Kitchen Garden Forum

I was under the impression that broken pieces of flower pots were put into the bottom of larger pots as they retained moisture as well as stopping soil falling through the holes in the bottom of the pot.
A number of posters (on another forum) have told us they use other "stuff" such as bottle tops, polystyrene, etc. These do not retain moisture.
I am confused.

Dear WestHamRon, the crocks are to stop the drainage holes getting blocked, so avoiding waterlogging.
This was probably more importatant in the days of clay flowerpots, as they only had the one large hole, but the plastic pots of today have a far better draining set-up.

Thanks for your swift reply .
So the water-retaining characteristics are irrelevant ?
I hope not, because I'm trying to start an argument on the other site.

I don't think any of the materials mentioned including polystyrene have water retaining properties, the polystyrene allows you to bulk up large pots and use less compost and also to drain more effectively. Bottle tops the same I guess.

The best thing for water retention is not to let the compost dry out, use water retaining gel or hyrdralecia (not sure of the spelling) but these are clay beads, that can be added to the bottom of the pot or in a central column they allegedly retain water and leach it out when the plants need it.

CoMpO

Morning WestHamRon, in my opinion, yes, crocking a pot is just for drainage and not for water retaining.
Water retaining gel, or a sump, such as a container or plastic sheet is what is needed for this.

Unless you want to make an argument over it.

oldherbaceous wrote:Morning WestHamRon, in my opinion, yes, crocking a pot is just for drainage and not for water retaining.
Water retaining gel, or a sump, such as a container or plastic sheet is what is needed for this.

Unless you want to make an argument over it.

Everyone seems to agree that water-retention isn't involved. I shall blame the wife.

The only reason to crock a pot is to stop compost falling out of the bottom, and even then it doesn't fall out all that easily. If I pot into a clay pot, I use a single shard of broken pot to cover the hole, and nothing more.

Recent research has shown that our forebears were flogging a dead horse when it came to their obsessive use of layers of crocks, grit and fibre, None of these make any difference to the "rooting environment" and it's the how the pot is watered, and how frequently, and what the pot is standing on that makes the difference.

Around the beginning of January I start saving all my used teabags and put an inch of padding in the bottom of the pots in which I grow peppers, aubergines and chillis. They stop the compost leaching out and also retain a certain amount of moisture until they disintegrate at the end of the season. The plant roots don't seem to mind and grow quite happily into the material. I also mix in some water retention crystals as I grow my plants on a sunny patio and they quickly dry out, even though I store them all in drip trays to ensure that any surplus water containing liquid plant food can be collected and re-used if I've over-watered. I'm not sure I see the point of part-filling a large tub with a quantity of crock to economise on compost. Surely it's a big hassle if the plant starts outgrowing the soil available and you have to empty the whole pot and add additional compost at the bottom? In my view it's better to start off with a smaller pot and then move up to a bigger size if required.

My eight year old grandaughter loves the fact that I use crocks in the bottom of my clay pots. WHY? Because I save old cups, plates etc that are chipped and wearing grandads safety goggles she's allowed to smash them even more.Beats computer games any day

i use plastic pots , no crocks, never had any problem with compost falling out the bottom. allways stand the pots in a plastic tray or container and keep it well watered so theres allways some left in the bottom.

Hi WHR,
Both Vermiculite and Perlite added to your potting compound will retain water but not to the same extent as the Super Gel.
JB.