Fourteen members and 2 visitors (with close club connections) gathered at Conrad’s on Sunday, August 6 for a new-grower workshop. What did we learn? The main message, no matter what type of orchid, is: If there’s a problem, tip the plant out and look at the roots. The difference between healthy roots (white) and degrading roots (brown) is obvious. Many plants are able to remake their root system when they’re happy.
BEFORE: A mass of tired Cymbidium roots. Photo: Sandra Simpson
AFTER: Conrad’s haircut didn’t leave much but he was confident it would regenerate new roots. Photo: Sandra Simpson
Roots are for drinking/feeding and breathing so what’s going on under the plant is essential to the health of the top of the plant.
Keep working tools clean and sterile and treat wounds/damage with Flowers of Sulphur or Conrad was using Physan in a squirt bottle.
Worms, centipedes, cockroaches or slaters in a pot means the bark is breaking down and it’s time to change the medium. Some caterpillars live in the bark and come out to eat leaves. If cockroaches are a problem put the pot in a sealable plastic bag, spray the bark with fly spray, seal and leave until the cockroaches are dead.
Sphagnum moss is likely to keep the roots too wet and cold, or too dry – it’s better to use a chunky bark mix to let air round the roots, and water more frequently.
Roots go where the air and water flow so if a plant’s roots are growing along the inside wall of a pot it means the medium at the centre of the pot needs replacing.
Conrad puts coarser bark at the bottom of the pot and finer on top. If you use all fine bark it will start to clog the pot’s drainage holes as it breaks down, causing problems. Good-quality orchid bark is essential (the club makes an annual order, keep your eyes peeled for the notice).
Use a knitting needle or similar to work bark in around the plant roots, tapping and shaking the pot to settle the mix as you go.
The building block of plant cells is calcium so feed this to the plants for good health (calcium nitrate is available from Barry).
Conrad spreads dolomite lime over his pots when the weather starts to warm (September / October) and waters it in. The lime sweetens the bark. (Move any that don’t like lime!) Blood and bone is another good topdressing for watering in.
Tiny, but healthy roots. This little plant is grown only in a coir wrap. Photo: Sandra Simpson
A recycled computer part makes a nifty orchid mount. Photo: Sandra Simpson
Some plants, eg Oncidiums and Phalaenopsis, can grow with their roots exposed to the air so are better suited to slab culture (grown on a mount). When you split a plant, Conrad advises trying some in pots and some on mounts to see what happens.
Use warm water on cold days. If you have larger, clumpy plants soak them for half a day in a bucket of water mixed with the appropriate amount of fertiliser.
Orchid pseudobulbs and canes store carbohydrates (= sugars) so can rot easily. If you see it happening, cut out the affected bulbs/canes and sterilise the wound(s).