Plastic Pots

[Tina]

I get my large plastic bowls from Richard & sheena drane, they do mail order and even have the extra large ones at a reasonable price.

[Sylv]

Thank you for that Link DaveW,very interesting and informative.

Sylv.

[FaeLLe]

Just wanted to leave this resource here as well as they have really good quality and cheap pots; the plastic is atleast 1.5-2 mm thick.

They are also doing free next day UPS delivery above a low minimum order limit which sweetens the deal.

http://www.onestopgrowshop.co.uk/grow-s ... -pots.html
http://www.onestopgrowshop.co.uk/grow-s ... -pots.html
http://www.onestopgrowshop.co.uk/grow-s ... ckets.html

[jerryb23]

Try this link for plastic display bowls, they are based in Colne, Lancashire. I bought a load last year and I believe they are exactly the same as the ones that were at the national + they are excellent value for money:

https://www.lbsbuyersguide.co.uk/catalo ... splay+bowl

[Peter]

Be careful not to buy pots that are too deep for the plants otherwise the compost could stay too wet. Not all cacti have tap roots extending down and a cube shaped pot better suits most young cacti, preventing root rot.

[DaveW]

Afraid it is an old gardeners myth that deep pots stay wetter Peter, just as a layer of grit or crocks in the bottom of the pot helps drainage. It may appear logical, but is not scientific fact. The only crock if any that is needed is one over a pot drainage hole if that is overlarge so soil runs out of it, not a problem with small multi holed plastic pots, rather the old large single hole clay ones.

In a deep container water sinks to the bottom of the pot away from the neck of the plant far quicker, therefore the plant dries out quicker around the neck. In fact shallow pans retain water nearer the plant for much longer rather than being dryer. Therefore a plant that is rot prone will probably survive better in a deep pot than a shallow pan given the same watering. After all in habitat they are in deep soils, not shallow soils as in a pot and water drains to lower depths far more quickly and away from the plant body.

See:-

http://forums.gardenweb.com/discussions ... -container

http://oregonstate.edu/dept/nursery-wee ... rties.html

As to different layers in a pot (stratification) such as soil over a layer of gravel for drainage, another old gardeners myth, this actually forms a barrier to water draining from one layer to the other, not aids drainage.

See:-

http://www.telegraph.co.uk/gardening/ga ... -idea.html

http://gardenprofessors.com/container-p ... s-reality/

https://www.youtube.com/watch?v=J729VzBeI_g

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

Therefore if you want good drainage you should never have different layers in a pot, the compost should be uniformly mixed from top to bottom without supposed "drainage layers" at the bottom and a deep pot will remove surplus water quicker from around the neck of a plant than a shallow one.

[ragamala]

The problem is, Dave, that the links you refer to on PWT basically say the same thing from same source. The caveats on the result as far as practical purposes are concerned are firstly, that it is assumed that all pots are watered to saturation. I don't water that way. Secondly it is clear that the medium used affects PWT, which means there is no answer-all solution.

I would go with my feeling developed over many years that shallow-rooted species in my experience do fine in shallow pots with my watering regime (I have always grown cacti hard), and deep-rooted species of course demand deeper pots. At the end of the day why waste money on deeper pots and extra compost, especially if you just might risk root rot as winter approaches? This is after all a practical endeavour not a scientific one.

[Tina]

Thanks Jerry
That's a good Co link, it's the same as the pots I buy from the Dranes at a fraction of the price.
I had to phone them for a conversion of litres to pot rim diameter though.

[Peter]

With all respect to you Dave, and all the learned folk at the other end of the links that you posted, I prefer to base my comment based on my experience over very many years. I used to try to save money by using the black, square and deep pots that you get in garden centres - but most of the plants didn't thrive as well as in standard BEF style pots and it turned out to be false economy. And I can tell you that deeper pots stay wetter here in Shropshire (weird, I know), and if the top of the compost looks dry, I can rely on the rest of the BEF potful also being dry and the roots aren't rotting away in damp, stale compost.

Why would you want to use pots so deep that the roots wouldn't reach down? And try to tell me that compost doesn't go stale and you won't succeed.

My opinion is that it's far better to use pots of the size that roots will fill and then pot on. And so far as habitat plants are concerned, you can't make a comparison because they aren't growing in John Innes with additives, or peat or whatever, in a pot with a label, in a greenhouse in an alien climate and with artificial fertiliser.

[DaveW]

A friend of mine says you can grow cacti in anything as long as you get the watering right. What he means is as long as you treat each plant individually regarding watering and give just what is needed you will be OK. Once you get a collection of over 500 plants and certainly 1000+ you cannot give them that sort of individual attention. You probably don't overwater the shallow pans therefore they don't stay wet for long.

I have a 2ft deep greenhouse bed and I can tell you if I water that with a hosepipe and all the plants on the staging similarly the top six inches of the bed will be drier long before the pots on the staging's, due to the water rapidly sinking down to a lower level below their roots. I have rotted a few cacti in pots in my time, but never yet rotted one in the deep centre bed. Graham Charles made the same comment to me about plants planted in beds, that they needed a lot more watering than plants in pots.

As to black pots, well they will obviously heat up in a greenhouse quicker than most other colours and possibly the roots did not like that. The old gardeners used to plunge their pots on the staging's in sand or peat for that very reason. Plants in open ground do not get their roots baked from the sides.

As to shallow pans or pots. I have often found plants that are considered difficult as they age, but seem to grow quite well whilst small often tend to sulk or rot when they clump and are transferred from smaller pots that are proportionally higher than wide into pans that are now wider than high, therefore the perched water table is higher so they stay wetter around the neck than they did as seedlings.

Why does soil in open ground not go stale or sour as fast as it does in small pots then? A larger volume takes longer to go toxic, as in a large pot rather than a smaller one. Larger volumes of compost remain more stable than do smaller ones. One reason compost in pots often goes toxic is they are being watered too sparingly as well as regularly fed, therefore there is not enough clean water throughput to rinse out all the excess salts any fertilisation leaves.

When you water pots it should freely flow out of the drainage holes to help to prevent salt build up. In fact a good flush out for the pots with unfertilized water fairly regularly will help the compost stay sweet. Also for those on windowsills with saucers underneath it is never good practice to leave the water that has drained into the saucer to be reabsorbed again since it is simply reabsorbing the flushed salts. The same problem occurs with constantly bottom watering plants without occasionally top watering the pot to flush salts out.

https://www.maximumyield.com/remember-to-flush/2/1206

The old gardeners could grow plants well by usually giving each individual care, but often got it right for the wrong reasons that science has now explained.