Are chippings essential to top dress alpine pots?

[newstart]

I have noticed that my compost is now better and more free draining since we had disscussions on loam compost with grit added etc etc. We briefly talked about chippping as a top dressing so plants do not become overwatered. I also noticed in a book that it says the purpose for this is for the right amount of water to end up going into the plant. It said the surplus water falls over the sides if to much is added. Is this the only reason for it or is this of little consiquence really? I noticed I get alot of problem with my top greenhouse shelf dripping onto the bottom shelf plants. At a guess is it also the chippings are meant to stop dripping problems too ?

I guess alot of this is common sense but I thought I'd ask.

Thanks David.

[Lesley Cox]

I think if you water too copiously then the pot will overflow regardless of whether you have chippings on top or not. It won't, only if the compost is so free draining that the water sinks immediately.

To my mind, the purpose of chippings is A) because an alpine from a rocky habitat looks so much better when surrounded by chippings (I like them, to be be not too even in size and shape) and B) to discourage slugs and snails from walking across them to the plant. In theory they don't like the rocky surface on their slimy underbellies. Many weeds can be easier to remove from a chipped surface too, though you sometimes have to poke down among the chips to get the root.

But there are the "chippers" who put chips on everything and I don't think they look right on woodland plants or plants which would naturally grow among composting leafage or spaghnum, trilliums or cypripediums for instance. Better to use a surface mulch of that type of material. Both chips and humusy stuff also keep the pot surface cool of course, helping with watering.

[mark smyth]

you cant beat southern fried chips

[Darren]

I never top dress any bulb pots unless they are going to a show or meeting. I like to be able to visually assess the dampness of the pot surface.  Otherwise I find some bulbs too easy to overwater, especially in plastic pots.

Though I no longer grow many,  I think cushions certainly benefit from something between their base and damp compost. Problem is that nobody has found an effective way of similarly insulating them from the sodden atmosphere here in winter! Duncan Lowe's cushion plants book suggests that thick flakes of slate or similar flat stones are better at keeping the base of cushions dry than chippings and my limited experience supports this. I also think they look more natural. As Lesley also indicates - alpines will probably also enjoy the effect of a layer of stone keeping the roots cool.

Oh - I do put a thick layer of coarse gravel on top of Corydalis popovii and similar, mostly to support the new shoots.

[newstart]

I think all in all I will cover them in chips in summer when its hot and more P&D are likely to be around. Thanks very much indeed for your views and opinions as always very useful.

Have a nice day!

[Maggi Young]

A top dressing of chippings or stone flakes in a pot will also prevent small plants from being splashed with soil when watered....  and outside, little alpines can get filthy and quite spoiled by being splattered with dirt from the rain.

[TheOnionMan]

To my mind, the purpose of chippings is ... B) to discourage slugs and snails from walking across them to the plant. In theory they don't like the rocky surface on their slimy underbellies.

I'm firmly convinced stone chips are no deterrent to slugs whatsoever.  For the four years I lived in the Pacific Northwest (near Seattle Washington) these bad boys would cross anything anytime to get to choice plant morsels, they would handily cross a sharp gravel driveway, or any other gravel expanse, with their mucousy propulsion and tough "foot" undersides, to devour any choice Campanula, or snag a few rosettes on Erigeron aureus.  The major problem was not only slugs, but the diversity and types of slugs there, the worst being "banana slugs", so named because the grow to 6" (15 cm) long and as thick as a cigar, appearing in great numbers nightly, often traveling in bunches

[Gerry Webster]

To my mind, the purpose of chippings is ... B) to discourage slugs and snails from walking across them to the plant. In theory they don't like the rocky surface on their slimy underbellies.

I'm firmly convinced stone chips are no deterrent to slugs whatsoever.  For the four years I lived in the Pacific Northwest (near Seattle Washington) these bad boys would cross anything anytime to get to choice plant morsels, they would handily cross a sharp gravel driveway, or any other gravel expanse, with their mucousy propulsion and tough "foot" undersides, to devour any choice Campanula, or snag a few rosettes on Erigeron aureus.  The major problem was not only slugs, but the diversity and types of slugs there, the worst being "banana slugs", so named because the grow to 6" (15 cm) long and as thick as a cigar, appearing in great numbers nightly, often traveling in bunches

My experience too, but thank God no "banana slugs" here (yet).

[Luc Gilgemyn]

I 've had more slugs than ever this year ...
Grey, brown, heaps of snails, etc....  I've got the distinct impression that pellets have pretty much become useless too... and neither gravel nor chippings wil definitely not deter them here...
I feel so lucky NOT to be growing any bananas though...

[angie]

I 've had more slugs than ever this year ...
Grey, brown, heaps of snails, etc....

Same here Luc, I never seen so much snails. I gathered mine for weeks , walked a little bit down the road and threw them into the woods then I read in a gardening magazine that they come back this I did not believe but I have read again that some lady painted her snails and they did come back to her garden.
I wonder if it's true.

Angie

[Luc Gilgemyn]

I've never heard of snails coming back Angie, but it does sound frightening.... 
I despatched a lot of mine into the sewers... here's hoping they couldn't swim.... 

[Darren]

We chuck our snails across the busy road at the front. If they want to come back they must first run the gauntlet. There are at least two potential pitfalls:

1) There is a danger of vehicles skidding on the slimy result of a particularly good harvest.

2) And eventually natural selection will result in our creating a race of super-fast and agile roadrunner snails. 

[Gerry Webster]

Apparently they do return. BBC radio 4 recently had some programmes on amateur scientists & in one a lady investigated & found that they would return to their home gardens - I can't remember over what sort of distance. I find the heel of a boot is a good deterrent to this sort of behaviour.

[Lesley Cox]

To my mind, the purpose of chippings is ... B) to discourage slugs and snails from walking across them to the plant. In theory they don't like the rocky surface on their slimy underbellies.

I'm firmly convinced stone chips are no deterrent to slugs whatsoever.  For the four years I lived in the Pacific Northwest (near Seattle Washington) these bad boys would cross anything anytime to get to choice plant morsels, they would handily cross a sharp gravel driveway, or any other gravel expanse, with their mucousy propulsion and tough "foot" undersides, to devour any choice Campanula, or snag a few rosettes on Erigeron aureus.  The major problem was not only slugs, but the diversity and types of slugs there, the worst being "banana slugs", so named because the grow to 6" (15 cm) long and as thick as a cigar, appearing in great numbers nightly, often traveling in bunches

Well, I did say "in theory" Mark. I hate to have to tell you this but I have no snails at all and I haven't seen a slug - of any kind - for about 6 months, and THAT one, came in on a garden centre plant. It was quickly dispatched and the plant examined for eggs.

When I lived at a different address in Dunedin city, there were hundreds of snails and I threw them out onto the road to start with but after a few days the stench of rotten meat was so bad I stopped that. Then I hired the neighbour's kids to hand pick them into buckets of brine. Also horrible, and ultimately very expensive even at a cent a snail.

[Diane Whitehead]

I remember a photograph in Life magazine lo-o-ng ago.  It showed
a slug going up and over the sharp side of a knife.  No way is gravel
going to discourage them.

And then there was the lecture by a Seattle professor about slugs.
One anecdote:  a commercial greenhouse full of orchids about to
flower was secured against slugs on floor and pot level.  They came
down on ropes of slime from the top ventilators and ate the flowers.
I'm not sure that all slugs can do this.  Our banana slugs climb and
then twine together on slime ropes when they are mating.