Growing Medium |
Clivias do not like to be planted into a pot using soil. Their roots are not designed for living in soil, so they often rot off. Clivia roots have a requirement for lots of oxygen around the roots. Tall pots drain more than short pots. Drainage requires a physical connection from the bottom of the pot onto soil. Place Clivia pots onto a layer of sand or onto capillary mats. Do not put gravel or polystyrene chunks at the bottom of pots, keep it all one medium. They can be planted into the soil in the garden, in a shady spot.
Drainage from pure sand or pure gravel is high. But when they are mixed in the right ratio, drainage is reduced to very little. If we add sand to a bark medium, we make it heavier, with less oxygen and it drains less well. Remember that Clivia is very dependent on high oxygen content in its growing medium.
Sand is not all the same. It depends upon what rocks it came from originally. Silica sand is the best to use because it has the right chemical and physical properties. River sand may have disease and nematodes (eelworm). It is important to sieve out the fine particles (<0.25mm), using the coarser particles for growing purposes.
Compost and growing media are not all the same. What one is looking for is:
A physical and chemically stable medium (not decompose further)
Good water holding capacity
A good oxygen content, hence good drainage
A good cation exchange capacity (ability to hold and release fertilizer)
The following artificial growing media is available:
Composted pine bark. Mature Clivias prefer coarse medium.
Coca peat - useful to add to a composted pine bark medium to increase water retention, use less than 30% in mixture.
Prof Mark Laing - University of Natal
Hints on growing Clivia - Aug 2000
Gert Wiese used the following mixture:
The growing medium should ideally be a slightly acid, very well drained loam with much well composed organic matter. Bone meal can also be mixed into the soil. Most importantly, the soil must be prepared well, because once Clivia’s have been planted, they should remain undisturbed for many years. Best flowering results are always obtained from well-established clumps.
Graham Duncan
Newsletter Vol. 2 No 1 Jan 1993
Much of what I said in my paper may be debatable but for the layman it is for example better not to use any compost in the soil mixture than to use mushroom compost. My own son would not listen – after 3 weeks all the roots rotted! The amazing thing now is that he planted all these in ground pine bark chips and there recovery after 1 month is unbelievable. Well pine barks is also organic and so is palm peat and I often use both in my sand mixtures for adult plants.
Sand dry too quickly. One will have to add a clay factor and then concentrate on drainage. Prof. Orchard used to emphasize ‘pore-space and water retention’. What I have learned though is that root rot occurs even in course sand with over watering and bad drainage.
Christo Lotter
Newsletter Vol 5 No 3 Sept 1996 .
You will know you are on the right track of the roots come out pure white when you wash all the compost off.
Coarse river sand is invaluable for the cultivation of Clivias. It provides adequate drainage for seeds and young and old plants alike. Seeds planted in it germinate well, and plants in pots are well aerated if river sand is included in the potting mixture.
Buying packets of coarse washed river sand from the nursery can save much time, effort and water. It is beautifully white, clean, even texture and comes in handy packs.
Meg Hart
Newsletter Vol 6 No 1 Jan 1997 .
John Winter’s growing mixture is made up of 7 parts milled pine bark and 3 parts of milled pine needles, He does not use any sand with his mixture.
Gert Wiese
Newsletter Vol. 8 No 1 Autumn 1999
The potting mix should approximate simulate the medium in which Clivias thrive in their natural habitat ie. the leaf litter found on the forest floor. My mix consists primarily of garden compost to which some milled pinebark has been added.
Dr Bing Wiese
Newsletter Vol. 8 No 2 Winter 1999
Christo spoke on growing mediums that can be used:
He uses sand and showed us how well the roots and plants develop in sand - and his plants flower in three years! He suggested the following mix: Leaf mould and sterilised manure compost as one part mix 50:50 with building sand. His advice on seed - don't overwater and overfeed.
Christo Lotter
Newsletter Vol. 9 No 1 Autumn 2000
These growing conditions indicate that Clivia require little water and in cultivation they require a very sharply drained growing medium and cool conditions.
John Winter
Clivia yearbook 2 Page 6
I find some of your comments interesting and on the mark; however, I do not agree with your description of the preferred soil mix. There are
several of us here in Santa Barbara with fairly extensive collections. All are grown outdoors and generally in containers. The soil mix is more like 60% compost with 40% washed sand. Peat should be avoided since it retains too much water. In general, clivia seem to like being on the dry side. I do agree that clivia are tough and will tolerate a wide range of growing conditions. In my particular location temperature seldom gets above 85 degrees and in the winter stays above 40 degrees.
Maris Andersons, Santa Barbara
Enthusiast e-mail Jan 2003.
There are several factors which contribute to the cultural success that the nursery is having. First of all, they are in Florida , where the plants are less stressed by cold weather than anywhere else in the US , and where (I assume) the weather conditions closely parallel the subtropical areas of Clivia habitat. This area in Florida is not all that warm in the winter, but all in all, not that bad. This guy's plants had seen many days at 20F but more days in the range around 26F over the years. These plants had been sitting in the nursery for about 8 years with nobody wanting them. These plants were under big oak trees which helps with the shade and the frost.
As far as the soil mix goes, Clivia prefer organic matter, so a 50% peat-mush mixed with 50% bark seems like it would be fine - especially in a container, where water can move through it reasonably well. A soil which leans toward the acid side would duplicate conditions found in nature, which can be surprisingly acidic, according to personal accounts posted in this forum. Consider also that several members of this group have managed to maintain epiphytic Clivia in cultivation, as well as occasionally encountering them in habitat, and one doesn't get much more acidic than that. Recently, I read (here?) of someone who has kept a Clivia growing in a bucket of water for several years. That should illustrate the toughness and adaptibility of the plant.
Finally, I feel that the real stroke of genius, the single, most prominent factor in their success, was accomplished by increasing the total planting mix formula to 105% via the use of extra sand - a move I would have expected from a Texas nurseryman rather than one from
Florida, but clever, nonetheless.
Actually the mix I mentioned is the standard mix that just about every nursery owner uses in this area. There are at least 100 wholesale nurseries using this exact mix all within 30 miles from me. The problem why I don't like this mix is that the lower pH locks up the efficient use of many fertilizers. It also loses air space which the people on this list seem to think is important for Clivias. I know it is important for cycads, but we are talking about a different plant group.
I have used the Florida peat-pine bark mixture for bushes when I sold woody ornamentals wholesale but found that I could grow cycads better with a cleaner mix. My mix now is:
40% Canadian peat
30% coarse sand
20% cypress sawdust
10% perlite
This form of peat breaks down much slower and is good for plants that have to be in the same sized pot for a longer period of time. It also keeps the pH pretty steady in the mid 6 range. It has good drainage and I was thinking this might work pretty good for Clivias. I know people have mentioned other organic materials, but a lot of that material sounds rather unsterile. There are many posts mentioning rot in the roots and it sounds as if people used less of these kinds of organic materials there would be less concern about pathogens. If someone can grow these plants in just water, I can't see why my mix wouldn't be too bad.
I have seen a little about what the plants can tolerate, so that helps. I have also read about fertilization, and I'm thinking some sort of Nutricote should work well. I have been using 360 day Nutricote for 10 years and it works great for a steady time release fertilizer. Some of the articles mention that Clivias should be fed for around 6 months and lay off the other six. If this is true, then the 180 day formula might be better. Both have the same minor element packages, and there are different formulas that all work for 180 days. I'm using 18-6-8 for the Zamias, but it sounds like 20-20-20 might be better for these plants. Just to play with I was wondering if using my 18-6-8 with a top dress of super triple phosphate as well might get some more flowers?
I'm going to try lots of different things just to see what I can do, you never know what can happen when you experiment. I just got my new Clivia book today, so I'm going to start reading to see what else I can find out. All I got to do today was to look at the pictures and look at a couple of the chapter titles. I see there is a lot on the history of Clivias, I'm sure reading this kind of thing will give me a better appreciation for the plants.
Tom Broome
Enthusiast e-mail Jan 2003.
This clivia was grown in what we call a "container mix" which consists of composted pine bark with size range of 15-20mm for about 80% of its volume. Remainder is pine bark fines and about 5% washed river sand. This is a good draining mix with an air fill perosity of about 28%.
Nick Stanmore
Enthusiast e-mail April 2003.
In production we try to keep the pH between 5 and 6 (optimum between 5.2 and 5.7). Above 6 you might have some problems with yellowing leaves due to iron deficienty.
Last year Pierre De Coster and I brought some soil back home from Clivia Caulescens in habitat (collected during the Caulescens tour organised by James and Connie Abel). The pH of these samples were around pH 4, so very low if you ask me.
Dirk Lootens, from sunny Belgium (15°C today, far to hot for our Clivia’s, they need cold to get a good blooming season).
Enthusiast e-mail November 2003.
There is a product made of the fibres found around coconut and it is called coco-peat. Of course not related to peat at all. It takes some adjustment to mixtures to get the mix right, but works well. If anybody wants to buy coco-peat, (the eco-friendly option for the greenies) please check the chemical assay and make sure it has a low Sodium (Na) content. Some companies do not wash their coco-peat and the high Na can create havoc in your pots. I find coco very water retentive and it lasts longer (i.e. aeration) in a mix.
Mike Viviers
Enthusiast e-mail Jul 2004.
I use coco peat as a medium to germinate clivia seeds in. Works extremely well for me. I usually buy it in a compressed block form and re-hydrate it by soaking the block in a bucket of water.
Eryan Paten
Enthusiast e-mail Jul 2004.
I am using Coconut fiber for the first time to germinate some seeds. The brand I bought is called "Down to Earth Distribution Inc.". It says it is "Neutral to slightly acidic PH 5.2 to 6.8. Weed and pathogen free. Resists bacterial mold and fungal growth". Doesn't mention about Sodium/salt levels though. 1 brick yields approx. 1.3 cft and it cost about USD2.80 in the nursery here in Washington State .
The thing I like about it is that it holds the moisture without being soggy. Also, my seeds seem to being staying very fresh looking, no signs of rot or mold or deterioration/ discoloration. What I didn't really like about it is that it is sort of messy to work with. You need a fairly big container to reconstitute it (with 5 qts water). But that is a minimal inconvenience, I think.
Julie LaJambe
Enthusiast e-mail Jul 2004.
Most Home Building Suppliers, here in the US , have bagged sand in grades which are usually rated as coarse ( 20 grade), medium (30 grade) and fine (40 grade), at least around here in Southern California they do. Some of the better building supply yards also carry a coarser grade of bagged sand ( grade 11 to 13). This coarser grade looks like small pebbles and is a very good media to allow your mix to drain, while not getting clogged by sand and other ingredients in your drainage holes of your containers.
I have found that one can also use a coarse washed sand which is sold in bulk at building material yards. It is of a grade between the 11/13 and the 20 and works well, when mixed into the potting soil. A 90 lb. bag of ultra coarse (11/13) sand costs approximately $9, while, a cubic yard (about 2300 lb.) of wash coarse sand cost $25. That is quite a cost savings, the only problem is, where does one store a Yard of Sand, not everyone can accommodate that quantity.
A good rule of thumb seems to be, if you can see grains of sand, which appear like small rocks, then it will work in your mix.
Tom Wells
Enthusiast e-mail Aug 2004
Clivias grow on quartzites and sandstones, and also quartz sand. Slightly acid, lots of humic material. Granite grit and compost will be fine, as long as they are free draining. Do not use oyster shell.
Roger
Enthusiast e-mail Aug 2004
Heard on the radio that Lime added to the soil has several benificial results. It disinfests the soil through hightening the ph level. It also helps to break down plant material in the soil and thus make it available to the plant roots.
Johan Schoombee
Radio 041105
For repotting adult plants, I have been adding well matured (i.e.. more than 1 year old) racing horse manure about 1:10 to milled bark, as well as 1:5 rough large grained sand. My plants have thrived.
Conrad Calitz, Stellenbosch
Enthusiast e-mail Aug 2004
In my personal experience and those of other prominent growers here in the Western Cape there is a strong opinion that well rotted horse manure is favoured by our Clivias. So you will find most of us including it as an important constituent in our Potting mix.
Johan Schoombee
Enthusiast e-mail Jan 2005
My potting mix for seedlings consists of:
I plant my seedlings in pairs into 12 x 22 cm plastic bag where they grow for two years before being potted on.
I feed them every fortnight with Seagro(5:1:2), a 100% organic fertelizer made from a fish emulsion.
I have lost maybe 4 seedlings out of some 500, and they were probably weak on transplanting.
Johan Schoombee
Enthusiast e-mail Jan 2005
We in Australia also have many "bark" planting materials. I noticed that the ones labelled for Landscaping work are young to old barks but mainly uncomposted. I use these with my other plants on the ground.
For Clivia I too use a bark material for potting. This is a product that is semi-composted and marketed as "Orchid Bark". In this case the nitrifying bacteria have worked on the bark until the outer "softer tissue" is composted and dark brown in colour. Have a look at the ones that I use. They are barks from the pots itself. Note that my first Bark 001 is prior to watering.
That's how dry I let it go to. The barks are 10 to 18 mm size barks. I have shown barks at different stages of "dryness" and "wetness" and also cut open (dry). Note that as soon as the barks are wet, they turn a dark colour. Also note that the colours on the clivia leaves are not affected.
New barks and woods will give out a reddish sap and I suspect this is what is being absorbed by the plants. Just suspect, not certain. I really don't know if there is any detrimental effect on the plant. Looks like Sam's plant is doing well enough. However, in a variegated plant where we want "clean" striations, this colouration may become a problem. Looks like Sam has done a test and there are no exudates. I think a better test will be to soak in warm water or for a couple of days.
It will be interesting if Sam can re-pot one of his plants and then see how they (the 2, one in old and one in new media) perform over a 2 months period. Will the new growth gets clearer? Please note that the barks also gets composted as they aged in the pots. So the effect might just wear off by themselves, but if we can find out earlier, perhaps it'll be possible for us to pre-composted them before use.
Chris Ong, NSW, Australia
Enthusiast e-mail Mar 2005
My own way a few years ago when I grew a large amount of plants.
I use to make it in bins, 3 in all, each measured about 6 feet wide by about 7 long and about 5 1/2 feet tall. Made out of bricks. I used what ever indegredians that were avaible cheeply. Mostly stable staw and manure from horse stables. fresh Chicken manure ( Very Hot and very nicely fragrant!) Freshly harvested pine bark that was roughly choped up to about 1/4 to 1/2 inch size. Lawn clippingss weed free from a pedigree lawn (!) Leaves of decidious trees in winter. Etc. I usually made this up in autumn each years as the weather was cooler to work in then 10 to 12 deg. C. I mixed in about 10 kg of urea to about 2 tons of compost mix. This also helped the microbes to break down the compost and also the tannims and toxins in the bark. This was all mixed together then shoveled into the large bins. I keeped this mixture just moist damp as it was stacked. then covered with bags or what ever was avaible. This was checked daily for moisture content and the whole lot was turned over into the next bin each week.. I can tell you the mix got very hot and steamy. this was done for about 6 weeks, end result by then was a lovely earthly smelling compost base. If I need the bark for any special purpose out of this compost I just seived out what ever I needed. I grew all my plants includeing my clivias in this base mix. sometime adding coarse sand etc. as required. There are many good book avaible on how to compost perfectly. But this is my basic method. Now as I no longer live at the same place and do not grow as many plants I buy all my bark all ready treated and ready to go into my favorited mix.
Ron Boyd
Enthusiast e-mail Mar 2005