Stones, pebbles, cracked terra at the bottom of pots worsens the drainage. Solved

[D^L]

One we return to from time to time and I hold a different view to some.
If a pot is too deep for a plant or if I want to reduce water I fill the bottom of the pot with stones; a third or half way up. It has no impact on drainage, water draining out of the bottom of plastic pots. They don't drain better or worse.
But it reduces the volume of soil that stores water when I go round with the hose.
At the bottom of the fine material there is a region where the compost is saturated after watering. All the air volume is filled with water. This is a result of the surface tension at the bottom of the water layer holding back a certain height of water. So raising the base of the compost moves the saturated region up the pot, closer to the plants.
However, my pots are usually full of roots. Down to the bottom and round and round. So wherever the saturated layer is there will be root. In fact with larger stones at the bottom, the majority of roots are in a relatively dry region.
Just my view.
David Lambie
Bristol

[KarlR]

Yes, kitchen paper towel works great. Once I started using it I've never looked back.

[Diane]

I use newspaper - no problems.

[MalcolmP2]

Interesting topic, thanks.

Kitchen paper for me too.
Pebbles etc can add weight at the bottom for stability ?wot think?
Two refs have been made to previous discussions, if anyone has a(the) link(s) that would be good, ta.

Instead of a drill to add holes in plastic pots I use a hot soldering iron (another hobby, electronics ), with a conical tip the size of hole is easily varied. (usual admonishments apply : seek assistance from an adult, do it in well ventilated place )

[Bonsai2]

Terry, thanks for the advice.

I currently use a plastic mesh at the bottom of the pot which stops soil coming through and enables free drainage. ( I just bought 5 x A4 sheets of plastic mesh for £3.50 on Ebay. Much less expensive than others on offer as it comes from China.)

[Bonsai2]

Thank you all for your comments.

I will also bear the paper over the holes in mind.

Thank you kohinoor for the YouTube video link below.

https://www.youtube.com/watch?v=ego2FkuQwxc

I also found the article below from a Master Gardener in the USA.

"Plants like good drainage, especially those in containers. If water pools around plant roots too long, root rot will damage and possibly even kill the plant. For too long, gardeners have been covering the bottom of containers with gravel, pieces of broken pottery, Styrofoam packing material and the like. Do not do this . . . only potting mix should be put into a plant container.
Instead of water draining immediately through the soil, then into gravel or other material and on out the drainage holes, water will completely saturate the soil so that no air spaces are left. This could take a long time and in the interim, plant roots will be starved for oxygen."

[Brian]

Either newspaper or kitchen roll for me in plastic pots. Terracotta pots I use a pebble or small broken piece of old pot, avoiding pots which are too deep. Always works a treat.

[Terry S.]

The technical term for what D.L. is talking about above is "perched water table". For any particular soil mix, the compost retains water for a fixed distance above the bottom of the column of soil after it has been watered. So in a shallow pot, the soil saturated with water is close to the bottom of the plant whereas in a deep pot the saturated compost is much further away from the bottom of the plant.

Also if you change the soil mix within a pot, e.g. put richer compost in the bottom and gritty soil at the top, the interface will impede drainage.

[el48tel]

Just come across this idea in http://centralarizonacactus.org newsletter

[MikeT]

Used newspaper is cheaper, so favoured in my part of Yorkshire