tips on planting cactus in the ground

[CoLaNuT]

Hello there,

I have an area 8m x 4m that I would like to plant out with cacti and succulents

(currently clay soil. Dry tropical climate).

Are there any soil preparation golden rules I should follow when planting?

Any tips would be much appreciated.

I want to it right.

Cheers

[Stillman]

I made a cacti garden recently, we have in that spot similar heavy soil. Rather than trying to improve the existing soil I built a raised bed, probably built it up about 200mm, first two thirds was peat/sand organic matter mix last third (top dressing) was sand. So far so good, plants seem to love it and we have had a fair bit of rain with no issues with wet "feet" yet. I have a mixture of trichs and various smaller clumping cacti in it.

[Stillman]

Mind you may not be cost efficient to build up an 8 by 4 metre patch.

[CoLaNuT]

Thanks for the info. Stillman.

Looks nice!

I was planning to build it up, I have a mate with a quarry that owes me some favs.

Planned on adding gypsum to the site first before I raised it up.

Just wasn't sure what mix to use.

I have a variety of cacti and succulents to plant.

I want to do it right

Edited January 27, 2012 by Ive Fargottin

[naja naja]

aslong as the ground was sandy enough to cope with this, I'd encorporate well rotten manure, quality potting mix, and top dress with a complete peletized fert like kateks, organically cert super growth or similar product. maybe some seamungus top dress or water in with seaweed solution.

[CoLaNuT]

OK

Lots of sand..........................tick

lots of well rotted manure......tick

other ferts.............................tick

should I incorporate crusher dust, rocks, pebbles?

[Stillman]

I wouldn't use crusher dust it may compact to heavily but pebbles and rocks for sure I mean at the end of the day different species of cacti have different requirements so maybe some of the big trichs might favour more traditional garden soil while others may need more sand, just have a play with it. That size area will look amazing I only had a couple metres to work with but you could really layer it amd landscape it up a treat.

[bit]

wouldn't use sand AT ALL!! No matter that it has no nutritional value, sand forms CAKES over time which hold water and inhibit root spread, especially when mixed with dirt. Sand is not a well draining medium, it is far too fine unless you get a really really coarse grade (like the type that hurts to walk on in bare feet), and even then use it only by itself, not combined with anything else that will help cake it together.

Bear in mind that cacti roots seldom go down more than a foot - most of their roots are just below the surface.

If I was building a raised bed for cact over clay i I would first plant something that will turn the clay into soil - I think potatoes and possibly other legumes do a good job ot breaking it up and turning it into a better quality soil. This would obviously take 6 months or more of prep..

Failing that, put down a 3" or more layer of free draining material such as scoria, river stones etc. The soil mix itself should be a 50/50 of pumice (5-10mm grade)( or perlite or similar material which won't break down), and a rich compost/manure/topsoil.

Just my 2c. But for the love of plants stay away from sand unless you live on a beach an there's absolutely nothing else!

*edit, just as an aside, if you have any local cacti/succulent nurseries with ground beds, doesn't hurt to ask them what they use in their mix.

Edited December 29, 2011 by bit

[naja naja]

I didn't mean to add sand, just if the ground was already sandy as apposed to clay. Then u could beef it up with organic matter. However if it was clay, I'd suggest the raised bed too

[Foo]

gypsum Helps to break down clay, but i would still avoid clay if poss

[CoLaNuT]

Can't avoid the clay mate.

I add heaps of gypsum all the time to allow the clay to drain, works a treat.

I plant my fruit trees on raised mounds, adding lots of compost, manure, etc.

put down a 3" or more layer of free draining material such as scoria, river stones etc. The soil mix itself should be a 50/50 of pumice (5-10mm grade)( or perlite or similar material which won't break down), and a rich compost/manure/topsoil.

Thanks bit, thats what I needed to know.

[Stillman]

I used course sand as a top dress which provides a nice effect for the cacti garden, underneath this layer is an organic /peat mix which has excellent moisture retention and holds nutrients etc. Depending on your climate and rainfall I wouldn't completely disregard using a sandy mix at least. Trichs, cereus, gymnos etc might not mind a bit more moisture but some species will struggle if kept too wet especially in the winter months. Like I said above with such a large space you might be better off having various soil mediums in different areas specific to species requirements which would be pretty cool.

[indigo264nm]

It's good you let us know what soil type you have, and the tropical climate mention...

I seriously recommend, like mentioned above, cultivating the soil with gypsum to break down the clay. Clay soil, even in the case of vascular plants, is shite because it's hard to guarantee to consistent drainage throughout a level bed. It's also a pain in the ass after a hot dry stretch because dry clay is a nightmare to re-wet.

In horticulture it was never recommended to put sand or similar inorganic materials into the soil of a garden bed in the instance of heavy clay. The only course of action was to put in the hard labour and cultivate the soil with gypsum and a mattock. After you do that and you have a nice loose topsoil that drains well, wait for the soil to dry out and then pour a lil bit of water onto the soil and see whether it repels water (it gathers into little puddles instead of drains immediately). If it repels water then you'll want to put in a little bit or organic material like good compost or pasteurized cow manure through it, water thoroughly and wait about a week before planting.

I would also recommend if possible building a slightly raised bed up for it with clay soil just because the drainage will be much more consistent.

Like Stillman mentioned it is often nice to put something like coarse sand, or scoria etc on the top just because it looks nice. In your case I would actually recommend doing such because it works well as a cover to keep weeds etc out... if you had sandy, or sandy loam I would have recommended something like sugar cane mulch because they love it in summer when the rains hit - but in your instance it's better to use a rocky covering because you won't have to worry about keeping the soil moist.

Either that or you could try and 'import' a better draining topsoil if you know somebody on a property that has better soil, and building a raised bed but even then I'd suggest breaking up the clay first as it's no use having a well draining topsoil if the layer underneath doesn't drain properly.. importing a topsoil, as silly as it sounds, is a reality these days. Often for newly built houses\apartment blocks building companies will purposely tax the topsoil before building and flog it to the landscapers to use on other jobs.. good topsoil is worth good money.

It is really worth the effort to make sure you've got a good, even garden bed before you plant out because you'll have very few problems in the future that way.

Oh, and if you're going to go to effort that I suggest - test the pH as often clay soils can be quite alkaline in my experience and it's far easier to change the pH of your bed BEFORE you plant out... and if you do make sure you take 3 different samples along the bed and below 2.5cm from the surface.

[indigo264nm]

I forgot to mention when choosing where to put in ground........ SUNLIGHT SUNLIGHT SUNLIGHT.

[CoLaNuT]

Thanks guys,

is there a preferred PH?

[Stillman]

I would think for most cacti slightly acidic to neutral ie 6 to 7 ish anything much below would be getting too acidic above would probably be too alkaline? But just check that for specific species others may have a specific ph that works well for them.

[indigo264nm]

Neutral pH is always a good guess for most things (except rhododendrons).. Can anybody remember Trout's talk at EGA where he mentioned optimum pH??? Might have been for Lophs and not Trichs anyway but I specifically remember that he brought up pH - my guess slightly acidic just because sandy soils tend to swing that way.