I love orchids and love giving tips on how to grow them in your garden.
Sarcochilus Orchid Care Guide
Did you know that orchids have colonised most places on Earth? Well then, let's take a look at growing the cool Sarcochilus orchids (referred to by growers as Sarcs).
These monopodial and compact orchids are easy to grow and can make delightful houseplants positioned perhaps on a cool windowsill, in a shade-house or like mine, under a shelter. Sarcs have attractive fleshy green leaves and produce short racemes with numerous flowers, some of which are scented, like S. falcatus.
If you love flowers you will be pleasantly mesmerised when you visit an orchid show and find yourself amidst a spectacular sea of colour from whites and pinks to reds and other colours. Just let temptation run its course and spend, spend, spend!
Sarcochilus come from Greek.
Sarco = flesh; cheilos = lip (refers to the fleshy labellum)
There are around 15 species of these charming spring to summer flowering orchids and these are nearly all endemic to eastern Australia. In the wild, lithophytic Sarc's grow on rocky outcrops, cliffs, gullies and mountains, while the epiphytic types are at home in trees.
Sarcs thrive in shady places with plenty of air movement and quick drainage as most Sarcs in the wild endure their roots flooded regularly.
Those of you that are lovers of history might appreciate that the genus Sarcochilus was established back in 1810 by Robert Brown which was for S. falcatus (orange blossom orchid)—an epiphytic orchid.
You want your Sarc to produce racemes of flowers, right!
Then you must take note of the cultural requirements.
These are shade-loving (I find 50 - 60% is fine), cool growing orchids. Sarcs thrive with plenty of air movement and humidity so trying to replicate the Sarcs natural environment is beneficial to their success. I have mentioned seven aspects of Sarcochilus culture below:
1. Air Movement
This is crucial to Sarcs and also aids in regulating plant temperature and reducing any bacterial or fungal infections. If there is not enough air movement, then install an artificial means like a fan.
Although most growers recommend temperatures 8 - 25C ( 40 - 80F) for optimal growth I use it as a guide. If anything, I am more concerned with the heat in summer when I am unable to dampen down because plants will stress and cease photosynthesis if they reach around 29C.
My Sarc shelter endures up to eight frosts annually. In the summer, the mercury has reached 36C on rare occasions, prompting watering down under the orchids to lower the temperature and increase the humidity.
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Sarcs should never be subjected to frosts at all so this is why the shelter gets wrapped with plastic at night in the winter.
Sarcs need to be misted daily, including the mounted Sarcs like S. hirticalcar, especially in the heat of summer.
A great method that raises the humidity is to place Sarcs in trays of water with pebbles for them to stand on without getting wet feet, and the ideal humidity to aim for is 60%.
On hot days dampen down the floor under the Sarcs to provide that cooling humid environment. Serious shade-houses will need an automated watering system unless you have plenty of time to regularly hose the floor!
Always use room temperature rainwater (if possible) and water the plants once a week (more often in hot weather) because there are no storage bulbs and Sarc's like to be kept damp. The opposite applies too as they do not like to have wet roots.
It is also wise to check that there is no water sitting is in the leaf axil or crown in the evenings to decrease the chances of developing rot when it is cooler.
On hot days dampen down the floor under the Sarcs to provide that cooling humid environment. Serious shade-houses will need an automated watering system unless there is plenty of time to regularly hose the floor!
If the leaves appear shriveled, your plant may not be getting enough water, so it is helpful to be able to judge the weight of dry Sarc by picking the pot up. It will need watering if it is light in weight.
Rainwater is best collected from the roof in large containers, but filling large juice bottles and leaving for several days suffices as well (I do this—space issues!).
5. Repotting and Potting Mix
Sarcs have a habit of clumping and can be divided by carefully removing a clump from the rest of the plant and repotting it into a pot relevant to the size of the removed clump. Always label the Sarcs and write the date on one side of the label for your records.
The potting mix I use is medium-sized pinus radiata bark with gravel base for weight. I source my bark through Napier Orchid Supplies, but various types of orchid potting mixes are available from garden centres.
Thrive produces an Orchid Potting Mix made with bark chips and peat nodules as well as a controlled food additive that lasts up to four months, but due to the warning regarding the micro-organisms in it, I do not want to use it. After all, we have enough health issues without unwillingly breathing this stuff in, mask or not!
It is imperative that a free draining compost mix is used and there are many different combinations of potting mediums available. It is good practice to soak the bark for 24 hours or so prior to repotting so the Sarc is remaining damp.
Generally, I use smaller-sized bark in small pots and medium-sized bark for everything else. Remember to never over-pot! After a Sarc is carefully removed from its pot, pick off the old potting mix from the growing healthy roots and remove any dead roots using sterilised secateurs. Always remember to sterilise cutting tools (flaming is a great method!) so infection is minimised.
I dab on cinnamon powder (yes - the same you use in cooking! It has anti-fungal properties) onto the trimmed roots to reduce the chances of any fungal infection. This can be purchased from supermarket bulk bins or Bin In Stores. There are anti-fungal spray concentrates on the market. Have a look at fungal infections under pests and diseases below.
Weakly, weekly (note the spelling!)
I fertilise weakly (about 1/8 strength) once per week for three out of four in a month. The fourth week is for flushing out any build-up of salts and any food left thus minimising the chance of burning the roots. Towards winter, I feed twice monthly, decreasing to once per month during winter while the Sarcs are resting.
Always read the instructions and guidelines on fertiliser strength, and use 1/8 strength because Sarcs are not heavy feeders. There is a variety of different orchid foods are available on the market and through orchid clubs.
For those busy people with limited time there are slow-release granules, and for those with time on hand (like me!) fertilisers such as Phostagen (general all purpose soluble plant food) will keep your Sarcs in good growing condition. Although the Phostagen box does not state the ratio of nitrogen, phosphate, potash and trace elements, it is popular with orchid growers.
Yates Nature's Way Bio-Gold Liquid Plant Food provides nutrients from blood and bone, fish and seaweed components which are absorbed by the foliage and the roots. The NPK ratio10:4:6 is a percentage with nitrogen being important leaf growth and potassium being important for flower development. Biogold also contains trace elements as well as growth stimulants and can be purchased as a 500ml container. It instructs you to dilute 5ml/1L of water but use an even weaker solution, depending on what you buy there may be a need for a calculator to make life easier.
As potassium contributes to flowering an occasional 1g/1L of high potassium solution can be beneficial and a few Osmocote pellets in early spring for a boost.
7. Pests and Diseases
Sarcochilus are generally known as healthy orchids that are easy to grow, but pests are out there! Check these out!
- Slugs and snails: Go out at night with a torch and a long stick and crush the snails and handpick any off the Sarcs. They feast on the new leaf buds and flower racemes so on the one rainy night you neglect, I guarantee they will be living it large feasting. Slugs can drop down to your precious Sarcs by a disgusting slimy thread so beware! I also use snail bait like Quash ($10 at New World) which lasts after being wet. Quash is safe to use near children, animals and birds as it contains 52.3g/kg of iron EDTA chelate as the active ingredient. Compare Quash with a cheap bait like Blitzem (less than $2 at Mega 10 stores) which will last until the pellets become wet and develop mould.
- Spider mites: These arachnids are no match for the environmentally friendly Neem Oil or Yates Mavrik (harmful to the soil environment as it contains 9.6g/tau-fluvalinate and only used when mite population has got out of control when holidaying!) Check for instructions listed under ornamental for Mavrik and wear protective gear as Mavrik could cause irritation! Apply monthly, especially in warmer, drier weather as mites find dry conditions more favourable and will weaken plants given time and an infestation from one Sarc will spread to other healthy Sarcs.
- Aphids: Use Confidor spray should these sap-sucking insects get onto the flowers of Sarcs causing the flowers to become distorted.
- Passion vine hoppers: The juvenile stage has been blown into my Sarc shelter from a flowering vine on the western fence and I discovered them on my Sarcs. The shock and horror! These are a sucking insect and the adult form can fly. These insects are not a general pest but if they are present in your garden, they will suck sap as long as they are able! Confidor will suffice.
- Mealybugs: These sucking insects are white, fluffy and obvious and attempt to crawl away! Spray with methylated spirits or dab cotton buds with methylated spirits on.
- Scale insects: The young stage are crawlers that take up residence on Sarc leaves, insert their proboscis, grow a brown shell and discolour the leaves by sucking the plant sap. I have scraped them off Sarc leaves (snapping off their proboscis' ) and used methylated spirits to clean the leaves, but I think an oil like Neem or Conqueror Oil is superior because they work by smothering the scale and killing them that way. This will need reapplying monthly to destroy all the stages of the scale.
- Fungal infection: With good air circulation this will not be an issue. There are anti-fungal sprays available. Yates have the 200ml Bravo Fungicide which can be applied fortnightly. the active ingredient in Bravo is 500g/L Chlorothalonil (15ml is diluted to 5L). Yates Champ DP Copper Fungicide can be applied at one to two weekly intervals during the growing season.
The species fitzgeraldii (ravine orchid), hartmanii (Hartmann's orchid) and fal