use the moisture crystals either ;-) Some do though and seem to be pleased with the results.

Quote: Water sitting around the roots doesn't matter.

That makes the reason why pots have drainage holes a big lie.
Water that sits in soil constantly at the roots causes the plant to keep trying to take up such water....and the plant can only take so much...then it rebels.
Water sitting there, not being drawn up, has to do something...much like a person sitting in bath water too long, it dries the skin. The plants roots dry up, even tho sitting in water...because they cant do anything with it.
Rot ensues and if not corrected, the plant will die.

Oxygen is removed from the water by way of respiration through the leaves. If the roots no longer can feed the water to the leaves, they stop respiration.
The succulent has the advantage to then use what water it has in reserve...but in time, it too will succumb.

Plants should be given water only as they need it, only when they can use it, not on any schedule and not certainly giving them a pool to drown in.

Certtain plants, such as those that do well in ponds, are by their nature, able to survive this curious way of living.
There are pond plants....and such plants would not survive being treated in any other fashion.

Quote: Water sitting around the roots doesn't matter.

That makes the reason why pots have drainage holes a big lie.
Water that sits in soil constantly at the roots causes the plant to keep trying to take up such water....and the plant can only take so much...then it rebels.

I am sorry to be disagreeing with you, but if that was the case then hydroponic growing would be impossible, as would self watering containers. As long as there is sufficient oxygen in the water, rot will not develop.

There have been numerous studies done on the various fungi responsible for root rot and in some cases water isn't even required for rot to occur in some species of plants with some species of fungi, it occurs in dry soils. In other cases the water *and* low oxygen have to be present. High water content alone doesn't favor growth of rotting fungi. The point is it varies from species to species, but the common denominator is low oxygen whether the low oxygen is from water displacement or just highly compact, but dry soils. Oxygen is removed from the water by way of respiration through the leaves. If the roots no longer can feed the water to the leaves, they stop respiration.

This can only occur in a medium low in oxygen. The use of water retaining crystals doesn't cause this. A medium consisting of heavy, tiny particles does.

Again, I apologize for disagreeing, I would rather find something to agree upon.