Top dressing for succulents

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WayneM
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Top dressing for succulents

Post by WayneM » Fri Jan 18, 2019 8:14 pm

Sorry if this has been covered before, but as a newbie I wondered what is your preferred kind of gravel or top dressing for succulents?

What would you suggest? Does anyone use aquatic gravel?

What works well for you ? Where do you source it from?

Would be happy to hear of your comments.

Thanks Wayne
Stevium
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Re: Top dressing for succulents

Post by Stevium » Sat Jan 19, 2019 8:56 am

I know it's very traditional to use top dressing, and it definitely can make a visual statement (I know people who use neon pink and black aquatic stones which looks super unique - and I've personally used tiny tan and white aquatic pebbles against teal plants which looks amazing), but I've moved away from doing this for three reasons.

First, I found it keeps my soil saturated for longer after watering and I'm convinced it's the reason I lost a few of my plants - and it additionally attracted fungus gnats which, whilst mostly harmless, are a pain in the arse. Secondly, I'm interested to see what's going on with the soil - I can tell whether it's wet or dry, any pups from plants that have stolons, surface pests, etc. Finally, if your plants are indoors and you accidentally knock one over, it's painful to stand there and pick up all the stones - though I guess this depends on what your setup looks like.
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rodsmith
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Re: Top dressing for succulents

Post by rodsmith » Sat Jan 19, 2019 9:19 am

Conversely from Stevium's policy, I use a top dressing of small stones/large grit on all my succulent plants. I agree it is a nuisance if you accidentally knock a pot over but soil would probably spill out anyway. The received wisdom as I understood it is that a top dressing of small stones deters sciarid flies as they can't penetrate the grit to lay their eggs. I do have an occasional loss due to overwatering causing the plant to rot but it is easy to scrape aside a bit of the grit to check the soil for dampness - or to look underneath the pot where it has been standing. So I am all for a top dressing.
Rod Smith

Growing a mixed collection of cacti & other succulents; mainly smaller species with a current emphasis on lithops & conophytum.
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conolady
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Re: Top dressing for succulents

Post by conolady » Sat Jan 19, 2019 9:22 am

I don't use top dressing except for showing. I agree with all Stevium's points, plus a lot of gravel makes pots even heavier, a major consideration for me. I like to eyeball my substrate before watering.
First it was orchids, then, since c.2001, cacti and succulents. I'm into South African plants, mainly conos, lithops and haworthias, with a few cacti, especially 'posh' mamms, turbs and other smalls.
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Peter
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Re: Top dressing for succulents

Post by Peter » Sat Jan 19, 2019 9:57 am

A major benefit of top dressing is that it supports newly potted plants in their pots and thus helps the plants establish.
Very beneficial to those taller plants. For those of us who water from the top it helps to prevent compost from being washed off.
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Re: Top dressing for succulents

Post by Chez2 » Sat Jan 19, 2019 11:01 am

conolady wrote:
Sat Jan 19, 2019 9:22 am
I don't use top dressing except for showing. I agree with all Stevium's points, plus a lot of gravel makes pots even heavier, a major consideration for me. I like to eyeball my substrate before watering.
I find the weight a problem too. I have some decent size pots and I have trouble lifting them. I do add decorative topping, sometimes quite chunky to outdoor pots. I add perlite as well as grit and sand to my tubs that stay out in summer. I know perlite can retain water as well as help with drainage and aeration but my plants have been fine even after heavy rain. They do only go out in summer though. Tops dressing helps keep down weeds and helps with contrast so the plants show up better. I bought a soil moisture probe to help me check if they need watering.
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Re: Top dressing for succulents

Post by Terry S. » Sat Jan 19, 2019 12:03 pm

I'm with Stevium on this one, top-dressing reduces evaporation from the soil surface and you can't see what is going on underneath the dressing. With most summer-growing plants, the reduced evaporation probably makes little difference and under some conditions and with the quick-growing species, it might actually be an advantage. However at least half of my collection consists of winter-growing plants and I do not want excess moisture hanging around in the pots for too long after watering.
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Re: Top dressing for succulents

Post by juster » Sat Jan 19, 2019 12:29 pm

Interesting to read the different opinions here. I use a top dressing of smallish gravel and just buy a large bag from my local Garden Centre, I had to hunt around a bit before I found one that I liked, it needs washing through before use. I don't use a thick layer as the weight of the pots is also an issue for me. With rosette forming Succulents like Echeverias, it does keep the bottom leaves away from any damp in the compost and reduces the possibility of rot.
Croydon Branch member, growing mainly cacti and Echeverias
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KarlR
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Re: Top dressing for succulents

Post by KarlR » Sat Jan 19, 2019 12:51 pm

I've usually always used top dressing (mostly for decoration) but there are obviously some considerations.

First of all, I can't really think of any plants that specifically need a form of top dressing in habitat. Perhaps Lithops in the sense that they mimic the colour of the pebbles around them but, in terms of needing a layer of top dressing to reduce chances of rot or to create some form of necessary micro climate, I can't think of any habitat examples. Please correct me if I'm wrong.

For adult plants the benefits of a top dressing are in my view restricted to such things as keeping the soil in place when watering from above, keeping tall plants with a fairly small root ball in place in a pot, and for decoration. I don't subscribe to the theory that top dressing reduces chances of rotting. I think that has everything to do with the soil used, the watering regime, bad luck with infections or pests and so on.

If using ingredients like coco coir or perlite, I think a top dressing works very well to keep the soil in place, but if you go for a wholly mineral mix, then I wouldn't perhaps see a particular need for top dressing other than decoration. For particularly rot prone species top dressing might lead to more moisture being retained for longer, although for cacti at least I'd go with a 100% mineral mix for such species in any case. And for plants needing more constant and reliable levels of moisture in the soil, I would agree that no top dressing makes it easier to judge when to water.

As for what to use, I'd say use what is easy to get and which satisfies your aesthetic sense. Very fine gravel might not suit your needs though, particularly if you plan on watering from above.
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conolady
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Re: Top dressing for succulents

Post by conolady » Sat Jan 19, 2019 3:52 pm

Terry S. wrote:
Sat Jan 19, 2019 12:03 pm
I'm with Stevium on this one, top-dressing reduces evaporation from the soil surface and you can't see what is going on underneath the dressing. With most summer-growing plants, the reduced evaporation probably makes little difference and under some conditions and with the quick-growing species, it might actually be an advantage. However at least half of my collection consists of winter-growing plants and I do not want excess moisture hanging around in the pots for too long after watering.
Absolutely. I hadn't thought specifically about winter growers, as about two thirds of mine are, but one wants them to dry out quickly in the winter damp and anything that slows evaporation must be a bad idea!
First it was orchids, then, since c.2001, cacti and succulents. I'm into South African plants, mainly conos, lithops and haworthias, with a few cacti, especially 'posh' mamms, turbs and other smalls.
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