My plants have suffered in heavy non porous ceramic pots even if they have some kind of hole. I say, be very aware if using any pot with one single hole. It can easily clog.
But I suspect, even more, that nursery pots with their generous holes not only avoid that clog, but also give multiple points of air access to the lower root zone, and I think it really helps.
I now never go straight into ceramic. I find a cheap plastic that fits inside it to my liking, enough wiggle room that I can pull the plastic pot out, also good if it lets air seep around it to under the pot. Those orchid pots and liners, I elevate the liner with stones or corks so the liner isn't snugly fit to the ceramic. Better air underneath.

I've been growing in containers since about 1970 and I've never had a clogged drain hole, or a pot that drained slowly enough that it was a problem. All the clay pots I grow in and at least half of the bonsai pots have one one hole. I give a lot of plants and bonsai starts away, so I often buy inexpensive but attractive bowls to use as pots. They require my adding the drain hole, and I usually drill a hole somewhere between 1/8 to 1/2" in size.

This ^^^ particular pot has a very large drain hole, and I typically secure the piece of plastic canvas (the mesh/screen) with a piece of aluminum wire as seen in the image. The square cut-out in the screen is to accommodate a drainage wick. Even with the very fast-draining and highly aerated media I use, I still like to use a drainage wick like so:


The knot keeps the wick from being pulled out of the pot if I slide it across the grow benches.

Some very small clay pots have holes that are 3/16-1/4" such that no screen is required. I simply tie an overhand knot in the mop strand/wick, then pull the tag end through the hole until the knot/stopper covers the hole. Even then, with the entire hole covered by the knot in the wick, there are no drainage issues.

One thing I would mention is, if you have a plastic pot w/o holes in it, make sure the holes are through the bottom at the sidewall, or through the sidewall so the bottom of the hole is tangent to (touching) the bottom of the pot. Holes only through the side of the pot but above the bottom trap water at the bottom of the pot, which creates issues on several fronts.

Speaking strictly from the standpoint of drainage. It doesn't matter if there is 1 hole in the bottom or twenty. Assuming the pots are the same size/shape and both are filled with the same grow medium, when the pots stop draining there will be exactly as much water in both pots, so multiple holes to make a pot drain faster offers no benefit.

Finally, if a medium supports excess (perched) water, the maximum ht of the perched water table will be the same, no matter what the size or shape of the pot, and changing the number of holes in the container has no impact on how much excess water a planting holds. All pots in the image below are filled with the same medium, and the shaded area in these pots represents excess water.


Al

For my pots with multiple drainage holes (including ones toward the walls) I tend to hold the pot at a 45 degree angle after watering it, with one of those holes facing down towards the sink, to allow the water in the pot to pool in that spot and more easily flow out. I also place my finger at the hole opening so that the water cohesion/adhesion property (I confuse which is the proper term here) helps the water to flow out. For pots with a single hole, I hold the pot straight and insert my finger into the hole for the same effect. For pots with a hole too small to insert my finger, I take a paper towel and roll it till it's thin enough to insert into the hole to absorb the excess water. Admittedly, this doesn't work so well with large pots that are too heavy to lug to my kitchen sink, which I don't yet have too many of. The whole process can be time consuming as well.
But it's just what I do and I find it helps avoid overwatering!

tapla said: I've been growing in containers since about 1970 and I've never had a clogged drain hole, or a pot that drained slowly enough that it was a problem. All the clay pots I grow in and at least half of the bonsai pots have one one hole. I give a lot of plants and bonsai starts away, so I often buy inexpensive but attractive bowls to use as pots. They require my adding the drain hole, and I usually drill a hole somewhere between 1/8 to 1/2" in size.

This ^^^ particular pot has a very large drain hole, and I typically secure the piece of plastic canvas (the mesh/screen) with a piece of aluminum wire as seen in the image. The square cut-out in the screen is to accommodate a drainage wick. Even with the very fast-draining and highly aerated media I use, I still like to use a drainage wick like so:


The knot keeps the wick from being pulled out of the pot if I slide it across the grow benches.

Some very small clay pots have holes that are 3/16-1/4" such that no screen is required. I simply tie an overhand knot in the mop strand/wick, then pull the tag end through the hole until the knot/stopper covers the hole. Even then, with the entire hole covered by the knot in the wick, there are no drainage issues.

One thing I would mention is, if you have a plastic pot w/o holes in it, make sure the holes are through the bottom at the sidewall, or through the sidewall so the bottom of the hole is tangent to (touching) the bottom of the pot. Holes only through the side of the pot but above the bottom trap water at the bottom of the pot, which creates issues on several fronts.

Speaking strictly from the standpoint of drainage. It doesn't matter if there is 1 hole in the bottom or twenty. Assuming the pots are the same size/shape and both are filled with the same grow medium, when the pots stop draining there will be exactly as much water in both pots, so multiple holes to make a pot drain faster offers no benefit.

Finally, if a medium supports excess (perched) water, the maximum ht of the perched water table will be the same, no matter what the size or shape of the pot, and changing the number of holes in the container has no impact on how much excess water a planting holds. All pots in the image below are filled with the same medium, and the shaded area in these pots represents excess water.


Al

Great post:)

I've shifted to a lot of plants in their original plastic pots instead of transplanting into terracotta but have never modified the drainage that way with either. Short of some window screen or preferably hardware cloth covering the hole if the drainage is too big.

As far as watering at certain angles...if it works for you keep doing it.

I like to go by hefting the plant before and after watering (with a small volume pre-watering if the soil's especially dry).