Well were to start…lets start with a couple of things, firstly most books written about Sarc growing are written by growers in NSW. Conditions up there are very different to Melbourne, it is hotter and drier here in summer and colder and wetter in winter. To grow Sarcs well you will need a dedicated house for them or at least a covered pergola / veranda they are not really that fussy but some control over how wet they are in the depths of our cold winters is good. We have had our Sarcs down to -6 and up to 50 degrees….even on summer they did a few days in the 40s with no water due to a watering system malfunction so they are tough.
Now lets talk about growing them well – so I am not taking minimum requirements – I am talking what do we need to do to make them happy:
Humidity – in my experience they want and need humidity and lots of it. Melbourne is very dry (in terms of air humidity) I watch my plants adventitious roots (the ones floating around in the air) and aim to keep them in active growth year round – they will stop growing in the depths of winter for us especially if we have a long cold winter – they will also stop if the humidity gets too low in summer and/or your temps are too high. We use a propagation misting controller – we bought it along with some helpful advice from Orchid Species Check it out here you can also run a full humififier but these are more fiddly to run well. With the misting controller we increase the time the misters run and decrease the gap in between mistings as the summer heats up and to opposite pattern in autumn – giving the unit (and misting) a break through the coldest 3 or 4 months of winter.
Temperatures – ideally would be say 5 or 8 degrees C up to 30 odd – you will here all sorts of claims out there “Sarcs stop growing over 25 degrees”, “Sarcs die if the air temp hits 38” all sorts of crap – none if it proven. Remember too everyone conditions are different. We aim to still withing the range 5-30, we do not use heat in Melbourne and I do not think its needed. I know Wayne and some other growers to use heat in winter in Melbourne but at one stage we grew Sarcs in central vic (with savage frosts) and still never had one bit of frost damage (obviously under a hard roof) when temps are over 30 in the orchid house (hottest we have hit inside the Sarcochilus house is 53 and no the Sarcs did explode or die or really do anything bad) on these extreme days we water first thing in the morning – turn the mister right up (maintaining max humidity) and then if possible water at say 3pm once the full heat has passed – and when I say water I mean WATER like crazy for up to an hour – the aim being to get the temp in the orchid house back to under 30 degrees before we stop watering. A 15-20 degree temp drop from heavy watering on these days is quite common and with the heat of the sun off the house the temp then does not get back up into the searing temps. Radical I know but works for us.
(again you will read don’t water on a hot afternoon or don’t water in the afternoon ?!? This is right in winter when you don’t want your plants sitting wet overnight but in summer Sarcs and many natives love an afternoon / early evening drink – think about the tropics and sub tropics where rain often comes in the afternoon or evening – even in Sydney an arvo shower is very common in Summer)
Other than the above watering done only in extreme temp days we water mounted orchids once to twice a day any day of say 20 degrees or so and above, with potted plants we water as the majority of plants are just drying out (not quite dry but maybe just a dab of moisture left) we judge this by looking at the tags of the plants (pull out from pot and see if damp in the middle). Most of the year we water in the morning – say April – end of Oct and then start watering more in the evenings but some mix of mornings and evenings depending on conditions, how dry the plants are and work and life schedules etc.
Shading – over time I have found Sarcs actually like more sun than you would initially think based on looking at them and reading books etc. Something around 70% shade is good – we actually have a main large plants under 40% shade year round with a second layer of 70% cloth added in summer. The second sheet is probably slightly too much shade but we are also keeping the heat down by adding this.
Well that’s it for part 1 for now – I will come back and discuss pots, mounts, mix and fertiliser another day.